Chalk up yet another historic discovery for NASA's orbiting Kepler telescope, a spacecraft with strong Boulder ties.
Astronomers now credit Kepler for having detected the most Earth-like planet to date, a distant body similar in size to our own planet, existing in the Goldilocks zone not too hot or cold to sustain life.
The latest achievement for Kepler was announced Thursday by NASA and is detailed in today's issue of the journal Science. It is based on data collected before the Kepler telescope was compromised by a mechanical failure last year.
"It's amazing," said Bill Possel, director of mission operations and data systems for the Kepler mission at the University of Colorado's Laboratory for Atmospheric and Space Physics. "This is something that we've been striving for, for years.
"We knew it was there, but to find an Earth-like planet in an Earth-like orbit and an Earth-like size, it's really exciting for us."
The Kepler flight system was developed by Boulder's Ball Aerospace & Technologies Corp., which supports mission operations with LASP.
"When I first heard about the Kepler mission back in the 2002 time frame, I was really skeptical," said John Troeltzsch, Kepler program manager for Ball. "It seemed almost impossible that you could point a large telescope in deep space for this long, with the stars so far away and hold it steadily enough to see planets around other stars. And wow, we have found an Earth-size planet in the habitable zone. This is fantastic."
He added, "This goes around its star every 130 days, so it's more like a cousin than a twin" of Earth.
"The other thing that is a little different, we don't know what the gravity is on the surface of this planet. We don't know the density. But other than that, this could have liquid water on its surface, and it is the Earth's size and so it's fascinating."
Reports of Kepler's demise were premature
Kepler, which orbits the sun, studies the galaxy for subtle changes in brightness that indicate an orbiting planet is crossing in front of a star. Scientists can calculate, from those changes, a planet's size and draw certain conclusions about its characteristics.
The newfound object, which is being called Kepler-186f, circles a red dwarf star 500 light-years from Earth in the constellation Cygnus. A light-year is almost 6 trillion miles.
Scientists said the planet is about 10 percent larger than Earth and may very well have liquid water.
Obituaries were being written for Kepler and its four-year mission last year after engineers were unsuccessful in fixing two broken reaction wheels critical to pointing and stabilizing the spacecraft.
But reports of Kepler's demise may have been premature, as both Possel and Troeltzsch said a proposal is now before NASA for what is being called K2. The Kepler-NASA team has submitted to NASA administration a proposal for about $32 million in new funding to continue Kepler's examination of the heavens, on a more limited basis.
Troeltzsch said that in response to a NASA request for ideas on ways to continue using Kepler, Ball started working on "a very unique, very innovative way to fly the spacecraft, where we use the two remaining reaction wheels and the solar radiation pressure from the sun to hold it stable."
'I think everybody is pretty confident'
Based on work over recent months, Troeltzsch said results from Kepler's prime were about four times better than what is being seen so far from K2, "but it's still significantly better than what we can do from the ground, so it's compelling."
Due to the spacecraft's condition, should K2 be approved, it would only be capable of keeping its photometer fixed on one part of the solar system for 80 days at a time before then shifting to another patch of stars, whereas Kepler could focus on one region for far greater periods.
"I think everybody is pretty confident that Kepler will keep looking for planets, and we'll keep finding planets," Possel said.
Troeltzsch said he expects a NASA announcement on K2 to come in June.
The Associated Press contributed to this report
Contact Camera Staff Writer Charlie Brennan at 303-473-1327 or firstname.lastname@example.org.