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 ; Wed, 21 Jun 89 05:16:58 -0400 (EDT) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Wed, 21 Jun 89 05:16:51 -0400 (EDT) Subject: SPACE Digest V9 #500 SPACE Digest Volume 9 : Issue 500 Today's Topics: EMI/EMC TEST FACILITY WANTED Re: DO IT YOURSELF SPACE PROBES PT.2 Let's go back ---------------------------------------------------------------------- Date: 15 Jun 89 20:52:59 GMT From: agate!sag4.ssl.berkeley.edu!egp@ucbvax.Berkeley.EDU (Earl Powell) Subject: EMI/EMC TEST FACILITY WANTED The Space Sciences Laboratory of the University Of California, Berkeley is looking for a California vendor and/or facility do EMC testing on it's ATLAS 1 payload (FAUST). The test should be to MSFC-SPEC-521A, (Electromagnetic Compatibility Requirements on Spacelab Payload Equipment) section 4. This testing is a requirment of our verification plan. Your help is appreciated. Thank you Earl Powell, Project Manager Faust ------------------------------ Date: 15 Jun 89 15:03:52 GMT From: mcvax!ukc!etive!bob@uunet.uu.net (Bob Gray) Subject: Re: DO IT YOURSELF SPACE PROBES PT.2 In article <2393@blake.acs.washington.edu> wiml@blake.acs.washington.edu (William Lewis) writes: >In article <890612.21420918.098644@RMC.CP6> EDWARDJ@RMC.BITNET writes: >>phases of the mission. [Query, did the Phobos probes fail because of the use >>of cheap components, human error, both or neither?] > I don't remember the reason for the other probe's failure, although I >think it was a probe failure and not an Earth failure... (?) A space exibition featuring some of the results from Phobos 2 opened at the Science Museum in London last week. In what they called an exclusive report, C4 news interviewed some of the Soviet scientists responsible for the Phobos mission. Three very strange details of the mission were revealed. First, a number of the images taken of an area near the equator in the infra-red clearly show an area covered with a series of regular rectangular features about two miles across. One of these images was shown in the report, and is in the exhibition. (Anyone in London reading this who has been to the exhibition and care to comment?) Second, one of the images shown features the shadow of what could only be one of the Martian moons. Except that there wasn't any moon in the place and time it would have to have been to cast the shadow. Third, Phobos 2 was transmitting an image to Earth when the signal died. In the words of one of the scientists interviewed, it "showed something that shouldn't have been there". The report interpreted this to mean that the last image shows some debris in the same orbit as the moon Phobos, and that it was collision with this that destroyed Phobos 2. The Soviets haven't released this image. The report tried hard to avoid being identified with the "little green men" and "faces on Mars" group, but I am surprised that the "newspapers" which regularly feature that type of article haven't caught onto this story yet. Bob. ------------------------------ Date: 13 Jun 89 07:55:43 GMT From: amdcad!weitek!sci!daver@ucbvax.Berkeley.EDU (Dave Rickel) Subject: Let's go back The 20th anniversary is coming up in a month. To celebrate, the Smithsonian's AIR AND SPACE June/July issue was dedicated to Apollo. Anyway, it started me wondering just what you'd need to get there again. Using my CRC and a calculator, i came up with the followin numbers (again, i'm good at making simple arithmetic mistakes; if you find some, send me email): Delta v which 5.383 km/sec Earth Orbit (500 km) to escape velocity (i was too lazy to figure a lunar transfer trajectory, this should be reasonably close) 1.360 km/sec Lunar transfer to Lunar Orbit (100 km) (this is too high-- it's to get from a hyperbolic orbit into lunar orbit) 1.363 km/sec Lunar Orbit to Lunar Surface (this is too low--it doesn't count delta-v wasted fighting lunar gravity) 0.292 km/sec Three minutes hover at the lunar surface (this is to make up for the previous entry being too low) 2.480 km/sec Lunar transfer to Lunar Surface (if we don't want to go into a lunar orbit before hitting (crashing if the engines don't restart) into the moon) (again, this doesn't figure delta-v wasted fighting lunar gravity--add in the hover time). The 5.4 km/sec figure is nasty; it sounds like we need LOx/LH. Oh well. When they come back to earth, they can use aerobraking, and either go into LEO or do a direct reentry. Let's do this in a big way, like in the A. C. Clarke stories. Let's look at a cargo moonship first. Say it's supposed to softland 20 tons on the moon; the 20 tons to include engines and guidance and landing gear and so on. Clearly, that'd take the shortest path--blast from LEO directly to the moon. 5.4 + 2.5 + .3 = 8.2 km/sec delta v. The SSMEs have an Isp of 4.464 km/sec in vacuum; say we can get 4.4 km/sec. That's a mass ratio of about 6.45 (wet weight to dry weight). Call it 131 tons fuel, 4 tons tanks, 20 tons for the rest of the moonship; 155 tons total. That allows a bit of slop. We could send up two dry cargo ships per shuttle load (i think--it has about a 45 ton capacity, doesn't it?). Fuel is, of course, a problem. It seems the solution would be to ship up fuel as water to an orbiting cracker/ refigerator (use expendables for this). I guess that of the 20 tons eventually soft-landed, 15 tons could be useful payload. Oh well. The return trip is much simpler. Let's say we take off 20 tons from the moon, the 20 tons again including engines and guidance and all that stuff. This is 2.5 + .2 = 2.7 km/sec delta v. Call it 18 tons fuel, .5 tons tanks, for a wet weight of 39 tons. So. One ship could be a return vessel (and a bit of fuel), another could be more fuel for the return vessel, and one could be astronauts. Probably on the order of six astronauts. Send up ten vessels (three return, three fuel, three astronauts, one general-purpose cargo) resupply periodically, always send enough fuel in the resupply ships to keep at least one of the return vessels fully fueled, in case of accidents. Let's see. At $6M/metric ton to LEO, that's about $3 billion for a set of three moon ships. Not including materials or development (there is a quote from WIERD SCIENCE that would be appropriate here. Something along the lines of "Shut up. I know what reality is. This is fantasy."). david rickel decwrl!sci!daver ------------------------------ End of SPACE Digest V9 #500 *******************