A derivative of the Apollo Lunar Module is being developed to support the operation of a manned, earth orbiting solar observatory. Its thermal control and life support systems demonstrate how previously developed technology and hardware are satisfying mission requirements which differ significantly from those for which the vehicle was originally designed.Thermal control is accomplished by active and passive means. The active portion of the system employs liquid heat transport and rejection networks. Insulation systems, thermal coatings, and conductive couplings are used as much as is practical to minimize the effects on the vehicle of variations in the external thermal environment. The Apollo Lunar Module life support system has been extensively modified to permit both shirtsleeve and extravehicular crew activities.