what was the purpose of the last challenger mission
STS-51-L STS-51-L was the 25th mission of the United States Space Shuttle program, and disastrous final mission of the Space Shuttle Challenger. The mission to carry out several lessons from space and observe Halley's Comet never made its target landing date of February 3, 1986. A structural failure during its ascent phase 73 seconds after launch on January 28 from Kennedy Space Center Launch Complex 39 killed all seven crew members – Commander Dick Scobee, Pilot Michael J. Smith, Mission Specialists Ellison S. Onizuka, Judith A. Resnik and Ronald E. McNair, and Payload Specialists Gregory Jarvis and Christa McAuliffe—and destroyed the orbiter. The Rogers Commission determined that the cause of the destruction was due to the failure of an O-ring seal on the starboard Solid Rocket Booster (SRB). Space Shuttle flights were suspended for 32 months while the hazards with the shuttle were addressed.
Deep Impact (spacecraft) Deep Impact was a NASA space probe launched from Cape Canaveral Air Force Station at 18:47 UTC on January 12, 2005.[3] It was designed to study the interior composition of the comet Tempel 1 (9P/Tempel), by releasing an impactor into the comet. At 05:52 UTC on July 4, 2005, the impactor successfully collided with the comet's nucleus. The impact excavated debris from the interior of the nucleus, forming an impact crater. Photographs taken by the spacecraft showed the comet to be more dusty and less icy than had been expected. The impact generated an unexpectedly large and bright dust cloud, obscuring the view of the impact crater.