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 ; Sat, 21 Apr 90 02:53:25 -0400 (EDT) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Sat, 21 Apr 90 02:52:56 -0400 (EDT) Subject: SPACE Digest V11 #299 SPACE Digest Volume 11 : Issue 299 Today's Topics: Re: Questions about the Voyagers Re: Pegasus launch techniques NASA Headline News for 04/20/90 (Forwarded) Re: Decompression and 2001 Re: Fermi Paradox Re: Decompression and 2001 ---------------------------------------------------------------------- Date: 20 Apr 90 16:32:02 GMT From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!henry@ucsd.edu (Henry Spencer) Subject: Re: Questions about the Voyagers In article <92233@philabs.Philips.Com> rfc@briar.philips.com.UUCP (Robert Casey) writes: >>much of the (fairly boring and routine) data the Voyagers are sending will >>be lost... >I would have thought that the Voyagers would store the data for transmission >at scheduled times, chosen to be received at Earth when the antennas are not >needed for the newer probes... They'll undoubtedly be doing that to some extent, but if I were planning the missions, I'd go easy on using the tape recorders during routine cruise, as they may be wanted badly when something interesting (like hitting the heliopause) occurs, and their lifetime is finite. -- With features like this, | Henry Spencer at U of Toronto Zoology who needs bugs? | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 21 Apr 90 00:03:48 GMT From: phoenix!woodhams@princeton.edu (Michael Woodhams) Subject: Re: Pegasus launch techniques In article <1990Apr20.162536.29021@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In article <9004182349.AA14764@aqua.whoi.edu> capnal@AQUA.WHOI.EDU (Alan Duester) writes: >>However, those things carry a lot of typically overweight people, so it >>might be able to move fast and high, 'specially if you're not worried >>about fuel economies like the airlines supposedly are. > >Even figuring people at 200 lbs, a 40klb Pegasus is equivalent to 200+ >people, the "+" being because Pegasus adds drag as well as mass. I don't >think performance is going to be spectacularly better than normal airliner >levels. The "weight" of one person is very much more than the weight of their body, as they need a seat, luggage, sound-proofed cabins, food, people to serve it ... Not having passengers should reduce the payload by about 2 or 3 times the weight of humanity. Not carrying any comercial cargo in the hold would help alot too. I liked the dirgible idea. It's low tech, so there will be few unexpected hitches in building it, and it can get VERY high altitude. Michael Woodhams ------------------------------ Date: 21 Apr 90 04:07:57 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: NASA Headline News for 04/20/90 (Forwarded) ----------------------------------------------------------------- Friday, April 20, 1990 Audio: 202/755-1788 ----------------------------------------------------------------- This is NASA Headline News for Friday, April 20...... Charging of the Hubble Space Telescope batteries has been completed at Kennedy Space Center and they are being re-installed today. It's the last major task needed to go ahead with the launch of the STS-31 mission. The launch window opens at 8:31 a.m., EDT, Tuesday. With the batteries up to "full charge" the Shuttle launch team will have up to April 28 to launch before the batteries need to be charged again. The launch countdown starts at 3:00 p.m., EDT, Saturday. Crew arrival is scheduled for Sunday at 1:00 p.m. Mating of the Columbia with the Solid Rocket Boosters and External Tank is underway in the Vehicle Assembly Building. Rollout to the pad is scheduled for 8:00 a.m., Sunday. During the rollout the huge crawler-transporter will rack up its 1000th mile. * * NASA Administrator Richard Truly says agency studies of extravehicular activity needed for Space Station Freedom will be completed by late spring. Truly told AEROSPACE DAILY yesterday, "We'll deal with it, whatever the results. I think it's going well." Truly also told the publication...NASA and the Pentagon have made tremendous progress in the management aspects of the National Aerospace Plane program. * * On Capitol Hill...the House Budget Committee has approved a $1.2 trillion money bill for fiscal 1991. The resolution, which is non-binding, includes funding for the construction of Space Station Freedom. The Senate Budget Committee begins public hearings next week. * * NASA Administrator Truly speaks at the Earthfest 90 ceremonies, today, on the Mall in Washington, D.C. The event features exhibits by 10 federal agencies to celebrate Earth Day 1990. A NASA exhibit highlights the agency's environmental research missions. *************** ----------------------------------------------------------------- Here's the broadcast schedule for Public Affairs events on NASA Select TV. All times are EDT. Sunday, April 22...... 1:00 p.m. STS-31 crew arrives at Kennedy Space Center. Monday, April 23...... 9:00 a.m. STS-31 Countdown Status Report. 10:00 a.m. Hubble Space Telescope/APU Status Report. 11:00 a.m. Pre-launch News Conference. Tuesday, April 24..... 4:00 a.m. Launch and mission coverage of the STS- 31 mission begins. All events and times are subject to change without notice. Note: NASA Select TV will provide near continuous coverage of the STS-31 mission on Satcom F2R, transponder #13. In addition, mission TV highlights will be transmitted on F1R, transponder # 13, each day during the mission, at 12 midnight, EDT, for use by broadcasters and educational institutions in Hawaii and Alaska. F1R is located at 139 degrees west longitude. ----------------------------------------------------------------- These reports are filed daily, Monday through Friday, at 12 noon, EDT. ----------------------------------------------------------------- A service of the Internal Communications Branch, NASA Hq. ------------------------------ Date: 21 Apr 90 04:13:44 GMT From: swrinde!zaphod.mps.ohio-state.edu!samsung!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!henry@ucsd.edu (Henry Spencer) Subject: Re: Decompression and 2001 In article <5685@hplabsb.HP.COM> dsmith@hplabsb.UUCP (David Smith) writes: >>I have read (from multiple sources) that an individual should be able to >>survive about 30 sec. in a vacuum ... > >"survive." The same sources had said that the time of useful consciousness >is about 8 seconds... As Arthur C. Clarke pointed out, one could improve this quite a bit by hyperventilating first to flood the blood with oxygen. (Incidentally, among Clarke's credentials are considerable experience in both snorkel and scuba diving when he was younger.) >... Dave went longer than that before he pulled the lever. Sure about that? Timed it? (It's been too long since I've seen the movie for me to be sure, but 8 seconds is actually quite a long time.) -- If OSI is the answer, what on | Henry Spencer at U of Toronto Zoology Earth could be the question?? | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 21 Apr 90 04:29:00 GMT From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!henry@ucsd.edu (Henry Spencer) Subject: Re: Fermi Paradox In article <8300@hydra.gatech.EDU> ccoprmd@prism.gatech.EDU (Matthew DeLuca) writes: >>Actually, silicon makes a lousy carbon substitute... > >If I remember my organic chemistry from high school correctly, the reason for >all this is that silicon atoms cannot form double or triple bonds; many, if >not most, organic compounds have at least one multiple bond in there somewhere. I got curious about this and dug out my college chemistry texts. (Yes, texts plural -- I was about halfway to a degree in chemistry when I (re)discovered computers and got distracted. :-)) I didn't get it quite right in my original posting, actually. The underlying problem is that carbon-carbon bonds are comparable in strength to the bonds carbon forms with other common elements, while silicon-silicon bonds are relatively weak compared to silicon-other bonds. This makes long silicon chains etc. quite unstable, because there is a very strong tendency for those weak bonds to break when something more attractive wanders by. The longest known silicon analog to the alkanes (single-bonded carbon chains) is only six silicons long and quite unstable. The weak silicon-silicon bond also makes double and triple bonds out of the question, as they are (with certain exceptions) less stable than singles. The same goes, in spades, for the higher elements in the same group: germanium, tin, and lead. -- If OSI is the answer, what on | Henry Spencer at U of Toronto Zoology Earth could be the question?? | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 21 Apr 90 04:10:19 GMT From: news-server.csri.toronto.edu!utgpu!utzoo!henry@rutgers.edu (Henry Spencer) Subject: Re: Decompression and 2001 In article <35682@ucbvax.BERKELEY.EDU> bwood@janus.Berkeley.EDU.UUCP (Blake Philip Wood) writes: >>As any scuba diver will tell you, holding your breath during decompression >>is a thoroughly bad idea... > >In scuba you can have a differential of several atm, but in decomp to >a vacuum the maximum is 1 atm. The proper question is whether something >less than 1 atm can rupture the alveoli... Yes. Quite a bit less. -- If OSI is the answer, what on | Henry Spencer at U of Toronto Zoology Earth could be the question?? | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ End of SPACE Digest V11 #299 *******************