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 ; Tue, 17 Apr 90 02:51:54 -0400 (EDT) Message-ID: <0a-fnjC00VcJM8lk5b@andrew.cmu.edu> Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Tue, 17 Apr 90 02:51:28 -0400 (EDT) Subject: SPACE Digest V11 #274 SPACE Digest Volume 11 : Issue 274 Today's Topics: Re: Teenage Mutant Ninja Tomatoes A brief survey. Re: Fermi Paradox Project HARP and Dr. Bull ---------------------------------------------------------------------- Date: 16 Apr 90 18:44:00 GMT From: deimos.cis.ksu.edu!uafhp!bmccormi@uunet.uu.net (Brian L. McCormick) Subject: Re: Teenage Mutant Ninja Tomatoes In article <1990Apr16.180456.29686@elroy.jpl.nasa.gov>, pjs@aristotle.Berkeley.EDU (Peter Scott) writes: > How about that announcement from NASA backpedalling on the possibility > of the tomato seeds having mutated into toxic forms from the extra > cosmic radiation they underwent? The news station I was watching showed [stuff zapped] > But anyway, what kinds of mutations might we expect, given the > especially energetic particles these seeds had to deal with? One thing that struck me about this incident was when NASA officials said that they wouldn't have any problem with eating a tomato from one of these plants. Excuse my paranoia, but I don't think I would. It strikes me that the fruit of most members of the genus Solanum (of which the tomato is a member) contains a poison, solanin. I would be worried that a relatively minor mutation had occured that would render the fruit poisonous. Does anyone know what the actual likelihood of such a mutation is? Am I justified? ------------------------------------------------------------------- Brian McCormick bmccormi@uafhp.uark.edu I deny being in any way affiliated with the College of Engineering. ------------------------------------------------------------------- ------------------------------ Date: 17 Apr 90 05:39:11 GMT From: zaphod.mps.ohio-state.edu!brutus.cs.uiuc.edu!jarthur!tcourtoi@tut.cis.ohio-state.edu (Todd Courtois) Subject: A brief survey. Fellow usenetters: Sorry to disturb this illustrious newsgroup, but I am hoping that you can help me. Currently I am working on a research paper which asks the "simple" question, "Why are there disproportionally few women in math and science?" So how can you help me? Well, below are just a few short questions with standardized answers. Both males and females are encouraged to reply, but note that we will only accept one reply per username. Please send your replies to one of the following addresses : tcourtoi@jarthur.claremont.edu tcourtoi@jarthur.bitnet uunet!jarthur!tcourtoi Please put "SURVEY" in the subject line. Note that following the questionnare is a sample e-mail answer. Please follow this format EXACTLY (it isn't difficult) because we are going to process these through the computer, and it's going to reject anything that isn't standard (thus your views won't count). Questions: 1. Are you female or male? F M 2. Are you a scientist, engineer, mathematician or computer scientist? Y N (This includes any technical area requiring at least a bachelor's degree, and programmers or technical support staff). 3. Do you feel you've been discriminated against in hiring, promotion, recognition, etc. because of your gender? Y N 4. In your opinion, which sex receives preferential treatment in hiring, promotion, recognition, etc. in your profession? F M 5. Do you feel you are treated the same as people of the opposite sex with similar background and qualifications? Y N 6. In your opinion, is less gender bias apparent in your profession than in other, non-technical professions? Y N 7. Do you feel inferior in technical ability (programming skill, math ability, design creativity) to your counterparts of the opposite sex? Y N (NOTE this means *inherent ability*, NOT training-- see next question). 8. Do you feel that your educational background or training was less strong than your peers' of the opposite sex? Y N 9. Do you feel that, in general, there is a bias against women in your profession? Y N 10. Do you feel women sacrifice their careers for family more often/more severely than men? Y N Sample Answer reply (just send an e-mail message which has this format): M Y Y M Y Y Y N N N Note that there are ten questions and ten answers. Each answer is only one upper case letter. Any messages which do not follow this format will be destroyed. Please do not include .sig files or any text but the answers. Thanks for your cooperation! In a few weeks when all the replies have been processed I will post the results to all the newsgroups in which this questionaire has appeared. Please don't send requests, as this mail address has been set up exclusively for processing the questionaires. ------------------------------ Date: 17 Apr 90 05:32:21 GMT From: mentor.cc.purdue.edu!f3w@purdue.edu (Mark Gellis) Subject: Re: Fermi Paradox My own candidates for the solution to the Fermi Paradox are as follows: 1) We actually are alone. (Or at least, we are the first technically advanced civilization in the galaxy.) 2) There is no way around the lightspeed limit and intelligent civilizations are fairly uncommon. I played around, writing some sf stories, with realistic STL drives for spacecraft, and the simple fact is that making them work is a real problem. Unless you have practical FTL travel, interstellar trade and colonization is going to be a very slow process, and not one that many beings, even very long-lived ones, are likely to find interesting, if they are anything like us (of course, they might not be). Thus, the expanding sphere of solar systems around a home system would be expanding at a very slow rate, perhaps one light year per thousand years, perhaps even slower. 3) The aliens know about us and have set our solar system (and perhaps even a small zone of systems nearby, like a 10 LY radius) off limits. Enforcement would certainly be a problem, but I imagine it would only be a minority of beings ("perverts") who would break the interdict, and unless they were very smart and very careful, they would probably be caught before they did too much damage. If technological intelligences are uncommon, we may be very precious to the galactic community, and the level of protection may be very high, and the penalties for breaking the interdict hideous beyond our imagination. (UFO's may be either poachers, licensed research craft, or galactic police.) Enjoy. ------------------------------ Date: 15 Apr 90 19:35:36 GMT From: van-bc!rsoft!mindlink!a752@ucbvax.Berkeley.EDU (Bruce Dunn) Subject: Project HARP and Dr. Bull Dr. G. Bull was recently murdered in Europe. It is believed that he was killed as a result of his activities related to military weapons in the Middle East. In the 1960s, Dr. Bull was associated with project HARP (High Altitude Research Project), run out of McGill University in Montreal, with U.S. Army funding. Project HARP involved the use of large guns to fire instrumented ballistic projectiles and rockets to high altitudes. The program seems to have been terminated in approximately the mid 1960s. Bull later became an arms designer and arms broker, who had dealings with Iraq among other countries. Recent news reports say that the British have intercepted a shipment of "pipe segments" to Iraq, and feel that it represents pieces that could be assembled into a very large gun for military purposes. Bull seems to have been involved in the design and/or acquisition of these potential gun components. For background information in interpreting the potential usefulness of such a large gun, this message gives some basic information about project HARP from the open literature, coupled with some personal comments. Material in quotation marks is from the cited papers. Paper 1: Bull, G.V. (1964) Development of Gun Launched Vertical Probes for Upper Atmosphere Studies. Canadian Aeronautics and Space Journal 10:236-247. This paper was written to accompany a speech made by Bull in Toronto in May 1964. In the Introduction to the paper: "During the past several years, both theoretical and experimental investigations have been undertaken to determine the applicability of guns to scientific studies of the ionosphere. Such possibilities have intrigued ordnance workers for many years, but involve a complex mixing of advanced gunnery techniques, scientific experiment considerations and economics. "In late 1961, with material support from the US Army, McGill University undertook the development of a 16 inch gun system. In early 1962 this program came under full support of the US Army through the Army Research Office and the Ballistic Research Laboratories" In a section on sub-calibre ballistic projectiles, Bull says: "For example, in the case of a 16 inch naval gun which normally fires shells in the 3,000 lb. class at velocities of 2,800 fps, velocities as high as 6,000 fps can be obtained with shot weights of the order of 400 lbs., the sub-caliber vehicle in this case having a ballistic coefficient considerably higher than the normal shell. By re-design of the gun (i.e. extending the chamber and barrel) to optimize at this lighter shot weight, velocities approaching 7,000 fps are possible." A series of sub-calibre "Martlet 2" vehicles were built, which were sub-calibre and rode the barrel in a fall-away sabot. Canted fins on the projectile maintained aerodynamic stability, and spun the projectile up so that it was stable once leaving the atmosphere. These were fired at elevations of from 60 to 90 degrees from a 16 inch naval gun (on loan from the U.S.) which was located in Barbados. The gun was bored out to 16.5 inches and made into a smooth-bore cannon. Altitudes of approximately 500,000 to 600,000 feet (100 miles, 160 km) were projected for this arrangement, and early trial reported in the reference cited went as high as 112 km. Martlet vehicles carried instruments made from discrete solid-state electronics - they were potted in a mix of epoxy and sand (!) and the designers did not seem to have any real trouble getting the electronic to survive the launch acceleration which peaked at approximately 20,000 g. Martlet vehicles also routinely carried a liquid mixture of trimethyl-aluminum and triethyl-aluminum to be released at high altitudes for ionosphere studies. Another option was to carry sodium-thermite mixes which when ignited would release sodium vapor (a type of experiment similar to the Pegasus satellite barium releases). If projectiles of a similar weight were fired for range rather than height then ranges of up to 150 to 200 miles were calculated, depending on the ballistic coefficient. Shots from the gun were routine and relatively inexpensive. Bull states: "Normally, loading of the gun can be accomplished in under one half hour, allowing a firing rate of one an hour." "Standard service propellant available as surplus (WM/.245) has been used, and the gun geometry has not been modified. Firing programs are planned for the summer and fall of this year [1964] when the gun barrel will be extended and lighter sabots used with propellant designed to match the light projectiles, which should extend the Martlet 2A apogee to 200 km." [if I remember correctly, the gun was fitted with a fiberglass muzzle extension which was successful in improving the performance]. "The economics of the gun launched probe has been as predicted, with the Martlet 2A airframes loaded with TMA/TEA and a flare in the nose cone varying in price between $2500 and $3500, with gun launch costs (propellant and gun wear) included." After having discussed ballistic projectiles, Bull discusses gun- launched rockets: "Gun fired artillery rockets have been developed extensively since World War II and normally must withstand barrel acceleration loads of the order of 30,000 g along with the rotational loads superposed by shell spin. The performance of this type of rocket is only of marginal interest in the vertical probe application where non-spinning (from a stress viewpoint) vehicles are flown at acceleration levels of less than 10,000 g and relatively very large rocket motors are desired with high mass fractions. In May of 1963, work was started on what was designated as the Martlet 3A rocket assist vehicle as part of the HARP program. The objective of this activity was the development of a 16 inch gun launched probe which would carry some 40 lbs. of payload to altitudes in the 500 km range." The Martlet 3A and later 3B rocket vehicles were sub-calibre and used various solid propellants in various configurations. The main problem with gun launched rockets is supporting the solid propellant during the launch acceleration so that it does not collapse into the internal cavities molded into the propellant grain, and a lot of development work was performed to investigate the performance of various solid propellant grains. From their knowledge of the performance of the 16 inch gun system and general information about the specific impulse and mass fraction of solid fuel rockets, it was calculated that it would be fairly easy to put a payload into orbit using the HARP gun and a multistage solid fuel rocket. Orbital Launch Vehicle Characteristics from Figure 31 in the Bull paper: Total launch weight: 2000 lbs Stage 1 weight: 1440 lbs Stage 2 weight: 403 lbs Stage 3 weight: 117 lbs Payload: 40 lbs Muzzle velocity 4500 fps Mass fraction 0.8 Specific impulse 300 sec (vacuum) The first and second stages were to be fired at relatively low altitude, but clear of the atmosphere. The third stage was to circularize the orbit, and would be fired horizontally at orbital altitude. Such a vehicle was never built, although motors of the first stage size were developed. The HARP group was also involved in exploring the possibilities of launching liquid fueled rockets from the gun. These could be thin-shelled as long as they had no gas spaces in them (you can accelerate a balloon full of water at any g force you like, as long is it is fully supported during the acceleration). Paper 2: Eyre, F.W. (1966) The Development of Large Bore Gun Launched Rockets. Canadian Aeronautics and Space Journal 12:143-149. "The concept of a rocket launched from a gun is not new. It will suffice to affirm in this paper that the gun launched artillery rocket was in full development during the Second World War and this investigation still continues. Like so much work in allied fields, a great deal of what has been done and is being done is classified and cannot here be repeated." "The conventional solid propellant gun, firing meaningful projectiles, currently appears able to develop a maximum muzzle velocity of some 6000 to 9000 fps. Allowing an 80% recovery of muzzle kinetic energy as potential energy, this corresponds to a ceiling for sounding work of some 800,000 to 1,000,000 ft. (say 160 to 200 statute miles). Significant improvements beyond this level must come either from use of a different type of gun or from rocket boost during vehicle flight, which is here considered." "Figure 3 shows muzzle velocity vs. shot weight for the Barbados gun. [HARP]" "Assumed conditions: Max. pressure 60000 psi Fixed charge, 1000 lbs M8M propellant Web size optimized." [some approximate data points from Figure 3 graph, and from Figure 4 showing acceleration vs. shot weight] Shot weight Muzzle velocity Max. acceleration 500 lbs 7700 fps 13,000 g 1000 lbs 6400 fps 9,000 g 1500 lbs 5700 fps 6,500 g 2000 lbs 5200 fps 5,000 g Eyre then goes into a long technical discussion related to how to support propellants of various types in a solid fuel rocket during the gun acceleration. Perhaps the neatest concept is to simply fill all empty spaces in the rocket with a fluid which then can support the propellant grain hydrostatically during launch (sort of a rocket water- bed). The rocket is then accelerated using some form of pusher plate, which seals the liquid in. The plate drops away after launch, and the fluid is then vented or drained before ignition. With regard to practicality and performance, Eyre writes: "It has transpired in design studies that although structural problems do arise due to the acceleration loads, and additional problems are posed by the necessity to use a folding stabilizer assembly, mass fractions almost as high as conventional rockets can be achieved and the design problems are partially alleviated by an all supersonic flight regime. Given this condition the advantage of the gun can be seen in that a typical vehicle of mass fraction 0.8 would have an apogee of 176 miles used conventionally, 257 miles at 1000 fps launch, 342 miles at 2000 fps, 435 miles at 3000 fps, 529 miles at 4000 fps and so on." Eyre then discusses the fabrication of a full-scale, full bore (16 inch) motor with a weight of 1450 lbs., designated the Martlet 4A and designed for the Barbados gun. At the time of writing of the paper, it does not appear as if this had yet been test launched - I do not know how far the program was carried before it was cancelled. "Current work is directed towards development and application of a thin plastic wear resistant coating [they were worried about excessive wear on the rocket casing], and launching of 16 inch motors to investigate scale factor effects. At the time of writing [1966] full bore Aerojet General Corp. grains are awaiting launch. ... At the present time a heavy test program is about to commence with many agencies participating and for the most part full scale hardware ready for launch." In summary, up until the time of writing of the later of the two quoted papers in the mid 1960s, HARP under Dr. Bull appeared to have been highly successful using a surplus 16 inch naval cannon in firing projectiles to high altitudes and in firing solid fueled rockets. If the gun had been aimed more horizontally, great ranges would have been acheived. It might be argued that the "doomsday" gun which Iraq was said to be trying to assemble would not be practical in an engineering sense. However, Bull has been called the most brilliant gun designer of this century. If, as is probable, he was involved in the Iraq gun, his track record suggests he would get it right. His comment on vehicle design for guns of different scales is interesting: "Obviously since launch weight (ie payload) is increasing roughly as the cube of the scale, while peak accelerations are decreasing linearly, the larger the gun the simpler the vehicle engineering problem." This comment applies to vehicle design, but related arguments could be advanced for the problems of gun design in relation to size. If a large gun can be fixed in position (ie. by putting it in a sloping tunnel) then gun length no longer has to be maintained at 50 to 100 calibres or so. If the gun were given external support, a long thin- walled gun with a modest internal pressure and modest projectile acceleration could well give the same performance as a conventional short gun with thick walls, high pressure, and high acceleration. Such a long, low pressure gun would also be easier to make than a conventional cannon of the same projectile size and velocity. The walls could be thin enough to be fabricated by relatively conventional industry, and the gun could be assembled on the spot by joining a number of sections. Military implications: If such a weapon were assembled, it would be dandy for repeated delivery of tons of high-explosive or chemical to a fixed target such as a distant city. The downside would be that the gun would have a fixed, known site and would be vulnerable to counterattack. But then again, missile silos can be hardened to survive all but very close hits by nuclear weapons, and there is nothing inherently delicate in an underground cannon which would be damaged by ground shock. If properly protected in a tunnel, it might take a direct hit by nuclear weapons to put it out of action. Space implications: The Pegasus vehicle is solid fueled. Remove its wings and give the B-52 back. Develop a hydrostatic support system for the motors, and harden anything delicate in the avionics. Throw away the delicate satellite-type payload, and substitute a g-insensitive bulk payload such rocket propellant, liquid oxygen, water etc. Launch from a long, wide- bore, thin walled gun buried in a sloping tunnel. With a launch velocity of say 1500 m/sec, the payload to orbit will be a lot higher than Pegasus can launch with the same rocket motors. This may be a low- cost approach to space station resupply. Bruce Dunn a752@mindlink.UUCP -- Bruce Dunn Vancouver, Canada a752@mindlink.UUCP ------------------------------ End of SPACE Digest V11 #274 *******************