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 ; Thu, 7 Jun 1990 01:44:35 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Thu, 7 Jun 1990 01:44:09 -0400 (EDT) Subject: SPACE Digest V11 #498 SPACE Digest Volume 11 : Issue 498 Today's Topics: Re: HAWAII/ROCKET very long - 61k Re: SPACE Digest V11 #495 NASA Headline News for 06/06/90 (Forwarded) Re: Terraforming Venus (was: Manned mission to Venus) Ulysses: Status and opposition to launch Re: Does DoD Want Hawaii? (was: Re: Haw Re: "CCD imagers in HST" from EE Times Ulysses risks II: PuO2 dangers Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription notices, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: 6 Jun 90 15:11:15 GMT From: serre@boulder.colorado.edu (SERRE GLENN) Subject: Re: HAWAII/ROCKET very long - 61k Jay Hanson writes: A Federal Government publication entitled "REDUCING LAUNCH OPERATING COSTS", Sept. 1988, states that the minimum reliability for the Delta rocket is 90%, for the Atlas rocket, it is 81%. This means if the operators of the facility have bad luck, one out every ten Delta rockets and one out of every five Atlas rockets will explode. This number of failures is considered acceptable to those who launch rockets. Correction: The last sentence above is simply NOT true. I am not sure obout Delta or Atlas, but I can only assume that their situation is similar to Titan. The Titan IV contract for payload integration requires a 100% launch success rate in order for Martin Marietta to receive the full award fee. One launch failure reduces payload integration award fees for present, future, and past [not a typo] launches. Anything less than 100% success is clearly not acceptable, from a profit-making perspective. Other comment: Agreed, a realistic enivronmental impact statement is a very good idea, but what else is new? I see no other point to the posting (as regards this newsgroup). --Glenn Serre serre@tramp.colorado.edu ------------------------------ From: AZM@CU.NIH.GOV Date: Wed, 06 Jun 90 13:41:04 EDT Subject: Re: SPACE Digest V11 #495 Re "Plymouth," the proposed new sci-fi TV show. Just what the american idiot box audiences need, another TV show about this country's nonexistent space program. We keep doin' it on TV, and the Soviets, and the Japanese, and the French, and the British, and the Indians, and just about everybody who is anybody, keep DOIN' IT IN SPACE. Like I said a couple of weeks ago, the u.s. doesn't have a space program, it has a program to use large bullets to put smaller but more powerful "bullets" into low Earth orbit. And from the postings apparently the Congress is about to sound the final death knell for the u.s. space program. Marlen AZM@NIHCU ------------------------------ Date: 6 Jun 90 17:23:37 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: NASA Headline News for 06/06/90 (Forwarded) ----------------------------------------------------------------- Wednesday, June 6, 1990 Audio Service: 202/755-1788 ----------------------------------------------------------------- This is NASA Headline News for Wednesday, June 6........ Kennedy Space Center managers are analyzing the test data that revealed leakage in the orbiter Columbia's 17-inch and 4-inch propulsion lines. Technicians concluded a tanking test this morning to isolate the leaks. Liquid hydrogen was flowed through the orbiter and into the external tank. Extra sensors were placed in strategic areas for the test. Launch of STS-35 has been put on hold until the leak can be corrected. A news conference is planned tomorrow to announce a proposed launch date. ******** Although visual inspection has shown no obvious damage, there remains some concern for hidden damage to the orbiter Discovery's payload bay door. An accident caused one edge of the 60-foot long door panels to be flexed out of shape for a short time. A review board will focus on possible damage to the door latches. ******** Meanwhile, preparations are underway to roll the Space Shuttle Atlantis to the Vehicle Assembly Building at KSC early tomorrow. The orbiter was powered down yesterday to conduct a structural leak check. Technicians will perform weight and center of gravity checks before attaching the Atlantis to the orbiter transporter. ******** A historic photo from the Voyager I probe is most likely the only shot we may ever see looking back at our own solar system. Jurrie van der Woude of the Jet Propulsion Laboratory said the once-in-a-lifetime picture is a series of images crafted into a mosaic taken last February 13. It took Voyager 30 minutes to transmit each image while traveling at 186,000 miles per second taken at 3.98 billion miles away from Earth. The picture will be available at this afternoon's news conference. ******** Operators report the Hubble Space Telescope has successfully taken two more images. The checkout procedures are operating extremely well. The telescope can now hold a fine lock on guide stars through multiple day to night transitions. Work will continue to improve the performance of the pointing control systems and further refine the secondary mirror. ******** --------------------------------------------------------------- Here's the broadcast schedule for Public Affairs events on NASA Select TV. All times are Eastern. Wednesday, June 6....... 2:00 P.M. Voyager I Solar System "Family Portrait" news conference. Thursday, June 7........ 11:30 A.M. NASA Update will be transmitted. ----------------------------------------------------------------- All events and times are subject to change without notice. These reports are filed daily, Monday through Friday, at 12:00 P.M. EDT. This is a service of the Internal Communications Branch, NASA HQ. Contact: JSTANHOPE on NASAmail or at 202/453-8425. ----------------------------------------------------------------- NASA Select TV: Satcom F2R, Transponder 13, C-Band 72 Degrees West Longitude, Audio 6.8, Frequency 3960 MHz. ----------------------------------------------------------------- ------------------------------ Date: 5 Jun 90 20:54:16 GMT From: decvax.dec.com!jfcl.dec.com!imokay.dec.com!borsom@mcnc.org (Doug Borsom) Subject: Re: Terraforming Venus (was: Manned mission to Venus) Acutally there is an old science fiction story titled "Maxwell's Demon," in which a Hilsch vortext tube plays a major role. As I recall from an old _Scientific_American_ "Amateur Scientist" article, the feed line into the tube has to be at a pretty high pressure to yield any useful temperature differential between the two output tubes. There goes that free lunch. ------------------------------ Date: Wed, 6 Jun 90 19:22 CDT From: William Higgins Subject: Ulysses: Status and opposition to launch Original_To: SPACE I want to review the current status of Ulysses, then discuss what I know about ongoing efforts to prevent NASA from launching it this fall. The Ulysses solar probe is intended to study the solar wind, magnetic field, X-ray and radio emissions, and plasma waves at high solar latitudes. All previous probes (including Earth-based observatories) have orbited near the plane of the ecliptic, and so have had a good view of the Sun's equator. But no spacecraft has ever observed the Sun's poles. Leaving Noordwijk and Amsterdam, the Ulysses spacecraft arrived at Cape Canaveral Air Force Station on 17 May. (Aboard a plane, of course.) It's scheduled for launch 5 October aboard the Shuttle orbiter *Discovery* on mission STS-41. Ulysses will be boosted toward Jupiter on an IUS (Inertial Upper Stage, Interim Upper Stage, call it what you will...) combined with a PAM-S. In a February 1992 encounter the planet's gravity will bend the spacecraft's trajectory southward, out of the ecliptic, so that it will pass over the Sun's south pole in May 1994. It crosses the ecliptic in February 1995, more or less reaching perihelion at this time. (Sorry, I don't have the numbers, but my best guess is perihelion about 1.3 AU, aphelion at Jupiter's distance, 5.2 AU. [Thanks for the cribsheet, Dale Greer!]) Then Ulysses passes over the north solar pole in May 1995. The 369-kg probe carries a radioisotopic thermoelectric generator (gee, what a mouthful! But one should always spell out acronyms the first time, no? Hereinafter, RTG.), an electric power source containing 11 kilograms of plutonium-238, in the form of plutonium dioxide ceramic. Note that this device is NOT a nuclear reactor; it works on different principles, and the nature of its radiation hazard is quite different. Plutonium-238 decays with the very short half-life of 88 years, and it emits all its radiation in the form of alpha particles. So it can be shielded safely by a very thin cladding, yet it puts out lots of energy; the lump of PuO2 is warm to the touch. Pu238 must be specially produced for RTG's. The fissionable isotope used in nuclear weapons is Pu239. Last fall three groups-- the Florida Coalition for Peace and Justice, the Christic Institute, and the Foundation on Economic Trends-- joined to seek a temporary restraining order to prevent NASA from launching the RTG-powered Galileo probe, but they were unsuccessful. They did, however, manage to attract a great deal of attention, both from the press and from Space Digest/sci.space readers. (-: The Christic Institute is now seeking an injunction against all launches of RTG's. In addition to this, many groups have filed comments on NASA's Environmental Impact Statement for the launch, including the Florida Coalition for Peace and Justice, the Federation of American Scientists, Physicians for Social Responsibility, and the Committee to Bridge the Gap. Other organizations filing (my list is incomplete at this time) are the National Space Society (which favors the launch and points out the environmental risks of *failing* to study the Sun's poles) and the United States Air Force. Bruce Gagnon, state coordinator of the FCFP&J, has contacted leaders of other peace groups asking for help in opposing the Ulysses launch. Working in his favor are two things: (1) he and his cause have a much higher profile than they did this time last year, thanks to the attention the Galileo affair gained, and (2) there are four months remaining, time to prepare more than the hasty effort of 1989. A good review of the technical facts and issues is given by Daniel Salisbury in "Radiation Risk and Planetary Exploration-- The RTG Controversy," *Planetary Report*, May-June 1987, pages 3-7. Another good article, which also reviews the events preceding Galileo's launch, "Showdown at Pad 39-B," by Robert G. Nichols, appeared in the November 1989 issue of *Ad Astra*. (Both magazines are published by pro-space organizations, the Planetary Society and the National Space Society respectively.) For details of the Ulysses mission, see *ESA Bulletin* No. 60, November 1989, page 8-12, and No. 48, November 1986. I'll bet NASA has a slick pamphlet on Ulysses, too, but I have yet to dig it up. In another posting soon I'll try to review the technical details of the RTG's, and the risks associated with them. I have made inquiries to learn more about the struggle to stop Ulysses; I'll post new information as I receive it. ______meson Bill Higgins _-~ ____________-~______neutrino Fermi National Accelerator Laboratory - - ~-_ / \ ~----- proton Bitnet: HIGGINS@FNALB.BITNET | | \ / SPAN/Hepnet/Physnet: 43011::HIGGINS - - ~ Internet: HIGGINS@FNALB.FNAL.GOV ------------------------------ Date: 6 Jun 90 05:30:00 GMT From: swrinde!zaphod.mps.ohio-state.edu!uwm.edu!bionet!arisia!cdp!jhanson@ucsd.edu Subject: Re: Does DoD Want Hawaii? (was: Re: Haw I am trying to figure out what kind of impression you wish to leave? ------------------------------ Date: 6 Jun 90 19:25:58 GMT From: hao.hao.ucar.edu!dlb@handies.ucar.edu (Derek Buzasi) Subject: Re: "CCD imagers in HST" from EE Times In article <435@mtndew.UUCP> friedl@mtndew.UUCP (Stephen J. Friedl) writes: #From _EE Times_, 4 June 1990, pg 33 (reproduced w/o permission) # # TI CCD Imagers Give Hubble Better Vision - Greenbelt, MD # # The first image returned from the Hubble Space Telescope # was matched with a similar image from a telescope in Chile, # and proved to be distinctly clearer. # # Texas Instruments supplied the thermoelectrically-cooled # CCD imager arrays on the Hubble; they are set up in four # tiled, 2048x2048 pixel imagers. # # Ground-based observatories have telescopes based on lower # quality (fallout) CCD imagers, also often supplied by TI. # I hate to rain on anyone's parade, but the CCDs used on the HST are not even close to being state of the art by modern standards, although they may qualify based on 1982 standards. These chips have low quantum efficiency (around 32% at best), high noise levels (~15 electrons), and relatively low dynamic range by modern standards. Ground-based observatories have access to significantly superior CCD arrays -- I can speak from experience, having last month used a TEK 512x512 CCD at Kitt Peak. Although it is true that HST produces (for the time being -- beware active optics, though!) "clearer" (i.e. higher resolution) images than any ground-based instrument, this is due to the lack of atmosphere in orbit, which enables HST to approximate it theoretical resolution limit, something not possible from the ground. #-- #Stephen J. Friedl, KA8CMY / Software Consultant / Tustin, CA / 3B2-kind-of-guy #+1 714 544 6561 / friedl@mtndew.Tustin.CA.US / {uunet,attmail}!mtndew!friedl # #"I will defend to your death my right to my opinion" - me -- ****************************************************************************** Derek Buzasi * "History is made at night. High Altitude Observatory * Character is what you are in the dark." dlb@hao.ucar.edu * -- Lord John Whorfin ------------------------------ Date: Wed, 6 Jun 90 21:36 CDT From: William Higgins Subject: Ulysses risks II: PuO2 dangers Original_To: SPACE This continues the discussion of the Ulysses probe, its radiothermal generators, and their risks. HOW DANGEROUS IS THE PLUTONIUM? I hope to research the toxicology of plutonium dioxide further. Here's what I've got so far. Plutonium-238 is an isotope with a half-life of 88.6 years. It is an excellent choice for RTG fuel because the only radiation it gives off is alpha particles of 5.5 MeV, making it very easy to shield (though there are fuels with higher power density). The plutonium dioxide fuel is a yellow-green compound with a density of 11.46 grams/cubic centimeter. It has a melting point of 2240 Celsius. My CRC Handbook says that it is insoluble in water and slightly soluble in hot concentrated sulfuric, nitric, or hydrofluoric acids. This implies that even if there is a breach of the RTG cladding (within the impact shell, within the insulator, within the aeroshell, within the GPHS housing), it would not easily get into the environment. If ingested by animals or people, it wouldn't dissolve and would likely be excreted after a short time. The alpha radiation given off by plutonium-238 has a very short range, and would be unlikely to do much damage during a few days in the digestive system. Note this point (for it seems to come up again and again in discussions of RTG's): Plutonium dioxide is not the most toxic substance known, and in fact is not very toxic at all if ingested. The greatest danger posed would be from particles inhaled into the lungs. A small particle of PuO2 would give off lots of alphas, which are highly ionizing and lose energy in a very short distance. (This is why they're so easy to shield against.) If a particle were in proximity to lung tissue, a small thickness of tissue would be pounded over and over, and the chances of inducing cancer would become very high. For Ulysses to cause this kind of problem, an accident must breach the RTG fuel cladding, somehow pulverize the plutonium dioxide, and disperse it into the air where somebody can breathe it in. A launch accident with enough violence to do this is *highly* improbable. For example, the *Challenger* accident, in which flames leaking from the solid rocket boosters triggered the explosion and rupture of the hydrogen-bearing external tank, exposed payload-bay components to 10 psi of overpressure. The RTG aeroshells and impact shells have been tested at overpressures up to 2000 psi with no release of the fuel. Downrange of the Kennedy Space Center launch site is ocean for several thousand miles. In the case of a launch accident, debris will most likely end up underwater, where it will be harmless. Reentry accidents are another possibility. (At the moment, I have little hard information on this topic, and will discuss it at length after I've snagged some more documentation.) The Apollo 13 lunar module, with an RTG aboard to power lunar surface instruments, re-entered at over 40,000 km/hour in 1970. A program of air and ocean sampling around its impact site detected no release of plutonium. REFERENCES Gordon L Chipman, Jr., "Advanced Space Nuclear Systems" (AAS 82-261), in *Developing the Space Frontier*, edited by Albert Naumann and Grover Alexander, Univelt, 1983, p. 193-213. *Handbook of Chemistry and Physics*, Chemical Rubber Company, 1989. William Corliss and Douglas Harvey, *Radioisotopic Power Generation*, Prentice-Hall, 1964. Robert G. Nichols, "Showdown at Pad 39-B," *Ad Astra*, November 1989, p. 8-15. Daniel Salisbury, "Radiation Risk and Planetary Exploration-- The RTG Controversy," *Planetary Report*, May-June 1987, p. 3-7. ______meson Bill Higgins _-~ ____________-~______neutrino Fermi National Accelerator Laboratory - - ~-_ / \ ~----- proton Bitnet: HIGGINS@FNALB.BITNET | | \ / SPAN/Hepnet/Physnet: 43011::HIGGINS - - ~ Internet: HIGGINS@FNALB.FNAL.GOV ------------------------------ End of SPACE Digest V11 #498 *******************