text: Nixon visited Atlanta, Georgia, on August 26, and acquired a very large turnout to his event. He rode through a parade in Atlanta, and was greeted by 150,000 people. Nixon mentioned in his speech in Atlanta, "In the last quarter of a century, there hasn't been a Democratic candidate for President that has bothered to campaign in the State of Georgia." However, Kennedy would not let Nixon take the Democratic states that easily. Kennedy would change that statistic, and visit some surprising states, including Georgia. He visited the cities of Columbus, Warm Springs, and LaGrange on his campaign trail in Georgia. In his visit to Warm Springs, state troopers tried to keep Kennedy from an immense crowd; however, Kennedy reached out to shake hands of those who were sick with polio. He also visited small towns across Georgia and saw a total of about 100,000 people in the state. Kennedy also spoke at a rehabilitation facility in Warm Springs. Warm Springs was near and dear to Kennedy's heart, due to the effects the facility had on Franklin D. Roosevelt. Roosevelt spent time at the rehabilitation facility, and died there in 1945.


title: 1960 United States presidential election

text: In Warm Springs, Kennedy spoke to supporters at the facility, and mentioned Roosevelt in his speech. He admired Roosevelt, and commended him for sticking up for the farmers, workers, small towns, big cities, those in poverty, and those who were sick. He said Roosevelt had a "spirit of strength and progress, to get America moving". Kennedy discussed his six-point plan for health care. He wanted a medical program set up for retirement, and federal funding for the construction of medical schools and hospitals. He also planned for the government to loan students money to attend medical school, and provide grants to renovate old hospitals. He called for more money to be spent on medical research and, finally, expand effort for rehabilitation and come up with new ways to assist those in need. Many Republicans disapproved of Kennedy's plans and described them as an "appeal to socialism". Nevertheless, many residents of Warm Springs were supportive of Kennedy, with women wearing hats reading "Kennedy and Johnson" and signs around the town saying "Douglas County For Kennedy, Except 17 Republicans 6 Old Grouches". Joe O. Butts, the mayor of Warm Springs during Kennedy's visit, said: "He must've shaken hands with everybody within two miles of him, and he was smiling all the time."


text: Despite the reservations Robert F. Kennedy had about Johnson's nomination, choosing Johnson as Kennedy's running mate proved to be a masterstroke. Johnson vigorously campaigned for Kennedy, and was instrumental in helping the Democrats to carry several Southern states skeptical of him, especially Johnson's home state of Texas. Johnson made a "last-minute change of plans, and scheduled two 12-minute whistlestop speeches in Georgia". One of these visits included stopping in Atlanta to speak from the rear of a train at Terminal Station. On the other hand, Ambassador Lodge, Nixon's running mate, ran a lethargic campaign and made several mistakes that hurt Nixon. Among them was a pledge, made without approval, that Nixon would name at least one African American to a Cabinet post. Nixon was furious at Lodge and accused him of spending too much time campaigning with minority groups instead of the white majority.


text: There were four presidential debates and no vice presidential debates during the 1960 general election.


text: The key turning point of the campaign came with the four Kennedy-Nixon debates; they were the first presidential debates ever (the Lincoln–Douglas debates of 1858 had been the first for senators from Illinois), also the first held on television and thus attracted enormous publicity. Nixon insisted on campaigning until just a few hours before the first debate started. He had not completely recovered from his stay in hospital, and thus looked pale, sickly, under-weight, and tired. His eyes moved across the room during the debate, and at various moments, sweat was visible on his face. He also refused make-up for the first debate, and as a result, his facial stubble showed prominently on the black-and-white TV screens at the time. Furthermore, the debate set appeared darker once the paint dried up, causing Nixon's suit color to blend in with the background, reducing his stature. Nixon's poor appearance on television in the first debate was reflected by the fact that his mother called him immediately following the debate to ask if he was sick. Kennedy, by contrast, rested and prepared extensively beforehand and thus appeared tanned, confident, and relaxed during the debate. An estimated 70 million viewers watched the first debate.


text: It is often claimed that people who watched the debate on television overwhelmingly believed Kennedy had won, while radio listeners (a smaller audience) thought Nixon had ended up defeating him. However, that has been disputed. Indeed, one study has speculated that the viewer/listener disagreement could be due to sample bias, in that those without TV could be a skewed subset of the population:


text: Nonetheless, Gallup polls in October 1960 showed Kennedy moving into a slight but consistent lead over Nixon after the candidates were in a statistical tie for most of August and September. For the remaining three debates, Nixon regained his lost weight, wore television make-up, and appeared more forceful than in his initial appearance.


text: However, up to 20 million fewer viewers watched the three remaining debates than the first. Political observers at the time felt that Kennedy won the first debate, Nixon won the second and third debates, while the fourth debate, which was seen as the strongest performance by both men, was a draw.


text: The third debate has been noted, as it brought about a change in the debate process. This debate was a monumental step for television. For the first time ever, split-screen technology was used to bring two people from opposite sides of the country together so they were able to converse in real time. Nixon was in Los Angeles, while Kennedy was in New York. The men appeared to be in the same room, thanks to identical sets. Both candidates had monitors in their respective studios, containing the feed from the opposite studio, so that they could respond to questions. Bill Shadel moderated the debate from a different television studio in Los Angeles. The main topic of this debate was whether military force should be used to prevent Quemoy and Matsu, two island archipelagos off the Chinese coast, from falling under Communist control.


text: A key concern in Kennedy's campaign was the widespread skepticism among Protestants about his Roman Catholic religion. Some Protestants, especially Southern Baptists and Lutherans, feared that having a Catholic in the White House would give undue influence to the Pope in the nation's affairs. Radio evangelists such as G. E. Lowman wrote that, "Each person has the right to their own religious belief ... [but] ... the Roman Catholic ecclesiastical system demands the first allegiance of every true member, and says in a conflict between church and state, the "church" must prevail". The religious issue was so significant that Kennedy made a speech before the nation's newspaper editors in which he criticized the prominence they gave to the religious issue over other topics – especially in foreign policy – that he felt were of greater importance.


text: To address fears among Protestants that his Roman Catholicism would impact his decision-making, Kennedy told the Greater Houston Ministerial Association on September 12, 1960: "I am not the Catholic candidate for president. I am the Democratic Party's candidate for president who also happens to be a Catholic. I do not speak for my Church on public matters – and the Church does not speak for me." He promised to respect the separation of church and state, and not to allow Catholic officials to dictate public policy to him. Kennedy also raised the question of whether one-quarter of Americans were relegated to second-class citizenship just because they were Roman Catholic. Kennedy would become the first Roman Catholic to be elected president—it would be 60 years before another Roman Catholic, Joe Biden, was elected.


text: Kennedy's campaign took advantage of an opening when Rev. Martin Luther King Jr., the civil-rights leader, was arrested in Georgia while taking part in a sit-in. Nixon asked President Dwight D. Eisenhower to pardon King, but the President declined to do so. Nixon refused to take further action, but Kennedy placed calls to local political authorities to get King released from jail, and he also called King's father and wife. As a result, King's father endorsed Kennedy, and he received much favorable publicity among the black electorate. A letter to the Governor of Georgia regarding Martin Luther King, Jr.'s, arrest also helped Kennedy garner many African American votes. John F. Kennedy asked Governor Ernest Vandiver to look into the harsh sentencing, and stated his claim that he did not want to have to get involved in Georgia's justice system. A member of Kennedy's civil rights team and King's friend, Harris Wofford, and other Kennedy campaign members passed out a pamphlet to black churchgoers the Sunday before the presidential election that said, """No Comment" Nixon versus a Candidate with a Heart, Senator Kennedy."" On election day, Kennedy won the black vote in most areas by wide margins, and this may have provided his margin of victory in states such as New Jersey, South Carolina, Illinois, and Missouri. Researchers found that Kennedy's appeal to African American voters appears to be largely responsible for his receiving more African-American votes than Adlai Stevenson in the 1956 election. The same study conducted found that white voters were less influenced on the topic of civil rights than black voters in 1960. The Republican national chairman at the time, Thruston Ballard Morton, regarded the African-American vote as the single most crucial factor.


text: The issue that dominated the election was the rising Cold War tensions between the United States and the Soviet Union. In 1957, the Soviets had launched Sputnik, the first man-made satellite to orbit Earth. Soon afterwards, some American leaders warned that the nation was falling behind communist countries in science and technology. In Cuba, the revolutionary regime of Fidel Castro became a close ally of the Soviet Union in 1960, heightening fears of communist subversion in the Western Hemisphere. Public opinion polls revealed that more than half the American people thought that war with the Soviet Union was inevitable.


text: Kennedy took advantage of increased Cold War tension by emphasizing a perceived "missile gap" between the United States and Soviet Union. He argued that under the Republicans, the Soviets had developed a major advantage in the numbers of nuclear missiles. He proposed a bi-partisan congressional investigation about the possibility that the Soviet Union was ahead of the United States in developing missiles. He also noted in an October 18 speech that several senior US military officers had long criticized the Eisenhower Administration's defense spending policies.


text: Both candidates also argued about the economy and ways in which they could increase the economic growth and prosperity of the 1950s, and make it accessible to more people (especially minorities). Some historians criticize Nixon for not taking greater advantage of Eisenhower's popularity (which was around 60–65% throughout 1960 and on election day), and for not discussing the prosperous economy of the Eisenhower presidency more often in his campaign. As the campaign moved into the final two weeks, the polls and most political pundits predicted a Kennedy victory. However, President Eisenhower, who had largely sat out the campaign, made a vigorous campaign tour for Nixon over the last 10 days before the election. Eisenhower's support gave Nixon a badly needed boost. Nixon also criticized Kennedy for stating that Quemoy and Matsu, two small islands off the coast of Communist China that were held by Nationalist Chinese forces based in Taiwan, were outside the treaty of protection the United States had signed with the Nationalist Chinese. Nixon claimed the islands were included in the treaty, and accused Kennedy of showing weakness towards Communist aggression. Aided by the Quemoy and Matsu issue, and by Eisenhower's support, Nixon began to gain momentum, and by election day, the polls indicated a virtual tie.


text: The election was held on November 8, 1960. Nixon watched the election returns from his suite at the Ambassador Hotel in Los Angeles, while Kennedy watched them at the Kennedy Compound in Hyannis Port, Massachusetts. As the early returns poured in from large Northeastern and Midwestern cities, such as Boston, New York City, Philadelphia, Pittsburgh, Cleveland, Detroit, and Chicago, Kennedy opened a large lead in the popular and electoral votes, and appeared headed for victory. However, as later returns came in from rural and suburban areas in the Midwest, the Rocky Mountain states, and the Pacific Coast states, Nixon began to steadily close the gap on Kennedy.


text: Before midnight, "The New York Times" had gone to press with the headline, "Kennedy Elected President". As the election again became too close to call, "Times" managing editor Turner Catledge hoped that, as he recalled in his memoirs, "a certain Midwestern mayor would steal enough votes to pull Kennedy through", thus allowing the "Times" to avoid the embarrassment of announcing the wrong winner, as the "Chicago Tribune" had memorably done twelve years earlier in announcing that Thomas E. Dewey had defeated President Harry S. Truman.


text: Nixon made a speech at about 3 a.m., and hinted that Kennedy might have won the election. News reporters were puzzled, as it was not a formal concession speech. He talked of how Kennedy would be elected if "the present trend continues". It was not until the afternoon of the next day that Nixon finally conceded the election, and Kennedy claimed his victory.


text: Kennedy won in twenty-seven of the thirty-nine largest cities, but lost in Southern cities that had voted for Adlai Stevenson II although he maintained Atlanta, New Orleans, and San Antonio. New Orleans and San Antonio were the only cities in the Southern United States to have large Catholic populations and Atlanta was a traditional Democratic stronghold.


text: Of the 3,129 counties and county-equivalents making returns, Nixon won in 1,857 (59.35%), while Kennedy carried 1,200 (38.35%). "Unpledged" electors came first in 71 counties and parishes (2.27%) throughout Mississippi and Louisiana, and one borough (0.03%) in Alaska split evenly between Kennedy and Nixon.


text: A sample of how close the election was can be seen in California, Nixon's home state. Kennedy seemed to have carried the state by 37,000 votes when all of the voting precincts reported, but when the absentee ballots were counted a week later, Nixon came from behind to win the state by 36,000 votes.


text: Similarly, in Hawaii, official results showed Nixon winning by a small margin of 141 votes, with the state being called for him early Wednesday morning. Acting Governor James Kealoha certified the Republican electors, and they cast Hawaii's three electoral votes for Nixon. However, clear discrepancies existed in the official electoral tabulations, and Democrats petitioned for a recount in Hawaii circuit court. The court challenge was still ongoing at the time of the Electoral Count Act's safe harbor deadline, but Democratic electors still convened at the Iolani Palace on the constitutionally-mandated date of December 19 and cast their votes for Kennedy. The recount, completed before Christmas, resulted in Kennedy being declared winner by 115 votes. On December 30, the circuit court ruled that Hawaii's three electoral votes should go to Kennedy. It was decided that a new certificate was necessary, with only two days remaining before Congress convened on January 6, 1961, to count and certify the Electoral College votes. A letter to Congress saying a certificate was on the way was rushed out by registered air mail. Both Democrat and Republican electoral votes from Hawaii were presented for counting on January 6, 1961, and Vice President Nixon who presided over the certification, graciously, and saying "without the intent of establishing a precedent", requested unanimous consent that the Democratic votes for Kennedy to be counted.


text: In the national popular vote, Kennedy beat Nixon by less than two tenths of one percentage point (0.17%), the closest popular-vote margin of the 20th century. So close was the popular vote that a shift of 18,858 votes in Illinois and Missouri, both won by Kennedy by less than 1%, would have left both Kennedy and Nixon short of the 269 electoral votes required to win, thus forcing a contingent election in the House of Representatives.


text: In the Electoral College, Kennedy's victory was larger, as he took 303 electoral votes, to Nixon's 219. A total of 15 electors – eight from Mississippi, six from Alabama, and one from Oklahoma – all refused to vote for either Kennedy or Nixon, and instead cast their votes for Senator Harry F. Byrd of Virginia, a conservative Democrat, even though he had not been a candidate for president. Kennedy carried 12 states by three percentage points, or less, while Nixon won six by similarly narrow margins. Kennedy carried all but three states in the populous Northeast, and he also carried the large states of Michigan, Illinois, and Missouri in the Midwest. With Lyndon Johnson's help, he also carried most of the South, including the large states of North Carolina, Georgia, and Texas. Nixon carried all but three of the Western states (including California), and he ran strong in the farm belt states, where his biggest victory was in Ohio.


text: "The New York Times", summarizing the discussion in late November, spoke of a "narrow consensus" among the experts that Kennedy had won more than he lost "as a result of his Catholicism", as Northern Catholics flocked to Kennedy because of attacks on his religion. Interviewing people who voted in both 1956 and 1960, a University of Michigan team analyzing the election returns discovered that people who voted Democratic in 1956 split 33–6 for Kennedy, while the Republican voters of 1956 split 44–17 for Nixon. That is, Nixon lost 28% () of the Eisenhower voters, while Kennedy lost only 15% of the Stevenson voters. The Democrats, in other words, did a better job of holding their 1956 supporters.


text: Kennedy said that he saw the challenges ahead and needed the country's support to get through them. In his victory speech, he declared: "To all Americans, I say that the next four years are going to be difficult and challenging years for us all; that a supreme national effort will be needed to move this country safely through the 1960s. I ask your help, and I can assure you that every degree of my spirit that I possess will be devoted to the long-range interest of the United States and to the cause of freedom around the world."


text: Some Republicans believed that Kennedy had benefited from vote fraud, especially in Texas, where his running mate Lyndon B. Johnson was senator, and Illinois, home of Mayor Richard Daley's powerful Chicago political machine. These two states were important because if Nixon had carried both, he would have earned 270 electoral votes, one more than the 269 needed to win the presidency. Republican senators such as Everett Dirksen and Barry Goldwater claimed vote fraud "played a role in the election", and that Nixon actually won the national popular vote. Republicans tried, and failed, to overturn the results in both Illinois and Texas at the time, as well as in nine other states. Earl Mazo, a conservative journalist and close friend of Nixon who later became Nixon's biographer, made unfounded accusations of voter fraud.


text: Nixon's campaign staff urged him to pursue recounts and challenge the validity of Kennedy's victory in several states, especially Illinois, Missouri, and New Jersey, where large majorities in Catholic precincts handed Kennedy the election. Nixon gave a speech three days after the election, stating that he would not contest the election. The Republican National Chairman, Senator Thruston Ballard Morton of Kentucky, visited Key Biscayne, Florida, where Nixon had taken his family for a vacation, and pushed for a recount. Morton challenged the results in 11 states, keeping challenges in the courts into mid-1961, but the only result of these challenges was the loss of Hawaii to Kennedy on a recount.


text: Kennedy won Illinois by less than 9,000 votes, out of 4.75 million cast, a margin of 0.2%. Nixon carried 92 of the state's 101 counties. Kennedy's victory in Illinois came from Chicago, which had favorable demographics for Kennedy, with its large populations of Catholic and African-American voters. His victory margin in the city was 318,736, and 456,312 in Cook County. A myth arose that Mayor Daley held back much of the city's vote until the late morning hours of November 9. When the Republican "Chicago Tribune" went to press, 79% of Cook County precincts had reported, compared with just 62% of Illinois's precincts overall. Moreover, Nixon never led in Illinois, and Kennedy's lead merely shrank as election night went on.


text: In Texas, Kennedy defeated Nixon by a 51 to 49% margin, or 46,000 votes. Some Republicans argued, without evidence, that Johnson's formidable political machine had stolen enough votes in counties along the Mexican border to give Kennedy the victory. Kennedy's defenders, such as his speechwriter and special assistant Arthur M. Schlesinger Jr., argued that Kennedy's margin in Texas was simply too large for vote fraud to have been a decisive factor.


text: Allegations of voter fraud were made in Texas. Fannin County had only 4,895 registered voters; yet, 6,138 votes were cast in that county, three-quarters for Kennedy. In an Angelina County precinct, Kennedy received 187 votes, to Nixon's 24, though there were only 86 registered voters in the precinct. When Republicans demanded a statewide recount, they learned that the state Board of Elections, whose members were all Democrats, had already certified Kennedy as the winner. This analysis has been challenged, since registered voter figures only counted people who had paid the poll tax,and "veterans and senior citizens and some other isolated groups" were exempt from that tax.


text: Schlesinger and others have pointed out that even if Nixon had carried Illinois, the state would not have given him a victory, as Kennedy would still have won 276 electoral votes, to Nixon's 246. More to the point, Illinois was the site of the most extensive challenge process, which fell short, despite repeated efforts spearheaded by Cook County state's attorney, Benjamin Adamowski, a Republican, who also lost his re-election bid. Despite demonstrating net errors favoring both Nixon and Adamowski (some precincts, 40% in Nixon's case, showed errors favoring them, a factor suggesting error, rather than fraud), the totals found fell short of reversing the results for the candidates. While a Daley-connected circuit judge, Thomas Kluczynski (later appointed a federal judge by Kennedy, at Daley's recommendation), threw out a federal lawsuit "filed to contend" the voting totals, the Republican-dominated State Board of Elections unanimously rejected the challenge to the results. Furthermore, there were signs of possible irregularities in downstate areas controlled by Republicans, which Democrats never seriously pressed, since the Republican challenges went nowhere. More than a month after the election, the Republican National Committee abandoned its Illinois voter fraud claims.


text: An academic study in 1985 later analyzed the ballots of two disputed precincts in Chicago which were subject to a recount. It found that while there was a pattern of miscounting votes to the advantage of Democratic candidates, Nixon suffered less from this than Republicans in other races, and, furthermore, the extrapolated error would only have reduced his Illinois margin from 8,858 votes (the final official total) to just under 8,000. It concluded there was insufficient evidence that he had been cheated out of winning Illinois.


text: A special prosecutor assigned to the case brought charges against 650 people, which did not result in convictions. Three Chicago election workers were convicted of voter fraud in 1962, and served short terms in jail. Mazo, Nixon's conservative reporter friend, later claimed, without evidence, that he "found names of the dead who had voted in Chicago, along with 56 people from one house". He claimed to have found cases of Republican voter fraud in southern Illinois, but said that the totals "did not match the Chicago fraud he found". After Mazo had published four parts of an intended 12-part voter fraud series documenting his findings, which was re-published nationally, he said: "Nixon requested his publisher stop the rest of the series so as to prevent a constitutional crisis." Nevertheless, the "Chicago Tribune" (which routinely endorsed GOP presidential candidates, including Nixon in 1960, 1968, and 1972) wrote that "the election of November 8 was characterized by such gross and palpable fraud as to justify the conclusion that [Nixon] was deprived of victory".


text: The situation in Alabama was controversial, as the number of popular votes that Kennedy received in Alabama is difficult to determine because of the unusual situation there. Instead of having the voters use one vote to choose from a slate of electors, the Alabama ballot had voters choose the electors individually with up to 11 votes. In such a situation, a given candidate is traditionally assigned the popular vote of the elector who received the most votes. For instance, all 11 Republican candidates in Alabama were pledged to Nixon, and the 11 Republican electors received anywhere from as low as 230,951 votes (for George Witcher) to as high as 237,981 votes (for Cecil Durham); Nixon is therefore assigned 237,981 popular votes from Alabama.


text: The situation was more complicated on the Democratic side. The Alabama statewide Democratic primary had chosen 11 candidates for the Electoral College, five of whom were pledged to vote for Kennedy, but the other six of whom were unpledged and could therefore vote for anyone that they chose to be president. All 11 of these Democratic candidates won in the general election in Alabama, from as low as 316,394 votes for Karl Harrison, to as high as 324,050 votes for Frank M. Dixon. All six of the unpledged Democratic electors ended up voting against Kennedy, and instead voted for the Dixiecrat segregationist Harry F. Byrd. The number of popular votes that Kennedy received is therefore difficult to calculate. There are typically three methods that can be used. The first method, which is mostly used and the method used on the results table on this page below, is to assign Kennedy 318,303 votes in Alabama (the votes won by the most popular Kennedy elector, C.G. Allen), and to assign 324,050 votes in Alabama (the votes won by the most popular unpledged Democratic elector, Frank M. Dixon) to unpledged electors. However, using this method gives a combined voting total that is much higher than the actual number of votes cast for the Democrats in Alabama. The second method that can be used is to give Kennedy 318,303 votes in Alabama, and count the remaining 5,747 Democratic votes as unpledged electors.


text: The third method would give a completely different outlook in terms of the popular vote in both Alabama and in the USA overall. The third method is to allocate the Democratic votes in Alabama between Kennedy electors and unpledged electors on a percentage basis, giving 5/11s of the 324,050 Democratic votes to Kennedy (which comes to 147,295 votes for Kennedy) and 6/11s of the 324,050 Democratic votes to unpledged electors (which comes to 176,755 votes for unpledged electors). Bearing in mind that the highest Republican/Nixon elector in Alabama got 237,981 votes, this third method of calculating the Alabama vote means that Nixon wins the popular vote in Alabama, and wins the popular vote in the USA overall, as it would give Kennedy 34,049,976 votes nationally, and Nixon 34,108,157 votes nationally.


text: The number of popular votes Kennedy and Nixon received in Georgia is also difficult to determine because voters voted for 12 separate electors. The vote totals of 458,638 for Kennedy and 274,472 for Nixon reflect the number of votes for the Kennedy and Nixon electors who received the highest number of votes. The Republican and Democratic electors receiving the highest number of votes were outliers from the other 11 electors from their party. The average vote totals for the 12 electors were 455,629 for the Democratic electors, and 273,110 for the Republican electors. This shrinks Kennedy's election margin in Georgia by 1,647 votes, to 182,519.


text: Many Southern Democrats were opposed to voting rights for African Americans living in the South. There was a call from segregationists for electoral votes to be withheld, or to be cast for Virginia senator Harry F. Byrd, a segregationist Democrat, as an independent candidate. Both before and after the convention, they attempted to put unpledged Democratic electors on their states' ballots, in the hopes of influencing the race; the existence of such electors might influence which candidate would be chosen by the national convention, and in a close race, such electors might be in a position to extract concessions from either the Democratic or Republican presidential candidates in return for their electoral votes.


text: Most of these attempts failed. The Democrats in Alabama put up a mixed slate of five electors loyal to Kennedy and six unpledged electors. The Democrats in Mississippi put up two distinct slates – one of Kennedy loyalists, and one of unpledged electors. Louisiana also put up two distinct slates, although the unpledged slate did not receive the "Democratic" label. Georgia freed its Democratic electors from pledges to vote for Kennedy, although all 12 Democratic electors in Georgia did end up voting for Kennedy. Governor Ernest Vandiver wanted the Democratic electors to vote against Kennedy. Former governor Ellis Arnall supported Kennedy getting the electoral votes, with Arnall calling Vandiver's stand "utterly disgraceful".


text: In total, 14 unpledged Democratic electors won election from the voters and chose not to vote for Kennedy, eight from Mississippi and six from Alabama. Because electors pledged to Kennedy had won a clear majority of the Electoral College, the unpledged electors could not influence the results. Nonetheless, they refused to vote for Kennedy. Instead, they voted for Byrd, even though he was not an announced candidate and did not seek their votes. In addition, Byrd received one electoral vote from a faithless Republican elector in Oklahoma, for a total of 15 electoral votes. The faithless Republican elector in Oklahoma voted for Barry Goldwater as vice president; whereas the 14 unpledged Democratic electors from Mississippi and Alabama voted for Strom Thurmond as vice president.


text: There were 537 electoral votes, up from 531 in 1956, because of the addition of two U.S. senators and one U.S. representative from each of the new states of Alaska and Hawaii. The House of Representatives was temporarily expanded from 435 members to 437, to accommodate this, and went back to 435 when re-apportioned, according to the 1960 census. The re-apportionment took place after the 1960 election.


text: Source (Popular Vote): Note: Sullivan / Curtis ran only in Texas. In Washington, the Constitution Party ran Curtis for president and B. N. Miller for vice president, receiving 1,401 votes.


title: Jurnee Smollett

text: Jurnee Diana Smollett (born October 1, 1986) is an American actress. She began her career as a child actress appearing on television sitcoms, including "On Our Own" (1994–1995) and "Full House" (1992–1994). She gained greater recognition with her role in the critically acclaimed Kasi Lemmons' directed film "Eve's Bayou" (1997).


title: Jurnee Smollett

text: As an adult, Smollett has starred in the films "The Great Debaters" (2007), "" (2013), and "Birds of Prey" (2020). Her television roles include the NBC sports drama "Friday Night Lights" (2009–2011), the WGN America period drama "Underground" (2016–2017), and the HBO fantasy horror dramas "True Blood" (2013–2014) and "Lovecraft Country" (2020), receiving a nomination for the Primetime Emmy Award for Outstanding Lead Actress in a Drama Series for the latter. In 2020, Smollett portrayed superhero Dinah Lance / Black Canary in the DC Extended Universe (DCEU) feature film "Birds of Prey", a role which she will reprise in the HBO Max film "Black Canary", starring in the latter.


title: Jurnee Smollett

text: Jurnee Diana Smollett was born in New York City, to Janet Harris and Joel Smollett. Her father was Ashkenazi Jewish, with ancestors from Romania, Russia and Poland, while her mother is African American. She is the fourth of six siblings, all performers: one sister, Jazz Smollett, and four brothers, Jussie, JoJo, Jake, and Jocqui.


title: Jurnee Smollett

text: Smollett began her acting career appearing on "Martin" and "Out All Night" in 1992. She then had recurring roles as Denise Frazer on the ABC family sitcoms "Full House" and "Hangin' with Mr. Cooper". From 1994 to 1995, she co-starred with her siblings in the short-lived ABC sitcom "On Our Own". In 1996, she appeared in the Francis Ford Coppola film "Jack", making her big-screen debut.


title: Jurnee Smollett

text: Smollett received critical acclaim for her performance as 10-year-old Eve in the 1997 film "Eve's Bayou" opposite Lynn Whitfield, Samuel L. Jackson and Debbi Morgan. In casting the role, writer-director Kasi Lemmons envisioned "a light-skinned black child who could convey the nuances of a Creole child in the 60s." She received the Critic's Choice Award and was nominated for a NAACP Image Award. The following year, she joined the cast of the CBS sitcom "Cosby", for which she won two NAACP Image Awards. In 1999, Smollett starred in the ABC TV film "Selma, Lord, Selma". In 2000, she co-starred with Sharon Stone and Billy Connolly in the film "Beautiful Joe". In 2001, she played the daughter of Angela Bassett in the television film "Ruby's Bucket of Blood". In 2005, she co-starred with Bow Wow and Brandon T. Jackson in the roller skating film "Roll Bounce". In 2006, she appeared in the drama film "Gridiron Gang".


title: Jurnee Smollett

text: In 2007, Smollett portrayed Samantha Booke (loosely based on Henrietta Bell Wells), the sole female debater at Wiley College in the historical film "The Great Debaters". The film was produced by Oprah Winfrey and Harvey Weinstein and starred Denzel Washington, who also directed the feature. For her performance, Smollett received NAACP Image Award for Outstanding Actress in a Motion Picture. The following year, she returned to television, appearing in two episodes of ABC medical drama "Grey's Anatomy". From 2009 to 2011, she was a regular cast member in the DirecTV drama series "Friday Night Lights" playing Jess Merriweather. From 2010 to 2011, she also co-starred with Jim Belushi and Jerry O'Connell on the short-lived CBS legal drama "The Defenders".


title: Jurnee Smollett

text: In 2013, Smollett played the leading role in the drama film "" directed by Tyler Perry. The film received negative reviews from critics, but was a box-office hit, grossing $53,125,354. It is the highest-grossing Tyler Perry film which the writer-director did not star in, and the highest-grossing Tyler Perry drama. From 2013 to 2014, she was a regular on the HBO series "True Blood". She later played Juanita Leonard, the wife of boxer Sugar Ray Leonard, in the 2016 biographical sport film "Hands of Stone" co-starring with Usher and Robert De Niro.


title: Jurnee Smollett

text: In 2015, Smollett was cast as lead character in the WGN America period drama series "Underground". Smollett played Rosalee, a shy house slave working on a plantation in 1857. She portrayed Black Canary in the 2020 film "Birds of Prey," and Letitia "Leti" Lewis in the 2020 HBO series "Lovecraft Country". In August 2021, it was revealed that Smollett will star in a solo Black Canary Movie from Warner Bros. and DC Films at HBO Max. In November 2021, she joined Jamie Foxx and Tommy Lee Jones in Amazon Studios' courtroom drama project "The Burial" directed by Maggie Betts. In 2022, she executive produced and co-starred in the Netflix thriller film, "Lou".


title: Jurnee Smollett

text: Smollett has been active in HIV/AIDS causes since she was 11. Her first encounter with the disease came at age seven when a crew member of "On Our Own" died of AIDS. She was inspired by the HIV/AIDS survivor Hydeia Broadbent, with whom she eventually worked for HIV/AIDS awareness, including for the Black AIDS Institute and Red Cross. She spoke at the Ryan White Youth Conference, and is on the Board of Directors of Artists for a New South Africa, an organization dedicated to HIV/AIDS in Africa. Smollett is also on the Board of Directors for the Children’s Defense Fund.


title: Jurnee Smollett

text: On October 24, 2010, Smollett married musician Josiah Bell. Their first child, a son named Hunter, was born on October 31, 2016. In March 2020, Smollett filed for divorce.


title: Hubble Space Telescope

text: The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versatile, renowned both as a vital research tool and as a public relations boon for astronomy. The Hubble telescope is named after astronomer Edwin Hubble and is one of NASA's Great Observatories. The Space Telescope Science Institute (STScI) selects Hubble's targets and processes the resulting data, while the Goddard Space Flight Center (GSFC) controls the spacecraft.


title: Hubble Space Telescope

text: Hubble features a mirror, and its five main instruments observe in the ultraviolet, visible, and near-infrared regions of the electromagnetic spectrum. Hubble's orbit outside the distortion of Earth's atmosphere allows it to capture extremely high-resolution images with substantially lower background light than ground-based telescopes. It has recorded some of the most detailed visible light images, allowing a deep view into space. Many Hubble observations have led to breakthroughs in astrophysics, such as determining the rate of expansion of the universe.


title: Hubble Space Telescope

text: Space telescopes were proposed as early as 1923, and the Hubble telescope was funded and built in the 1970s by the United States space agency NASA with contributions from the European Space Agency. Its intended launch was in 1983, but the project was beset by technical delays, budget problems, and the 1986 "Challenger" disaster. Hubble was finally launched in 1990, but its main mirror had been ground incorrectly, resulting in spherical aberration that compromised the telescope's capabilities. The optics were corrected to their intended quality by a servicing mission in 1993.


title: Hubble Space Telescope

text: Hubble is the only telescope designed to be maintained in space by astronauts. Five Space Shuttle missions have repaired, upgraded, and replaced systems on the telescope, including all five of the main instruments. The fifth mission was initially canceled on safety grounds following the "Columbia" disaster (2003), but after NASA administrator Michael D. Griffin approved it, the HST was completed in 2009. It completed 30 years of operation in April 2020 and is predicted to last until 2030–2040.


title: Hubble Space Telescope

text: Hubble forms the visible light component of NASA's Great Observatories program, along with the Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the Spitzer Space Telescope (which covers the infrared bands).


title: Hubble Space Telescope

text: The mid-IR-to-visible band successor to the Hubble telescope is the James Webb Space Telescope (JWST), which was launched on December 25, 2021.


title: Hubble Space Telescope

text: In 1923, Hermann Oberth—considered a father of modern rocketry, along with Robert H. Goddard and Konstantin Tsiolkovsky—published "" ("The Rocket into Planetary Space"), which mentioned how a telescope could be propelled into Earth orbit by a rocket.


title: Hubble Space Telescope

text: The history of the Hubble Space Telescope can be traced back as far as 1946, to astronomer Lyman Spitzer's paper entitled "Astronomical advantages of an extraterrestrial observatory". In it, he discussed the two main advantages that a space-based observatory would have over ground-based telescopes. First, the angular resolution (the smallest separation at which objects can be clearly distinguished) would be limited only by diffraction, rather than by the turbulence in the atmosphere, which causes stars to twinkle, known to astronomers as seeing. At that time ground-based telescopes were limited to resolutions of 0.5–1.0 arcseconds, compared to a theoretical diffraction-limited resolution of about 0.05 arcsec for an optical telescope with a mirror in diameter. Second, a space-based telescope could observe infrared and ultraviolet light, which are strongly absorbed by the atmosphere of Earth.


title: Hubble Space Telescope

text: Spitzer devoted much of his career to pushing for the development of a space telescope. In 1962, a report by the U.S. National Academy of Sciences recommended development of a space telescope as part of the space program, and in 1965 Spitzer was appointed as head of a committee given the task of defining scientific objectives for a large space telescope.


title: Hubble Space Telescope

text: Also crucial was the work of Nancy Grace Roman, the "Mother of Hubble". Well before it became an official NASA project, she gave public lectures touting the scientific value of the telescope. After it was approved, she became the program scientist, setting up the steering committee in charge of making astronomer needs feasible to implement and writing testimony to Congress throughout the 1970s to advocate continued funding of the telescope. Her work as project scientist helped set the standards for NASA's operation of large scientific projects.


title: Hubble Space Telescope

text: Space-based astronomy had begun on a very small scale following World War II, as scientists made use of developments that had taken place in rocket technology. The first ultraviolet spectrum of the Sun was obtained in 1946, and the NASA launched the Orbiting Solar Observatory (OSO) to obtain UV, X-ray, and gamma-ray spectra in 1962. An orbiting solar telescope was launched in 1962 by the United Kingdom as part of the Ariel programme, and in 1966 NASA launched the first Orbiting Astronomical Observatory (OAO) mission. OAO-1's battery failed after three days, terminating the mission. It was followed by Orbiting Astronomical Observatory 2 (OAO-2), which carried out ultraviolet observations of stars and galaxies from its launch in 1968 until 1972, well beyond its original planned lifetime of one year.


title: Hubble Space Telescope

text: The OSO and OAO missions demonstrated the important role space-based observations could play in astronomy. In 1968, NASA developed firm plans for a space-based reflecting telescope with a mirror in diameter, known provisionally as the Large Orbiting Telescope or Large Space Telescope (LST), with a launch slated for 1979. These plans emphasized the need for crewed maintenance missions to the telescope to ensure such a costly program had a lengthy working life, and the concurrent development of plans for the reusable Space Shuttle indicated that the technology to allow this was soon to become available.


title: Hubble Space Telescope

text: The continuing success of the OAO program encouraged increasingly strong consensus within the astronomical community that the LST should be a major goal. In 1970, NASA established two committees, one to plan the engineering side of the space telescope project, and the other to determine the scientific goals of the mission. Once these had been established, the next hurdle for NASA was to obtain funding for the instrument, which would be far more costly than any Earth-based telescope. The U.S. Congress questioned many aspects of the proposed budget for the telescope and forced cuts in the budget for the planning stages, which at the time consisted of very detailed studies of potential instruments and hardware for the telescope. In 1974, public spending cuts led to Congress deleting all funding for the telescope project.


title: Hubble Space Telescope

text: In 1977, then NASA Administrator James C. Fletcher proposed a token $5 million for Hubble in NASA's budget. Then NASA Associate Administrator for Space Science, Noel Hinners, instead cut all funding for Hubble, gambling that this would galvanize the scientific community into fighting for full funding. As Hinners recalls:


title: Hubble Space Telescope

text: The political ploy worked. In response to Hubble being zeroed out of NASA's budget, a nationwide lobbying effort was coordinated among astronomers. Many astronomers met congressmen and senators in person, and large-scale letter-writing campaigns were organized. The National Academy of Sciences published a report emphasizing the need for a space telescope, and eventually, the Senate agreed to half the budget that had originally been approved by Congress.


title: Hubble Space Telescope

text: The funding issues led to something of a reduction in the scale of the project, with the proposed mirror diameter reduced from 3 m to 2.4 m, both to cut costs and to allow a more compact and effective configuration for the telescope hardware. A proposed precursor space telescope to test the systems to be used on the main satellite was dropped, and budgetary concerns also prompted collaboration with the European Space Agency (ESA). ESA agreed to provide funding and supply one of the first generation instruments for the telescope, as well as the solar cells that would power it, and staff to work on the telescope in the United States, in return for European astronomers being guaranteed at least 15% of the observing time on the telescope. Congress eventually approved funding of US$36 million for 1978, and the design of the LST began in earnest, aiming for a launch date of 1983. In 1983, the telescope was named after Edwin Hubble, who confirmed one of the greatest scientific discoveries of the 20th century, made by Georges Lemaître, that the universe is expanding.


title: Hubble Space Telescope

text: Once the Space Telescope project had been given the go-ahead, work on the program was divided among many institutions. Marshall Space Flight Center (MSFC) was given responsibility for the design, development, and construction of the telescope, while Goddard Space Flight Center was given overall control of the scientific instruments and ground-control center for the mission. MSFC commissioned the optics company Perkin-Elmer to design and build the optical tube assembly (OTA) and Fine Guidance Sensors for the space telescope. Lockheed was commissioned to construct and integrate the spacecraft in which the telescope would be housed.


title: Hubble Space Telescope

text: Optically, the HST is a Cassegrain reflector of Ritchey–Chrétien design, as are most large professional telescopes. This design, with two hyperbolic mirrors, is known for good imaging performance over a wide field of view, with the disadvantage that the mirrors have shapes that are hard to fabricate and test. The mirror and optical systems of the telescope determine the final performance, and they were designed to exacting specifications. Optical telescopes typically have mirrors polished to an accuracy of about a tenth of the wavelength of visible light, but the Space Telescope was to be used for observations from the visible through the ultraviolet (shorter wavelengths) and was specified to be diffraction limited to take full advantage of the space environment. Therefore, its mirror needed to be polished to an accuracy of 10 nanometers, or about 1/65 of the wavelength of red light. On the long wavelength end, the OTA was not designed with optimum IR performance in mind—for example, the mirrors are kept at stable (and warm, about 15 °C) temperatures by heaters. This limits Hubble's performance as an infrared telescope.


title: Hubble Space Telescope

text: Perkin-Elmer intended to use custom-built and extremely sophisticated computer-controlled polishing machines to grind the mirror to the required shape. However, in case their cutting-edge technology ran into difficulties, NASA demanded that PE sub-contract to Kodak to construct a back-up mirror using traditional mirror-polishing techniques. (The team of Kodak and Itek also bid on the original mirror polishing work. Their bid called for the two companies to double-check each other's work, which would have almost certainly caught the polishing error that later caused such problems.) The Kodak mirror is now on permanent display at the National Air and Space Museum. An Itek mirror built as part of the effort is now used in the 2.4 m telescope at the Magdalena Ridge Observatory.


title: Hubble Space Telescope

text: Construction of the Perkin-Elmer mirror began in 1979, starting with a blank manufactured by Corning from their ultra-low expansion glass. To keep the mirror's weight to a minimum it consisted of top and bottom plates, each thick, sandwiching a honeycomb lattice. Perkin-Elmer simulated microgravity by supporting the mirror from the back with 130 rods that exerted varying amounts of force. This ensured the mirror's final shape would be correct and to specification when finally deployed. Mirror polishing continued until May 1981. NASA reports at the time questioned Perkin-Elmer's managerial structure, and the polishing began to slip behind schedule and over budget. To save money, NASA halted work on the back-up mirror and put the launch date of the telescope back to October 1984. The mirror was completed by the end of 1981; it was washed using of hot, deionized water and then received a reflective coating of 65 nm-thick aluminum and a protective coating of 25 nm-thick magnesium fluoride.


title: Hubble Space Telescope

text: Doubts continued to be expressed about Perkin-Elmer's competence on a project of this importance, as their budget and timescale for producing the rest of the OTA continued to inflate. In response to a schedule described as "unsettled and changing daily", NASA postponed the launch date of the telescope until April 1985. Perkin-Elmer's schedules continued to slip at a rate of about one month per quarter, and at times delays reached one day for each day of work. NASA was forced to postpone the launch date until March and then September 1986. By this time, the total project budget had risen to US$1.175 billion.


title: Hubble Space Telescope

text: The spacecraft in which the telescope and instruments were to be housed was another major engineering challenge. It would have to withstand frequent passages from direct sunlight into the darkness of Earth's shadow, which would cause major changes in temperature, while being stable enough to allow extremely accurate pointing of the telescope. A shroud of multi-layer insulation keeps the temperature within the telescope stable and surrounds a light aluminum shell in which the telescope and instruments sit. Within the shell, a graphite-epoxy frame keeps the working parts of the telescope firmly aligned. Because graphite composites are hygroscopic, there was a risk that water vapor absorbed by the truss while in Lockheed's clean room would later be expressed in the vacuum of space; resulting in the telescope's instruments being covered by ice. To reduce that risk, a nitrogen gas purge was performed before launching the telescope into space.


title: Hubble Space Telescope

text: While construction of the spacecraft in which the telescope and instruments would be housed proceeded somewhat more smoothly than the construction of the OTA, Lockheed still experienced some budget and schedule slippage, and by the summer of 1985, construction of the spacecraft was 30% over budget and three months behind schedule. An MSFC report said Lockheed tended to rely on NASA directions rather than take their own initiative in the construction.


title: Hubble Space Telescope

text: The two initial, primary computers on the HST were the 1.25 MHz DF-224 system, built by Rockwell Autonetics, which contained three redundant CPUs, and two redundant NSSC-1 (NASA Standard Spacecraft Computer, Model 1) systems, developed by Westinghouse and GSFC using diode–transistor logic (DTL). A co-processor for the DF-224 was added during Servicing Mission 1 in 1993, which consisted of two redundant strings of an Intel-based 80386 processor with an 80387 math co-processor. The DF-224 and its 386 co-processor were replaced by a 25 MHz Intel-based 80486 processor system during Servicing Mission 3A in 1999. The new computer is 20 times faster, with six times more memory, than the DF-224 it replaced. It increases throughput by moving some computing tasks from the ground to the spacecraft and saves money by allowing the use of modern programming languages.


title: Hubble Space Telescope

text: Additionally, some of the science instruments and components had their own embedded microprocessor-based control systems. The MATs (Multiple Access Transponder) components, MAT-1 and MAT-2, utilize Hughes Aircraft CDP1802CD microprocessors. The Wide Field and Planetary Camera (WFPC) also utilized an RCA 1802 microprocessor (or possibly the older 1801 version). The WFPC-1 was replaced by the WFPC-2 during Servicing Mission 1 in 1993, which was then replaced by the Wide Field Camera 3 (WFC3) during Servicing Mission 4 in 2009. The upgrade extended Hubble's capability of seeing deeper into the universe and providing images in three broad regions of the spectrum.


title: Hubble Space Telescope

text: When launched, the HST carried five scientific instruments: the Wide Field and Planetary Camera (WF/PC), Goddard High Resolution Spectrograph (GHRS), High Speed Photometer (HSP), Faint Object Camera (FOC) and the Faint Object Spectrograph (FOS). WF/PC used a radial instrument bay, and the other 4 instruments were each installed in an axial instrument bay.


title: Hubble Space Telescope

text: WF/PC was a high-resolution imaging device primarily intended for optical observations. It was built by NASA's Jet Propulsion Laboratory, and incorporated a set of 48 filters isolating spectral lines of particular astrophysical interest. The instrument contained eight charge-coupled device (CCD) chips divided between two cameras, each using four CCDs. Each CCD has a resolution of 0.64 megapixels. The wide field camera (WFC) covered a large angular field at the expense of resolution, while the planetary camera (PC) took images at a longer effective focal length than the WF chips, giving it a greater magnification.


title: Hubble Space Telescope

text: The Goddard High Resolution Spectrograph (GHRS) was a spectrograph designed to operate in the ultraviolet. It was built by the Goddard Space Flight Center and could achieve a spectral resolution of 90,000. Also optimized for ultraviolet observations were the FOC and FOS, which were capable of the highest spatial resolution of any instruments on Hubble. Rather than CCDs, these three instruments used photon-counting digicons as their detectors. The FOC was constructed by ESA, while the University of California, San Diego, and Martin Marietta Corporation built the FOS.


title: Hubble Space Telescope

text: The final instrument was the HSP, designed and built at the University of Wisconsin–Madison. It was optimized for visible and ultraviolet light observations of variable stars and other astronomical objects varying in brightness. It could take up to 100,000 measurements per second with a photometric accuracy of about 2% or better.


title: Hubble Space Telescope

text: HST's guidance system can also be used as a scientific instrument. Its three Fine Guidance Sensors (FGS) are primarily used to keep the telescope accurately pointed during an observation, but can also be used to carry out extremely accurate astrometry; measurements accurate to within 0.0003 arcseconds have been achieved.


title: Hubble Space Telescope

text: The Space Telescope Science Institute (STScI) is responsible for the scientific operation of the telescope and the delivery of data products to astronomers. STScI is operated by the Association of Universities for Research in Astronomy (AURA) and is physically located in Baltimore, Maryland on the Homewood campus of Johns Hopkins University, one of the 39 U.S. universities and seven international affiliates that make up the AURA consortium. STScI was established in 1981 after something of a power struggle between NASA and the scientific community at large. NASA had wanted to keep this function in-house, but scientists wanted it to be based in an academic establishment. The Space Telescope European Coordinating Facility (ST-ECF), established at Garching bei München near Munich in 1984, provided similar support for European astronomers until 2011, when these activities were moved to the European Space Astronomy Centre.


title: Hubble Space Telescope

text: One rather complex task that falls to STScI is scheduling observations for the telescope. Hubble is in a low-Earth orbit to enable servicing missions, but this means most astronomical targets are occulted by the Earth for slightly less than half of each orbit. Observations cannot take place when the telescope passes through the South Atlantic Anomaly due to elevated radiation levels, and there are also sizable exclusion zones around the Sun (precluding observations of Mercury), Moon and Earth. The solar avoidance angle is about 50°, to keep sunlight from illuminating any part of the OTA. Earth and Moon avoidance keeps bright light out of the FGSs, and keeps scattered light from entering the instruments. If the FGSs are turned off, the Moon and Earth can be observed. Earth observations were used very early in the program to generate flat-fields for the WFPC1 instrument. There is a so-called continuous viewing zone (CVZ), within roughly 24° of Hubble's orbital poles, in which targets are not occulted for long periods.


title: Hubble Space Telescope

text: Due to the precession of the orbit, the location of the CVZ moves slowly over a period of eight weeks. Because the limb of the Earth is always within about 30° of regions within the CVZ, the brightness of scattered earthshine may be elevated for long periods during CVZ observations. Hubble orbits in low Earth orbit at an altitude of approximately and an inclination of 28.5°. The position along its orbit changes over time in a way that is not accurately predictable. The density of the upper atmosphere varies according to many factors, and this means Hubble's predicted position for six weeks' time could be in error by up to . Observation schedules are typically finalized only a few days in advance, as a longer lead time would mean there was a chance the target would be unobservable by the time it was due to be observed. Engineering support for HST is provided by NASA and contractor personnel at the Goddard Space Flight Center in Greenbelt, Maryland, south of the STScI. Hubble's operation is monitored 24 hours per day by four teams of flight controllers who make up Hubble's Flight Operations Team.


title: Hubble Space Telescope

text: By January 1986, the planned launch date for Hubble that October looked feasible, but the "Challenger" disaster brought the U.S. space program to a halt, grounded the Shuttle fleet, and forced the launch to be postponed for several years. During this delay the telescope had to be kept in a clean room, powered up and purged with nitrogen, until a launch could be rescheduled. This costly situation (about per month) pushed the overall costs of the project even higher. This delay did allow time for engineers to perform extensive tests, swap out a possibly failure-prone battery, and make other improvements. Furthermore, the ground software needed to control Hubble was not ready in 1986, and was barely ready by the 1990 launch. Following the resumption of shuttle flights, successfully launched the Hubble on April 24, 1990, as part of the STS-31 mission.


title: Hubble Space Telescope

text: At launch, NASA had spent approximately in inflation-adjusted 2010 dollars on the project. Hubble's cumulative costs are estimated to be about in 2015 dollars, which include all subsequent servicing costs, but not ongoing operations, making it the most expensive science mission in NASA history.


title: Hubble Space Telescope

text: Hubble accommodates five science instruments at a given time, plus the Fine Guidance Sensors, which are mainly used for aiming the telescope but are occasionally used for scientific astrometry measurements. Early instruments were replaced with more advanced ones during the Shuttle servicing missions. COSTAR was a corrective optics device rather than a science instrument, but occupied one of the four axial instrument bays.


title: Hubble Space Telescope

text: Since the final servicing mission in 2009, the four active instruments have been ACS, COS, STIS and WFC3. NICMOS is kept in hibernation, but may be revived if WFC3 were to fail in the future.


title: Hubble Space Telescope

text: Of the former instruments, three (COSTAR, FOS and WFPC2) are displayed in the Smithsonian National Air and Space Museum. The FOC is in the Dornier museum, Germany. The HSP is in the Space Place at the University of Wisconsin–Madison. The first WFPC was dismantled, and some components were then re-used in WFC3.


title: Hubble Space Telescope

text: Within weeks of the launch of the telescope, the returned images indicated a serious problem with the optical system. Although the first images appeared to be sharper than those of ground-based telescopes, Hubble failed to achieve a final sharp focus and the best image quality obtained was drastically lower than expected. Images of point sources spread out over a radius of more than one arcsecond, instead of having a point spread function (PSF) concentrated within a circle 0.1 arcseconds (485 nrad) in diameter, as had been specified in the design criteria.


title: Hubble Space Telescope

text: Analysis of the flawed images revealed that the primary mirror had been polished to the wrong shape. Although it was believed to be one of the most precisely figured optical mirrors ever made, smooth to about 10 nanometers, the outer perimeter was too flat by about 2200 nanometers (about mm or inch). This difference was catastrophic, introducing severe spherical aberration, a flaw in which light reflecting off the edge of a mirror focuses on a different point from the light reflecting off its center.


title: Hubble Space Telescope

text: The effect of the mirror flaw on scientific observations depended on the particular observation—the core of the aberrated PSF was sharp enough to permit high-resolution observations of bright objects, and spectroscopy of point sources was affected only through a sensitivity loss. However, the loss of light to the large, out-of-focus halo severely reduced the usefulness of the telescope for faint objects or high-contrast imaging. This meant nearly all the cosmological programs were essentially impossible, since they required observation of exceptionally faint objects. This led politicians to question NASA's competence, scientists to rue the cost which could have gone to more productive endeavors, and comedians to make jokes about NASA and the telescope. In the 1991 comedy "", in a scene where historical disasters are displayed, Hubble is pictured with RMS "Titanic" and LZ 129 "Hindenburg". Nonetheless, during the first three years of the Hubble mission, before the optical corrections, the telescope still carried out a large number of productive observations of less demanding targets. The error was well characterized and stable, enabling astronomers to partially compensate for the defective mirror by using sophisticated image processing techniques such as deconvolution.


title: Hubble Space Telescope

text: A commission headed by Lew Allen, director of the Jet Propulsion Laboratory, was established to determine how the error could have arisen. The Allen Commission found that a reflective null corrector, a testing device used to achieve a properly shaped non-spherical mirror, had been incorrectly assembled—one lens was out of position by . During the initial grinding and polishing of the mirror, Perkin-Elmer analyzed its surface with two conventional refractive null correctors. However, for the final manufacturing step (figuring), they switched to the custom-built reflective null corrector, designed explicitly to meet very strict tolerances. The incorrect assembly of this device resulted in the mirror being ground very precisely but to the wrong shape. A few final tests, using the conventional null correctors, correctly reported spherical aberration. But these results were dismissed, thus missing the opportunity to catch the error, because the reflective null corrector was considered more accurate.


title: Hubble Space Telescope

text: The commission blamed the failings primarily on Perkin-Elmer. Relations between NASA and the optics company had been severely strained during the telescope construction, due to frequent schedule slippage and cost overruns. NASA found that Perkin-Elmer did not review or supervise the mirror construction adequately, did not assign its best optical scientists to the project (as it had for the prototype), and in particular did not involve the optical designers in the construction and verification of the mirror. While the commission heavily criticized Perkin-Elmer for these managerial failings, NASA was also criticized for not picking up on the quality control shortcomings, such as relying totally on test results from a single instrument.


title: Hubble Space Telescope

text: Many feared that Hubble would be abandoned. The design of the telescope had always incorporated servicing missions, and astronomers immediately began to seek potential solutions to the problem that could be applied at the first servicing mission, scheduled for 1993. While Kodak had ground a back-up mirror for Hubble, it would have been impossible to replace the mirror in orbit, and too expensive and time-consuming to bring the telescope back to Earth for a refit. Instead, the fact that the mirror had been ground so precisely to the wrong shape led to the design of new optical components with exactly the same error but in the opposite sense, to be added to the telescope at the servicing mission, effectively acting as "spectacles" to correct the spherical aberration.


title: Hubble Space Telescope

text: The first step was a precise characterization of the error in the main mirror. Working backwards from images of point sources, astronomers determined that the conic constant of the mirror as built was , instead of the intended . The same number was also derived by analyzing the null corrector used by Perkin-Elmer to figure the mirror, as well as by analyzing interferograms obtained during ground testing of the mirror.


title: Hubble Space Telescope

text: Because of the way the HST's instruments were designed, two different sets of correctors were required. The design of the Wide Field and Planetary Camera 2, already planned to replace the existing WF/PC, included relay mirrors to direct light onto the four separate charge-coupled device (CCD) chips making up its two cameras. An inverse error built into their surfaces could completely cancel the aberration of the primary. However, the other instruments lacked any intermediate surfaces that could be configured in this way, and so required an external correction device.


title: Hubble Space Telescope

text: The Corrective Optics Space Telescope Axial Replacement (COSTAR) system was designed to correct the spherical aberration for light focused at the FOC, FOS, and GHRS. It consists of two mirrors in the light path with one ground to correct the aberration. To fit the COSTAR system onto the telescope, one of the other instruments had to be removed, and astronomers selected the High Speed Photometer to be sacrificed. By 2002, all the original instruments requiring COSTAR had been replaced by instruments with their own corrective optics. COSTAR was removed and returned to Earth in 2009 where it is exhibited at the National Air and Space Museum in Washington, D.C. The area previously used by COSTAR is now occupied by the Cosmic Origins Spectrograph.


title: Hubble Space Telescope

text: Hubble was designed to accommodate regular servicing and equipment upgrades while in orbit. Instruments and limited life items were designed as orbital replacement units. Five servicing missions (SM 1, 2, 3A, 3B, and 4) were flown by NASA Space Shuttles, the first in December 1993 and the last in May 2009. Servicing missions were delicate operations that began with maneuvering to intercept the telescope in orbit and carefully retrieving it with the shuttle's mechanical arm. The necessary work was then carried out in multiple tethered spacewalks over a period of four to five days. After a visual inspection of the telescope, astronauts conducted repairs, replaced failed or degraded components, upgraded equipment, and installed new instruments. Once work was completed, the telescope was redeployed, typically after boosting to a higher orbit to address the orbital decay caused by atmospheric drag.


title: Hubble Space Telescope

text: The first Hubble servicing mission was scheduled for 1993 before the mirror problem was discovered. It assumed greater importance, as the astronauts would need to do extensive work to install corrective optics; failure would have resulted in either abandoning Hubble or accepting its permanent disability. Other components failed before the mission, causing the repair cost to rise to $500 million (not including the cost of the shuttle flight). A successful repair would help demonstrate the viability of building Space Station Alpha.


title: Hubble Space Telescope

text: STS-49 in 1992 demonstrated the difficulty of space work. While its rescue of Intelsat 603 received praise, the astronauts had taken possibly reckless risks in doing so. Neither the rescue nor the unrelated assembly of prototype space station components occurred as the astronauts had trained, causing NASA to reassess planning and training, including for the Hubble repair. The agency assigned to the mission Story Musgrave—who had worked on satellite repair procedures since 1976—and six other experienced astronauts, including two from STS-49. The first mission director since Project Apollo would coordinate a crew with 16 previous shuttle flights. The astronauts were trained to use about a hundred specialized tools.


title: Hubble Space Telescope

text: Heat had been the problem on prior spacewalks, which occurred in sunlight. Hubble needed to be repaired out of sunlight. Musgrave discovered during vacuum training, seven months before the mission, that spacesuit gloves did not sufficiently protect against the cold of space. After STS-57 confirmed the issue in orbit, NASA quickly changed equipment, procedures, and flight plan. Seven total mission simulations occurred before launch, the most thorough preparation in shuttle history. No complete Hubble mockup existed, so the astronauts studied many separate models (including one at the Smithsonian) and mentally combined their varying and contradictory details.


title: Hubble Space Telescope

text: Service Mission 1 flew aboard "Endeavour" in December 1993, and involved installation of several instruments and other equipment over ten days. Most importantly, the High Speed Photometer was replaced with the COSTAR corrective optics package, and WF/PC was replaced with the Wide Field and Planetary Camera 2 (WFPC2) with an internal optical correction system. The solar arrays and their drive electronics were also replaced, as well as four gyroscopes in the telescope pointing system, two electrical control units and other electrical components, and two magnetometers. The onboard computers were upgraded with added coprocessors, and Hubble's orbit was boosted.


title: Hubble Space Telescope

text: On January 13, 1994, NASA declared the mission a complete success and showed the first sharper images. The mission was one of the most complex performed up until that date, involving five long extra-vehicular activity periods. Its success was a boon for NASA, as well as for the astronomers who now had a more capable space telescope.


title: Hubble Space Telescope

text: Servicing Mission 2, flown by "Discovery" in February 1997, replaced the GHRS and the FOS with the Space Telescope Imaging Spectrograph (STIS) and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS), replaced an Engineering and Science Tape Recorder with a new Solid State Recorder, and repaired thermal insulation. NICMOS contained a heat sink of solid nitrogen to reduce the thermal noise from the instrument, but shortly after it was installed, an unexpected thermal expansion resulted in part of the heat sink coming into contact with an optical baffle. This led to an increased warming rate for the instrument and reduced its original expected lifetime of 4.5 years to about two years.


title: Hubble Space Telescope

text: Servicing Mission 3A, flown by "Discovery", took place in December 1999, and was a split-off from Servicing Mission3 after three of the six onboard gyroscopes had failed. The fourth failed a few weeks before the mission, rendering the telescope incapable of performing scientific observations. The mission replaced all six gyroscopes, replaced a Fine Guidance Sensor and the computer, installed a Voltage/temperature Improvement Kit (VIK) to prevent battery overcharging, and replaced thermal insulation blankets.


title: Hubble Space Telescope

text: Servicing Mission 3B flown by "Columbia" in March 2002 saw the installation of a new instrument, with the FOC (which, except for the Fine Guidance Sensors when used for astrometry, was the last of the original instruments) being replaced by the Advanced Camera for Surveys (ACS). This meant COSTAR was no longer required, since all new instruments had built-in correction for the main mirror aberration. The mission also revived NICMOS by installing a closed-cycle cooler and replaced the solar arrays for the second time, providing 30 percent more power.


title: Hubble Space Telescope

text: Plans called for Hubble to be serviced in February 2005, but the "Columbia" disaster in 2003, in which the orbiter disintegrated on re-entry into the atmosphere, had wide-ranging effects to the Hubble program and other NASA missions. NASA Administrator Sean O'Keefe decided all future shuttle missions had to be able to reach the safe haven of the International Space Station should in-flight problems develop. As no shuttles were capable of reaching both HST and the space station during the same mission, future crewed service missions were canceled. This decision was criticised by numerous astronomers who felt Hubble was valuable enough to merit the human risk. HST's planned successor, the James Webb Space Telescope (JWST), by 2004 was not expected to launch until at least 2011. JWST was eventually launched in December 2021. A gap in space-observing capabilities between a decommissioning of Hubble and the commissioning of a successor was of major concern to many astronomers, given the significant scientific impact of HST. The consideration that JWST will not be located in low Earth orbit, and therefore cannot be easily upgraded or repaired in the event of an early failure, only made concerns more acute. On the other hand, NASA officials were concerned that continuing to service Hubble would consume funds from other programs and delay the JWST.


title: Hubble Space Telescope

text: In January 2004, O'Keefe said he would review his decision to cancel the final servicing mission to HST, due to public outcry and requests from Congress for NASA to look for a way to save it. The National Academy of Sciences convened an official panel, which recommended in July 2004 that the HST should be preserved despite the apparent risks. Their report urged "NASA should take no actions that would preclude a space shuttle servicing mission to the Hubble Space Telescope". In August 2004, O'Keefe asked Goddard Space Flight Center to prepare a detailed proposal for a robotic service mission. These plans were later canceled, the robotic mission being described as "not feasible". In late 2004, several Congressional members, led by Senator Barbara Mikulski, held public hearings and carried on a fight with much public support (including thousands of letters from school children across the U.S.) to get the Bush Administration and NASA to reconsider the decision to drop plans for a Hubble rescue mission.


title: Hubble Space Telescope

text: The nomination in April 2005 of a new NASA Administrator, Michael D. Griffin, changed the situation, as Griffin stated he would consider a crewed servicing mission. Soon after his appointment Griffin authorized Goddard to proceed with preparations for a crewed Hubble maintenance flight, saying he would make the final decision after the next two shuttle missions. In October 2006 Griffin gave the final go-ahead, and the 11-day mission by "Atlantis" was scheduled for October 2008. Hubble's main data-handling unit failed in September 2008, halting all reporting of scientific data until its back-up was brought online on October 25, 2008. Since a failure of the backup unit would leave the HST helpless, the service mission was postponed to incorporate a replacement for the primary unit.


title: Hubble Space Telescope

text: Servicing Mission 4 (SM4), flown by "Atlantis" in May 2009, was the last scheduled shuttle mission for HST. SM4 installed the replacement data-handling unit, repaired the ACS and STIS systems, installed improved nickel hydrogen batteries, and replaced other components including all six gyroscopes. SM4 also installed two new observation instruments—Wide Field Camera 3 (WFC3) and the Cosmic Origins Spectrograph (COS)—and the Soft Capture and Rendezvous System, which will enable the future rendezvous, capture, and safe disposal of Hubble by either a crewed or robotic mission. Except for the ACS's High Resolution Channel, which could not be repaired and was disabled, the work accomplished during SM4 rendered the telescope fully functional.


title: Hubble Space Telescope

text: Since the start of the program, a number of research projects have been carried out, some of them almost solely with Hubble, others coordinated facilities such as Chandra X-ray Observatory and ESO's Very Large Telescope. Although the Hubble observatory is nearing the end of its life, there are still major projects scheduled for it. One example is the current (2022) ULLYSES project (Ultraviolet Legacy Library of Young Stars as Essential Standards) which will last for three years to observe a set of high- and low-mass young stars and will shed light on star formation and composition.


title: Hubble Space Telescope

text: In an August 2013 press release, CANDELS was referred to as "the largest project in the history of Hubble". The survey "aims to explore galactic evolution in the early Universe, and the very first seeds of cosmic structure at less than one billion years after the Big Bang." The CANDELS project site describes the survey's goals as the following:


title: Hubble Space Telescope

text: The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey is designed to document the first third of galactic evolution from z = 8 to 1.5 via deep imaging of more than 250,000 galaxies with WFC3/IR and ACS. It will also find the first Type Ia SNe beyond z > 1.5 and establish their accuracy as standard candles for cosmology. Five premier multi-wavelength sky regions are selected; each has multi-wavelength data from Spitzer and other facilities, and has extensive spectroscopy of the brighter galaxies. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to 10 solar masses out to z ~ 8.


title: Hubble Space Telescope

text: The program, officially named "Hubble Deep Fields Initiative 2012", is aimed to advance the knowledge of early galaxy formation by studying high-redshift galaxies in blank fields with the help of gravitational lensing to see the "faintest galaxies in the distant universe". The Frontier Fields web page describes the goals of the program being:


title: Hubble Space Telescope

text: The Cosmic Evolution Survey (COSMOS) is an astronomical survey designed to probe the formation and evolution of galaxies as a function of both cosmic time (redshift) and the local galaxy environment. The survey covers a two square degree equatorial field with spectroscopy and X-ray to radio imaging by most of the major space-based telescopes and a number of large ground based telescopes, making it a key focus region of extragalactic astrophysics. COSMOS was launched in 2006 as the largest project pursued by the Hubble Space Telescope at the time, and still is the largest continuous area of sky covered for the purposes of mapping deep space in blank fields, 2.5 times the area of the moon on the sky and 17 times larger than the largest of the CANDELS regions. The COSMOS scientific collaboration that was forged from the initial COSMOS survey is the largest and longest-running extragalactic collaboration, known for its collegiality and openness. The study of galaxies in their environment can be done only with large areas of the sky, larger than a half square degree. More than two million galaxies are detected, spanning 90% of the age of the Universe. The COSMOS collaboration is led by Caitlin Casey, Jeyhan Kartaltepe, and Vernesa Smolcic and involves more than 200 scientists in a dozen countries.


title: Hubble Space Telescope

text: Anyone can apply for time on the telescope; there are no restrictions on nationality or academic affiliation, but funding for analysis is available only to U.S. institutions. Competition for time on the telescope is intense, with about one-fifth of the proposals submitted in each cycle earning time on the schedule.


title: Hubble Space Telescope

text: Calls for proposals are issued roughly annually, with time allocated for a cycle lasting about one year. Proposals are divided into several categories; "general observer" proposals are the most common, covering routine observations. "Snapshot observations" are those in which targets require only 45 minutes or less of telescope time, including overheads such as acquiring the target. Snapshot observations are used to fill in gaps in the telescope schedule that cannot be filled by regular general observer programs.


title: Hubble Space Telescope

text: Astronomers may make "Target of Opportunity" proposals, in which observations are scheduled if a transient event covered by the proposal occurs during the scheduling cycle. In addition, up to 10% of the telescope time is designated "director's discretionary" (DD) time. Astronomers can apply to use DD time at any time of year, and it is typically awarded for study of unexpected transient phenomena such as supernovae.


title: Hubble Space Telescope

text: Other uses of DD time have included the observations that led to views of the Hubble Deep Field and Hubble Ultra Deep Field, and in the first four cycles of telescope time, observations that were carried out by amateur astronomers.


title: Hubble Space Telescope

text: In 2012, the ESA held a contest for public image processing of Hubble data to encourage the discovery of "hidden treasures" in the raw Hubble data.


title: Hubble Space Telescope

text: The first director of STScI, Riccardo Giacconi, announced in 1986 that he intended to devote some of his director discretionary time to allowing amateur astronomers to use the telescope. The total time to be allocated was only a few hours per cycle but excited great interest among amateur astronomers.


title: Hubble Space Telescope

text: Proposals for amateur time were stringently reviewed by a committee of amateur astronomers, and time was awarded only to proposals that were deemed to have genuine scientific merit, did not duplicate proposals made by professionals, and required the unique capabilities of the space telescope. Thirteen amateur astronomers were awarded time on the telescope, with observations being carried out between 1990 and 1997. One such study was "Transition Comets—UV Search for OH". The first proposal, "A Hubble Space Telescope Study of Posteclipse Brightening and Albedo Changes on Io", was published in "Icarus", a journal devoted to solar system studies. A second study from another group of amateurs was also published in "Icarus". After that time, however, budget reductions at STScI made the support of work by amateur astronomers untenable, and no additional amateur programs have been carried out.


title: Hubble Space Telescope

text: Regular Hubble proposals still include findings or discovered objects by amateurs and citizen scientists. These observations are often in a collaboration with professional astronomers. One of earliest such observations is the Great White Spot of 1990 on planet Saturn, discovered by amateur astronomer S. Wilber and observed by HST under a proposal by J. Westphal (Caltech). Later professional-amateur observations by Hubble include discoveries by the Galaxy Zoo project, such as Voorwerpjes and Green Pea galaxies. The "Gems of the Galaxies" program is based on a list of objects by galaxy zoo volunteers that was shortened with the help of an online vote. Additionally there are observations of minor planets discovered by amateur astronomers, such as 2I/Borisov and changes in the atmosphere of the gas giants Jupiter and Saturn or the ice giants Uranus and Neptune. In the pro-am collaboration backyard worlds the HST was used to observe a planetary mass object, called WISE J0830+2837. The non-detection by the HST helped to classify this peculiar object.


title: Hubble Space Telescope

text: In the early 1980s, NASA and STScI convened four panels to discuss key projects. These were projects that were both scientifically important and would require significant telescope time, which would be explicitly dedicated to each project. This guaranteed that these particular projects would be completed early, in case the telescope failed sooner than expected. The panels identified three such projects: 1) a study of the nearby intergalactic medium using quasar absorption lines to determine the properties of the intergalactic medium and the gaseous content of galaxies and groups of galaxies; 2) a medium deep survey using the Wide Field Camera to take data whenever one of the other instruments was being used and 3) a project to determine the Hubble constant within ten percent by reducing the errors, both external and internal, in the calibration of the distance scale.


title: Hubble Space Telescope

text: Hubble has helped resolve some long-standing problems in astronomy, while also raising new questions. Some results have required new theories to explain them.


title: Hubble Space Telescope

text: Among its primary mission targets was to measure distances to Cepheid variable stars more accurately than ever before, and thus constrain the value of the Hubble constant, the measure of the rate at which the universe is expanding, which is also related to its age. Before the launch of HST, estimates of the Hubble constant typically had errors of up to 50%, but Hubble measurements of Cepheid variables in the Virgo Cluster and other distant galaxy clusters provided a measured value with an accuracy of ±10%, which is consistent with other more accurate measurements made since Hubble's launch using other techniques. The estimated age is now about 13.7 billion years, but before the Hubble Telescope, scientists predicted an age ranging from 10 to 20 billion years.


title: Hubble Space Telescope

text: While Hubble helped to refine estimates of the age of the universe, it also upended theories about its future. Astronomers from the High-z Supernova Search Team and the Supernova Cosmology Project used ground-based telescopes and HST to observe distant supernovae and uncovered evidence that, far from decelerating under the influence of gravity, the expansion of the universe is instead accelerating. Three members of these two groups have subsequently been awarded Nobel Prizes for their discovery. The cause of this acceleration remains poorly understood; the term used for the currently-unknown cause is dark energy, signifying that it is dark (unable to be directly seen and detected) to our current scientific instruments.


title: Hubble Space Telescope

text: The high-resolution spectra and images provided by the HST have been especially well-suited to establishing the prevalence of black holes in the center of nearby galaxies. While it had been hypothesized in the early 1960s that black holes would be found at the centers of some galaxies, and astronomers in the 1980s identified a number of good black hole candidates, work conducted with Hubble shows that black holes are probably common to the centers of all galaxies. The Hubble programs further established that the masses of the nuclear black holes and properties of the galaxies are closely related.


title: Hubble Space Telescope

text: A unique window on the Universe enabled by Hubble are the Hubble Deep Field, Hubble Ultra-Deep Field, and Hubble Extreme Deep Field images, which used Hubble's unmatched sensitivity at visible wavelengths to create images of small patches of sky that are the deepest ever obtained at optical wavelengths. The images reveal galaxies billions of light years away, thereby providing information about the early Universe, and have accordingly generated a wealth of scientific papers. The Wide Field Camera3 improved the view of these fields in the infrared and ultraviolet, supporting the discovery of some of the most distant objects yet discovered, such as MACS0647-JD.


title: Hubble Space Telescope

text: On March 3, 2016, researchers using Hubble data announced the discovery of the farthest confirmed galaxy to date: GN-z11, which Hubble observed as it existed roughly 400 million years after the Big Bang. The Hubble observations occurred on February 11, 2015, and April 3, 2015, as part of the CANDELS/GOODS-North surveys.


title: Hubble Space Telescope

text: The collision of Comet Shoemaker-Levy 9 with Jupiter in 1994 was fortuitously timed for astronomers, coming just a few months after Servicing Mission1 had restored Hubble's optical performance. Hubble images of the planet were sharper than any taken since the passage of "Voyager 2" in 1979, and were crucial in studying the dynamics of the collision of a large comet with Jupiter, an event believed to occur once every few centuries.


title: Hubble Space Telescope

text: In March 2015, researchers announced that measurements of aurorae around Ganymede, one of Jupiter's moons, revealed that it has a subsurface ocean. Using Hubble to study the motion of its aurorae, the researchers determined that a large saltwater ocean was helping to suppress the interaction between Jupiter's magnetic field and that of Ganymede. The ocean is estimated to be deep, trapped beneath a ice crust.


title: Hubble Space Telescope

text: HST has also been used to study objects in the outer reaches of the Solar System, including the dwarf planets Pluto, Eris, and Sedna. During June and July 2012, U.S. astronomers using Hubble discovered Styx, a tiny fifth moon orbiting Pluto.


title: Hubble Space Telescope

text: From June to August 2015, Hubble was used to search for a Kuiper belt object (KBO) target for the "New Horizons" Kuiper Belt Extended Mission (KEM) when similar searches with ground telescopes failed to find a suitable target. This resulted in the discovery of at least five new KBOs, including the eventual KEM target, 486958 Arrokoth, that "New Horizons" performed a close fly-by of on January 1, 2019.


title: Hubble Space Telescope

text: In April 2022 NASA announced that astronomers were able to use images from HST to determine the size of the nucleus of comet C/2014 UN271 (Bernardinelli–Bernstein), which is the largest icy comet nucleus ever seen by astronomers. The nucleus of C/2014 UN271 has an estimated mass of 50 trillion tons which is 50 times the mass of other known comets in our solar system.


title: Hubble Space Telescope

text: On December 11, 2015, Hubble captured an image of the first-ever predicted reappearance of a supernova, dubbed "Refsdal", which was calculated using different mass models of a galaxy cluster whose gravity is warping the supernova's light. The supernova was previously seen in November 2014 behind galaxy cluster MACS J1149.5+2223 as part of Hubble's Frontier Fields program. The light from the cluster took roughly five billion years to reach Earth, while the light from the supernova behind it took five billion more years than that, as measured by their respective redshifts. Because of the gravitational effect of the galaxy cluster, four images of the supernova appeared instead of one, an example of an Einstein cross. Based on early lens models, a fifth image was predicted to reappear by the end of 2015. Refsdal reappeared as predicted in 2015.


title: Hubble Space Telescope

text: In March 2019, observations from Hubble and data from the European Space Agency's Gaia space observatory were combined to determine that the mass of the Milky Way Galaxy is approximately 1.5 trillion times the mass of the Sun, a value intermediate between prior estimates.


title: Hubble Space Telescope

text: Other discoveries made with Hubble data include proto-planetary disks (proplyds) in the Orion Nebula; evidence for the presence of extrasolar planets around Sun-like stars; and the optical counterparts of the still-mysterious gamma-ray bursts. Using gravitational lensing, Hubble observed a galaxy designated MACS 2129-1 approximately 10 billion light-years from Earth. MACS 2129-1 subverted expectations about galaxies in which new star formation had ceased, a significant result for understanding the formation of elliptical galaxies.


title: Hubble Space Telescope

text: In 2022 Hubble detected the light of the farthest individual star ever seen to date. The star, WHL0137-LS (nicknamed "Earendel"), existed within the first billion years after the big bang. It will be observed by NASA's James Webb Space Telescope to confirm Earendel is indeed a star.


title: Hubble Space Telescope

text: Many objective measures show the positive impact of Hubble data on astronomy. Over 15,000 papers based on Hubble data have been published in peer-reviewed journals, and countless more have appeared in conference proceedings. Looking at papers several years after their publication, about one-third of all astronomy papers have no citations, while only two percent of papers based on Hubble data have no citations. On average, a paper based on Hubble data receives about twice as many citations as papers based on non-Hubble data. Of the 200 papers published each year that receive the most citations, about 10% are based on Hubble data.


title: Hubble Space Telescope

text: Although the HST has clearly helped astronomical research, its financial cost has been large. A study on the relative astronomical benefits of different sizes of telescopes found that while papers based on HST data generate 15 times as many citations as a ground-based telescope such as the William Herschel Telescope, the HST costs about 100 times as much to build and maintain.


title: Hubble Space Telescope

text: Deciding between building ground- versus space-based telescopes is complex. Even before Hubble was launched, specialized ground-based techniques such as aperture masking interferometry had obtained higher-resolution optical and infrared images than Hubble would achieve, though restricted to targets about 10 times brighter than the faintest targets observed by Hubble. Since then, advances in adaptive optics have extended the high-resolution imaging capabilities of ground-based telescopes to the infrared imaging of faint objects. The usefulness of adaptive optics versus HST observations depends strongly on the particular details of the research questions being asked. In the visible bands, adaptive optics can correct only a relatively small field of view, whereas HST can conduct high-resolution optical imaging over a wider field. Moreover, Hubble can image more faint objects, since ground-based telescopes are affected by the background of scattered light created by the Earth's atmosphere.


title: Hubble Space Telescope

text: In addition to its scientific results, Hubble has also made significant contributions to aerospace engineering, in particular the performance of systems in low Earth orbit (LEO). These insights result from Hubble's long lifetime on orbit, extensive instrumentation, and return of assemblies to the Earth where they can be studied in detail. In particular, Hubble has contributed to studies of the behavior of graphite composite structures in vacuum, optical contamination from residual gas and human servicing, radiation damage to electronics and sensors, and the long term behavior of multi-layer insulation. One lesson learned was that gyroscopes assembled using pressurized oxygen to deliver suspension fluid were prone to failure due to electric wire corrosion. Gyroscopes are now assembled using pressurized nitrogen. Another is that optical surfaces in LEO can have surprisingly long lifetimes; Hubble was only expected to last 15 years before the mirror became unusable, but after 14 years there was no measureable degradation. Finally, Hubble servicing missions, particularly those that serviced components not designed for in-space maintenance, have contributed towards the development of new tools and techniques for on-orbit repair.