The Marshall Space Flight Center (MSFC) and the Johnson Space Center (JSC) were each awarded 16-month contracts in April 1976 for the Space Station Systems Analysis Study (SSSAS). Grumman Aerospace Corporation was MSFC's contractor and McDornell Douglas Aerospace Company was JSC's contractor. The goal of this study was to formulate plans for a permanent operational base and laboratory facility in Earth orbit in addition to developing a space construction base design for implementing the program. An expended Space Shuttle external tank was to be the central core platform of the base, and additional pressurized modules could be added to provide laboratory facilities. This artist's concept depicts a space construction base design for implementing the SSSAS.