ROSAT

Telecommunications Description

ROSAT has two onboard tape recorders with a capacity of 700 Megabit each to store all science data from the XRT and WFC, as well as housekeeping and attitude. On average the spacecraft has ground contacts with the ground station at GSOC for six consecutive orbits daily, for 6 to 8 minutes per contact. This is followed by 10 orbits (about 16 hours) without any ground contact. During the contact period, stored data must be downlinked and all telecommands necessary for ROSAT operations for the coming contact-free time must be loaded. NASA assisted ROSAT operations by providing Deep Space Network (DSN) support in the spacecraft initial on-orbit check out period, and backup DSN support throughout the mission.