Frederick Gordon, Goddard Space Flight Center, Greenbelt, MD
Michael C. W. Sandford, Science and Engineering Research
Council, London, U.K. The receiving site for NASA's ground
system was, until April 1986, located at the Goddard Space
Flight Center (GSFC), Greenbelt, Maryland. Subsequently it has
been removed to NASA's facility at Wallops Island, Virginia
(WPS). NASA's spacecraft and science operations facilities have
always been located at GSFC. Commands and received data are now
transmitted between GSFC and WPS by a commercial communications
satellite link. NASA has three principal areas of responsibility
in operations: first, overall responsibility for monitoring and
maintaining the health of the spacecraft; second, providing a
backup system for the purpose of spacecraft safety during the
shift controlled by ESA's ground station; and third, operating
IUE for two 8 hour shifts each day, designated US1 and US2. The
spacecraft-related tasks are carried out on a 24 hour per day
basis by the GSFC IUE Operation