Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from beak.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Fri, 2 Mar 90 02:10:56 -0500 (EST) Message-ID: <4ZvVlbe00VcJA4pU4z@andrew.cmu.edu> Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Fri, 2 Mar 90 02:10:32 -0500 (EST) Subject: SPACE Digest V11 #99 SPACE Digest Volume 11 : Issue 99 Today's Topics: Funding is not the Problem (was: Re: Fun Space Fact #1: Launcher Development Costs) Re: LDEF - Protection from atmosphere? Re: What happened to Pegasus? SLC-6 Re: Voyager Update - 02/23/90 Re: Experimentation Pegasus Update - 02/26/90 Re: Geosync DSN (was Re: Cheap DSN?) Any news on a new comet? Re: Spacecraft drives and fuel efficiency Re: Did SEASAT See More Than It Was Supposed To? Re: Beanpole ---------------------------------------------------------------------- Date: 28 Feb 90 06:36:59 GMT From: agate!usenet@ucbvax.Berkeley.EDU (William Baxter) Subject: Funding is not the Problem (was: Re: Fun Space Fact #1: Launcher Development Costs) In article <9002222000.AA09567@ti.com>, mccall@skvax1 writes: >>> is "agate!usenet@ucbvax.Berkely.EDU (William Baxter)" >Yes, and if one really looks one can also find things about what >NASA originally wanted to build, which has been mentioned by both >Henry Spencer and myself. Why do you suppose that that original >system wasn't built, Mr. Baxter? Because NASA is a bunch of evil >people who just want to rip off the American taxpayer? Hardly seems >credible, to me. Development contracts are much more lucrative than research contracts. There is strong pressure for bureaucracies like NASA or DoD and their contractors to push into development prematurely, rather than doing the necessary research. The shuttle is a perfect example of just this tendency. One original goal for the STS was a $100/lb cost to LEO. The shuttle is a spectacular failure in this respect. The NASA officials who made these wildly optimistic claims of launch cost did not have any basis for them other than their 'expertise.' Looking back, it is clear that they didn't know how much it was going to cost. The current NASA budget is $12,323 million. That's plenty of money to run a government space program. It may not be enough to run THE space program, but it shouldn't have to be. A more fundamental problem is the lack of policy. There is almost total confusion between 'research' and 'development.' There is also no clear definition of the appropriate roles of government and private industry. I think that government should support basic research and keep out of development, leaving the risks and rewards of development to commercial industry which is much better suited to it. >It will also not be solved by just 'bashing' them for it. If you >want to do something to correct it, start at the top where such >attitudes are engendered, and that means starting with the Congress >and the way the budgetary process is run (or not run) from the top. That is why I am working with my congressman to pass HR2674, and to terminate development boondoggles like Space Station, ALS and NASP in favor of basic research projects. William Baxter ARPA: web@{garnet,brahms,math}.Berkeley.EDU UUCP: {sun,dual,decwrl,decvax,hplabs,...}!ucbvax!garnet!web P.S. Is this a sentence? --> As is, it would >appear, assuming that any disagreement with their opinions >automatically means that the person disagreeing must have whatever >their particular generalized stereotype for the attitudes of 'the >enemy' is. ------------------------------ Date: 28 Feb 90 17:19:55 GMT From: usc!cs.utexas.edu!jarvis.csri.toronto.edu!utgpu!utzoo!henry@ucsd.edu (Henry Spencer) Subject: Re: LDEF - Protection from atmosphere? In article wmartin@stl-06sima.army.mil (Will Martin) writes: >... I would have thought that the LDEF is being so contaminated >by exposure to Earth's atmosphere that a lot of the information that could >have been obtained from it has been lost... It would have been nice to keep it in vacuum, but the fact is, it's very difficult. The most fundamental problem is simply that the shuttle cargo bay can't do that. There are a host of subsidiary problems with handling and so forth. Exposing it to air is less than ideal but would be very hard to avoid. That's one of the reasons why the crew spent several hours photographing it in space before reeling it in. >By the way, during the retrieval, at least several of the thin-film panels >were fluttering, as if in a breeze. What was causing that? Thruster exhaust >from the shuttle? If so, didn't THAT contaminate and ruin some of the test >panels? I haven't seen footage of the retrieval, but the obvious possible causes are shuttle thrusters and movement of LDEF itself. Yes, thruster exhaust is a concern, to the point that some designs for future spacecraft have included a second low-contamination thruster system for maneuvering close to space stations etc. Again, I think it's a nuisance but hard to avoid with current equipment. -- "The N in NFS stands for Not, | Henry Spencer at U of Toronto Zoology or Need, or perhaps Nightmare"| uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 26 Feb 90 18:27:58 GMT From: cs.utexas.edu!hellgate.utah.edu!uplherc!esunix!bambam!bpendlet@tut.cis.ohio-state.edu (Bob Pendleton) Subject: Re: What happened to Pegasus? From article <86.25e66ece@ubvms.cc.buffalo.edu>, by v071pzp4@ubvms.cc.buffalo.edu: > Does anyone know what's been going on with the Pegasus launcher > by Orbital Sciences Corp. lately? Were'nt they supposed to launch > soon? Please, don't forget that Hercules has a big part in Pegasus. I've heard a rumor that electrical problems were discovered during captive carry tests. It can't fly until those are fixed. OSC did the electronics. There was also a problem with insulation blowing off of the wing. On the other hand, OSC/Hercules has signed up a couple of more customers. Bob P. -- Bob Pendleton, speaking only for myself. UUCP Address: decwrl!esunix!bpendlet or utah-cs!esunix!bpendlet X: Tools, not rules. ------------------------------ Date: Thu, 1 Mar 90 13:14:23 PST From: Peter Scott Subject: SLC-6 X-Vms-Mail-To: EXOS%"space@andrew.cmu.edu" Has anyone heard of any plans for de-mothballing the Shuttle Launch Complex at Vandenburg? BTW, what happened to SLC-1 thru -5? Peter Scott (pjs@grouch.jpl.nasa.gov) ------------------------------ Date: 28 Feb 90 21:10:12 GMT From: psivax!torkil@uunet.uu.net (Torkil Hammer) Subject: Re: Voyager Update - 02/23/90 In article <2919@jato.Jpl.Nasa.Gov> baalke@mars.jpl.nasa.gov (Ron Baalke) writes: # On February 14, an RFSCMD (threshold) test was executed by the DSN station #in Goldstone, California. Due to procedural errors during the test, the test #was not completely successful. Procedural changes will be made before the next Is this the same as an (inadvertent) RTFM test? :-) ------------------------------ Date: 28 Feb 90 16:30:48 GMT From: cs.utexas.edu!jarvis.csri.toronto.edu!utgpu!utzoo!henry@tut.cis.ohio-state.edu (Henry Spencer) Subject: Re: Experimentation In article <20704@cfctech.cfc.com> joel@cfctech.cfc.com (Joel Lessenberry) writes: > I understand that these days the world would rather simulate > than experiment, but... has anyone even worked in planning > simple missions to actually demonstrate new propulsion > technologies? Surely this type of experimentation could be > done by *someone* without the 20 year, multi billion dollar > design cycles which are so prevalent. It could be done, yes, and there have been various proposals to do it, e.g. the Lunar Getaway Special proposal which would (finally!) space-test ion propulsion. The problem is that nobody is funding such things. NASA basically gave up on advanced technology work in the post-Apollo crunch. They've been talking about getting back into it in a serious way, but so far it's been mostly talk. -- "The N in NFS stands for Not, | Henry Spencer at U of Toronto Zoology or Need, or perhaps Nightmare"| uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 27 Feb 90 01:43:07 GMT From: elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@cs.ucla.edu (Ron Baalke) Subject: Pegasus Update - 02/26/90 Pegagus Update February 26, 1990 The launch of the Pegasus satellite (Pegsat) is now scheduled for March 13, according to project officials. The satellite will be carried aloft by a NASA B-52, from which it will be launched at 40,000 feet altitude about 50 miles west of Vandenberg Air Force Base, CA. Project Manager Bob Pincus and other members of the project are in California this week readying the 422-pound satellite for the flight. Yesterday, they conducted a simulated flight. Today and tomorrow, they will conduct spacecraft checks. Thursday, they will install the thermal blankets, and on Friday they will load the unarmed chemical canisters. The three-function payload, developed at Goddard, will carry instrumentation to measure variations in launch vehicle and spacecraft attitude, temperature, pressure, structural loading and vibrations. It also will dispense a small, experimental communications satellite for the Navy. Once those two operations are complete, NASA will use Pegsat to conduct two barium chemical releases. The discharges will be made between March 15 and March 30 over central Canada. Ron Baalke | baalke@mars.jpl.nasa.gov Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov 4800 Oak Grove Dr. | Pasadena, CA 91109 | ------------------------------ Date: 1 Mar 90 06:00:31 GMT From: sco!natei@uunet.uu.net (Nathaniel Ingersoll) Subject: Re: Geosync DSN (was Re: Cheap DSN?) In article <2937@jato.Jpl.Nasa.Gov> baalke@mars.UUCP (Ron Baalke) writes: :BIG guidable antenna arrays are not feasible for earth orbit. A 70 meter :antenna on the earth weighs 8 million pounds. The cost of placing such :an antenna into orbit would be astronomcal. And this is before the antenna The antenna on Earth weighs 8 million pounds because earch has a lot of gravity that the antenna has to avoid folding due to. I'm sure you could build a much lighter antenna if you don't have to worry about supporting it. : : Ron Baalke | baalke@mars.jpl.nasa.gov -- ________________________________________________________________________________ I told the police that I was not injured, but on removing my hat, I found that I had a skull fracture. -- from an insurance accident form ------------------------------ Date: 27 Feb 90 13:36:58 GMT From: usna!nardi@uunet.uu.net (LT Peter A. Nardi) Subject: Any news on a new comet? Sender: Reply-To: nardi@cad.usna.mil.UUCP (Peter A. Nardi (CompSci) ) Followup-To: Distribution: Organization: U.S. Naval Academy, Annapolis Keywords: comet I read in a recent newspaper article that there is a new comet approaching the Sun. It's called Comet Austin, and was discovered by an amatuer astronomer in Australia (I think). The article said if the comet tracks as predicted that it could prove to be a pretty spectacular event. (Around magnitude zero in the early morning hours near the end of April.) The article was quick to point out that comets as a rule are VERY fickle and it's too soon to tell exactly what it will do. Has anyone else heard anything about this? -==- pete nardi nardi@cad.usna.mil ------------------------------ Date: 28 Feb 90 07:29:02 GMT From: unisoft!hoptoad!tim@ucbvax.Berkeley.EDU (Tim Maroney) Subject: Re: Spacecraft drives and fuel efficiency In article <589@intelisc.nosun.UUCP> snidely@intelisc.UUCP (David Schneider) writes: >>...an academic advisor (back when I was a physicist-to-be) showing me >>his back-of-the-envelope calculations that showed an matter-anitmatter >>reaction for 1G acceleration (producing gamma rays as a matter of efficiency) >>would fry the departure site... Unless there is no "departure site". An antimatter spacecraft would probably be built in orbit or on the moon, but even if not there's no good reason to run the drive in the atmosphere. It can be lifted into space by "conventional" means, and it would probably use chemical propellants to take it a good distance from the Earth before firing up. I think the antimatter should be produced in lunar factories and should never enter the atmosphere regardless. It's just too dangerous to the ecosystem, and the containment is intrinsically iffy. But the basic craft could be built on the Earth if that was cheaper. In article <1990Feb22.042223.26948@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >It all ends up as gamma rays (or stray >electrons and positrons) eventually, but you want that happening as far >away as possible, a kilometer or so back in the exhaust jet when the muons >decay. There *are* a lot of gamma rays even so, enough to be a problem. Yeah, and it's a little tricky to outrun them... :-) >You may not have noticed :-), but all existing space propulsion systems >fry the immediate vicinity when they take off... Hmm. How much antimatter would you have to annihilate to escape the gravity well? Micrograms per launch? I tend to think it would "fry" the immediate vicinity a little worse than extreme heat does. Wouldn't there be a good deal of residual radiation, especially after multiple launches of large craft? Current launch pads are reusable pretty quickly, and the atmospheric pollution is insignificant. -- Tim Maroney, Mac Software Consultant, sun!hoptoad!tim, tim@toad.com "Starting in a hollowed log of wood -- some thousand miles up a river, with an infinitesimal prospect of returning! I ask myself 'Why?' and the only echo is 'damned fool! ... the Devil drives!" -- Sir Richard Francis Burton in correspondence to Monckton Miles, 1863 ------------------------------ Date: 26 Feb 90 17:17:43 GMT From: mcsun!ukc!icdoc!syma!nickw@uunet.uu.net (Nick Watkins) Subject: Re: Did SEASAT See More Than It Was Supposed To? In article <1990Feb23.175643.13944@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In article <2235@syma.sussex.ac.uk> nickw@syma.susx.ac.uk (Nick Watkins) writes: >as implausible that it could stay secret for over a decade, especially >since I don't think DoD has any "prerogative" over civilian research >satellites. Jonathan McDowell has pointed out to me that the DoD sponsored the Geosat ERM (exact repeat mission) which repeated some of the measurements, so the "murder" theory seems pretty unlikely. Nick -- Nick Watkins, Space & Plasma Physics Group, School of Mathematical & Physical Sciences, Univ. of Sussex, Brighton, E.Sussex, BN1 9QH, ENGLAND JANET: nickw@syma.sussex.ac.uk BITNET: nickw%syma.sussex.ac.uk@uk.ac ------------------------------ Date: 28 Feb 90 07:26:04 GMT From: mailrus!b-tech!kitenet!russ@tut.cis.ohio-state.edu (Russ Cage) Subject: Re: Beanpole In article <17426@boulder.Colorado.EDU> johnsonr@spot.colorado.edu (Richard Johnson) writes: >> An interesting idea I heard about but have no references for. >>A sat is placed in LEO with a long, conducting tether extending upwards >>from it. A current is run through the tether, the Earth's magnetic >>field interacts with it, and the sat raised into a higher orbit. >>Cheap and efficient, but very slow. > >That idea showed up as a plot device in a SF story in Analog a few years >back. I think the author picked it up from a Space Studies Institute report >on Space Shuttle External Tanks, which probably picked it up from somewhere >else. The story is "Tank Farm Dynamo", by David Brin. It also appears in the collection "The River of Time". I recommend it. The idea of an electrodynamic tether (using a tide-locked conductor as the armature of a homopolar motor, with the earth providing the stator field and the near-earth plasma the return path) is about 15 years old. I own (but do not have handy, it's on loan) the proceedings of the 1986 conference on tethers in space, which has lots of neat details of the research done so far. In short, it appears that tethers system can provide: 1.) Energy storage (motor/generator much more powerful than batteries) 2.) Orbital reboost (byproduct of energy storage operation) 3.) Emergency power generation (tap orbital motion for power) 4.) Momentum/energy loans or transfers (not an electrodynamic effect) all of which can be very useful to a space station or LEO habitat, or the experiments done from one. For example, dropping a Shuttle orbiter on a tether from a space station raises the orbit of the station, giving it angular momentum and energy. This can extend the interval between reboosts, provide energy to be tapped with the tether-generator, allow satellites to be launched to higher orbits via tether without dropping too far, etc. etc. -- I am paid to write all of RSI's opinions. Want me to write some for you? (313) 662-4147 Forewarned is half an octopus. Russ Cage, Robust Software Inc. russ@m-net.ann-arbor.mi.us ------------------------------ End of SPACE Digest V11 #99 *******************