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 ; Mon, 16 Apr 90 03:01:24 -0400 (EDT) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Mon, 16 Apr 90 03:00:54 -0400 (EDT) Subject: SPACE Digest V11 #268 SPACE Digest Volume 11 : Issue 268 Today's Topics: Re: Pegasus launch from Valkyrie (or ... Re: Fermi Paradox space news from March 5 AW&ST, etc. Re: Interstellar travel Re: National Space Society NASA Headline News for 04/13/90 (Forwarded) Re: Interstellar travel and the Fermi paradox ---------------------------------------------------------------------- Date: 15 Apr 90 23:54:57 GMT From: cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!henry@tut.cis.ohio-state.edu (Henry Spencer) Subject: Re: Pegasus launch from Valkyrie (or ... In article shafer@skipper.dfrf.nasa.gov (Mary Shafer (OFV)) writes: >The only drawback I see at first glance is that the B-58 is too close >to the ground. The gear wouldn't touch if there was a Pegasus under >the wing. Surely Pegasus would go in place of the B-58's bomb/fuel pod, under the fuselage, not under a wing? The bomb pod was both longer (62ft) and fatter (7-8ft) than Pegasus, and it weighed about as much (40klbs) at takeoff, although drop weight was about half that and some work would be needed to qualify the B-58 for dropping Pegasus. Clearance for the Pegasus wing between the inboard engines looks adequate at first glance, although I don't have B-58 drawings and it isn't a large aircraft. You might have to fit a slot in the fuselage for Pegasus's tailfin (if OSC+H ends up using a Tristar for commercial launches, such a slot will be needed in it). -- With features like this, | Henry Spencer at U of Toronto Zoology who needs bugs? | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 16 Apr 90 00:02:09 GMT From: snorkelwacker!usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!henry@tut.cis.ohio-state.edu (Henry Spencer) Subject: Re: Fermi Paradox In article <1025@larry.sal.wisc.edu> scherb@larry.sal.wisc.edu.UUCP (Frank Scherb) writes: >Why not consider the idea that the Galaxy is so big that given about >a million years of exploration you still only see a very small piece >at best? ... Exploring from a central point, this would be true. But it shouldn't take more than a thousand years at most for a major colony to become a starfaring civilization itself. If we figure major colonies ten light-years apart, and assume travel time is short compared to the thousand-year buildup time, that's a light-year per century, or about ten million years to cross the galaxy. There's been plenty of time for that; the galaxy is old. -- With features like this, | Henry Spencer at U of Toronto Zoology who needs bugs? | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 16 Apr 90 01:05:43 GMT From: clyde.concordia.ca!news-server.csri.toronto.edu!utgpu!utzoo!henry@uunet.uu.net (Henry Spencer) Subject: space news from March 5 AW&ST, etc. USAF issues RFP for initial design work on converting the Vandenberg shuttle pad for Titan 4. (The USAF wanted to build a new Titan pad, but Congress told them to investigate using the shuttle pad first.) Ariane pieces being recovered, failure investigation underway. Looking at the telemetry, it seems water flow to one of the main engines was cut off. (The water is used to regulate combustion pressure.) There has been one past case of a momentary drop in engine pressure thought due to interruption in water flow. This time, at T+6.2s, chamber pressure of one main engine dropped from 58 atmospheres to 30 atmospheres quite abruptly, and stayed there. The guidance system gimballed the other engines to compensate, but as speed and acceleration built up, they had to gimbal further and further. At about T+90s, they hit their stops. The unbalanced thrust started to turn the booster sideways, and it quickly broke up under the aerodynamic stresses. The range safety officer then triggered the destruct system to be sure that the launch was completely destroyed. There was some concern about the cloud of toxic fuel vapors resulting from the explosion, but it was blown out to sea and caused no problems. Arianespace is basically assuming that the interruption in flights will be short, and is still signing customers for new launches and building Arianes at full production rate. The next mission probably will be delayed several months. It was meant to go up April 3, carrying a pair of European comsats. The first and second stages of the Ariane for that mission, and its strap-on boosters, were assembled and are being held in the vertical assembly building at Kourou. The satellites similarly had arrived and are in storage at Kourou. One real concern that has been raised is that the failing Ariane passed within about 2m of the top of the umbilical mast, because the ailing engine was the one closest to the mast. The exhaust struck the mast, in fact, although damage was minimal and repairs will not be a problem. The trouble is, if the booster had *hit* the mast, it and 420 tons of fuel could have crashed back down onto the pad. A working group is looking at pad hardening and what would be involved in rebuilding it after a major pad accident. [Score one successful prediction for me: a year or so ago I said that Arianespace would regret being dependent on a single operational pad. They are now taking that vulnerability a bit more seriously...] Arianespace's tenth-anniversary celebrations, set for March, will be postponed! Arianespace is unhappy about the commercial implications. It has been trying hard to establish itself in the Japanese market, and both of the destroyed comsats were Japanese. Competition is getting stronger, and although most of Arianespace's competitors formally expressed sympathy, privately there were few tears: customers are suddenly more interested in hedging their bets, and inquiries are up. There is also a definite possibility that Japan will boost funding for development of its own H-2 launcher. The insurers say this is the biggest loss in history, although recent launches have generally been successful, the industry is healthy, and insurance rates have been slowly dropping from their all-time peak in 1986 (a very bad year). Rates probably won't rise, but they aren't going to fall much in the near future. Atlantis launches AFP-731 spy/snoopsat, after repeated delays due to weather and minor problems. The launch was visible along much of the US Atlantic coast due to the very high orbital inclination. Pictures of the Gamma Ray Observatory, which has been delivered to NASA for launch in November. The launch was originally set for June, but slipped in the latest shuttle shuffle. The experimenters are impatient because they would like to get GRO up as soon as possible to observe the current solar-activity maximum and the evolution of supernova 1987A. GRO has been a bit of a construction challenge because the large size of sensitive gamma-ray instruments has produced a big, dense, heavy spacecraft. (One aspect of this has been careful planning for the eventual reentry, since quite a bit of it will survive to impact.) Expected orbital lifetime is eight years, given a high-altitude shuttle launch to minimize fuel consumption. GRO also is built for on-orbit refueling, although there are no firm plans to use this. Inmarsat awards a study contract for a system to monitor the health of Navstar and Glonass navsats and transmit updates on malfunctions via Inmarsat's comsats. [From Flight International, 7 Feb:] Pictures of various upgraded Delta configurations that McDonnell Douglas is studying, in particular to try to make Delta hefty enough to compete with Atlas-Centaur. The first one, already being marketed, will have an oxyhydrogen second stage using a single RL-10 [Centaur uses two], plus a fatter payload fairing. The second would fatten and lengthen the oxyhydrogen stage and fatten the payload fairing still further; the thing looks topheavy. The final two configurations use a pair of Delta first stages strapped together [!], solid strap-ons clustered around the base, with either a stretched version of the current second stage and a PAM-D third stage, or the fat oxyhydrogen second stage. Feature article on the Medilab module that will go up to Mir sometime this decade, to provided dedicated facilities for studying long-term effects of free fall, for use by pairs of specialist medical cosmonauts. [Flight International, 21 Feb:] Iraq claims plans to launch two types of indigenous non-military satellites for scientific purposes, date and launcher unspecified. The launcher is likely to be the Abid three-stage rocket which flew a suborbital test in December; its capabilities are probably similar to Israel's Shavit. [Flight International, 28 Feb:] Visual inspection of LDEF turned up many micrometeorite/debris craters, some substantial. Atomic-oxygen erosion was serious, especially in the mounting material of four solar-cell modules on LDEF's leading face: one was gone, one floated away during retrieval, the third was picked off the bottom of the payload bay after landing, and only one stayed put throughout. Copper and silver coatings had oxidized, to the point where thin ones often disappeared completely. Paint samples had been darkened considerably by ultraviolet. A micrometeorite collector lost most of its thermal blanketing to oxygen erosion. A particular puzzle is discoloration of "reflecting materials such as Teflon" [I assume they mean Teflon coated with something]. -- With features like this, | Henry Spencer at U of Toronto Zoology who needs bugs? | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 13 Apr 90 16:04:15 GMT From: cs.utexas.edu!uwm.edu!ogicse!blake!milligan@tut.cis.ohio-state.edu (Gregory Milligan) Subject: Re: Interstellar travel I'm sure that people tried to discourage Columbus with much the same arguments (with obvious adjustments for available technology, of course). Greg Milligan ------------------------------ Date: 13 Apr 90 05:21:17 GMT From: agate!agate!web@apple.com (William Baxter) Subject: Re: National Space Society Posted for Jim Bowery. Please direct responses to him. William Baxter ----------------------------------------------------- Date: Tue, 10 Apr 90 11:21:43 PDT From: jim@pnet01.cts.com (Jim Bowery) Subject: Re: National Space Society Craig Ward's attempt to excuse NSS's distribution of a leading "survey" as a pragmatic way to garner membership is a better demonstration of the failed character of NSS and it's current supporters than I could have hoped for. The claim that NSS's leading survey is simply doing what all organizations must do in recruiting supporters fails to address the main concern of the vast majority of us who felt that it tricked people to give answers which NSS could say support NASA's current programs, such as Space Station. How does this help NSS gain members? But the worst condemnation of NSS and its supporters is the constant use of the results of such "surveys" to claim that the "grassroots" want every greater expenditures for a bankrupt "space program". When those responsible for such "grassroots" misrepresentation, such as Scott Pace, then seek positions within civil service, it only consumates the sleaze. NSS and its supporters are attacking the foundation of democracy on behalf of those in NASA who would force all progress in space to be dependent on them, using a "survey" barely worthy of a third world communist government's bureau of propoganda. When one reflects on the critical stage we are at, not just as a nation, but as a planet, NSS deserves every bit of the condemnation it receives, and far more. If they are lucky, history will simply forget those, such as Craig Ward and Scott Pace, who, in their craven submission to bureaucracy, helped cripple the spaceward drive. --- Typical RESEARCH grant: $ Typical DEVELOPMENT contract: $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ ------------------------------- -- William Baxter ARPA: web@{garnet,brahms,math}.Berkeley.EDU UUCP: {sun,dual,decwrl,decvax,hplabs,...}!ucbvax!garnet!web ------------------------------ Date: 13 Apr 90 21:50:59 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: NASA Headline News for 04/13/90 (Forwarded) ----------------------------------------------------------------- Friday, April 13, 1990 Audio Service: 202/755-1788 ----------------------------------------------------------------- This is NASA Headline News for Friday, April 13..... The launch target date of the Hubble Space Telescope aboard the STS-31 Discovery at the Kennedy Space Center is scheduled for Wednesday, April 25 at 8:29 A.M. EDT. The new target date accomodates all critical path activities to include the auxiliary power unit replacement and recharging the Hubble Space Telescope batteries. All will be completed without changing the time-line for future launch plans. KSC ground crews are preparing to work in a parallel position to replace the auxiliary power unit number one. This will include depressurizing the APU of hydrazine in preparation for changeout beginning early Saturday morning. The new unit has arrived on schedule for replacement Sunday. Mission managers have examined the best possible work scenarios to maximize the most efficient equipment handling options and minimize the possibilities to contaminate the the Hubble Space Telescope. Cautionary steps include a clean air purge through the payload bay, closing off the platform activity above level three and keeping the payload bay doors closed during the APU removal activities. To date, the detectors that have recently been removed from the payload bay indicate no concern for contamination. Meanwhile, two new detectors will be installed this evening inside the Discovery payload bay to monitor any contamination during the turnaround activities. The Hubble Space Telescope batteries will be removed on Saturday. While at the battery lab at the Vertical Assembly Building, they will be chilled down and recharged for approximately 130 hours this Sunday. * * * In Other News: An Arianespace accident inquiry board reports the recent Ariane 44L booster explosion at launch on February 22 is apparently due to a piece of cloth lodged in a water pipe. NASA engineers announced a successful test of an advanced Space Shuttle main engine today. It was the 19th test firing in the Marshall Test Bed facility in the West Test Area. The facility is used to study and evaluate new engine technology. *********** ----------------------------------------------------------------- Here's the broadcast schedule for Public Affairs events on NASA Select TV. All times are Eastern. Thursday, April 19...... 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 Noon, EDT. ----------------------------------------------------------------- A service of the Internal Communications Branch, NASA HQ. ------------------------------ Date: 15 Apr 90 14:38:50 GMT From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!watdragon!watyew!jdnicoll@ucsd.edu (Brian or James) Subject: Re: Interstellar travel and the Fermi paradox Perhaps the local solution to the Fermi paradox is that, *if* other technologically inclined species tend to fill their galaxies to the saturation point in a few hundred millenia, and *if* the conditions caused by the saturation of the galaxy preclude new technological species from evolving, then our present existance requires that the industrialisation of our galaxy has not yet occured. This model is fairly hard to disprove, so it probably not useful. If other galaxies do have wide spread civilisations, I wonder if we could detect them remotely. Perhaps that's the explaination for the 'Great Wall'. The universe is more or less identical [in terms of mass/volume], but the techno types are blocking the visible light with all those darn Dyson spheres :). I'd expect the big dark areas to be sources of infra-red radiation, if this were true. JDN ------------------------------ End of SPACE Digest V11 #268 *******************