alb@alice.UUCP (07/09/83)
I assume ''the communications satellites'' to which you refer are the TDRS (tracking and data relay satellite) series. A network of three geosynchronous TDRS's is planned. One is now in its proper orbit and, after it has been tested, will be placed in the correct longitude, over Brazil, by STS-8 launch time. TDRS-2 was to have been launched on STS-8, but that plan was scrubbed due to the STS-6 IUS failure. No word has been given on when it will be launched. Due to the fact that only one TDRS will be operative by STS-9, the Spacelab flight, Spacelab will not be able to accomplish all of its goals. This is because the lab itself has little data storage capacity, and NASA had planned to have it in constant communication with the ground (two TDRS's would have sufficed) With only TDRS-1 in place, the shuttle will be in contact via satellite only 20% of the time. If TDRS-1 for some reason doesn't work, Spacelab on STS-9 will be scrubbed. Obviously, with all the doubt over IUS and the further doubt over when TDRS-2 will be launched, there is no indication whatsoever as to when TDRS-3 will go up.