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 ; Wed, 24 Oct 1990 01:25:13 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Wed, 24 Oct 1990 01:24:39 -0400 (EDT) Subject: SPACE Digest V12 #482 SPACE Digest Volume 12 : Issue 482 Today's Topics: Tentative Date for Launch of 10th GPS Block II Satellite GPS Satellite Constellation Status Planetary coordinates (was: Re: planetary north and names) Re: You Can't Expect a Space Station to be Cheap HST Update Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription notices, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: Tue, 23 Oct 90 15:36:45 ADT From: LANG%UNB.CA@BITNET.CC.CMU.EDU Subject: Tentative Date for Launch of 10th GPS Block II Satellite Apparently-To: The tentative date for the launch of the 10th Navstar GPS Block II satellite is 20 November 1990. The satellite will be placed in orbit from Cape Canaveral onboard a Delta-II booster. A successful launch will bring the total number of usable GPS satellites to 16. (Source: USNO) ================================================================================ Richard B. Langley BITnet: LANG@UNB.CA or SE@UNB.CA Geodetic Research Laboratory Phone: (506) 453-5142 Dept. of Surveying Engineering Telex: 014-46202 University of New Brunswick FAX: (506) 453-4943 Fredericton, N.B., Canada E3B 5A3 ================================================================================ ------------------------------ Date: Tue, 23 Oct 90 15:18:18 ADT From: LANG%UNB.CA@BITNET.CC.CMU.EDU Subject: GPS Satellite Constellation Status Apparently-To: Navstar GPS Constellation Status (90-10-23) Blk NASA Orbit II PRN Internat. Catalog Plane Launch Seq SVN Code ID Number Pos'n Date Clock Comment -------------------------------------------------------------------------------- Block I 1 4 1978-020A 10684 (C-4) 78-02-22 Not usable since 85-07 2 7 1978-047A 10893 (A-4) 78-05-13 Not usable since 85-09 3 6 1978-093A 11054 A-3 78-10-06 Rb 4 8 1978-112A 11141 (C-3) 78-12-10 L-band signals turned off 89-10-14 5 5 1980-011A 11690 (C-1) 80-02-09 Not usable since 84-05 6 9 1980-032A 11783 A-2 80-04-26 Rb Operating on 2nd Rb clock 7 81-12-18 Launch failure 8 11 1983-072A 14189 C-2 83-07-14 Cs 9 13 1984-059A 15039 C-1 84-06-13 Cs 10 12 1984-097A 15271 A-1 84-09-08 Cs 11 3 1985-093A 16129 D-1 85-10-09 Rb Actually near position C-9; operating on Rb clock without temp. control Block II II-1 14 14 1989-013A 19802 E-1 89-02-14 Cs Became available 89-04-15 II-2 13 2 1989-044A 20061 B-3 89-06-10 Cs Became available 89-08-10 II-3 16 16 1989-064A 20185 E-3 89-08-18 Rb Became available 89-10-14 II-4 19 19 1989-085A 20302 A-4 89-10-21 Cs Became available 89-11-23 II-5 17 17 1989-097A 20361 D-3 89-12-11 Cs L-band signals enabled 90-01-06 II-6 18 18 1990-008A 20452 F-3 90-01-24 Cs Became available 90-02-14 22:26 UT II-7 20 20 1990-025A 20533 B-2 90-03-26 Cs Became available 90-04-18 23:13 UT II-8 21 21 1990-068A 20724 E-2 90-08-02 Cs Became available 90-08-22 15:00 UT II-9 15 15 1990-088A 20830 D-2 90-10-01 Cs Became usable 90-10-15 00:39 UT Notes 1. NASA Catalog Number is also known as NORAD or U.S. Space Command object number. 2. Bracketed orbital plane position = satellite no longer operational. 3. An earlier version of this table had PRN 16 in plane D. Note correction. 4. Clock: Rb = Rubidium; Cs = Cesium 5. A series of maneouvres to rephase the Block I and II satellites began on 15 March 1990. PRNs 2, 11, 14, 18, and 19 are still drifting to their final in-plane locations. 6. The orbit plane slots given for the Block I satellites are those positions before the current maneouvres. ================================================================================ Richard B. Langley BITnet: LANG@UNB.CA or SE@UNB.CA Geodetic Research Laboratory Phone: (506) 453-5142 Dept. of Surveying Engineering Telex: 014-46202 University of New Brunswick FAX: (506) 453-4943 Fredericton, N.B., Canada E3B 5A3 ================================================================================ ------------------------------ Date: Tue, 23 Oct 90 10:57 CST From: Bill Higgins-- Beam Jockey Subject: Planetary coordinates (was: Re: planetary north and names) Original_To: SPACE Different celestial bodies have different systems for designating latitude and longitude. On the Moon, latitude and longitude follow a system much like the Earth's: Latitude is measured as degrees north or south of the equator. Longitude is measured as degrees east or west of a prime meridian, so that the maximum value it can have is 180 degrees East or 180 degrees West. The prime meridian passes through the mean sub-Earth point, I believe. On Mars and other bodies, all longitudes are measured in degrees west of the prime meridian, so they range from 0 to 360. No "East" or "West" designation is necessary. For example, instead of being roughly at 90 degrees East, the city of Calcutta would be at "270 degrees" instead in such a system. This information comes from my reading of maps. How did space cartography get this way? Beats me. Moon maps, Mars maps, and Venus-and-everywhere-else maps were presumably started in different centuries, which probably had some influence on their evolution. Pointers to more information would be welcome. During the first and second stage Bill Higgins flights of the vehicle, if a serious Fermi National Accelerator Laboratory irretrievable fault should occur and HIGGINS@FNALB.BITNET the deviation of the flight attitude of HIGGINS@FNAL.FNAL.GOV the vehicle exceeds a predetermined SPAN/Hepnet: 43011::HIGGINS value, the attitude self-destruction system will make the vehicle self-destroyed. --Long March 3 User's Manual Ministry of Astronautics, People's Republic of China (1985) ------------------------------ Date: Tue, 23 Oct 90 22:06:42 -0400 From: "Allen W. Sherzer" Subject: Re: You Can't Expect a Space Station to be Cheap Newsgroups: sci.space Cc: In article <6747@hub.ucsb.edu>: >As a designer on Fred who is only superficially familiar with the LLNL >ideas, let me throw out some of the major design drivers on Fred, and I >would like to know how LLNL deals with them..... I'll do my best to answer although I don't have all the details. If you still have questions I would encourage you to research the program yourself. I can give you some references and addresses. >1 - Atomic oxygen, very few materials can survive thirty years in the AO >environment, Fred has a 30 year lifetime requirement. That means we have >to GUARANTEE 30 years, in reality it might last much longer; what material >is the inflatable habitat made of ? Exterior surfaces must all be metallic >to shield against AO, does the LLNL design do this ? The LLNL Earth station outer layer is PTFE-overcoated Kevlar. They are designed to deal with vacume and temprature. ILC, the company which has built all NASA space suits since Apollo has done a preliminary design and say it will work [1]. As for atomic oxygen, PTFE has exibited surface erosion when exposed to atomic O2 of less than 3 microns/year [2] so a coating 100 microns deep will do. I should also add that the LLNL station is designed for a life of ten years not thirty. But since it costs less than 5% of what Freedom costs this shouldn't be viewed as a problem. >2 - Radiation - need to guarantee to operate after a 30 year dose in LEO >(crews rotated every 90 days) kinda restricts the electrical design; My sources do not say anything on this for the Earth Station, just for the trip to Mars. However, in my readings of NASA objections to the Great Exploration they make no mention of it. It could be that LLNL presented an approach NASA accepted. What special steps is Freedom taking? >3 - orbital debris - need to have a Safe Haven configuration of multiple >interconnected nodes and modules with fast closing hatches in between, to >seal off the punctured section, can the LLNL design do this ? Yes, for details, see [1]. The Earth Station has an external shield plus 24 spearate airtight compartments. BTW, can Freedom do the same? From what I have seen the two main modules are all open. What would the Freedom crew do if there was a large breach in the main habitation module? >4 - Can LLNL assemble their Fred equivalent system using 22 shuttle >flights? This means weight is a big issue. The LLNL Earth Station goes up in 1 HLV flight. This can be done because the inflatable structures greatly reduce weight and launch volume. In [1], ILC states that the packed volume of the Earth Station would be 28.8 cubic meters for an all fabric design and 31.6 cubic meters for a design with hard pressure bearing floors. The total weight budget is 40.4 tons, but that includes everything. >LLNL's amorphous silicon >solar cells are certainly cheap to manufacture, but for watts per pound >they are inferior, and heavy to launch. They are claiming 1KW per kilo of silicon. NASA says that is an order of magnitude better than the state of the art. (Dr. Wood provided them with samples). Either way, this is a minor issue. The weight budget for power is big enough to use what NASA says is the state of the art. >5 - LLNL's Nickel-hydrogen batteries are nothing new, Fred uses the same >type; Interesting. The NASA assessment says these batteries won't work [3]. Why is Freedom using batteries which NASA says won't work? If they will work, why is NASA saying they won't? >6 - What experience does LLNL have in the following areas of space >applications:- airlocks, hyperbaric chambers, long life vacuum bearings, >BAPTAS (Bearing and Power Transfer Assemblies) = slip rings to get power >and data from the rotating panels to the station users, large space >structures attitude control, long life propulsion systems, low pressure >outgassing and offgassing; Don't know in detail (why don't you call and ask?). They have however, done work in space based systems and have experience running large complex technical programs. >The impression I have is that LNNL trades off safety and risk versus cost. And who doesn't? The only way for Freedom to avoid those trade offs is to not build it. >As a safety engineer that is anathema to me. As a safety engineer it is your job to quantify exactly that. Tell me something, as a safety engineer on Freedom what are the odds of a death due to a major breach of the habitation module? >There is nothing clever >about taking risks, any fool can do that. That implies that the people flying on Freedom are either not taking any risks or are fools. Yes this program is risky. It is about as risky as Apollo. The Earth Station however, has an assured crew return vehicle as part of its design so although the odds of a major failure are high, the odds of loss of crew are much lower. >However, they better be >prepared for the bad press they get when they have a Challenger style >disaster. They are. They are preparing by being up front with the risks involved. Challenger was a disaster because people felt betrayed. NASA told them the system was safe enough to send a school teacher. Had they been more honest Challenger wouldn't have been so big a deal. > NASA clearly does not want anything like that to happen again, and >safety costs money guys, sorry but that is just the facts of life. NASA levels of safety will cost us half a trillion dollars to get to Mars. We can't affoard that. Exploration has always been very risky, there is no way around that. Dynamic research and exploratory organizations thrive on this risk and look forward to pushing the envelope. That spirit prevaded NASA during Apollo. I don't think that spirit is dead, but it is dying. Allen [1] Conceptual Design Study for Modular Inflatable Space Structure by ILC Dover inc. Dec. 4 1989 (LLNL Purchase order B098747) [2] High Power Inflatable Radiator for Thermal Rejection From Space Power Systems by D. Chittenden, Pro23 Intersociety Energy Conversion Engineering Conference, 1988 [3] NASA Assessment of the LLNL Space Exploration Proposal and LLNL Responses, LLNL doc. no. SS90-9 page 27. -- +-------------------------------------------------------------------------+ | Allen W. Sherzer | What should man do but dare? | | aws@iti.org | - Sir Gawain | +-------------------------------------------------------------------------+ ------------------------------ Date: Tue, 23 Oct 90 11:19:20 EDT From: John Roberts Disclaimer: Opinions expressed are those of the sender and do not reflect NIST policy or agreement. Subject: HST Update There was a very interesting update on the Hubble Space Telescope on NASA Select on Monday. Among other things, they described the uproar following the discovery of the spherical aberration, from the viewpoint of some of the people within NASA. I found it refreshingly candid, especially the descriptions of the misunderstandings and exaggerations that arose. For instance, they mentioned that one member of Congress gave an impassioned speech on "ultraviolet light is invisible, so what good are pictures taken in ultraviolet?". While NASA is not blameless in this situation, I think they got a lot more heat than the problem deserved. It seems in the past few months that the press has been trying to give a fairer presentation of the facts. There was considerable discussion of space science and future plans. I'll try to post some details tonight. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ End of SPACE Digest V12 #482 *******************