Editing Ulf Merbold (section)

== STS-42 Space Shuttle mission==
[[File:STS042-78-061 - STS-42 OV-103 crew poses for onboard in-space portrait in IML-1 SL module.jpg|thumb|right|STS-42 crew in the IML-1 Spacelab|alt=Seven astronauts in matching clothes floating in Spacelab]]
{{main|STS-42}}

In June 1989, Ulf Merbold was chosen to train as payload specialist for the International Microgravity Laboratory (IML-1) Spacelab mission.{{sfn|Evans|2013|p=203}} [[STS-42]] was intended to launch in December 1990 on ''Columbia'' but was delayed several times. After first being reassigned to launch with [[Space Shuttle Atlantis|''Atlantis'']] in December 1991,{{sfn|Evans|2013|pp=206–207}} it finally launched on the [[Space Shuttle Discovery|Space Shuttle ''Discovery'']] on 22 January 1992, with a final one-hour delay to 9:52&nbsp;a.m. EST caused by bad weather and issues with a hydrogen pump.{{sfn|Evans|2013|p=212}} The change from ''Columbia'' to ''Discovery'' meant the mission had to be shortened, as ''Columbia'' had been capable of carrying extra hydrogen and oxygen tanks that could power the fuel cells.{{sfn|Evans|2013|p=207}} Merbold was the first astronaut to represent reunified Germany.{{sfn|Evans|2013|p=207}} The other payload specialist on board was astronaut [[Roberta Bondar]], the first Canadian woman in space.{{sfn|Evans|2013|p=207}} Originally, [[Sonny Carter]] was assigned as one of three mission specialists, he died in a plane crash on 5 April 1991, and was replaced by [[David C. Hilmers]].{{sfn|Evans|2013|pp=208–209}}

The mission specialized in experiments in life sciences and materials science in microgravity.{{sfn|Evans|2013|p=213}} IML-1 included ESA's Biorack module,{{sfn|Krige|Russo|Sebesta|2000|p=602}} a biological research facility in which cells and small organisms could be exposed to weightlessness and cosmic radiation.{{sfn|Krige|Russo|Sebesta|2000|p=167}} It was used for microgravity experiments on various biological samples including frog eggs, fruit flies, and ''[[Physarum polycephalum]]'' slime molds. Bacteria, fungi and shrimp eggs were exposed to cosmic rays.{{sfn|Evans|2013|p=213}} Other experiments focused on the human response to weightlessness or crystal growth.{{sfn|Evans|2013|pp=213–215}} There were also ten [[Getaway Special]] canisters with experiments on board.{{sfn|Evans|2013|p=216}} Like STS-9, the mission operated in two teams who worked 12-hour shifts: a "blue team" consisting of mission commander [[Ronald J. Grabe]] together with [[Stephen S. Oswald]], payload commander [[Norman Thagard]], and Bondar; and a "red team" of [[William F. Readdy]], Hilmers, and Merbold.{{sfn|Evans|2013|p=211}} Because the crew did not use as many consumables as planned, the mission was extended from seven days to eight, landing at Edwards AFB on 30 January 1992, at 8:07{{nbsp}}a.m. [[Pacific Time Zone|PST]].{{sfn|Evans|2013|p=216}}