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 ; Wed, 27 Mar 91 02:26:53 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Wed, 27 Mar 91 02:26:46 -0500 (EST) Subject: SPACE Digest V13 #306 SPACE Digest Volume 13 : Issue 306 Today's Topics: SOLAR TERRESTRIAL BULLETIN - WARNING UPDATE - 21 MARCH Re: Linear launchers Ulysses Update - 03/21/91 Re: More cost/lb. follies Re: "Follies" Galileo asteroid imaging Re: railguns and electro-magnetic launchers Question about Phobos mission results One Small Step for a Space Activist... Vol 2 No 3 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: Thu, 21 Mar 91 01:01:28 MST From: oler%HG.ULeth.CA@BITNET.CC.CMU.EDU (CARY OLER) Subject: SOLAR TERRESTRIAL BULLETIN - WARNING UPDATE - 21 MARCH X-St-Vmsmail-To: st%"space+@andrew.cmu.edu" /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ SOLAR TERRESTRIAL BULLETIN 21 March, 1991 Solar Terrestrial Warning Updates Solar Information Update /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ UPDATED WARNING INFORMATION The potential for major flaring has declined with the continuing decay of Region 6545. Major flaring is still possible, but will probably originate from Region 6555. The warnings have been updated as follows: Cancelled Warnings: - POTENTIAL PROTON FLARE WARNING - POTENTIAL PCA ACTIVITY WARNING Warnings still in effect: - POTENTIAL SOLAR MAJOR FLARE WARNING - POTENTIAL SATELLITE PROTON EVENT WARNING These warnings will continue to be updated as necessary. SOLAR INFORMATION UPDATE Region 6545 (S08W57) does not appear to be capable of producing any further major flaring. It has decayed to the point where major flares are unlikely from this region. It currently consists of 27 spots encompassed in an FAI type optical configuration. The region has decayed to a beta magnetic configuration. Although major flaring is not likely from this region, continued low-level M-class flaring is possible. The most threatening region currently visible is Region 6555 (S24E41), which has now been analyzed in greater detail. This region is very large (6,810 million square kilometers in area) and encompasses 64 visible spots in an FKI optical configuration. It has a magnetic beta configuration at the present time. Development into a more threatening magnetic structure is certainly possible. The region has an east-west inversion line. Some shear is present in this group. This, combined with the complexity of the system as a whole, could be enough to spawn an isolated major flare. This region could easily evolve into a major flaring source. At the present time, numerous M-class flares have been observed from this region. It is currently a fairly active region, but is not yet a major threat. An impressive surge was seen on the west limb today. The region most likely responsible is Region 6538, which is beyond the west limb now. The surge was bright and was observed between 03:40 UT and 05:12 UT on 20 March. The event was associated with an M1.9 x-ray burst at 03:33 UT and was also responsible for a moderate intensity Type II sweep which drifted from 110 MHz to 22 MHz. The surge was ejected out to a distance of about 0.3 solar radii. ** End of Bulletin ** ------------------------------ Date: 21 Mar 91 21:02:37 GMT From: agate!bionet!uwm.edu!linac!pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo!henry@ucbvax.Berkeley.EDU (Henry Spencer) Subject: Re: Linear launchers In article <9103211823.AA20327@cmr.ncsl.nist.gov> roberts@cmr.ncsl.nist.gov (John Roberts) writes: >>Actually, a more fundamental problem is that anything launched to less >>than escape velocity from Earth's surface ends up in an orbit that >>intersects the surface. It needs at least a *bit* of apogee kick anyway. > >Is there any hope of getting a deflection from the atmosphere (i.e. >aerobraking) over the course of one or two passes, of sufficient magnitude >to circularize the orbit to a point at which use of thrusters could be put off >for several more orbits? Not really. The simple rule of thumb for such things is that when you change your orbit, the new orbit always passes through the point where you made the change. So aerobraking and such inevitably result in an orbit which intersects the atmosphere. There are tricks you can play, but nothing terribly promising for this case. >If not of sufficient magnitude for that, perhaps aerodynamic maneuvering could >be used to adjust the planes of the orbits so that projectiles launched at >different times of day could be brought together. This definitely sounds plausible, although I'd have to do numbers to see how well it would work. -- "[Some people] positively *wish* to | Henry Spencer @ U of Toronto Zoology believe ill of the modern world."-R.Peto| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 22 Mar 91 01:47:21 GMT From: swrinde!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: Ulysses Update - 03/21/91 ULYSSES STATUS REPORT March 21, 1991 The following orbital data was taken on the Ulysses spacecraft as of 9 AM (PST), March 19, 1991: Distance from Earth 185,654,657 miles (298,782,209 km) Distance from Jupiter 268,960,240 miles (432,849,549 km) Velocity relative to the Sun 56,058 mph (90,216 kph) Velocity relative to the Earth 94,197 mph (151,596 kph) Tape recorder operations based on recovering data acquired during the 16 hours out of view periods are continuing on a routinely scheduled basis. Experiment reconfigurations have been carried out as required. An average of 97.5% data recovery was achieved during the past week. An Earth pointing maneuver was performed on March 13. A very small nutation was observed which damped out after about 24 hours. A close watch is being kept for the possible return of nutation. Procedures are available to control it should it occur. However, the period of maximum forcing has now passed and it is considered unlikely to return during this period of the mission. The next period of solar forcing will occur when the spacecraft is in the region of the South Solar Pole in 1994. A slew maneuver will be carried out on March 21. Routine data gathering operations will continue together with experiment reconfigurations as required. On March 18, a failure occurred just prior to the start of the pass at the 34 meter site at Madrid making it impossible to move the antenna. The station reacted promptly to make available a downlink only antenna and then to replace the failed unit on the 34 meter antenna. The antenna was restored and the only serious impact to the pass was a delay in commanding the spacecraft. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant. /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | |_____|/ |_|/ |_____|/ | ------------------------------ Date: 20 Mar 91 15:56:07 GMT From: skipper!shafer@ames.arc.nasa.gov (Mary Shafer) Subject: Re: More cost/lb. follies In article <1991Mar20.002028.2377@dsd.es.com> bpendlet@oscar.dsd.es.com (Bob Pendleton) writes: [An extremely cogent discussion of rocket technology] Yours in Murphy Bob P. Just wanted to remind everyone that Murphy was working with rockets when he formulated his now-well-known law. Of course, they were used to drive the sleds down the flat track here at Edwards, but they were rockets. I've always found it reasuring that Capt. Murphy was here at Edwards, working in aerospace testing. Things haven't changed much. -- Mary Shafer shafer@skipper.dfrf.nasa.gov ames!skipper.dfrf.nasa.gov!shafer NASA Ames Dryden Flight Research Facility, Edwards, CA Of course I don't speak for NASA "A MiG at your six is better than no MiG at all"--Unknown US fighter pilot ------------------------------ Date: 20 Mar 91 20:50:46 GMT From: argosy!kevin@decwrl.dec.com (Kevin S. Van Horn) Subject: Re: "Follies" In article <7044@mace.cc.purdue.edu> dil@mace.cc.purdue.edu (Perry G Ramsey) writes: Allen W. Sherzer writes: >> A comparison with past efforts is interesting. According to (I think) G. >> Harry Stein, both the Plymouth Rock and Salt Lake City colonies where >> started with 50 middle to upper middle class famlies selling everything >> they owned to pay for the voyage. In the case of Salt Lake City, it was considerably more than 50 families who undertook the trek -- it was an entire city (Nauvoo, Illinois) of many thousands, although the advance group was probably on the order of 50 families. Perry G. Ramsey replies: >The obvious differences are that both Massachusetts and northern Utah >support human life quite readily. Food, water, building materials, >etc. are all readily and cheaply available. This is an overstatement in the case of Salt Lake City. Jim Bridger, an explorer who knew the area well, told the Mormons that they were going to their deaths, and was so confident that the land was too arid and barren to be cultivated that he offered to pay $1000 for the first ear of corn grown in the Salt Lake valley. Only the building of canals and the extensive use of irrigation made the area capable of supporting a significant population. ------------------------------------------------------------------------------ Kevin S. Van Horn | The means determine the ends. kevin@maspar.com | ------------------------------ Date: 20 Mar 91 17:15:24 GMT From: pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utgpu!watserv1!ria!uwovax.uwo.ca!17001_1511@tut.cis.ohio-state.edu Subject: Galileo asteroid imaging The question about Galileo imaging of asteroid 951 Gaspra prompts this reply: In November 1990 I spoke to Joe Veverka at Cornell about this - he is planning the observation sequences. The range is about 1000 km (not miles) but is not known very precisely because of uncertainty over the asteroid ephemeris (especially its range from Earth). Lightcurves suggest about a 9 hour period if I recall correctly (see a recent ICARUS paper), so about 4.5 hours before closest approach the view is of the side which will not be seen close up, assuming a low latitude approach (and we know very little about the axis orientation). Those images will resolve few features but will give an idea of shape. At closest approach the asteroid should overflow a single frame, as Miranda did at Uranus, so a mosaic will be needed for full coverage. The problem is with the image motion compensation - the rate depends on the exact flyby distance and there seems little chance it will be well known in time. The strategy will be to take as many redundant frames as possible with different image motion compensation rates, in order to get at least a few frames with very little smear. At least, that was the plan in November. The lightcurve variations suggest a complex shape, and the images may be quite dramatic. Phil Stooke, Department of Geography, University of Western Ontario, London, Ontario, Canada N6A 5C2 ------------------------------ Date: 21 Mar 91 21:11:02 GMT From: agate!bionet!uwm.edu!caen!news.cs.indiana.edu!ariel.unm.edu!triton.unm.edu!prentice@ucbvax.Berkeley.EDU (John Prentice) Subject: Re: railguns and electro-magnetic launchers In article <1991Mar20.163225.1063@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: > >Can we see some more precise numbers? Chemical guns routinely hit >*ten thousand* Gs and more. None of the EM-launcher proposals I've seen >have gone higher than that. > As I said originally, I don't know what EM launchers are supposed to do. My experience is with military railgun systems where the accelerations can be stupendous. Someone else just posted a note saying 1500 g's. John -- John K. Prentice john@unmfys.unm.edu (Internet) Dept. of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA Computational Physics Group, Amparo Corporation, Albuquerque, NM, USA ------------------------------ Date: 21 Mar 91 19:59:38 GMT From: usc!wuarchive!rex!rouge!pc.usl.edu!dlbres10@ucsd.edu (Phil Fraering) Subject: Question about Phobos mission results I have a question about some of the results of the Phobos mission to Mars. Does anyone know if there have been any follow-up papers of any sort to those published in Nature in 1989? I am specifically looking for any follow-ups to the plasma-physics and magnetometer experiments, with special attention to: 1. The transport of oxygen ions out of the martian ionosphere. I believe the authors of the paper (I just gave my copy to one of the professors here) had written that the equivalent of all of the oxygen (free and bound) in the martian atmosphere is 'carried off' (to use a probrably grossly inaccurate and nontechnical term) every 100 million years. For the purposes of comparison, Mars had running water on its surface roughly during the period of the late heavy bombardment, 3.8 billion years ago. 2. A possible gas torus of some sort at the orbit of Phobos. Phil Fraering dlbres10@pc.usl.edu ------------------------------ Date: Wed, 20 Mar 91 10:14:37 -0500 From: "Allen W. Sherzer" Subject: One Small Step for a Space Activist... Vol 2 No 3 One Small Step for a Space Activist... by Allen Sherzer & Tim Kyger Last month we wrote about a heavy lift vehicle McDonnell Douglas proposed to SDIO. Another alternative was proposed by Martin Marrietta based on their Titan launcher and was called the Zenith Star Launch System (ZSLS). Martin used their Titan IV as a baseline. Instead of clustering Titans as in the Heavy Lift Delta, Martin decided to make the Titan IV bigger. The core diameter of the Titan IV was stretched to 225 inches (from 120 inches), which was the largest size tank dome they could build. This gave room for going from two to five liquid fuel engines and from two to five Titan solid strap-on boosters. The second stage was stretched from 120 inches to 200 inches in diameter and the engine was replaced with a higher thrust alternative with a new higher expansion ratio nozzle. This stage ends flush with the payload fairing which is an off the shelf Titan IV fairing with a collar on the bottom. Like the Heavy Lift Delta, maximum use is made of off-the-shelf components. The engines (solid and liquid) are the same as used on existing Titans. In addition, the avionics suite exist today. All in all, 86% of the ZSLS dry weight is made up of existing components. In its initial version the ZSLS can put 118,000 pounds into LEO. Later, with higher thrust strap-on boosters (in the works today), that weight will go up to 150,000 pounds. How much does this beast cost? we have two estimates on that; each made under different assumptions. The Office of Technology Assessment (OTA) provided one estimate in a document called "Launch Options for the Future". In it they assumed that development would be funded under the usual rules used by the government when they develop similar hardware. They estimate the development cost at about $1.2B. The second estimate comes from SDIO and Martin Marrietta. Just as with the Heavy Lift Delta, ZSLS could be built for about $500M and future launches can be had for below $250M (some sources say launch cost will drop to $150M per launch in quantity). This is far cheaper than the Shuttle per launch yet two to three times the payload. Why the difference? OTA assumed the development would be managed like any other government project: lots of oversight and risk assumed by the Government. This adds cost both from the extra paperwork involved and the fact that the contractor has no incentive for the program to be efficient. SDIO assumed they were just buying a service at a fixed price. They would pay a fixed price for one launch. The contractor owned the vehicle and was liable for any extra costs. This gave the contractor the incentive to hold down costs and save money. Would you like to see one of these cheaper alternatives built? A lot of people inside and outside Congress would like to fund this instead of the ALS/NLV/ALDS alternative. However, it will be an uphill fight and your help is needed. Read the article on Heavy Lift Delta and ZSLS in the September 1990 'Aerospace America' and then meet with your representatives and ask them for their support. Legislative Roundup The Great Exploration The federal FY '92 budget has in it $30 million for Department of Energy civil space efforts: $7 million for nuclear propulsion, $6 million for space based nuclear power generation, and $17 million for Concepts and Technologies. Some of the Concepts and Technologies money will go toward the development of Great Exploration hardware (inflatable modules, prototype mining equipment, and other systems). If they meet with success this sum could be augmented later with Internal Research and Development funds which could double the size of the effort. Getting this through will be very hard. The Appropriations committees will be very reluctant to fund civil space with DoE funds despite the fact that DoE is a member of the Space Council. The showdown won't be for a few months but grassroots help is needed to show support. Things to do: 1. MEET with your Representative and Senators. Ask them to write a letter to Rep. Bevil (D-AL) and Senator Johnston (D-LA) supporting this new program. 2. If you talk with your Senator about DoE efforts in civil space don't give th impression that this effort will hurt NASA. NASA's support in the Senate is very strong. In fact, when supporters of commercial space legislation last year told senators that the legislation would get NASA out of the launch business it made it a lot harder to get the bill passed. Instead tell them that the Great Exploration will help leverage NASA's efforts (which it will) and that this effort is in line with the Augustine recommendations. Omnibus Space Act The Omnibus Space act from last year should be re-introduced around the time you read this. It has been delayed because they received a lot of good feedback from activists and they want to include some of the comments (again, we CAN have an effect if we try). Some changes include: 1. The private sector will be able to put advertisements on the sides of US launch vehicles (just like the Soviets). 2. Bonds issued to raise money for spaceports will be treated just like regular municipal bonds for tax purposes. In other words, spaceport bonds will be treated just like today's airport and sea port bonds. Allen Sherzer: (313) 769-4108 (W) (313) 973-0941 (H) aws@iti.org (net) Tim Kyger: (202) 225-2415 (W) (703) 548-1664 (H) (800) 673-1762 (voice mail) ------------------------------ End of SPACE Digest V13 #306 *******************