Editing Ulf Merbold (section)

== Ground-based astronaut work ==
In 1984, Ulf Merbold became the backup payload specialist for the Spacelab D-1 mission, which West Germany funded.{{sfn|Chladek|Anderson|2017|p=267}}{{sfn|Hitt|Smith|2014|pp=215–216}} The mission, which was numbered [[STS-61-A]], was carried out on the [[Space Shuttle Challenger|Space Shuttle ''Challenger'']] from 30 October to 6 November 1985.{{sfn|Croft|Youskauskas|2019|p=138}} In ESA parlance, Merbold and the three other payload specialists—Germans [[Reinhard Furrer]] and [[Ernst Messerschmid]] and the Dutch Wubbo Ockels—were called "science astronauts" to distinguish them from "passengers" like Saudi prince [[Sultan bin Salman Al Saud]] and Utah senator [[Jake Garn]], both of whom had also flown as payload specialists on the Space Shuttle.{{sfn|Croft|Youskauskas|2019|pp=138–139}} During the Spacelab mission, Merbold acted as crew interface coordinator, working from the [[German Space Operations Center]] in [[Oberpfaffenhofen]] to support the astronauts on board while working with the scientists on the ground.{{sfn|Croft|Youskauskas|2019|p=153}}

From 1986, Merbold worked for ESA at the [[European Space Research and Technology Centre]] in [[Noordwijk]], Netherlands, contributing to plans for what would become the ''[[Columbus (ISS module)|Columbus]]'' module of the [[International Space Station]] (ISS).<ref name="ESA2004" /> In 1987, he became head of the German Aerospace Center's astronaut office, and in April–May 1993 he served as science coordinator for the second German Spacelab mission D-2 on [[STS-55]].<ref name="ESA2004" />