al@aurora.UUCP (Al Globus) (09/03/85)
The U.S. proposes to test its new ASAT on an existing satellite in the near future. This satellite is, presumably, in low Earth orbit. Destruction of the satellite will undoubtedly create a great deal of debris in orbits close to the original orbit. Does anyone have a good idea of how much danger this will create for Shuttle, Space Station, the Space Industries Inc. facility, and Salyut? Should an environmental impact report be required to insure that DOD has carefully considered the problems that this test might create for peaceful users of near Earth space? Note that most of the debris currently in low Earth orbit was created by US boosters whose residual fuel ate through the internal tanks, combined, and exploded; and ***Soviet ASAT tests***. Lastly, might the national interest be better served by negotiating and monitoring a ban on all ASAT tests and, simultaneously, launching very large numbers of spy satellites to dilute the tactical advantage of the Soviet ASAT to negligable levels? The Soviets claim they are prepared to end ASAT tests if the US will follow suit.
karn@petrus.UUCP (Phil R. Karn) (09/09/85)
> > Lastly, might the national interest be better served by negotiating and > monitoring a ban on all ASAT tests and, simultaneously, launching very > large numbers of spy satellites to dilute the tactical advantage of the > Soviet ASAT to negligable levels? The Soviets claim they are prepared > to end ASAT tests if the US will follow suit. Yes, yes, YES!!! Reagan's decision to go ahead with ASAT testing has got to be one of the (if not THE) stupidest move of his career (and that honor has a lot of competition). We have nothing to gain (except a little "macho" from being able to brag that we leapfrogged the Russkies) and everything to lose from disturbing the present situation. See the Scientific American article on ASATs in the June 1984 issue for an excellent case for what you suggest. I am also very concerned about the debris issue, aside from the political and strategic aspects. The media has been referring to the test target as a "communications satellite", which implies a geostationary orbit. I can't think of a worse orbit to pollute with crap from an ASAT test than GEO, although it isn't certain that the satellite in question is really up there (the range of the American ASAT is apparently classified). Any test on an object in orbit (as opposed to a "point" in space or a suborbital target such as the Homing Overlay test) is bound to create an enormous amount of debris in relatively long-lived orbits. I pray that sooner or later there will have to be a treaty banning the testing of space weapons for the same reason that it became necessary to ban atmospheric testing of nuclear weapons. Phil
al@aurora.UUCP (Al Globus) (09/13/85)
> I am also very concerned about the debris issue, aside from the political > and strategic aspects. The media has been referring to the test target as > a "communications satellite", which implies a geostationary orbit. The target is in low Earth orbit.
karn@petrus.UUCP (Phil R. Karn) (09/14/85)
The press has been saying that the target for the ASAT test will be a satellite called SOLWIND. From the name I assume it's a defunct scientific satellite whose function was to monitor the solar wind. The August 31, 1984 NASA Satellite Situation Report lists SOLWIND as International Designator 1979-017A, catalog number 11278, launched 24 Feb 1979. At the time of the report (3 years ago) it was in a 524x553 km 97.6 deg inclination orbit (probably sun synchronous). My fears of long-lived debris are somewhat alleviated, since lifetime at this altitude is not very long. In fact, I would expect the debris from SOLWIND to re-enter sooner than the undamaged satellite would, since smaller particles have a higher area-to-volume ratio. I still think the test itself is an incredibly stupid political blunder. Phil "...but if you threaten to extend your violence, this earth of yours will be reduced to a burned-out cinder." --Klaatu
ashby@uiucdcsp.CS.UIUC.EDU (09/25/85)
Once again we hear from the spaceniks who bemoan our ASAT tests. They cry, "Oh, look at the Soviets, they have offered to stop all testing if only we would do the same." Well, of course they have made this offer, and so would we if we were in their shoes. What everyone seems to conveniently ignore is the fact that the Soviets already HAVE a working ASAT. "But it is crude," the voices will cry. Yes it is, but it is effective. Its relative crudeness is also the reason they want our program stopped. They see the F15 program as a cheap and highly efficient deterrent. If they can stop it with a propaganda tirade they win big. Where were all these voices of denunciation when the USSR had their tests? Once our tests are complete, then we can talk test ban - but not before. As far as the debris issue is concerned, why not condemn the Soviets for their use of nuclear power plants in their spacecraft. Talk about hot debris.
kotter@muscat.UUCP (Rich Kotter) (09/28/85)
> > Once again we hear from the spaceniks who bemoan our ASAT tests. > They cry, "Oh, look at the Soviets, they have offered to stop > all testing if only we would do the same." Well, of course they > have made this offer, and so would we if we were in their shoes. > What everyone seems to conveniently ignore is the fact that the > Soviets already HAVE a working ASAT. "But it is crude," the voices > will cry. Yes it is, but it is effective. Its relative crudeness > is also the reason they want our program stopped. They see the > F15 program as a cheap and highly efficient deterrent. If they > can stop it with a propaganda tirade they win big. Where were all > these voices of denunciation when the USSR had their tests? Once > our tests are complete, then we can talk test ban - but not before. > > As far as the debris issue is concerned, why not condemn the Soviets > for their use of nuclear power plants in their spacecraft. Talk about > hot debris. RIGHT ON! -- Rich Kotter decvax!decwrl!muscat!kotter
al@ames.UUCP (Al Globus) (10/01/85)
> > Once again we hear from the spaceniks who bemoan our ASAT tests. > They cry, "Oh, look at the Soviets, they have offered to stop > all testing if only we would do the same." Well, of course they > have made this offer, and so would we if we were in their shoes. > What everyone seems to conveniently ignore is the fact that the > Soviets already HAVE a working ASAT. Our ASAT will not stop theirs. Flying lots of spy satellites will effectively nullify its effect though. > Where were all > these voices of denunciation when the USSR had their tests? Once > our tests are complete, then we can talk test ban - but not before. The net did not exist at that time and I was more concerned with Rock and Roll than spacecraft. However, Soviet ASAT tests are responsible for a large portion of current space debre and I'm not happy about that at all. > > As far as the debris issue is concerned, why not condemn the Soviets > for their use of nuclear power plants in their spacecraft. Talk about > hot debris. Consider them condemed. If it makes you happy, I recently wrote Gorbachev (he's not on the net) and complained about a few things in true net fashion.
julian@osu-eddie.UUCP (Julian Gomez) (10/02/85)
> > ... > > As far as the debris issue is concerned, why not condemn the Soviets > > for their use of nuclear power plants in their spacecraft. Talk about > > hot debris. > > RIGHT ON! Another case of OK for us, not OK for them? The USA uses nuclear power plants. Take a look at the Voyager and Pioneer spacecraft. But those are deep space vehicles! you say? Until they get into deep space they can still fall. That's even more of a problem in these days of shuttle launch rather than booster launch. -- "If Chaos himself sat umpire, what better could he do?" Julian "a tribble took it" Gomez Computer Graphics Research Group, The Ohio State University {ucbvax,decvax}!cbosg!osu-eddie!julian
karn@petrus.UUCP (Phil R. Karn) (10/03/85)
> Another case of OK for us, not OK for them? The USA uses nuclear power > plants. Take a look at the Voyager and Pioneer spacecraft. But those > are deep space vehicles! you say? Until they get into deep space they > can still fall. That's even more of a problem in these days of shuttle > launch rather than booster launch. Very true. The US has flown plenty of plutonium-239-fueled thermisotope generators, since they are the only practical power sources for deep space probes like Pioneer and Voyager (not enough sunlight) or probes designed to operate continuously on the surfaces of other planets (Apollo ALSEP, Viking). However, to date we have actually flown only one nuclear reactor in orbit. I believe this was on a Transit navigational satellite in the middle 60's. The American space program has had its nuclear mishaps too. Remember Apollo 13? There is a few kg of plutonium sitting on the bottom of the Pacific Ocean somewhere if you want to get it. It was the fuel source for the ALSEP package which came back when the lunar module "lifeboat" burned up during re-entry. The real difference, however, between the American and Soviet uses of nuclear power in space is not just that the Soviets fly many more of them than we do. It's that they're incredibly irresponsible in their designs. Their nuclear-powered ocean survellance radar satellites operate in very low earth orbits. When such a satellite wears out, normal procedure is to boost it up to a long-lived orbit; however, if that move fails it is bound to re-enter within a few weeks or months, and that's exactly what happened with Cosmos 954 and 1402. This is much worse than having a launch failure for two reasons: 1. "Unburnt" plutonium or uranium is only weakly radioactive, and its alpha emissions are easily shielded (the Apollo astronauts handled the plutonium sources for ALSEP with their gloved hands). However, a reactor that has been running for a while becomes extremely hot because of accumulated fission products. 2. Re-entry could occur almost anywhere, instead of over the ocean or Siberia as would be the case with most launch failures. I wonder if the Americans have considered this point. It was mentioned in the Scientific American article that these ocean surveillance satellites are the ones that the Pentagon worries about the most. It just occurred to me that shooting one of these down with our ASAT would guarantee that its radioactive remains re-enter the atmosphere within a pretty short time. A real game of Russian Roulette. Phil
henry@utzoo.UUCP (Henry Spencer) (10/03/85)
> ... The USA uses nuclear power > plants. Take a look at the Voyager and Pioneer spacecraft. But those > are deep space vehicles! you say? Until they get into deep space they > can still fall. That's even more of a problem in these days of shuttle > launch rather than booster launch. We're talking about two very different kinds of nuclear power source here. The Soviet radar satellites use nuclear reactors, and rely on being boosted into high orbit to avoid destructive re-entry and radioactive debris. The US probes use the heat from encapsulated radioactive isotopes. The capsules of isotope are designed to survive re-entry without breaking up; several of them have re-entered without grave effects. The two technologies have very different characteristics and have to be dealt with separately. Note that even the Soviet reactors have no serious launch-safety problem, because the reactor doesn't fire up until it reaches orbit. The materials that are in the reactor to start with are not seriously dangerous; the nasty stuff is the result of lengthy reactor operation. -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry
henry@utzoo.UUCP (Henry Spencer) (10/03/85)
> [...supposed dangers of launch accidents with nuclear-powered satellites...] > ... That's even more of a problem in these days of shuttle > launch rather than booster launch. How so? The shuttle is expected to land safely after most kinds of launch failures, which is a major improvement on going into the ocean in pieces. -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry
wdm@ecn-pc.UUCP (William D Michael) (10/04/85)
In article <634@osu-eddie.UUCP> julian@osu-eddie.UUCP (Julian Gomez) writes: > > > > ... > > > As far as the debris issue is concerned, why not condemn the Soviets > > > for their use of nuclear power plants in their spacecraft. Talk about > > > hot debris. >Another case of OK for us, not OK for them? The USA uses nuclear power >plants. Take a look at the Voyager and Pioneer spacecraft. But those >are deep space vehicles! you say? Until they get into deep space they >can still fall. That's even more of a problem in these days of shuttle >launch rather than booster launch. Do you really not see the difference between a spacecraft that is intended for permanent earth orbit and one that simply needs to be spun up to reach escape velocity? Of course it is true that while one of the deep-space probes is in orbit it could fail. A booster can also fail on the ground endangering thousands, it is all a question of risk. Putting hot space- craft in permanent (or not so permanent, if you ask the Canadians) orbit is a huge risk compared to the American policy of just using that kind of power in deep-space probes.
henry@utzoo.UUCP (Henry Spencer) (10/04/85)
> The US has flown plenty of plutonium-239-fueled thermisotope generators... Fussy but important point: the isotope generators use plutonium 238, not 239. 238 is much harder to make, but is a fairly pure alpha emitter with a relatively short half-life (years), which is exactly what is needed for isotope power. 239, the fissionable isotope, has too long a half-life and too mixed a radiation output to be useful for this. > ...to date we have actually flown only one nuclear reactor > in orbit. I believe this was on a Transit navigational satellite in the > middle 60's. It was SNAP-10A in the mid-60s, which was explicitly a reactor test with no other mission. For obvious reasons, it's in a fairly high orbit. Some of the Transit satellites used isotope capsules, since solar cells are too vulnerable to attack for the military's liking. > 1. "Unburnt" plutonium or uranium is only weakly radioactive, and its alpha > emissions are easily shielded (the Apollo astronauts handled the plutonium > sources for ALSEP with their gloved hands). However, a reactor that has been > running for a while becomes extremely hot because of accumulated fission > products. Uranium or plutonium-239 can be handled with bare hands, if you aren't worried about toxicity. If you check, I believe you'll find that the Apollo crews used tongs for handling the plutonium-238 capsules, because they are *thermally* very hot -- sort of obvious given that they are used in thermal generators. > ... shooting one of these [Soviet ocean-surveillance satellites] down > with our ASAT would guarantee that its radioactive remains re-enter the > atmosphere within a pretty short time... A good point. One wonders why this has not been brought up before. -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry
karn@petrus.UUCP (Phil R. Karn) (10/07/85)
> Fussy but important point: the isotope generators use plutonium 238, not > 239. 238 is much harder to make, but is a fairly pure alpha emitter with a > relatively short half-life (years), which is exactly what is needed for > isotope power. 239, the fissionable isotope, has too long a half-life and > too mixed a radiation output to be useful for this. You are correct, I should have checked my references first. Pu-238 has a half life of 86 years, while Pu-239 has a half life of 24,400 years. Both decay by spontaneous fission or alpha emission, so Pu-238 will therefore put out a lot more heat per unit mass than Pu-239. However, I believe that all reasonably stable isotopes of plutonium are fissionable, and this is why the nonproliferation people are so concerned about it -- you can't "denature" it with a non-fissionable isotope like you can with U-235 and U-238. > Uranium or plutonium-239 can be handled with bare hands, if you aren't > worried about toxicity. If you check, I believe you'll find that the > Apollo crews used tongs for handling the plutonium-238 capsules, because > they are *thermally* very hot -- sort of obvious given that they are used > in thermal generators. There's a comment in my reference (History of Manned Space Flight) that Pete Conrad had considerable trouble getting the plutonium source out of its container on Apollo 12. It took him 10 minutes to free it, during which time his gloves protected his hands. > > ... shooting one of these [Soviet ocean-surveillance satellites] down > > with our ASAT would guarantee that its radioactive remains re-enter the > > atmosphere within a pretty short time... > > A good point. One wonders why this has not been brought up before. Probably because shooting down a Soviet satellite would be an act of war, and we'd have more serious consequences to worry about. Phil
lwall@sdcrdcf.UUCP (Larry Wall) (10/09/85)
In article <6024@utzoo.UUCP> henry@utzoo.UUCP (Henry Spencer) quotes: >> ... shooting one of these [Soviet ocean-surveillance satellites] down >> with our ASAT would guarantee that its radioactive remains re-enter the >> atmosphere within a pretty short time... > >A good point. One wonders why this has not been brought up before. [I suppose you also wonder why the sea is boiling hot...] In any conceivable situation in which we would be shooting down Soviet satellites, a few stray reactors would be the LEAST of our worries. Larry Wall {allegra,burdvax,cbosgd,hplabs,ihnp4,sdcsvax}!sdcrdcf!lwall P.S. I'd rather see a pig with wings, than the sea boiling hot... Did someone say those were OCEAN-surveillance satellites? oh oh
al@ames.UUCP (Al Globus) (10/16/85)
> > > > As far as the debris issue is concerned, why not condemn the Soviets > > for their use of nuclear power plants in their spacecraft. Talk about > > hot debris. > One of the two primary sources of space debris is fragments left over from Soviet ASAT tests. The other is US boosters that used to explode. Note that the recent ASAT test destroyed a satellite in a 320 nautical mile polar orbit - almost exactly the altitude of our future space station and above most shuttle orbits. That means that the shuttle will be dodging our ASAT's debris. Also note that both the shuttle and salyut have been struck by debris, although it is not known if the debris was man made or natural.