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 ; Sun, 25 Mar 90 01:27:01 -0500 (EST) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Sun, 25 Mar 90 01:26:25 -0500 (EST) Subject: SPACE Digest V11 #184 SPACE Digest Volume 11 : Issue 184 Today's Topics: Martian Stardard Time astronomy Re: Coilgun on a 747 - supplies to orbit at $20/lb? Re: Martian Stardard Time Astronaut brain damage What does it cost to push a pound into orbit? Whither sci.military? Amroc bows out of commercial launchers Re: Freedom finding related to LDEF? Lunar Orbital Elements Needed Comments on Space Digest Re: Intelsat / Titan failure ---------------------------------------------------------------------- Date: 24 Mar 90 23:57:53 GMT From: zaphod.mps.ohio-state.edu!brutus.cs.uiuc.edu!ux1.cso.uiuc.edu!pequod.cso.uiuc.edu!ahiggins@tut.cis.ohio-state.edu (Andrew Higgins) Subject: Martian Stardard Time > From: jdnicoll@watyew.waterloo.edu (Brian or James) > Subject: Martian Clocks and Calendars > Message-ID: <22304@watdragon.waterloo.edu> > > Possibly a foolish question, but does anybody out there know how > the hypothetical manned missions to Mars will deal with the slight > difference between the Martian day (88775.3 seconds) and our day > (86399.9 seconds)? I imagine most of the trip will use our standard > date and time systems, but it strikes me as inconvinient to have the > 'official' day slightly out of phase with the local day. > James Nicoll Not foolish at all! In fact, there is rather an extensive literature on the subject. A number of people have developed an extensive system of days, weeks, months, and years (including the Martian equivalent of leap years). I can refer you to the sources below for much greater detail. Unfortunately, no one has be clever enough yet to incorporate the periods of Phobos and Deimos into a Martian calendar system. References: Gangale, Thomas, "The Lost Calendars of Mars," _Spaceflight_, July 1988. Gangale, Thomas, "Martian Standard Time," _Journal_of_the_British_ _Interplanetary_Society_, June 1986. Lovelock, J. and Allaby, M., _The_Greening_of_Mars_, Warner Brooks, Inc., New York, 1984. "Mars Clock in Debut," _New_York_Times_, February 15, 1954. Levitt, I.M., "Mars Clock and Calendar," _Sky_&_Telescope_, May 1984. Richardson, Robert S., _Exploring_Mars_, McGraw-Hill Book Company, New York, 1954. -- Andrew J. Higgins | Illini Space Development Society prometheus@uiuc.edu | a chapter of the National Space Society phone: (217) 359-0056/244-0321 | at the University of Illinois P.O. Box 2255 - Station A, Champaign, IL 61825 "The ability of man to walk and actually live on other worlds has virtually assured mankind immortality." - Wernher von Braun ------------------------------ Date: 24 Mar 90 03:29:59 GMT From: csusac!sactoh0!tree!guest@ucdavis.ucdavis.edu (digerness) Subject: astronomy Decomposed thanks..having trouble climbing this TREE...it's my first time ------------------------------ Date: 23 Mar 90 16:32:26 GMT From: wuarchive!cs.utexas.edu!hellgate.utah.edu!uplherc!esunix!bambam!bpendlet@decwrl.dec.com (Bob Pendleton) Subject: Re: Coilgun on a 747 - supplies to orbit at $20/lb? Great ideas. Now, what happens if we apply Nivens' Law and a little paranoia? How good would this thing be as an antisatellite weapon? How about as an antimissile system? Or an anitaircraft system, antishipping system, antiarmor system... There are many military applications of a mach 30 crowbar. Especially an air mobile one. Oh well, just todays paranoia excercise. Bob P. -- Bob Pendleton, speaking only for myself. UUCP Address: decwrl!esunix!bpendlet or utah-cs!esunix!bpendlet X: Tools, not rules. ------------------------------ Date: 25 Mar 90 04:14:09 GMT From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!watdragon!watyew!jdnicoll@ucsd.edu (Brian or James) Subject: Re: Martian Stardard Time While it is pleasing to know that there are Martian calenders already being born, might I ask that the well-intentioned, but incredibly unworkable system of incorporating satellite orbital periods as quanta sizes for the calender be dropped? Our calender already creaks under the load of leap years, skipped leap years and the rarely commented on [and nonesistant] kilomillenial 'half-pfenig' days needed to cover the fact that twenty eight and a bit is not a useful unit to divide three hundred and sixty five and a bit by. Why cripple a new borne if we don't have to? JDN ------------------------------ Date: 25 Mar 90 02:12:23 GMT From: psuvm!fth@psuvax1.cs.psu.edu (Fred Houlihan) Subject: Astronaut brain damage The following is mentioned in: >Message-ID: <27460008@hpcvia.CV.HP.COM> >Date: 23 Mar 90 20:08:21 GMT >>Is the chief problem with a "full-time spacewalker" the radiation >>exposure? > >No, that's relatively minor, and the station itself doesn't give that much >more shielding. EVA as currently practised is a major hassle, with a lot >of overhead effort involved, and is considered relatively dangerous (less >redundancy than working inside in shirtsleeves). Perhaps my observations are outdated as a result of more recent data acquired since I last was involved with this, but about 5 years ago I was given an estimate that on a round-trip manned mission to Mars it was expected that approximately 5% of brain cells would be destroyed by solar and cosmic radiation. Does anyone have any more up-to-date estimates on this? I would guess that as LDEF results are reported we should get a better quantitative handle on radiation effects in earth orbit at least. Has the USSR published any results on brain deterioration from their long duration missions? Animal or human? I'll be looking forward to the results from those elementary and high schools who will be planting the LDEF tomato seeds. ------------------------------ Date: 24 Mar 90 13:05:36 GMT From: lilink.com!upaya!tbetz@rutgers.edu (Tom Betz) Subject: What does it cost to push a pound into orbit? From time to time in discussion of space-related topics, we need rules of thumb that aid in focussing the discussion. Among the things I'd like to have handy are good numbers for how much ($) it costs to push a pound of payload into: Low Earth Equatorial Orbit Low Earth Polar Orbit Geosynchronous Orbit Libration Points 1, 2, 3, 4, and 5 (are there more?) Lunar Orbit Lunar Soft Landing Solar "Landing" (into the Sun) Solar Escape Velocity (out of the system, both in and perpendicular to the plane of the ecliptic) Any other interesting places I haven't thought of With such a set of rules of thumb, it makes rough guesstimates of what it would cost to put a specific thing in such a place easier to do. I have little doubt that such rules exist - I just haven't ever seen them. Can any of the net.spacers here provide us with some good numbers, using existing launchers, and an approximation of what the maximum useful payload said launchers could put in those places? Has this info been collected somewhere already? Any help would be greatly appreciated. Thanks. -- "I don't run - I tend to black my eyes." - D.Parton | hombre!marob!upaya!tbetz ----------------------------------------------------| tbetz@upaya.lilink.com "One minute I'm in the pasture porkin' ponies, | Tom Betz - GBS the next I'm a can of Mighty Dog!" - Secretariat | (914) 375-1510 ------------------------------ Date: 25 Mar 90 02:28:26 GMT From: thorin!grover!beckerd@mcnc.org (David Becker) Subject: Whither sci.military? Is it just me, or has no one else seen anything go through sci.military this week? The sci.space cross posting is because many mil contributers also post there. I need my "50 Years Ago Today" fix. David Becker Have you crashed your machine today? beckerd@cs.unc.edu ------------------------------ Date: 25 Mar 90 02:31:34 GMT From: usc!samsung!umich!umeecs!itivax!vax3!aws@ucsd.edu (Allen W. Sherzer) Subject: Amroc bows out of commercial launchers Amroc had decided to back out of the commercial launch business according to the March 19 issue of Space News. Instead they have decided to become a supplier of rocket engines. They believe that the greater safety and reliability will give them an advantage. After the launch failure last year company officials considered building a sounding rocket. Later they reviewed their long term buisness plan and decided to concentrate on their strong points which is propultion technology. So far, no major US expendable firms have immediate plans to buy from Amroc. Let's hope they make it. Allen PS. Space News is a new publication put out by the same people who publish Defense News. It's focus is on the buisness end of space and not the technical end. If there is interest, I could post summaries like Henry's Avation Week summaries. ----------------------------------------------------------------------------- | Allen W. Sherzer | If guns are outlawed, | | aws@iti.org | how will we shoot the liberals? | ----------------------------------------------------------------------------- ------------------------------ Date: 24 Mar 90 23:15:26 GMT From: clyde.concordia.ca!news-server.csri.toronto.edu!utgpu!utzoo!henry@uunet.uu.net (Henry Spencer) Subject: Re: Freedom finding related to LDEF? In article <27460008@hpcvia.CV.HP.COM> kas@hpcvia.CV.HP.COM (ken_scofield) writes: > Last night on the program "Beyond 2000" (DISCOVERY Channel) they did a spot > on a new hardshell diving suit for deep water diving... > ... the interior pressure is maintained at 1 atm. Thus, there > is no compression/decompression time wasted... > Reportedly, NASA is very interested in the suit, and is looking into building > a space-worthy version in the next few years... A high-pressure suit for the space station, *probably* a hard-shell type, has been on the agenda for quite a while. However, it was one of the things deleted in the last round of cost-cutting. It may creep back in again; that has happened before with systems that NASA really wanted. -- "Apparently IBM is not IBM | Henry Spencer at U of Toronto Zoology compatible." -Andy Tanenbaum | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 24 Mar 90 20:25:52 GMT From: psuvm!mrw104@psuvax1.cs.psu.edu Subject: Lunar Orbital Elements Needed Hello-- could anyone out there in net.land e-mail me double precision orbital elements for the moon? I would prefer Keplerian elements, but I'll take what I can get. Thanks in advance. Mike Williams mrw104@psuvm.edu ------------------------------ Date: Sat, 24 Mar 90 20:54 EST From: It works better if you plug it in! <"STOSC::LUBERECKI"@STSCI> Subject: Comments on Space Digest X-Envelope-To: space@andrew.cmu.edu Todd, My name is Tony Luberecki and I work at the Space Telescope Science Institute, Baltimore (Ever heard of us? Keep your eyes on the next shuttle mission and you will). I wanted to take a minute of your time to give credit where credit is due. I really like reading SD daily, it helps suppliment the info we get here at the institute. I wish you the best of luck on continued success with SD. Have a great time in Florida, Tony Luberecki Space Telescope Science Institute Johns Hopkins University Baltimore, Maryland 21218 "Two Wrights don't make a wrong, they make an airplane" ------------------------------ Date: 24 Mar 90 23:12:26 GMT From: clyde.concordia.ca!news-server.csri.toronto.edu!utgpu!utzoo!henry@uunet.uu.net (Henry Spencer) Subject: Re: Intelsat / Titan failure In article <5194@itivax.iti.org> aws@vax3.UUCP (Allen W. Sherzer) writes: >>There is also the >>question of whether you want to bring it back down or tack a fresh upper >>stage onto it and send it on its way. I very strongly suspect the latter. > >Wouldn't tacking on a fresh upper stage using the shuttle cost more than the >Intelsat and launch are worth? I assume that would take a dedicated shuttle >flight. That plus the cost of the stage plus the cost of training seems like >it would cost a lot more than an new Intelsat and launch. The problem with *any* rescue scheme is that it's probably too expensive to make sense unless you have some serious ulterior motives. Bringing the stranded Intelsat back will require a lot of work on support cradles, docking hardware, and such, given that the bird was *not* designed for this, and the hardware will take up enough of the payload bay that it could seriously interfere with doing anything else on that mission. It's even possible that you can't do it at all, because the Intelsat cannot stand the side loads of a horizontal landing well enough for safety. Plans to launch those birds on the shuttle were scratched a while ago, so they are *not* shuttle-qualified, and that will add to the overhead. And then Intelsat has to pay for refurbishment and relaunch, and accept a considerable delay (time is money, remember) while waiting for a slot. Taking up a new stage avoids all that. On the other hand, it does mean hauling up a lot of weight, which again might make it difficult to do anything else on the same mission. It might be practical if you can find a relatively light mission to combine it with, because the rocket stage will be dense and won't take up much of the payload bay. It looks to me like neither mission is cost-effective in strictly commercial terms. NASA may be willing to take one on for PR reasons, if a suitable launch slot can be found (which will be tough). I would expect NASA to be a lot happier about simply lifting some extra weight than about all the unknowns of trying to retrieve a non-shuttle-compatible satellite, and the net cost of getting the thing where it's supposed to go will probably be lower. -- "Apparently IBM is not IBM | Henry Spencer at U of Toronto Zoology compatible." -Andy Tanenbaum | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ End of SPACE Digest V11 #184 *******************