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Notes:
Technically, the $3-4 billion Phase Two “Dual Keel” spacecraft assembly and servicing facility was still in the 1987 baseline. But there was no funding commitment and NASA officials privately expressed doubt it would ever be built. Advocates of manned planetary exploration (e.g. the Planetary Society) were upset when NASA removed the Station's large spacecraft assembly & checkout capability.
The expanded “Dual Keel” Space Station “Freedom” made a final comeback in 1989 when President Bush proposed a Moonbase by 2001-2005 and missions to Mars by 2018. NASA estimated the “Dual Keel” lunar spacecraft support facility, additional power generators, crew modules for 14-16 astronauts etc. would cost at least $1 billion.