STS 51-B was the seventeenth flight of a Space Shuttle and the seventh flight of Challenger. The launch of Challenger was delayed 2 minutes 18 seconds due to a failure in the launch processing failure. Challenger was initially rolled out to the pad to launch on the STS-51E mission. The shuttle was rolled back when there was a timing issue with the TDRS-B satellite. When STS-51E was canceled Challenger was re-manifested with the STS-51B payloads.
Launch date: April 29 1985, 16:02:18 UTC
Landing: May 6, 1985 16:11:04 UTC