space@mit-mc (03/29/85)
From: redford%doctor.DEC@decwrl.ARPA (John Redford) I don't want to get into the debate over the pros and cons of Star Wars, because I think that everyone on this list is already familiar with them. Personally I think that SDI is a terrible idea. It's a tribute to the power of the Presidency that anyone takes it seriously at all. But instead of getting into that argument, I would like to talk about the effect of SDI on space development. L5 and Spacepac may already have formulated a position on SDI, but what should that position be? All of us want to see further scientific and commercial activity in space. The question is, will this vast increase in military space activity hinder or aid our real goals? Let me provide one example in favor of military involvement and one against, and then throw the argument open. The US has an extensive research program under way in Antarctica. The research is expensive because of the remote and hostile environment. The government pays for it partly out of a love of basic research, but more out of a desire to keep a foothold on what might be a valuable continent. The bases down there are supplied and built by the military. The US Air Force, at considerable risk to its pilots and planes, is what makes science possible in Antarctica. No university or university consortium could afford the special modifications that planes in Antarctica need, or get pilots with the special training. An example against the military is the Navstar or GPSS global navigation system. This is a satellite system that permits a foot soldier to find his position within ten meters anywhere in the world. The military originally intended it for civilian use as well, but when they discovered just how good it would be, they changed the system so that only those with passwords could get its full accuracy. From their point of view this action was entirely justified; they didn't want enemy soldiers to buy a $200 box from Magnavox and get the same benefits that our own people had. The result, though, is that something that could be of enormous benefit to the American public has been denied to them. Civilian needs gave way before military ones. Now, what will SDI bring? Will its research help civilian efforts for large boosters and manned space stations? Or will civilian research be restricted because of its SDI implications? Will we see another space shuttle screw-up, where the shuttle was enlarged and therefore delayed by military requirements? What do you folks think? John Redford DEC-Hudson
wdr@faron.UUCP (William D. Ricker) (04/02/85)
>From: redford%doctor.DEC@decwrl.ARPA (John Redford) >Let me provide one example in favor of military involvement and one against, >and then throw the argument open. . . . >An example against the military is the Navstar or GPS global navigation system. >This is a satellite system that permits a foot soldier to find his position >within ten meters anywhere in the world. The military originally intended it >for civilian use as well, but when they discovered just how good it would be, >they changed the system so that only those with passwords could get its full >accuracy. From their point of view this action was entirely justified; they >didn't want enemy soldiers to buy a $200 box from Magnavox and get the same >benefits that our own people had. The result, though, is that something that >could be of enormous benefit to the American public has been denied to them. ***** ** ** ******** ******* >Civilian needs gave way before military ones. John, At least they're making a lower accuracy available to the public. That is revolutionarily open-minded for the military to begin with. KAL-007 could have benefited from the civilian-grade NAVSTAR receiver (assuming they weren't there intentionally...). I don't think a $200 receiver tied to a $1000 computer which translates Lat-Lon into street addresses qualifies as "enormous benefit". Could you explain to me why the American Public needs military accuracy? I wouldn't use 10m [your figure] GPS for landing an air-craft if I had it. I'm not sure what I'd use that granularity for; it won't tell me which side of the street I'm on, or which way to the nearest foxhole, but is much finer grain than I need to know which way is Cambridge, and which sector of the map I'm on. (If the map has features smaller than 10m, I'd ***** well better be able to figure out which one I'm on.) In short, I don't see how limiting civilian use of GPS to lower resolution (does anyone have figures for both modes they can publish?) has cut off any potential uses THAT SERIOUSLY AFFECT THE PUBLIC GOOD. I will agree, hypothetically, that to deny all GPS access would have been very dog-in-the-manger, but they compromised. Near as I can tell, we don't even HEAR about the technologies they're really depriving us of. -- William Ricker wdr@faron.UUCP (UUCP) decvax!genrad!linus!faron!wdr (UUCP) {allegra,ihnp4,utzoo,philabs,uw-beaver}!linus!faron!wdr (UUCP) Opinions are my own and not necessarily anyone elses. Likewise the "facts".
karn@petrus.UUCP (04/05/85)
Regarding GPS, I read recently that a clever new civilian use has been found that can give centimeter accuracy to surveying measurements. The scheme does Very Long Baseline Interferometry (VLBI) using the GPS satellites. The receivers treat the satellites as simply more powerful noise sources than the galactic sources normally used for VLBI, and therefore don't need to know the actual code sequences. The major limitations to accuracy under this scheme is atmospheric refraction, and uncertainty in the precise orbits of the satellites. Phil