Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from hogtown.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, 6 May 91 02:56:20 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Mon, 6 May 91 02:56:12 -0400 (EDT) Subject: SPACE Digest V13 #495 SPACE Digest Volume 13 : Issue 495 Today's Topics: Re: "Bussard Ramjets" AKA duct space drives Re: "Bussard Ramjets" AKA duct space drives One Small Step for a Space Activist... (Vol 2 No 5) SPACE Digest V13 #475 SPACE Digest V13 #475 PLEASE REMOVE ME FROM THE DL, THANX IN ADVANCE Re: mars orbiter Re: Terraforming Venus Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription requests, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: 4 May 91 07:31:03 GMT From: agate!lightning.Berkeley.EDU!fcrary@ucbvax.Berkeley.EDU (Frank Crary) Subject: Re: "Bussard Ramjets" AKA duct space drives In article <9105030307.AA23983@ucbvax.Berkeley.EDU> jd@tardis.computer-science.edinburgh.ac.uk writes: >I thought one of the problems in astrophysics at the moment was the >uniformity of the interstellar medium. Or am I getting it confused with >the M.B.R. ? You are right that the uniformity of material in the universe is a BIG problem in astrophysics (Cosmology more specifically). But you have the wrong scale. The problem is that the universe is much more uniform than expected, in terms of galaxy-sized clumps and gaps. For an interstellar ramjet, the interstellar medium should be uniform on the scale of a few million km. This level of nonuniformity could quite easily be possible. Frank Crary UC Berkeley ------------------------------ Date: 4 May 91 21:12:04 GMT From: usc!rpi!news-server.csri.toronto.edu!utzoo!henry@ucsd.edu (Henry Spencer) Subject: Re: "Bussard Ramjets" AKA duct space drives In article <9105030307.AA23983@ucbvax.Berkeley.EDU> jd@tardis.computer-science.edinburgh.ac.uk writes: >>As far as the uniformity of the ISM, all astronomical methiods of measuring >>its density give results which are the average over, at least, light years. >>Local density clumps are not detectable at this time. >> >I thought one of the problems in astrophysics at the moment was the >uniformity of the interstellar medium. Or am I getting it confused with >the M.B.R. ? You are. The problem -- on a vastly larger scale than anything relevant to a Bussard ramjet -- is that the universe is very lumpy while the microwave background radiation is very smooth, and it is difficult to explain the evolution of such a lumpy universe from such a uniform Big Bang. -- And the bean-counter replied, | Henry Spencer @ U of Toronto Zoology "beans are more important". | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Wed, 1 May 91 08:33:40 -0400 From: "Allen W. Sherzer" Subject: One Small Step for a Space Activist... (Vol 2 No 5) One Small Step for a Space Activist... by Allen Sherzer & Tim Kyger NASA's budget is now about as big as it is going to get in this decade. We may continue to see small increases, but nothing major. This places an upper bound on how many large programs NASA can undertake. NASA has room for three large multi-billion space programs this decade. Currently these are Freedom and Mission to Planet Earth. The third is the National Launch Development Program (NLDP). No other major initiatives realistically can be expected before the next century (unless things somehow change radically). NLDP is a program to develop the next generation of Heavy Lift Vehicles (HLV) and is sponsored by the Air Force and NASA. NLDP will develop a family of launch vehicles lifting up to 160,000 pounds to LEO for $300/pound. Is NLDP worth the money invested and the opportunity cost the US will invest in it? Will it work? Currently it looks like the answer is no. The Air Force and NASA seem to have very different views of the NLDP vehicle. The Air Force wants a Titan IV follow on and NASA wants an HLV. A recent story in the April 15 Aviation Week also says that NLDP costs will go up from $300/lb to $500 to $1,000/lb. It can only go up from here. What we are seeing now is something very similar to what happened when NASA began development of the Shuttle. The systemic problems which made the Shuttle so expensive and unreliable are still there. The Shuttle was designed by a committee with conflicting goals; so far NLDP is no different. NLDP will fail for the exact same reasons the Shuttle failed. What alternatives are there to the ten year, $14+ billion NLDP? We have written about some recently. Companies have offered to build HLV's for about 5% of NLDP's development cost and in half the time if the government will just buy the launches. For $1 billion we could have two different HLVs with operational costs far better than NLDP. If we were to build these other alternatives, we would have $13 billion to spend on other projects. Furthermore, Title II of last years NASA authorization act (which we all worked so hard for) seems to make NLDP development moot; why develop it if you can't buy it? For that matter why develop it when you can just buy it for far less? If we build NLDP, we will spend the rest of the decade and have nothing to show at the end. We will have no infrastructure to speak of and none on the horizon. Get a copy of the Sept. 90 Aerospace America and read the article on the Zenith Star Launch Systems. Meet with your Congresscritters and ask them to spend our money where it will do some good. We must stop spending dollars on what could be had for pennies. Legislative Roundup ISDC At this years Space Development Conference I will be running a workshop on legislation. The workshop will outline what goes into legislation, how it gets passed and how you can draft your own space legislation. As an optional second part, a group will be formed to use the lessons learned to pass a real piece of legislation. Current plans are to make the new version of the Omnibus Commercial Space Act the bill we work for. If you would like to help out, and are not going to ISDC, drop one of us a line and we will get you busy. Synthesis Group As of this writing (April 24) the Synthesis Group report is being finalized. It may will be out when you see this. Reports indicate that they will recommend their own Heavy Lift Vehicle using what amounts to a Saturn V at the core and SSME derived strap on boosters. In other news, Rep. Lamar Smith (R-TX) added some special language into the Report on the NASA Authorization bill for this year. This report language will require NASA to maintain a core Synthesis Group made up of current members. The NASA administrator is required to consult with them on enacting the Synthesis Group recommendations. This will make it a lot harder for NASA to put the Synthesis report on the back burner. Things to do: 1. Get a copy of the report and read it. If you like what you read, write to the Administrator of NASA and tell him. Ask him to support it and work to see it enacted. 2. Write to the Vice President and the Space Council. Ask them to enact the Synthesis proposals and push for funding. Spaceport Financing Act HR-1358, the Spaceport Financing Act, was recently introduced by Reps Bacchus (D-FL) and Shaw (R-FL). This bill will extend to spaceport bonds the tax status currently enjoyed by airport bonds. This is similar (but not as far reaching) as the equivalent provisions in last years Omnibus Space Commercialization bill of Rep. Bob Walker (R-PA). The bill has been referred to the House Ways and Means Committee for action. Things to do: 1. Write your Congresscritters and ask for support of this bill. This is especially important if your Representative is on Ways and Means. Ask him/her to cosponsor. Omnibus Space Commercialization Act The bill is close to completion and is in the hand of the House office of the Legislative counsel. These guys are bunch of lawyers who will read the bill and recommend changes to make the bill easier to interpret. Expect it to go 'in the hopper' around May first. We will provide a summary of the bill next month (assuming it is on schedule). Tidbits The NASA Authorization bill will go to the full house May first. By June first the Senate should be done as well... In testimony before the House the military seems to have done an about face on NASP. They now see lots of use for it which should ease the funding battles... Rep. Rohrabacher (R-CA) got an amendment to the NASA Authorization changing the name of one account from "Expendable launch vehicles and services" to "Launch services". The report language makes it very clear that the name was changed to show NASA that Congress is serious about Title II. Allen Sherzer: (313) 769-4108 (W) (313) 973-0941 (H) aws@iti.org (net) Tim Kyger: (202) 225-2415 (W) (703) 548-1664 (H) kyger@grebyn.com (net) ------------------------------ ReSent-Message-ID: Resent-Date: Wed, 01 May 91 13:36:26 EDT Resent-From: Tommy Mac <18084TM@msu.edu> Resent-To: space+@andrew.cmu.edu Date: Sun, 28 Apr 91 02:01:50 EDT Reply-To: space+%ANDREW.CMU.EDU@msu.edu From: space-request+%ANDREW.CMU.EDU%CARNEGIE.BITNET@msu.edu Subject: SPACE Digest V13 #475 Comments: To: space+@ANDREW.CMU.EDU To: david polito <15432DJP@MSU.BITNET>, Tom McWilliams <18084TM@MSU.BITNET> Re: Screwed up Galileo >>Perhaps a more sensible approach would be to jettison the reentry >>probe, change the second gravity assist and salvage some science by >>abandoning Jupiter and converting to a multiple asteroid flyby >>mission. It could repeatedly swing by earth and/or mars to be >>directed onto flybys of new asteroids. With luck, we could get >>pictures of half a dozen or so, with the data from each encounter >>played back over the low gain antenna at the next flyby of earth. >I dunno about this one. Getting a look at the atmospheric composition >of Jupiter from the 'top' of the atmosphere on down to where the probe >stops transmitting would seem (to me) to be worth a *lot* more than >a few extra asteroid encounters, especially considering that the original >encounters can still be done. Not to mention, the extra detail (as compared >to Voyager) we can get on the moons of Jupiter is worth a lot, especially >for Io and Europa. Dropping all this for a few measly asteroids seems to >be a waste. Sure dropping Jupiter for a 'few measly asteroids' would seem to be a waste. But dropping Jupiter for the most abundant, accessible resources and plantetary science specimens in the Solar System is a FANTASTIC idea. Remember that, unlike the Planets, we can (eventually) study every gram of the Asteroids, given the time and determinantion. We will never study the interior of any of Jupiter's moons, let alone Jupiter. This not only means the Asteroids would make better scientific specimens, but also means we can recover all the heavy metals (i.e. gold, iron, lead, copper) that are forever hidden at the center of the other planets. And finding those heavy metals could be the incentive that private industry needs to get their butts busy building a space infrastructure. You would like to see a space infrasturcture wouldn't you? Tommy Mac Acknowledge-To: <18084TM@MSU> ------------------------------ ReSent-Message-ID: Resent-Date: Wed, 01 May 91 14:11:08 EDT Resent-From: Tommy Mac <18084TM@msu.edu> Resent-To: space+@andrew.cmu.edu Date: Sun, 28 Apr 91 02:01:50 EDT Reply-To: space+%ANDREW.CMU.EDU@msu.edu From: space-request+%ANDREW.CMU.EDU%CARNEGIE.BITNET@msu.edu Subject: SPACE Digest V13 #475 Comments: To: space+@ANDREW.CMU.EDU To: david polito <15432DJP@MSU.BITNET>, Tom McWilliams <18084TM@MSU.BITNET> Subject: Re: Alexander Abian wants to blow up the moon? >> Very late last night (around 4 or 5 AM) I tuned in to CBS's >>"Nightwatch" news program in the middle of a "debate" between Bevan >>French of NASA and some crazy loon at Iowa State University named >>Alexander Abian. >> My question is basically... who IS this Abian guy and what >>exactly is he trying to say? >While standing in the checkout line last month with my bag of Doritos, >waiting for the cashier to figure out the price on a bar of soap for the >customer in front of me, I had the good luck to spy a copy of the Weekly >World News, with the headline 'SCIENTIST WANTS TO BLOW UP MOON!' in type >large enough to announce the advent of World War III. >Basically, this guy wants to blow up the moon in such a manner as to >have a large chunk drop into the Pacific, thereby knocking the planet >into a 0 degree (as opposed to the current 23.45 degree) axial tilt, >making it springtime forever over a large chunk of the earth and bringing >happiness to all. How he plans to do this wasn't made clear. >There weren't any sidebars or graphs, though, so I discounted the article >entirely. :-) Despite the lack of Sidebars and Graphs (I think USA Today had some :-), this kook is totally serious, or at least hard up for publicity. In this weeks Newseek, he got on the 'funny/stupid quotes of the week' page. He was talking about how we are victims of the 'celestial dictatorship' or some such revolutionary jargon. Aside from the possibility of cruching a highly poplulated area with moon-parts or creating a mile-high tidal wave, or all the other stupid parts of this guys idea there are other associated 'difficulties' Even if it did work, the plan would A) level the entire surface of the Earth due to the tourque induced as the angular momentum vector is wrenched 23 degrees. B) Freeze most of the Planet because the new rings would shade most of the Earth for years and years. However, that does not mean that nuclear explosions on the Moon would be all bad. 1) Wouldn't it make a hell-uv-a fireworks show? Better than an eclipse! 2) We could induce a spin on the moon! Then we could study the far side without those costly probes and rockets. 3) Better than testing the potentially dangerous things here! Tommy Mac :-) Acknowledge-To: <18084TM@MSU> ------------------------------ X-Ns-Transport-Id: 0000AA00268C396B2BDC Date: Wed, 1 May 1991 21:53:01 PDT From: Lisa_M._Owen.ES_M2@xerox.com Subject: PLEASE REMOVE ME FROM THE DL, THANX IN ADVANCE To the owner, Please remove me from the dl. I can't seem to be able to do it myself. Thanx in advance, Lisa ------------------------------ Date: 2 May 91 16:23:45 GMT From: sdd.hp.com!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo!henry@ucsd.edu (Henry Spencer) Subject: Re: mars orbiter In article <1991May1.121855.1@dev8a.mdcbbs.com> rivero@dev8a.mdcbbs.com writes: >As the original Viking Missions to Mars were winding down, there were already >plans and a launch date to send the next set. Vikings 3 and 4 were to >be similar to the first 2, with the addition of a detachable remote vehicle... >The project was placed on indefinate hold after the Challenger Incident. Um, really? References, please. There was talk of various Viking followons, but as far as I know, all of them died long before Challenger. (Remember, Challenger happened ten years after the Viking landings.) -- And the bean-counter replied, | Henry Spencer @ U of Toronto Zoology "beans are more important". | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 2 May 91 17:58:49 GMT From: news-server.csri.toronto.edu!helios.physics.utoronto.ca!aurora.physics.utoronto.ca!neufeld@uunet.uu.net (Christopher Neufeld) Subject: Re: Terraforming Venus In article <74253@eerie.acsu.Buffalo.EDU> v096my2q@ubvmsc.cc.buffalo.edu writes: >> >Since venus receives about twice? as >much solar energy as Earth the water has vaporized which causes the >huge atmospheric pressure, while on mars it may be frozen out in the >polar caps and soil. > Venus' high atmospheric pressure is not due to a huge mass of water in the atmosphere. There is very little water in the atmosphere because it tends to photodissociate and then the hydrogen leaves for deep space. The atmosphere is primarily carbon dioxide, freed up from surface rocks which tend to evolve it if heated in the absence of water. >I think the main issue here is to first heat up the >martian surface by throwing in some CFC's or something similar, or possibly >permanently shielding venus from the sun. After the atmosphere is >normalized by human standards then we can worry about wether or not it's >or not and how we would go about cleaning up that. > Heating up the martian atmosphere would not increase the atmospheric pressure. It's not just PV=nRT, V=constant type problems from high school chemistry. If anything the pressure would decrease marginally as more atmosphere escaped into space. Similarly for Venus, the atmospheric pressure is not going to decrease until the temperature drops to below the liquification temperature of CO2 at the relevant pressure. > Also when people talk about bombarding either mars or venus with >comets. Where are they going to come from and how are they going to get here? >Is their any evidence that their actually is an oort cloud, or is this >just a nice hypothesis? > The Oort cloud would be a long way to go for water. Comets dropped in from the Oort cloud would also take tens of thousands of years to get to the inner solar system if they were dropped in by simply cancelling their orbital motion about the Sun. You'd have to get out and push it all the way in if you were in a hurry. It might be more practical to extract hydrogen from the gas giants, or water from their satellites. >Mark Wieczorek -- Christopher Neufeld....Just a graduate student | Flash: morning star seen neufeld@aurora.physics.utoronto.ca Ad astra! | in evening! Baffled cneufeld@{pnet91,pro-cco}.cts.com | astronomers: "could mean "Don't edit reality for the sake of simplicity" | second coming of Elvis!" ------------------------------ End of SPACE Digest V13 #495 *******************