cobb@NBS-VMS@sri-unix (07/14/82)
(I tried the number during STS-3 but not during the last mission, so my info may not be current.) NASA doesn't include the ground station schedule because they only update the tape every 4 to 6 hours. That's two or three orbits! A list of ground stations for that far in advance would double or triple the length of the recording, and it wouldn't be all that useful (try picking the useful information out of several minutes of phrases like "Goldstone at twenty-oh-eight for six minutes"). To the best of my knowledge, NASA doesn't broadcast the "900 number" signal on shortwave radio (although they should -- it couldn't cost much, and they'd be reaching mostly technologists, who are their biggest supporters), so I assume you're talking about picking up the signals direct from the shuttle and Houston. The same problems that ground stations have also apply here, and in spades. You can only hear the shuttle when it's over you, which isn't often. The ground track of the shuttle doesn't cover all that much of the USA (we're too far north). Also, I seem to remember that the frequencies NASA uses to talk to the shuttle are up around 2Ghz. Common ham radio gear only goes up to about 450Mhz. So you're talking about buying or building an expensive piece of gear, waiting for the precise moment when the shuttle's overhead (repeat query: you need a program for that -- anobody got one?), and then listening to a couple of minutes of conversation before the shuttle moves out of range (that's assuming there's a ground station close enough to your location that NASA's talking while you can hear), and only being able to do even THAT just a couple of times a day. It's not as simple as just tuning in the dial. That's why they have the 900 number. However, if you do manage to call the number when Houston and the shuttle are on, you can find out the right time to call back when they go off. The key words here are LOS (Loss Of Signal) and AOS (Acquisition Of Signal). There's always a thirty-second warning before LOS, after which they generally say something like "Okay, see you at Dakar in twenty-one minutes". If they mention the next AOS, that means the same thing. You're right, there should be a cheap (free) way to find out what's going on on the shuttle. But AT&T isn't charging exorbitantly for their circuits -- 35 cents a minute is close to the standard long- distance rate. Broadcasting is always cheaper than point-to-point. What NASA really should do is put their signal on one of the ham bands used by stations like Voice of America and Radio Whatever (hey! why not put the shuttle right next to Radio Moscow?). It might help to include a ground-station schedule in the 900-number recording, but it probably wouldn't help all that much. Remember, the format of that number was designed for journalists, not the general public. Maybe when direct broadcast satellite TV gets started, NASA could give themselves a channel... Stewart PS - Speaking of satellites, it will only be a couple of years before we no longer have to worry about ground station coverage. NASA will soon be launching a set of geosynchronous satellites called TDRSS (Tracking and Data Relay Satellite System, I think). The shuttle talks to whichever TDRSS it can see, and that one relays to the one over Goddard, and Goddard relays between its TDRSS and Houston. No more ground-station windows. Godspeed TDRSS! -SC