Launch of Shuttle Mission STS-42. Shuttle Discovery leaves a curving trail of smoke as it climbs away from Kennedy Space Center at the beginning of Mission STS-42. The slightly brownish smoke comes from the two Solid Rocket Boosters (SRBs) that help propel the Shuttle in the first two minutes of the flight. STS-42 was launched on 22 January 1992, carrying the first International Microgravity Laboratory (IML-1) in its cargo bay. The crew of seven spent eight days in space, returning on 30 January 1992. This photograph was taken from one of the Shuttle Training Aircraft whilst performing weather observation duties.