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, 4 Nov 89 02:04:28 -0500 (EST) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Sat, 4 Nov 89 02:03:44 -0500 (EST) Subject: SPACE Digest V10 #202 SPACE Digest Volume 10 : Issue 202 Today's Topics: Re: Jovian radiation belts Re: Jupiter Balloon Re: Voyager trajectory diagram Re: What do you do? Re: Manned Jupiter Mission (was Re: Condensed CANOPUS - August 1989) Re: Fragile Space Shuttle Jovian radiation belts Re: Manned Jupiter Mission (was Re: Condensed CANOPUS - August 1989) SPACE Digest V10 RE: SPACE Digest V10 #177 Re: Jupiter Balloon Re: PowerSat Options Re: Magellan Status for 10/31/89 (Forwarded) Re: Voyager trajectory diagram Voyager's last photo Astro/Space on CompuServe ---------------------------------------------------------------------- Date: 3 Nov 89 01:40:40 GMT From: cs.utexas.edu!samsung!uakari.primate.wisc.edu!uwm.edu!ux1.cso.uiuc.edu!ux1.cso.uiuc.edu!daniel@tut.cis.ohio-state.edu Subject: Re: Jovian radiation belts schaper@pnet51.orb.mn.org write: > You said that travellers to Jupiter might want to head for under the Dragon's >Teeth, as the Jovian belts are called. > You wanna go first? > :-) Points that people have made about the radiation level of the Jovian belts being quite high are well taken. I guess that I had envisioned somehow ducking in across the poles. Energy wise, this would probably not be an easy maneuver since you would have to quickly plant yourself in such a low orbit. I suppose aerodynamic breaking might actually help here. This does bring up the point that aerodynmic breaking would probably not be useful when heading to Jovian moons since it would require a couple of passes directly through the Jovian radiation belts. -- Daniel Pommert ;-} ------------------------------ Date: 3 Nov 89 01:40:35 GMT From: cs.utexas.edu!uwm.edu!ux1.cso.uiuc.edu!ux1.cso.uiuc.edu!daniel@tut.cis.ohio-state.edu Subject: Re: Jupiter Balloon George W. Herbert (gwh@sandstorm.Berkeley.EDU) writes: >/* ---------- "Jupiter Balloon" ---------- */ > > A friend and I (George and Frank Crary) just worked out >specs for a nuclear heated balloon for dropping into the Jovian >atmosphere and leaving for an indefinite amount of time (years?). > ........ > The altitude target would be the five-bar altitude, though >the baloon should be able to handle from the two or three bar to the ten >bar levels. It is my understanding that the reason that biological life cannot be expected to survive on Jupiter is because the convection cells go too deep within Jupiter--so deep that any but the smallest molecules are baked into atoms. If this is the case, you would have trouble guiding a balloon away from the down drafts and hense away from premature distruction. All this IMHO -- Daniel Pommert ------------------------------ Date: 2 Nov 89 15:04:10 GMT From: cs.utexas.edu!samsung!gem.mps.ohio-state.edu!rpi!crdgw1!crdos1!davidsen@tut.cis.ohio-state.edu (Wm E Davidsen Jr) Subject: Re: Voyager trajectory diagram In article <1989Nov1.030224.7140@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes: | In black&white rather than pretty color, but larger and more legible | (and incidentally, much easier to reproduce). Don't suppose you have the stuff to scan that and convert it into PostScript so you could share it, do you? -- bill davidsen (davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen) "The world is filled with fools. They blindly follow their so-called 'reason' in the face of the church and common sense. Any fool can see that the world is flat!" - anon ------------------------------ Date: 2 Nov 89 17:42:06 GMT From: pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!gem.mps.ohio-state.edu!wuarchive!uwm.edu!ux1.cso.uiuc.edu!ux1.cso.uiuc.edu!m.cs.uiuc.edu!bucc2!moonman@tut.cis.ohio-state.edu Subject: Re: What do you do? I'm an undergrad physics major at Bradley University who writes for an amateur astronomical journal. uiucdcs\ noao>bradley!bucc2!moonman cepu/ Internet: bradley!bucc2!moonman@a.cs.uiuc.edu Arpa: cepu!bradley!bucc2!moonman@seas.ucla.edu ------------------------------ Date: 2 Nov 89 17:32:06 GMT From: pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!gem.mps.ohio-state.edu!samsung!cs.utexas.edu!mailrus!jarvis.csri.toronto.edu!utgpu!utzoo!henry@tut.cis.ohio-state.edu (Henry Spencer) Subject: Re: Manned Jupiter Mission (was Re: Condensed CANOPUS - August 1989) In article <1989Nov1.221207.5296@agate.berkeley.edu> gwh@sandstorm.Berkeley.EDU (George William Herbert) writes: >>... Human exploration of the outer solar system >>is difficult, verging on impractical, unless propulsion is good enough to >>let you forget about economy orbits and use fast ones instead. > >A friend did a design for a contest for a manned jupiter mission. His >solution was using NERVA rockets. Nothing else works, realistically. I'd consider even NERVA marginal, actually. Its performance advantage over good chemical rockets isn't that great. -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 2 Nov 89 18:44:24 GMT From: cs.utexas.edu!samsung!mailrus!jarvis.csri.toronto.edu!utgpu!utzoo!henry@tut.cis.ohio-state.edu (Henry Spencer) Subject: Re: Fragile Space Shuttle In article <14832@bfmny0.UU.NET> tneff@bfmny0.UU.NET (Tom Neff) writes: >Even commercial transport requires thorough checkout. There just aren't >any Public Affairs Offices keeping you informed on the maintenance being >done on the 747 you'll be flying later in the week. That's mostly because the manpower involved in said maintenance is several orders of magnitude smaller. 747 "thorough checkout" and NASA "thorough checkout" are enormously different things. 747 maintenance crews do not remove, examine, replace/refurbish, and re-install 5000 components on each engine after every flight. NASA crews do exactly that for each SRB. >My prediction is that we will never be allowed to stop checking spacecraft >with a fine toothed comb... Until we start designing them not to need fine-toothed-comb checkout, this is trivially true. -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 2 Nov 89 08:25:06 GMT From: bungia!orbit!pnet51!schaper@umn-cs.cs.umn.edu (S Schaper) Subject: Jovian radiation belts You said that travellers to Jupiter might want to head for under the Dragon's Teeth, as the Jovian belts are called. You wanna go first? :-) UUCP: {amdahl!bungia, uunet!rosevax, chinet, killer}!orbit!pnet51!schaper ARPA: crash!orbit!pnet51!schaper@nosc.mil INET: schaper@pnet51.cts.com ------------------------------ Date: 2 Nov 89 23:56:24 GMT From: uw-entropy!quick!thebes!polari!gtisqr!kevin@beaver.cs.washington.edu (Kevin Bagley) Subject: Re: Manned Jupiter Mission (was Re: Condensed CANOPUS - August 1989) In article <1989Oct30.015551.6258@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In article <1989Oct29.210152.27514@cs.rochester.edu> yamauchi@cs.rochester.edu (Brian Yamauchi) writes: >>Are there any technical obstacles to a Jovian mission other than the >>longer flight time (requiring more supplies, larger ships, etc.) and >>the radiation around Jupiter? [stuff deleted] >However, I'd say that the limitations imposed by Jupiter's Van Allen belts >are the only technical problems that couldn't be solved with reasonable >effort. One of the major problems with a manned Jupiter mission would be the general scope of the mission. If we are ambitious enough to send people to Jupiter, we will want to take as much advantage of that visit as is possible. Sending people there to orbit and collect data would be a waste of the people sent on such a mission. We will definitely want to land, retrieve samples, explore, set up long term experiments, etc. from much more than just 1 Jovian moon. This would greatly complicate such a mission since we would need to provide multiple use landing craft and the required fuel for operating them. The mission would also probably be very lengthy in terms of the time we would stay in the Jovian system. I wouldn't be suprized if such a mission were 100 times the cost of a mission to Mars. (But wow, it would sure be worth it!) >A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology >megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu -- _____ Kevin Bagley Global Technology Mukilteo WA 98275 (206)742-9111 )__) _ _ _ UUCP:uw-beaver!uw-nsr!gtisqr!kevin _/__) (_(_(_)_/_)_ ARPA:uw-nsr!gtisqr!kevin@beaver.cs.washington.edu ____________/ Disclaimer: "I did not say this. I am not here." ------------------------------ Date: Thu, 2 Nov 89 08:41:31 EST From: Michael S Trauth X-Title: Asst Collection Mngr Phone: 588-8750 Subject: SPACE Digest V10 To: "space+" Please discontinue my subscription to the space digest bitnet group please. In-Reply-To: note of 11/02/89 06:02 ------------------------------ Date: Thu, 2 Nov 89 11:05 CST From: BAWOLTERS%UALR.BITNET@VMA.CC.CMU.EDU Subject: RE: SPACE Digest V10 #177 PLEASE remove me from this LIST-SERV... Thank You! ------------------------------ Date: 2 Nov 89 20:02:35 GMT From: agate!typhoon.Berkeley.EDU!gwh@ucbvax.Berkeley.EDU (George William Herbert) Subject: Re: Jupiter Balloon In article <1989Nov2.173243.851@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >> A friend and I (George and Frank Crary) just worked out >>specs for a nuclear heated balloon for dropping into the Jovian >>atmosphere and leaving for an indefinite amount of time (years?). > >For heaven's sake don't tell the Christic Institute! :-) :-) :-) Oops, gee, o forgot all about them... well, we need to keep them amused _somehow_ :-) -george ------------------------------ Date: 3 Nov 89 01:44:37 GMT From: calvin!johns@cu-arpa.cs.cornell.edu (John Sahr) Subject: Re: PowerSat Options [Hay mucho haranguing about power density in a powersat microwave downlink] In article <1989Nov2.140102.2133@cs.rochester.edu> dietz@cs.rochester.edu (Paul Dietz) writes: >[deletions] The microwave beam has low power density because it is >diffraction limited (if it wasn't, we've made the transmitter too >big). All right. For a standard powersat design, what is the antenna size and frequency of operation? It is not obvious to me that the beam would be diffraction limited at the earth. Suppose the transmit antenna has a diameter of 2 km, and the frequency of operation is 3 GHz (lambda = 10 cm). Then, the earth at 40,000 km distance would be on the border between near and far field (Using D^2/lambda). As an aside, for the 70 cm radar at Arecibo, the E region is still in the near-field, 100 km away. I recall that someone posted design quidelines for this system a while back; I'm sorry I wasn't paying closer attention. -- John Sahr, | Electrical Engineering - Space Plasma Physics johns@alfven.spp.cornell.edu | Cornell University, Ithaca, NY 14853 ------------------------------ Date: 2 Nov 89 16:10:45 GMT From: hpfcso!cunniff@hplabs.hp.com (Ross Cunniff) Subject: Re: Magellan Status for 10/31/89 (Forwarded) > Velocity Geocentric 66,573 mph > Heliocentric 883,205 mph Boy, must be one helluva space/time warp it's passing through! :-) Ross Cunniff Hewlett-Packard Colorado Language Lab ...{ucbvax,hplabs}!hpfcla!cunniff cunniff%hpfcrt@hplabs.HP.COM ------------------------------ Date: 2 Nov 89 20:57:03 GMT From: cs.utexas.edu!mailrus!jarvis.csri.toronto.edu!utgpu!utzoo!henry@tut.cis.ohio-state.edu (Henry Spencer) Subject: Re: Voyager trajectory diagram In article <1535@crdos1.crd.ge.COM> davidsen@crdos1.UUCP (bill davidsen) writes: > Don't suppose you have the stuff to scan that and convert it into >PostScript so you could share it, do you? Alas, I'm afraid not. -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 3 Nov 89 00:21:13 GMT From: frooz!cfashap!wyatt@husc6.harvard.edu (Bill Wyatt) Subject: Voyager's last photo I just got back from a lecture by Edward Stone, the Voyager Project Scientist and Cal Tech prof. Wonderful pictures, but I thought I'd pass his news (first real confirmation I've heard, at least) that the camera will be turned on sometime next February for a last look-back picture of the solar system. Mercury will be too close to the Sun to distinguish, and Pluto is too faint/dark, but all the others should be imaged. The inner planets will be point sources, but the giants will be two or three pixels across. Bill Wyatt, Smithsonian Astrophysical Observatory (Cambridge, MA, USA) UUCP : {husc6,cmcl2,mit-eddie}!harvard!cfa!wyatt ARPA: wyatt@cfa.harvard.edu SPAN: cfa::wyatt BITNET: wyatt@cfa ------------------------------ Date: Fri, 03 Nov 89 00:58:03 EST From: Leonard Abbey Subject: Astro/Space on CompuServe There has been a great deal of discussion lately on both USENET and BITNET concerning the availability of GIF images of the recent Neptune encounter. The "mother lode" of this sort of thing is CompuServe Information Service. The GIF format is a CompuServe product, which has been placed in the public domain. CompuServe operates both a Space and an Astronomy forum. Between the two there are over 300 GIF files (over 6 Megs), many of them Voyager images. GIF interpreters are available online as public domain software for every major brand of computer. There are dedicated graphics support forums to assist with the reading of GIF and other graphics files. The Space and Astronomy forums have a combined membership of over 20,000. Participants are private citizens, members of the academic community, astronomers, and aerospace professionals from both private industry and NASA. Sky Telescope magazine, Celestron, Meade, and Televue maintain daily presence on the forums. The data libraries (about 30 in all, I think) are truly massive, and offer many, many megs of programs in addition to the GIF images. Regular postings of late-breaking news are supplied by the Public Affairs Office of the Jet Propulsion Laboratory as well as the NASA Headquarters News Room. The interactive communications facilities of the forums facilitate are one of the most exciting facets of these formus. Guest conferences in which forum members can communicate directly with "celebrity guests" in various astro- and space-related fields are regularly held. Forum members have been able to "talk" directly to astronomers such as Clyde Tombaugh, Tom VanFlandern, and Brian Marsden; astronauts Joe Allen, Steve Hawley, and Jay Apt; authors Arthur C. Clarke, Larry Niven, Jim Oberg, and G. Harry Stine; space advocates Louis Friedman and Ben Bova; as well as national policy shapers like former NASA Administrator Dr. Thomas Paine and Professor Minoru Oda, former head of the Japanese space program. The cast of Star Trek has appeared too. We've had Soviet exchange students with us (members of the "Young Cosmonauts"). One group of students who are forum members has had space aboard a future Shuttle mission donated to them to fly an experiment on non-destructive materials evaluation which they have designed. Users of BITNET and USENET are usually concerned about the cost of this commercial sercvice. Connecting to CompuServe is a local call from most cities in the US. The charge is $12.50 per hour at 1200 and 2400 baud ($6.00 at 300 baud, which is usually used for real-time conferencing). If a user is running one of the special dedicated terminal programs (which automate almost all CompuServe functions) it is possible to download 14K per minute at 2400 baud. This very reasonable when compared to long-distance charges usually incurred when calling out-ot-town BBS. And the really good Astro/Space BBS do usually seem to be out of town! USENET/BITNET users who are interested to trying out the CompuServe forums can do so at no charge. I have arranged for free "starter kits", which contain instructions, local node phone numbers, and usage credits good for a few hours. This should allow anyone to size up the situation for himself/herself. If you are interested, drop a note to the forum's administrator, Dick DeLoach at: CompuServe Space and Astronomy Forums 3533 Chesapeake Avenue Hampton, Virginia 23661 ====================================================================== Leonard Abbey Georgia Tech Research Institute BITNET labbey@gtri01.gatech.edu UUCP la3@prism.gatech.edu CIS 72277,566 ------------------------------ End of SPACE Digest V10 #202 *******************