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 ; Fri, 9 Feb 90 01:31:19 -0500 (EST) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Fri, 9 Feb 90 01:30:55 -0500 (EST) Subject: SPACE Digest V11 #23 SPACE Digest Volume 11 : Issue 23 Today's Topics: Re: More Info on SSX SPACE ACTIVIST ALERT Payload Status for 02/08/90 (Forwarded) LDEF inspection media briefing set (Forwarded) NASA Headline News for 02/08/90 (Forwarded) Re: More Info On SSX ---------------------------------------------------------------------- Date: 9 Feb 90 02:13:20 GMT From: rochester!dietz@louie.udel.edu (Paul Dietz) Subject: Re: More Info on SSX In article <5516@omepd.UUCP> larry@omews10.intel.com (Larry Smith) writes: >today there is another possibility. And that is structure. If the design >were left up to him, he would prefer to use a Methane+Oxygen or >Propane+Oxygen 2000 psi chamber pressure rocket engine. He also said >that he realizes that rocket engine design has been frozen for 15 >years, and one just cannot buy a Methane or Propane engine off >the shelf. I sat down and calculated the ratio of fuel tank to LOX tank volume for stochiometric mixtures of LH2, methane and RP-1. The numbers are: about 2:1 for LH2, about .6:1 for methane and RP-1 (I understand LH2/LOX engines actually run rich, so in practice the ratio would be higher). This is for LH2 and methane at their boiling points at 1 atmosphere. I was wondering: what determines fuel tank mass? If the tank just has to support the weight of the fuel, I get that tank mass is proportional to the linear dimensions of the tank and the mass of the fuel (or, for fixed fuel mass, as density^{-1/3}). There must also be contributions from fuel vapor pressure and insulation, which would go as r^2, and the tank would also have to be strong enough to survive reentry forces when empty. What dominates? I understand Aerojet (?) was looking into dual fuel engines using hydrogen + propane for SSTOs. That was back in the early eighties. I was wondering about plug and aerospike nozzles... the gas flow is bordered by the atmosphere while it is still exerting thrust, unlike in a conventional nozzle. Does (1) entrainment of air give thrust amplification, as in a ramrocket, and (2) would oxygen in the air react with unburned fuel, perhaps liberating additional energy? The later would conceivably be important in fuel-rich mixtures. Paul F. Dietz dietz@cs.rochester.edu ------------------------------ Date: 8 Feb 90 09:49:53 GMT From: agate!usenet@ucbvax.Berkeley.EDU (William Baxter) Subject: SPACE ACTIVIST ALERT Call the Secretary of Commerce (202/377-2113 or 202/377-4625) and inform him of Scott Pace's history of NASA cheerleading at the expense of development of private space industries. Tell him that Mr. Pace did nothing to promote HR2674 as head of the legislative committee in the National Space Society. Tell him to read the publicly available papers that Mr. Pace wrote for the Rand Corporation which reveal the poor quality of his past work on space policy. Tell him that Mr. Pace is unfit to formulate policy to promote private space industry. Be a pro-space activist. William Baxter ARPA: web@{garnet,brahms,math}.Berkeley.EDU UUCP: {sun,dual,decwrl,decvax,hplabs,...}!ucbvax!garnet!web ------------------------------ Date: 9 Feb 90 01:52:06 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: Payload Status for 02/08/90 (Forwarded) Daily Status/KSC Payload Management and Operations 02-08-90 - STS-36 (at SPIF) - MMSE operations continue. - STS-31R HST (at VPF) - At the OPF, ICBC IVT was completed yesterday. At Pad-B, fit check GSE was removed and transferred to hanger AM. At the VPF, HST confidence test continues today. - STS-32R SYNCOM/LDEF (at SAEF-2) LDEF deintegration continues. - STS-35 ASTRO-1/BBXRT (at O&C) - Bond wire and P-clamp troubleshooting were worked yesterday. Emissivity and BBXRT temperature checks will occur today. - STS-40 SLS-1 (at O&C) - Panel L14 was installed yesterday. ECS operations and rack shim thickness troubleshooting were worked yesterday and will continue today. - STS-42 IML (at O&C) - ECLS duct installation and racks 5 and 8 structural mods will be worked today. - STS-45 Atlas-1 (at O&C) - No activity. - HST M&R (at O&C) - M&R pallet will be moved to the transfer aisle today. ------------------------------ Date: 9 Feb 90 01:55:38 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: LDEF inspection media briefing set (Forwarded) Mary Sandy Headquarters, Washington, D.C. February 8, 1990 Jean Drummond Clough Langley Research Center, Hampton, Va. Patricia Phillips Kennedy Space Center, Fla. N90-10 EDITORS NOTE: LDEF INSPECTION MEDIA BRIEFING SET NASA will hold a news briefing on the initial close-up inspection of the Long Duration Exposure Facility (LDEF) on Tuesday, Feb. 13, 1990, 11 a.m, at NASA's Kennedy Space Center (KSC), Fla. LDEF Chief Scientist William H. Kinard, NASA Langley Research Center, Hampton, Va., will give an overview of LDEF's status, including processing since LDEF was returned to KSC following Shuttle mission STS-32. Also scheduled to participate in the briefing are six LDEF principal investigators: Ann F. Whitaker, NASA Marshall Space Flight Center, Huntsville, Ala.; Donald R. Wilkes, AZ Technology Co., Huntsville; Donald J. Kessler, NASA Johnson Space Center, Houston; Robert M. Walker, Washington University, St. Louis; James H. Adams, Jr., Naval Research Laboratory, Washington, D.C.; Jim A. Alston, George W. Park Seed Company, Inc., Greenwood, S.C. The principal investigators will address solar array and structural materials, thermal control and optical materials, space debris, meteoroid chemistry, thermal blankets and the Space Exposed Experiment Developed for Students (SEEDS). The briefing will be carried live on NASA Select television, Satcom F2R, Transponder 13 at 72 degrees W. Longitude, with two- way question and answer capability. News media interested in participating can access the satellite or view the event at NASA Headquarters, Washington, D.C., and at participating NASA field centers. ------------------------------ Date: 9 Feb 90 01:47:44 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Subject: NASA Headline News for 02/08/90 (Forwarded) ----------------------------------------------------------------- Thursday, February 8, 1990 Audio: 202/755-1788 ----------------------------------------------------------------- This is NASA Headline News for Thrusday, February 8.... Long Duration Exposure Facility project official Bill Kinard says visual inspection of the LDEF satellite, now at Kennedy Space Center, showed some deterioration from its six years in space, but not enough to stop plans for construction of Space Station Freedom. Meanwhile, requests for tomato seeds that flew aboard the LDEF are pouring into NASA headquarters from schools all over the country. About 3,000 requests per day are received. The single day record is over 5,000 teacher requests for seeds. A total 12.5 million tomato seeds provided by Parks Seed Company of Greenwood, South Carolina, were aboard the LDEF. The seeds will be grown under controled conditions by school students and be watched for any mutations caused by the exposure to space radiation. Better varities of vegetables are developed by mutating plants. Technicians at Kennedy Space Center have replaced a turbopump on engine #3 aboard the Atlantis now on the launch pad. There was some concern that necessary welds to the turbopump had not been recorded so the pump was replaced with a similar unit from a main engine aboard the orbiter Columbia. Meanwhile, NASA managers will meet Friday and Saturday at KSC for the STS-36 flight readiness review. Following completion of the review on Saturday, a firm launch date is expected to be announced. The present target date is February 22 for the classified DOD mission. The Galileo spacecraft is racing towards a close flyby of Venus early Saturday morning. Its velocity, relative to the sun, is now over 83,000 Miles per hour. The gravity assist fly-by will take Galileo to within 10,000 Miles of the Venusian cloud tops. About 80 images will be recorded during the 11-hour close approach along with many other scientific observations. Mission managers at JPL say the spacecraft is in excellent health. NASA Select TV will televise a news conference from JPL on the Galileo flight Saturday at 12 noon, Eastern time. ##### ----------------------------------------------------------------- Here's the broadcast schedule for public affairs events on NASA Select TV. All times are Eastern. Saturday, February 10..... 12 noon Galileo/Venus flyby news briefing from the Jet Propulsion Laboratory. All events and times are subject to change without notice. ----------------------------------------------------------------- These reports are filed daily, Monday through Friday, at 12 noon, Eastern time. ----------------------------------------------------------------- A service of the Internal Communications Branch (LPC), NASA Headquarters, Washington, D.C. ------------------------------ Date: 8 Feb 90 16:36:22 GMT From: rochester!dietz@rutgers.edu (Paul Dietz) Subject: Re: More Info On SSX In article <1990Feb8.012956.26815@cs.UAlberta.CA> james@cs.UAlberta.CA (James Bornyec; AGT Researcher) writes: >As I see it, SSX is quite small. It only gives a payload of >about 10,000 lbs. That is only 5 tons. According to previously posted >info, the total weight will be about 250 tons, and it will use up >90% of that or 225 tons of fuel. I am not sure what fuel costs >would be, but if you assume $1 a pound (probably rather high) it >costs about $45 for a pound of payload in fuel costs. I think this overestimates fuel costs a bit. According to the CRC handbook, oxygen gas costs about $15/ton. Since the major cost of making oxygen is the energy needed to liquify air (and since this energy is mostly recovered when the output is warm gas), I expect LOX would be more expensive. But even if it were an order of magnitude more expensive, that's still $0.10/pound. Someone please supply some real figures. Hydrogen would be more expensive, per pound. However, Hunter's comment about hydrocarbons suggests to me that they might instead want to use liquified methane. It is considerably more dense and less expensive than liquid hydrogen, yet should have better performance than RP-1. In some parts of the world (USSR, mideast, Nigeria) there is a great deal of surplus methane, since the gas is not easily transported great distances. Paul F. Dietz dietz@cs.rochester.edu ------------------------------ End of SPACE Digest V11 #23 *******************