hamish@waikato.ac.nz (10/12/90)
Just a quick question. What ever happened to the ion rocket research programs? I have a book that details 2 flights of ion powered engines, abord satellites, one of which couldn't be started, and the other that provided 5 MONTHS of continuous thrust at about an ounce. (several grammes). It was said that an electrical fault was to blame. Anybody got any data on the amount of velocity picked up by this little thing? After that it is said that the ion rocket research was dropped. Why? It's a cheap way (especially in payload) to get a fast engine into space. They may not have much thrust but after a year you could really get a bit of speed into a deep space probe. I have faith that if the research was continued that the amount of thrust generated would be much higher as well as the reliability. After all it was about 25 years ago. -- ============================================================================== | Hamish Marson | Internet hamish@waikato.ac.nz | | Computer Support Person | Phone (071)562889 xt 8181 | | Computer Science Department | Amiga 3000 for ME! | | University of Waikato | | ============================================================================== |Disclaimer: Anything said in this message is the personal opinion of the | | finger hitting the keyboard & doesn't represent my employers | | opinion in any way. (ie we probably don't agree) | ==============================================================================
henry@zoo.toronto.edu (Henry Spencer) (10/12/90)
In article <1952.2715c044@waikato.ac.nz> hamish@waikato.ac.nz writes: >... What ever happened to the ion rocket research programs? The post-Apollo budget cuts essentially killed all NASA propulsion research not directly related to the Shuttle, i.e. *all* advanced propulsion work. Little bits of ground-based work have been done since, but that's all. If you want a small ion thruster, e.g. for comsat station-keeping, you can buy one commercially from Japan. -- "...the i860 is a wonderful source | Henry Spencer at U of Toronto Zoology of thesis topics." --Preston Briggs | henry@zoo.toronto.edu utzoo!henry
spgreg@earth.lerc.nasa.gov (Greg Macrae) (10/16/90)
In article <1952.2715c044@waikato.ac.nz>, hamish@waikato.ac.nz writes... > >Just a quick question. What ever happened to the ion rocket research programs? Ion engine research continued to recieve funding at a low level in the US. Much progress has been made since the SERT and SERT II flights your book was refering to. (SERT II by the way is still operational as a satellite, but it is out of fuel, so the ion thrusters cannot be used.) Research also continues in Germany, Great Britain, and Japan. All three of those countries have plans to fly ion thrusters. The only near term US flights of electric propulsion systems currently plan to use arcjets, not ion thrusters. The worlds only flight qualified thrusters are available from Hughes. The Japanese thrusters are still in the engineering model stage of development. For more information on the SERT projects, look for a book by Kerslake and Mirtich to be published soon. >After that it is said that the ion rocket research was dropped. Why? It's a >cheap way (especially in payload) to get a fast engine into space. True, studies with real payloads suggest that it may even be possible to reduce the launch vehicle class by using ion engines. >I have faith that if the research was continued that the amount of thrust >generated would be much higher as well as the reliability. After all it was >about 25 years ago. Thrusts are up to the newton range (about 1/4 pound). The fuel has been changed from mercury to xenon or krypton. Projected lifetimes are greater than 5000 hours. (Greater than 10,000 hours life was demonstrated with a mercury system in 1977.) -------------------------------------------------------------------- MacRae | Too curious flower NASA LeRC | Watching us pass, met death... spgreg@csd.lerc.nasa.gov | Our hungry donkey. | -Basho --------------------------------------------------------------------
rnm8s@hagar3.acc.Virginia.EDU (Rory Mcleod) (03/25/91)
In article <1991Mar22.043009.5544@zoo.toronto.edu>, henry@zoo.toronto.edu (Henry Spencer) writes: |> |> What I'm looking for ON a solid rocket motor is dust, plus a museum placard |> saying "obsolete form of space propulsion system, abandoned in the early |> 1970s when ion rockets became practical". We've known for twenty years how |> to build rocket systems that perform far better than any solid rocket |> motor ever will. Ion engines cannot be used to launch payloads into space. A JPL/Hughs designed 30-cm diam HG bombardment thruster has a maximum thrust of 0.370 Newtons. The mass of this same engine is almost 250 kg. It can not even lift its own weight (on the Earth). Ion engines can only be used on spacecraft already in orbit. Typical uses would be for station keeping and unmanned interplanetary transfers. ( this last use may be to what H. Spencer was alluding ) An ion engine was successfully used on the NASA satellite SERT-2. The NASA-Lewis team shut down the engine on Apr 19, 1981, 11 years, 74 days after the satellite was launched. For more information read the Christian Science Monitor, Fri May 7, 1981. I haven't kept up with the technology, so there could well be ion engine equiped spacecraft in orbit today, though I doubt it, even though basic working designs are readily available, like most space systems, NASA or DoD will have to push to get it going before U.S. industry will even take a look at it. And without a real need (read: special interest) Congress won't fund it. ( If pro is the opposite of con, then what is the opposite of Congress? ) For the time being, and many years hence, chemical rockets - liquid, solid, and (hopefully) hybrid - will be the only method of escaping Earth orbit. Technologies to replace chemical rockets for getting stuff into orbit will not be perfected until after the turn of the century. The most promising are the airbreathing ramjet/scramjet engines being developed for the NASP, and perhaps laser propulsion. I know of no major project, though there may very well be one, for the development of laser propulsion. Mass drivers, which have been discussed at length on sci.space (where this probably belongs), are best for transporting materials from airless bodies, like the moon. Rory McLeod Dept of Mechanical & Aerospace Engineering University of Virginia
henry@zoo.toronto.edu (Henry Spencer) (03/26/91)
In article <1991Mar24.191051@hagar3.acc.Virginia.EDU> rnm8s@hagar3.acc.Virginia.EDU (Rory Mcleod) writes: >|> What I'm looking for ON a solid rocket motor is dust, plus a museum >placard >|> saying "obsolete form of space propulsion system, abandoned in the >early >|> 1970s when ion rockets became practical"... > > Ion engines cannot be used to launch payloads into space. Is it too much to ask that when you enter in the middle of a discussion, you read the back issues? The subject of this particular discussion was the IUS, which is not an Earth-to-orbit launcher. Furthermore, the more general point still stands. We could easily build Earth-to-orbit launch systems far superior to solid rockets. Even plain old liquid-fuel rockets are better in nearly every way. >... Technologies to replace chemical rockets >for getting stuff into orbit will not be perfected until after the >turn of the century. This I will agree with, but the problem is lack of effort, not inherent difficulty. >The most promising are the airbreathing >ramjet/scramjet engines being developed for the NASP... NASP is a fiercely difficult design problem. It would not be what one would choose as the most promising technology, if the objective was cheaper and better launches to orbit. NASP is doing it the hard way on purpose, aiming at development of hypersonic airbreathing technology rather than at an optimal system for space launches. >and perhaps >laser propulsion. I know of no major project, though there may very >well be one, for the development of laser propulsion... There is a minor project on laser propulsion at LLNL. The technique looks viable, and could progress very quickly if it got even a modest fraction of the money being spent on NASP. >Mass drivers, >which have been discussed at length on sci.space (where this probably >belongs), are best for transporting materials from airless bodies, like >the moon. Almost all non-airbreathing launch systems, including even solid rockets, work better on airless bodies. That doesn't mean they are unworkable for launch from Earth. -- "[Some people] positively *wish* to | Henry Spencer @ U of Toronto Zoology believe ill of the modern world."-R.Peto| henry@zoo.toronto.edu utzoo!henry
garrett@chopin.udel.edu (Joel Garrett) (04/04/91)
I heard mention of something on the news about a new "secret" development as part of the SDI program. The report seemed to indicate some type of heavy- lift launcher that was based upon "nuclear" technology... Does anyone else have more information on this topic? It seems to me that such a launch system would cause more problems than it would solve. Wouldn't the launch of a nuke-based system result in a lot of fallout/radiation? I read an article in Smitshonian Air & Space a while ago that told the story of a project called the Pluto, I believe, which would have been a nuclear- powered ramjet cruise missile. One part of the article kind of half-joked that in wartime, one of these missiles wouldn't have to carry a warhead, it could just loiter over selected parts of enemy territory and deposit plenty of radioactive materials as it went... I'm hoping they aren't thinking of resurrecting this kind of stuff... I thought the whole point behind SDI was to keep us from getting irradiated in a nuclear attack (maybe less radiated is a more realistic objective, but that's another story...) If we have launchers that are going to spread radiation on launch of equipment to stop a nuclear attack, then is this an improvement?
henry@zoo.toronto.edu (Henry Spencer) (04/05/91)
In article <16851@chopin.udel.edu> garrett@chopin.udel.edu (Joel Garrett) writes: >... cause more problems than it would solve. Wouldn't the >launch of a nuke-based system result in a lot of fallout/radiation? The ultimate answer has to be "it depends", but the general answer is no, not really. There would be some release of radioactive material into the air if such an engine were fired within the atmosphere; not a lot, compared to, say, a French or Chinese nuclear test. -- "The stories one hears about putting up | Henry Spencer @ U of Toronto Zoology SunOS 4.1.1 are all true." -D. Harrison| henry@zoo.toronto.edu utzoo!henry
crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) (04/05/91)
In article <16851@chopin.udel.edu> garrett@chopin.udel.edu (Joel Garrett) writes: >the whole point behind SDI was to keep us from getting irradiated in a >nuclear attack (maybe less radiated is a more realistic objective, but that's >another story...) If we have launchers that are going to spread radiation on >launch of equipment to stop a nuclear attack, then is this an improvement? The whole point of SDI is to protect against the explosion of ballistic missile warheads. The fact that radioactive materials are used to create the explosion is nearly a moot point. Many more people would die as the result of blast effects (and heat, fires ...) than would die of radiation sickness. Spreading radioactive substances an incredibly inefficient way of killing people. In any case, the spread of radioactive substances must be weighed against the amount of radioactivity generated. Face it, you spread radioactive substances with each bowel movement. We do not suggest shooting you because of this foul crime because we retain a sense of proportion. It would be nice if every time someone heard 'nuclear' or 'radioactivity', they would try to retain this same sense of proportion. Not holding my breath. dale bass -- C. R. Bass crb7q@virginia.edu Department of Mechanical and Aerospace Engineering University of Virginia Charlottesville, Virginia (804) 924-7926
heskett@titan.tsd.arlut.utexas.edu (Donald Heskett) (04/05/91)
>I heard mention of something on the news about a new "secret" development as >part of the SDI program. The report seemed to indicate some type of heavy- >lift launcher that was based upon "nuclear" technology... It was a cover story in the April 3rd issue of the New York Times, I believe.