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 ; Thu, 12 Jul 1990 01:26:57 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Thu, 12 Jul 1990 01:26:27 -0400 (EDT) Subject: SPACE Digest V12 #50 SPACE Digest Volume 12 : Issue 50 Today's Topics: Titan HLV Rocket Engines Re: Titan boosters Re: Titan boosters Magellan Update - 07/11/90 Re: Redshift Re: NASA's lobbying on the net Re: one opinion.... Re: NASA Budget Re: HST down and out HST and KH 9s Re: Oppose manned Mars exploration -- support robotics 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: 11 Jul 90 14:39:32 GMT From: serre@boulder.colorado.edu (SERRE GLENN) Subject: Titan HLV Allen refers to the development of the Titan HLV as taking three years from ATP (Authorization To Proceed). IMHO this is hopelessly optimistic. This timeline is probably a product of some marketing dog who is trying to get more business for Martin Marietta. The Titan HLV is currently only a concept (or concepts). For comparison, the Titan IV is a Titan III with stretched (longer) Stage I and II propellent tanks, longer SRMs (more segments), a bigger payload fairing (based on MOL work, I think), and a Centaur thats a stretched version of the Shuttle Centaur. The program was advertised as low-risk and minimal new design and was started around '84. After Changeller, it received new impetus, but the first launch (ILC for those who like acronyms), without the Centaur, was not until last year. The Titan HLV would require (at the least) completely new propellent tank designs and a new launch pad. It would probably also need a new payload fairing, among many other details. If Martin were proposing to strap two Titan IVs together, I might believe the three-year timeline, but for the Titan HLV I am skeptical, to say the least. To wrap up, I think a Titan V (HLV) is a good idea and a logical evolution, but the advertised (by Allen) three year timeline should be taken with a grain of salt. These opinions are mine alone, and do not represent those of Martin Marietta Astronautics Group or anyone else. Thanks for your attention. --Glenn Serre serre@tramp.colorado.edu ------------------------------ From: mnmon%CONNCOLL.BITNET@vma.cc.cmu.edu Date: Wed, 11 Jul 90 12:01:35 EDT Subject: Rocket Engines A collegue of mine needs to know the approximate exhaust velocity (not thrust) from a typical rocket engine such as the SRB's or main engines on the shuttle. Can anyone out there help us? Thanks! Please reply to mnmon@CONNCOLL on BITNET or thru the space network. ------------------------------ Date: 11 Jul 90 16:36:12 GMT From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!henry@ucsd.edu (Henry Spencer) Subject: Re: Titan boosters In article <732.269A3938@ofa123.fidonet.org> David.Anderman@ofa123.fidonet.org (David Anderman) writes: >... I am not too keen on the >idea for other reasons, specifically 2 - the two SRBs that the large >Titans use. They are nasty, and tend to explode, and create vibrations >that humans don't seem to like. Titan reliability is better than the Shuttle to date, based on actual flight records rather than theoretical guesswork. There were plans to man-rate the MOL variant of the Titan III, so the SRBs apparently don't pose fundamental problems. There is much more flight experience with the Titan SRBs than with the shuttle SRBs. >Why not use Apollo capsules for the emergency return craft for Freedom? I believe Rockwell was talking about proposing exactly that. -- NFS is a wonderful advance: a Unix | Henry Spencer at U of Toronto Zoology filesystem with MSDOS semantics. :-( | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 11 Jul 90 21:11:38 GMT From: usc!cs.utexas.edu!uwm.edu!bbn.com!orc!inews!td2cad!yoyodyne!jreece@ucsd.edu (john reece) Subject: Re: Titan boosters In article <5460@itivax.iti.org>, aws@vax3.iti.org (Allen W. Sherzer) writes: > > For a savings of $150 million per launch and the need for fewer > launches, they can get shaken up a bit. If you figure the vibration lasts > 10 min. that means we are spending $1.5 million per min. to lessen it with > the shuttle. Is that worth it? The vibration is not simply a matter of personal convenience for the crew. Once vibration exceeds a certain threshhold they are effectively incapacited until several minutes after it stops. John Reece Not an Intel spokesman jreece@yoyodyne.intel.com ------------------------------ Date: 11 Jul 90 20:22:25 GMT From: zaphod.mps.ohio-state.edu!samsung!sdd.hp.com!elroy.jpl.nasa.gov!forsight!jato!mars.jpl.nasa.gov!baalke@tut.cis.ohio-state.edu (Ron Baalke) Subject: Magellan Update - 07/11/90 MAGELLAN STATUS REPORT July 11, 1990 The Magellan spacecraft is progressing toward its insertion into Venus orbit Aug. 10, 30 days and about 8 million miles away. All star calibrations during the past week were executed perfectly yielding an average attitude update of only 0.058 degrees. The concern over heat has been essentially eliminated with predictions for maximum temperatures now below established redline limits. Testing of the new sequence called "Mini- Controller," the sequence which starts the Venus Orbit Insertion (VOI) block, was successfully completed in the System Verification Laboratory. SPACECRAFT Distance from Earth (mi) 125,919,167 Velocity Heliocentric 84,500 mph One-way light time 11 mins, 10 secs ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ Date: Wed, 11 Jul 90 19:10:11 EDT From: John Roberts Disclaimer: Opinions expressed are those of the sender and do not reflect NIST policy or agreement. Subject: Re: Redshift >Date: 9 Jul 90 17:09:57 GMT >From: hpfcso!hpfcdj!goris@hplabs.hpl.hp.com (Andy Goris) >Subject: Re: Red Shift >> It seems to me that everyone is pretty much agreed that the universe is >> expanding. Dr. Hubble and his collegues showed that there is a Red shift >> that can be observed. This dopler effect is believed to be caused by >> the universe expanding. >I have always been suspicious of the theory that the observed red-shift >of distant objects is caused by an expanding universe for the following >reason: It seems unlikely that a photon could travel millions (and >billions) of light-years (both time and space) without being affected >in at least SOME way by all the forces and particles that it would >encounter on its journey. A photon can lose energy by moving against a gravitational gradient, or by being absorbed and reemitted by matter. The former effect is very minor, and I believe for this to be causing the degree of redshift seen, the universe would have to be *many* times as massive as is currently thought. The latter effect does not preserve the spacing between spectral lines, and is thus inconsistent with observations. I would say that most of the photons that were affected by forces and particles never got here to be observed. The others are pretty much forced to keep about the same energy they started out with. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: 11 Jul 90 22:56:33 GMT From: zaphod.mps.ohio-state.edu!samsung!emory!mephisto!prism!ccoprmd@tut.cis.ohio-state.edu (Matthew DeLuca) Subject: Re: NASA's lobbying on the net In article <9007112052.AA24159@ibmpa.paloalto.ibm.com> szabonj@ibmpa.UUCP (Nicholas J. Szabo) writes: > >Look, I am not trying to be a grinch here, I just want to point out >that this is an unfair situation for other government agencies and >private companies, and that some (only a small fraction, actually, >but NASA posts quite a lot) of the posts have been legally and ethically >questionable. I certainly don't want to discourage Ron Baalke et. al. >from their informative, valuable postings. A agree with Tom Neff that >it would be a great loss if sci.space lost these postings. But I >strongly disagree that NASA equipment should be used for promoting the >agency. In other words, you want those nice people at NASA to take their time to publish useful information, but you don't want them to join in the discussion if it involves saying anything good about their employer. You seem to be following the path that many people on the network follow when they find that they are in the minority; they start pointing out the link between the poster and the poster's employer, then start mentioning that the employer wouldn't like what they are saying, if they only knew, and maybe they should be quiet before they get in trouble. A not-very-subtle attempt at censorship. If you value this network at all, you will sit down and can your noisemaking about the 'legal ramifications' of people from NASA posting; so far, the net has remained untouched by the brainless politicians that runn this country...however, there is already one legal case involving the net, where a junior high school that had net access as an educational project started getting alt.sex; we don't need another such case. People like you are going to be the ones who destroy what we have. -- Matthew DeLuca Georgia Institute of Technology Do not meddle in the affairs of wizards, Office of Information Technology for they are subtle, and quick to anger. Internet: ccoprmd@prism.gatech.edu ------------------------------ Date: 11 Jul 90 23:41:50 GMT From: mcgill-vision!clyde.concordia.ca!news-server.csri.toronto.edu!utgpu!utzoo!henry@BLOOM-BEACON.MIT.EDU (Henry Spencer) Subject: Re: one opinion.... In article <1990Jul11.061518.1259@csuchico.edu> rreid@cscihp.UUCP (Ralph Reid) writes: >... NASA has some big projects which are widely publicised, such >as the Teacher in Space project, which do not work out quite the way >they were planned... Well, let's be honest about this one: the Citizens In Space program, of which the Teacher In Space was the first phase, was jammed down NASA's throat by Ronald Reagan, over NASA's strenuous objections. In the post-Challenger era, this one has worked out exactly the way NASA wants, i.e. it's on the shelf indefinitely. -- NFS: all the nice semantics of MSDOS, | Henry Spencer at U of Toronto Zoology and its performance and security too. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 11 Jul 90 13:18:06 GMT From: ox.com!itivax!vax3.iti.org!aws@CS.YALE.EDU (Allen W. Sherzer) Subject: Re: NASA Budget Doug Mohney writes: >Sorry, you can't develop "cheap" alternatives and build Shuttle II. There are no plans to build Shuttle II right now nor are there likely to be in the future. This is a good thing because the exact same political forces which made shuttle I expensive and unreliable will do the same for shuttle II. Heavy Lift Titan however, is funded differently. They are not asking for up front money for development. All they ask for is a guarantee of 17 launches. Three years from the word go, they will provide a launch of 40 tons for $500 million. Launch 2-17 will send up 50 tons for $150 million. If they can't do it, they don't get their money. With Shuttle II the contractors get paid if it works or not. Which would you prefer: the company betting our money or the one betting it's own money? >You'll get stuck with one or the other. I would rather be stuck with HLT than Shuttle II. >Or don't you remember the original development cycle of the Shuttle? Quite well. As I said, that's why it would be a mistake to do Shuttle II. >You'll have to fly SOME missions of the Shuttle for the next 3 years, boss, >for no other reason than that SpaceLab and various other cargos are designed >to fit into her cargo bay. Agreed. We will need to use the three years of HLT development time to transition to the new mode; we can't drop the Shuttle tomorrow. One of the things we should do in this three year period is to design a small incrimentally growable space station. The first HLT launches will deploy it. The last shuttle flights will then take the various Shuttle specific lab modules and deploy them as co-orbiting platforms with the space station. That way we won't need to spend hundreds of millions to heave them up and scientists won't need to wait years for a slot to do their experiments. All of this could be paid for with the money saved not using the Shuttle for one year. Every year we use manned HLT instead of the shuttle, we save another $1.5 billion. Allen | | In War: Resolution | | Allen W. Sherzer | In Defeat: Defiance | | aws@iti.org | In Victory: Magnanimity | | | In Peace: Good Will | ------------------------------ Date: 11 Jul 90 06:26:41 GMT From: uoft02.utoledo.edu!fax0112@tut.cis.ohio-state.edu Subject: Re: HST down and out In article , bowers@elxsi.dfrf.nasa.gov (Al Bowers) writes: > >>I keep hearing this comparison for HST. I wonder if this is valid >>(I am not an expert in this field)... >>bright earth rather than a faint distant object. I know it is classified >>but I wonder how HST requirements compare to the keyhole sats. > > The equation for angular resolution as a function of aperature is > fairly simple. Why not calculate it and figure it out? Assume a > typical resolution, from photos in Jane's All the World's Aircraft I > would guess a license plate is about right. Assume a pretty standard > 100 mile orbit. Assume your optics are diffraction limited. > > I think HST still comes out as the largest optical system orbited yet, > by a couple of factors, though not an order of magnitude. > > Yes, I did that calculation first and with 2" you are pretty close to what you hear about the keyholes. that is why I posted because my suspicion is that Hubbles specs are actually more rigorous than the KHs, and therefore the comparison is not as simple. But this comment got edited out of my original post. Robert Dempsey Ritter Observatory ------------------------------ Date: 11 Jul 90 16:47:05 GMT From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!maytag!watdragon!watyew!jdnicoll@ucsd.edu (Brian or James) Subject: HST and KH 9s Someone [I cunningly can't recall *who*] mentioned that the Hubble bears some similarity to the KH 9 satellites. How expensive would it be to adapt the KH 9 design for use as a orbiting telescope, to be used for astronomy rather than recon? Are the differences between the criteria for a recon satellite and an astronomical telescope so great that whoever it is that makes the KH satellites would not be a reasonable source for future orbiting telescopes? JDN ------------------------------ Date: 11 Jul 90 21:13:30 GMT From: thorin!homer!leech@mcnc.org (Jonathan Leech) Subject: Re: Oppose manned Mars exploration -- support robotics In article <9007111825.AA16498@ibmpa.paloalto.ibm.com> szabonj@ibmpa.UUCP (Nicholas J. Szabo) writes: >In article <1990Jul10.181209.2729@maverick.ksu.ksu.edu> jerry@matt.ksu.ksu.edu (Jerry Anderson) writes: >>I strongly disagree. It is not a question of what can be done with the >>money available, it is a question of fighting for more money. As long as >>there is no manned presence in space, the space budget will dwindle year >>after year. > >This is a myth. Polls show that Americans support the unmanned space >program to an equal or greater degree than they support the manned >program. When dollar figures are included in the poll, the unmanned >program always recieves more support. Another myth is that the American public supports the space program. When compared to other federal programs, NASA comes out on the bottom, right after the military. -- Jon Leech (leech@cs.unc.edu) __@/ "We were driving along, minding our own business, when there was a sudden flash of blue light which blotted out the stars. I thought it was a nuclear bomb going off and despaired for my career." - Keith Hughes ------------------------------ End of SPACE Digest V12 #50 *******************