Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from corsica.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl) (->ota+space.digests) ID ; Fri, 9 Jun 89 05:19:18 -0400 (EDT) Message-ID: <4YXsiBu00UkV8=tk4V@andrew.cmu.edu> Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Fri, 9 Jun 89 05:19:10 -0400 (EDT) Subject: SPACE Digest V9 #479 SPACE Digest Volume 9 : Issue 479 Today's Topics: Re: Venus & the Greenhouse effect.. Re: Getting news about China from space Re: Amazon Forest Destruction Re: Venus & the Greenhouse effect.. Re: Hang gliders and "bailing out" Re: Space telescope optics Re: Space Station computer system Re: Venus & the Greenhouse effect.. Re: Venus & the Greenhouse effect.. Re: Russians bomb U.S. Re: Terraforming Venus Re: Magellan Hartsfield to head Space Flight/Space Station Integration Office (Forwarded) ---------------------------------------------------------------------- Date: 6 Jun 89 19:14:29 GMT From: china.uu.net!dan@uunet.uu.net (Dan Williams) Subject: Re: Venus & the Greenhouse effect.. In article <1989Jun3.220951.4252@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes: > There are other problems in making Venus habitable too, like a grave shortage > of water and an excessively long rotation period. Does Venus really have a lack of Water? I know it has no liquid H2O but doesn't the atmosphere still hold the balance? Also what about vulcanism releasing water and more in the rocks? If we manage to cool the planet would water begin to collect? Now the rotation period is a problem of a different magnitude. -- | Dan Williams (uunet!china!dan) | FRP: It's not just a game, | | MCDONNELL DOUGLAS | it's an adventure! | | Denver CO | "Of course thats just my opinion" | ------------------------------ Date: 7 Jun 89 03:34:14 GMT From: usc!merlin.usc.edu!nunki.usc.edu!denniskr@cs.ucla.edu (Dennis Kriz) Subject: Re: Getting news about China from space With the continuing crisis in China and with it for the most part being played out far from Tienanmen square these days, probably outside of Beijing even, I was wondering ... could satellite photos from spacecraft like Spot make any difference. I mean that's how the networks covered the Chernobyl accident when it first broke. I doubt that such a satellite could detect individual tanks but perhaps it could detect masses of them. Maybe it could detect them deployed by bridges, intersections and the like. Any comments? Dennis ------------------------------ Date: 7 Jun 89 17:38:01 GMT From: ncrlnk!ncrcce!johnson@uunet.uu.net (Wayne D. T. Johnson) Subject: Re: Amazon Forest Destruction In article <14384@bfmny0.UUCP> tneff@bfmny0.UUCP (Tom Neff) writes: >In article <386@v7fs1.UUCP> mvp@v7fs1.UUCP (Mike Van Pelt) writes: >>In article <1331@ncrcce.StPaul.NCR.COM> johnson@ncrcce.StPaul.NCR.COM (Wayne D. T. Johnson) writes: >>>Article in the local news last night: >>>ozone was being destroyed by electrons coming from the magnetosphere >>>this causing 14% of the ozone loss since 1975... > ^^^^ > note number I must correct myself, the figure they said was 14% of the ozone. That is a significant amount since the ozone varies in thickness and is thinest at the poles. Wayne Johnson (Voice) 612-638-7665 NCR Comten, Inc. (E-MAIL) W.Johnson@StPaul.NCR.COM or Roseville MN 55113 johnson@c10sd1.StPaul.NCR.COM These opinions (or spelling) do not necessarily reflect those of NCR Comten. ------------------------------ Date: 7 Jun 89 03:26:29 GMT From: mailrus!jarvis.csri.toronto.edu!me!ecf!murty@tut.cis.ohio-state.edu (Hema Sandhyarani Murty) Subject: Re: Venus & the Greenhouse effect.. > Does Venus really have a lack of Water? I know it has no liquid > H2O but doesn't the atmosphere still hold the balance? Also what about > vulcanism releasing water and more in the rocks? A recent New Scientist article says the Venus may have had water at one time. Apparently, a measure of deuterium to hydrogen in the atmosphere of Venus gives them the indication that at one time there was more water. When temperatures were lower, I suppose not all the water was boiled away. They even suggest that at one time there may have been large oceans of water on the surface of Venus. Magellan is supposed to look for signs of dried up river beds etc. Hema Murty Institute for Aerospace Studies, University of Toronto, Downsview, Ontario, M2M 3V8 Canada ------------------------------ Date: 7 Jun 89 01:45:03 GMT From: aeras!tneale@sun.com (Tom Neale) Subject: Re: Hang gliders and "bailing out" In article <16879@sequent.UUCP> jjb@sequent.UUCP (Jeff Berkowitz) writes: >Henry's analysis of the difference is (as usual :-) correct. Parafoil- >like designs, however, are in use both as kites and as human-carrying >gliders; the latter are popular especially in Europe. Their advantage >over hang gliders is that the lack of airframe makes them easy to fold >into a backpack and carry; they have a relatively poor glide, however, >and appear to be difficult for humans to flare (and therefore land) safely. On the contrary, ram air (squares as we call them) parachutes are quite the norm in sport parachuting today. Their glide is a respectible 3:1 or better (great when compared to a round parachute at <0.4:1). Forward speeds are 20-30 MPH for most models. Further, they are quite easy to flare and land safely. I have over 1300 square jumps with no problems and landings are normally tippy-toe soft. :-) This is no longer shuttle related but I felt compelled to clear up any mis-information about a subject near and dear to my heart. -- Blue skies, | ...sun!aeras!tneale | | in flight: N2103Q | The hurrieder I go Tom Neale | in freefall: D8049 | the behinder I get. | via the ether: WA1YUB | ------------------------------ Date: 7 Jun 89 17:43:33 GMT From: frooz!cfa.HARVARD.EDU@husc6.harvard.edu (Steve Willner) Subject: Re: Space telescope optics In article <8906052056.AA05592@cmr.ncsl.nist.gov> roberts@CMR.NCSL.NIST.GOV (John Roberts) wrote: > Several people have posted to the net stating that the Hubble Space > Telescope could not focus on an object as close as the earth. I > tend to be somewhat skeptical of this claim, because of the > phenomenon known as depth of field. > .... > but a few guesses and application of the formulas used for cameras > suggest that the hyperfocal distance may be only a few miles. Does > anyone have any better numbers? Then in article <10915@cit-vax.Caltech.Edu>, palmer@tybalt.caltech.edu (David Palmer) replied: > It is easy to see that when you focus an optical system at > infinity, the circle of confusion of an image at a finite distance > is the size of the aperture at that distance. > ... > This means that the HST cannot see objects smaller than its 2.4 m > mirror, compared to the pie-plate size of a Spy-sat. My initial reaction was that Mr. Roberts was right, but a calculation leads to the opposite conclusion. (Thanks to Mr. Palmer for further explication.) If an optical system focused at infinity observes an object at finite distance, the position of the image will be shifted. The amount of shift (for an object at distance d >> focal length) is s = (F D)^2 / d , where F is the focal ratio of the system, and D is the diameter. (Note that FD is the focal length.) For HST observing the ground, the numbers (very roughly) are F=20, D=2.4 m, and d=2E5 m. Thus the focal shift is of order 12 mm. The blur circle produced by the focal shift (assuming we do not refocus the telescope) is just s/F or about 0.6 mm in this case. For comparison, the diffraction blur circle is approximately 2.4 Fw, where w is the wavelength. This amounts to about 24 microns for HST in visible light, so the Earth would not be observable by HST without either refocusing or losing resolution. In general, for a diffraction-limited optical system focused at infinity, objects must be more distant than D^2/w to be effectively "in-focus." This is about 1E4 km for HST. My guess is that the amount of focal shift is within the range of adjustment for HST; if so, Mr. Palmers last statement needs the qualifier "without refocusing." Other forms of image blurring, notably spacecraft motion, would also be important. And the HST instruments are not really designed for ground observations. However, it's not hard to imagine an instrument very similar to HST but designed specifically for ground observations. Rumor has it that some have been built. Steve Willner Phone 617-495-7123 Bitnet: willner@cfa 60 Garden St. FTS: 830-7123 UUCP: willner@cfa Cambridge, MA 02138 USA Internet: willner@cfa.harvard.edu ------------------------------ Date: 7 Jun 89 18:48:51 GMT From: vsi1!daver!lynx!neal@ames.arc.nasa.gov (Neal Woodall) Subject: Re: Space Station computer system In article rg20+@andrew.cmu.edu (Rick Francis Golembiewski) writes: >> highlights: they're talking about thirty to forty IBM PS/2 model 80's >EEEK This sounds really frightening MS-DOS in space, >now I KNOW that the space program is in trouble... Who said that the computers had to run MS-DOS? Why not some other operating system? Neal ------------------------------ Date: 7 Jun 89 15:53:49 GMT From: jarvis.csri.toronto.edu!utgpu!utzoo!henry@rutgers.edu (Henry Spencer) Subject: Re: Venus & the Greenhouse effect.. In article <119@china.UUCP> dan@china.uu.net (Dan Williams) writes: > Does Venus really have a lack of Water? I know it has no liquid >H2O but doesn't the atmosphere still hold the balance? Unfortunately, no: when Venus's greenhouse effect ran away and the water ended up in the atmosphere, at high altitudes solar radiation cracked it to hydrogen and oxygen, and the hydrogen escaped into space. Not a fast process, but over time most of it went. What little hydrogen is left is noticeably deuterium-enriched because deuterium is twice as massive and doesn't escape nearly as easily; this is the definitive evidence of what happened. > Also what about >vulcanism releasing water and more in the rocks? Not significant over time scales that humans care about. > If we manage to cool the planet would water begin to collect? No, since there's none to collect. We'd have to import it, perhaps from the outer solar system. -- You *can* understand sendmail, | Henry Spencer at U of Toronto Zoology but it's not worth it. -Collyer| uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 7 Jun 89 21:08:06 GMT From: concertina!fiddler@sun.com (Steve Hix) Subject: Re: Venus & the Greenhouse effect.. In article <1989Jun7.155349.18236@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes: > In article <119@china.UUCP> dan@china.uu.net (Dan Williams) writes: > > Does Venus really have a lack of Water? I know it has no liquid > >H2O but doesn't the atmosphere still hold the balance? > > > If we manage to cool the planet would water begin to collect? > > No, since there's none to collect. We'd have to import it, perhaps from > the outer solar system. Say, if we throw enough comets and other iceballs at Venus to get the water back, and if they're placed correctly, maybe we could get the planet's spin rate up some. Probably not enough comets, huh? ------------------------------ Date: 7 Jun 89 14:05:20 GMT From: prism!ccoprmd@gatech.edu (Matthew DeLuca) Subject: Re: Russians bomb U.S. In article <1333@ncrcce.StPaul.NCR.COM> johnson@ncrcce.StPaul.NCR.COM (Wayne D. T. Johnson) writes: > >Upper stage from Proton booster crashs in U.S. near Canadian border. > >Any one have any details? >-- According to the local paper (Atlanta Constitution, from AP report) the stage did *not* crash, rather, its re-entry was visible from northern Minnesota. According to the report, the booster had launched three satellites into orbit. ARPA: ccoprmd@hydra.gatech.edu : ------------------------------ ReSent-Message-ID: ReSent-Date: Wed, 7 Jun 89 09:33:20 -0400 (EDT) ReSent-From: Ted Anderson ReSent-To: Resend this message to: Space , SAC.DYESGPF@E.ISI.EDU; Date: 6 Jun 1989 16:17-CDT Sender: SAC.DYESGPF@E.ISI.EDU Subject: Re: Terraforming Venus From: SAC.DYESGPF@E.ISI.EDU Concerning the questions on planetary cooling caused by clouds vs CO2 'Greenhouse' effect. If I remeber correctly in one of my classes years ago the discussion came up about clouds of water-vapour being highly reflective to near infrared and visible light and less reflective (Note: not transparent) to far infrared while CO2 is more reflective to far infrared than to near thus accounting for CO2 being better at trapping the longer wave-length far infrared which is generated when sunlight strikes a planetary surface. Please if I have this information incorrect or backwards, be gentle with the flames as this is really out of my area, I have spent the past 21 years as a para-professional in Aerospace Medicine. Al Holecek Disclaimer - the above is my own ramblings, but my bosses are welcome to 'em ------------------------------ Date: 7 Jun 89 17:18:33 GMT From: ncrlnk!ncrcce!johnson@uunet.uu.net (Wayne D. T. Johnson) Subject: Re: Magellan In article <890606100802.00002D2D0D1@grouch.JPL.NASA.GOV> PJS@GROUCH.JPL.NASA.GOV (Peter Scott) writes: > >In other words, if something sticks, give it a kick. > Rube Goldberg's law (my patrion saint): If it dosn't work, use a bigger hammer. An IUS is just about the biggest hammer I've seen yet. -- Wayne Johnson (Voice) 612-638-7665 NCR Comten, Inc. (E-MAIL) W.Johnson@StPaul.NCR.COM or Roseville MN 55113 johnson@c10sd1.StPaul.NCR.COM These opinions (or spelling) do not necessarily reflect those of NCR Comten. ------------------------------ Date: 7 Jun 89 23:10:56 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: Hartsfield to head Space Flight/Space Station Integration Office (Forwarded) Barbara E. Selby Headquarters, Washington, D.C. June 7, 1989 Billie A. Deason Johnson Space Center, Houston, Texas RELEASE: 89-88 HARTSFIELD TO HEAD SPACE FLIGHT/SPACE STATION INTEGRATION OFFICE Veteran astronaut Henry Hartsfield has been assigned temporary duty in the Office of Space Flight, NASA Headquarters, Washington, D.C., effective immediately. Hartsfield will serve as director of the Space Flight/Space Station Integration Office, reporting directly to the associate administrator for space flight. Hartsfield replaces astronaut Robert Parker who has returned to the Johnson Space Center to begin training for his mission specialist assignment on Space Shuttle mission STS-35, scheduled for launch in the spring of 1990. The Space Flight/Space Station Integration Office was established in 1987 to facilitate integration of the Space Station and its unique requirements into the Space Transportation System. The office coordinates the exchange of information between the two programs and serves as a forum for resolving technical and programmatic issues. Hartsfield began his Air Force career in 1955 and is a graduate of the USAF Test Pilot School at Edwards Air Force Base, Calif. He was an instructor there prior to his assignment in 1966 to the USAF Manned Orbiting Laboratory (MOL) program as an astronaut. After cancellation of the MOL program in June 1969, he was reassigned to NASA. Hartsfield retired from the Air Force in August 1977 and remained in the astronaut corps. He was pilot for STS-4 in June/July 1982 and commanded Shuttle missions STS 41-D in September 1984 and STS 61-A in November 1985. His most recent assignment was deputy director for flight crew operations at the Johnson Space Center. In addition to other awards, he has received the NASA Distinguished Service Medals in 1982 and 1988 and the NASA Exceptional Service Medal in 1988. ------------------------------ End of SPACE Digest V9 #479 *******************