Date: Sat, 14 Nov 92 05:03:38 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #423 To: Space Digest Readers Precedence: bulk Space Digest Sat, 14 Nov 92 Volume 15 : Issue 423 Today's Topics: Apollo fire Comet deflection & mining Feynmann's legacy... FTS Lunar "colony" reality check Magellan Update - 11/13/92 Metric again Telescope resolution What kind of computers are in the shuttle? Welcome to the Space Digest!! Please send your messages to "space@isu.isunet.edu", and (un)subscription requests of the form "Subscribe Space " to one of these addresses: listserv@uga (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle (THENET), or space-REQUEST@isu.isunet.edu (Internet). ---------------------------------------------------------------------- Date: 14 Nov 92 02:26:59 GMT From: Brian Stuart Thorn Subject: Apollo fire Newsgroups: sci.space I remember the incident, two men were killed while working inside the engine compartment of Columbia in March, 1981. This was prior to the maiden flight of the Space Shuttle, when ground procedures were still new and uncertain. I've forgotten the two men's names, but they wofor Rockwell. If memory serves, STS-1 astronauts Young and Crippen paid tribute to those two men while in orbit. -Brian ------------------------------ Date: 14 Nov 92 05:57:05 GMT From: Adrian Hassall Lewis Subject: Comet deflection & mining Newsgroups: sci.space,alt.sci.planetary szabo@techbook.com (Nick Szabo) writes: [...] >If upper-stage technology advances sufficiently over the next 30-40 >years, eg magsails powered by the solar wind + a very advanced nuclear >electric second stage, we might be able to catch up with P/Swift-Tuttle >at perihelion in 2057 to track it. Alternately, we might develop very >good telescopes capable of tracking it that far out, eg huge microgravity- >based reflectors combined with optical interferometry. Who knows what >technology we will have after 2100, but one possibility is to focus >sunlight with a large parabolic mirror over the period of several >months to change the time P/Swift-Tuttle crosses earth orbit by one day. >Even with this gentle method, we need to gaurd against the possibility >of disrupting the comet rather than deflecting it. Rendesvous with 50 km/s >incoming will also be a challenge, perhaps several years with a tacking >magsail. >-- >Nick Szabo szabo@techboook.com If you attatched a magsail to an asteroid/comet won't you have a problem with the rotation of the body (thrust vector continually changing). I have read several articles on magsails (including the original conference paper) and I was wondering how a magsail could be used to de-spin a large object like an asteroid, prior to moving it. Any suggestions anyone? ajax Adrian.Lewis@iasos.utas.edu.au ------------------------------ Date: 14 Nov 92 03:25:56 GMT From: "Michael K. Heney" Subject: Feynmann's legacy... Newsgroups: sci.space In article roberts@cmr.ncsl.nist.gov (John Roberts) writes: > >-From: pgf@srl03.cacs.usl.edu ("Phil G. Fraering") > >-Bad luck. Al Gore's campaign speeches on the topic indicated that >-NASA is going to continue to invest in the Shuttle well into the >-21st century; > >But Goldin, the Congress, Bush, Quayle, and the Augustine Commission also >support that policy. It makes sense to keep the existing manned launcher >until a better one is "on line". According to my latest "Space News", NASA is planning on flying the shuttle until at least 2005, with the current fleet of orbiters. They think that the orbiters look good for more than the designed 100 mission lifetime, and at a reasonably low launch rate (<8/year), should have the fleet in good shape. Some discussion of follow-ons, including the HL-20 and consideration of a "skunk-works" style program for developing a successor to the shuttle. -- Mike Heney | Senior Systems Analyst and | Reach for the mheney@access.digex.com | Space Activist / Entrepreneur | Stars, eh? Kensington, MD (near DC) | * Will Work for Money * | ------------------------------ Date: Fri, 13 Nov 92 23:56:05 EST From: John Roberts Subject: FTS -From: benson@gemed (Mark Benson 5-4228) -Subject: Re: Automated space station construction -Date: 9 Nov 92 22:06:20 GMT -Organization: GE Medical Systems, Milwaukee, WI -In article <1992Nov8.064256.7682@ucsu.Colorado.EDU> fcrary@ucsu.Colorado.EDU -(Frank Crary) writes: ->Is anyone looking into robots with very limited autonomy? That is, ->under direction from a human, but able to execute instructions on ->their own for periods of, say, ten seconds? -Yes, I believe so. SSF had (and I believe still has) a program for the -Flight Telerobotic Servicer (FTS). Under Phase B of the contract, various -options were studied, ranging from basically remote control to releatively -sophisticated, knowledge / rule based AI for functions ranging from task -planning and collision avoidance functions. Among these possible levels was -a basic "learn and play" mode, where the operator would do the first one, and -then basically just monitor the subsequent 'n' executions of the activity. -I was working for Martin-Marietta at the time, and heard they won the -contract. Haven't heard much since. -In fact, at the time, there was such a thing as the NASA / NBS Standard -Reference Model (NASREM), describing various levels of control over such -a system, from task planning and resource scheduling down to individual joint -motions and limit checks (kinematics). I believe the FTS has been cancelled, or at least deferred. Some time ago, the person who was in charge of the NIST part of the project said funding had been cut off. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: Sat, 14 Nov 1992 00:42:11 GMT From: "D.A. Svendsen" Subject: Lunar "colony" reality check Newsgroups: sci.space,alt.sci.planetary Joseph Versagg (joev@sioux.eel.ufl.edu) wrote: : : Also, to answer Nicks anti-lunar base stance: if you buy the theory, any of : them, that the moon was part of the earth, or was formed with it in the early solar system, then there is no reason that both bodies are composed of the same elements in similar quantities. Read: it has signifigant amounts of Si, Fe, C, : O etc. Is it mineable? Well we won't know until we get there(personally or through probes). : : C'Ya : Joe I'm no expert on this, and you can beat me about the head with a wet flounder if I'm wrong, but it seems to me that the moon would have the same proportion of elements that the earth has only if the earth was completely homogeneous when separation occured. If, however, the moon was sheared off after the earth's heavier elements had sunk to the centre, then it seems that the moon would be lacking in these heavier elements. And given that in a molten moon heavy elements would sink toward the centre, it might be a difficult job actually finding a vein of heavy metals near enough to the surface to be mined. I'm not sure about aluminium, but I'd not be too hopeful of finding appreciable quantities of mineable nickel and iron. =========================================================================== Dean Svendsen - 2nd Year Comp Science | Monash University - Clayton Campus | How much wood could a woodchuck Melbourne, Victoria, 3192. | chuck if a woodchuck could | chuck wood? email:ins866n@lindblat.cc.monash.edu.au | or | - Guybrush Threepwood ins866n@aurora.cc.monash.edu.au | Le Chuck's Revenge (Act I) =========================================================================== A day not wasted is a day wasted!!! ------------------------------ Date: Sat, 14 Nov 1992 11:53:10 GMT From: Ron Baalke Subject: Magellan Update - 11/13/92 Newsgroups: sci.space,sci.astro,alt.sci.planetary Forwarded from the Magellan Project MAGELLAN STATUS REPORT November 13, 1992 1. Magellan continues to operate normally, performing a starcal (star calibration) and desat (desaturation of the reaction wheels) on each orbit and transmitting a carrier plus 40 bps X-band signal. 2. On Wednesday Magellan ended its period of apoapsis occultations in which it passed through the shadow of Venus on each orbit. Temperatures are expected to increase gradually, requiring adjustment of the radar heaters and the length of "hides" (periods in the shadow of the High Gain Antenna). 3. The craft has completed 6086 orbits of Venus. So far in Cycle 4 the spacecraft has completed 450 orbits which is almost exactly 25% of the orbits in a 243 cycle. 4. The gravity data collected during the first ten days of Cycle 4 was affected by some residual effects of the Orbit Trim Maneuver to lower the periapsis, so the Mission Planning Team has recommended extending the gravity data collection to May 25, 1993. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Give people a second /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | chance, but not a third. |_____|/ |_|/ |_____|/ | ------------------------------ Date: 11 Nov 92 16:09:51 GMT From: Paul Campbell Subject: Metric again Newsgroups: sci.space In article <1992Nov8.222219.14106@infodev.cam.ac.uk> sl25@cus.cam.ac.uk (Steve Linton) writes: >My main beef about NASA metrication concerns precision. How often have you seen >"This tiny widget, only about 1 inch (2.54cm) across"? If the diameter is given >as "about 1 inch" the implied precision is about +-25%. As such, the proper >metric form is "two or three centimeters" or "a couple of centimeters". 2.54cm >implies a precision that just isn't there. My father wrote a gardening book many years ago in NZ, it's still in print and after we went metric (much easier than you think and well worth it) they released a new version that had been 'metricfied' (my father didn't write this bit), it included such gems as replacing: "Plant the seeds about an inch apart .... with "Plant the seeds about 2.5cm apart .... And this is long before anything was computerized - it wasn't done with global search and replace .... Paul -- Paul Campbell UUCP: ..!mtxinu!taniwha!paul AppleLink: CAMPBELL.P "There once was a president named Bush, we started giving him a push, Then we went hunting Quayle, got the Republicans nailed, And tossed them out on their tush" - Anon. ------------------------------ Date: Fri, 13 Nov 92 23:53:24 EST From: John Roberts Subject: Telescope resolution -From: nickh@CS.CMU.EDU (Nick Haines) -Newsgroups: sci.space -Subject: Re: Putting air on the moon -Date: 9 Nov 92 16:21:57 GMT -Organization: School of Computer Science, Carnegie Mellon University -In article roberts@cmr.ncsl.nist.gov (John Roberts) writes: - [about big telescopes] - The formula I found for the diffraction resolution limit of a telescope - (which ought to be put in the FAQ list) is - alpha = 2.1E5 x lambda / d - where alpha is the resolution in arc seconds, lambda is the - wavelength being observed, and d is the diameter of the telescope - (same units as lambda). -The easy formula is - alpha = lambda / r -where alpha is in radians, and r is the radius of the telescope. That comes out to double the formula I found in the astronomy textbook. Could it be that "r" in your formula should be aperture (=diameter)? John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: Sat, 14 Nov 1992 02:09:10 GMT From: "I am a terminator." Subject: What kind of computers are in the shuttle? Newsgroups: sci.space In article , roberts@cmr.ncsl.nist.gov (John Roberts) writes: |> |> -From: choy@skorpio.usask.ca (I am a terminator.) |> -Subject: What kind of computers are in the shuttle? |> -Date: 11 Nov 92 17:53:36 GMT |> -Organization: University of Saskatchewan, Saskatoon, Canada |> |> -The computers used to control the shuttle use very complex programs |> -that people don't want to rewrite for newer computers. Has any |> -upgrades been done or are the computers still the same old beasts? |> |> Most or all of the orbiters now have the new computers, which are much more |> powerful (and have more memory) than the old computers. I believe they're |> software-compatible. (I *don't* know whether any new functions were added, |> or whether the software has been changed (other than lookup tables, etc.). |> The Shuttle control software is claimed to be the most nearly error-free |> complex code ever created - millions of dollars went into assuring that.) |> >From: yee@trident.arc.nasa.gov (Peter E. Yee) |> Subject: STS-49 Press Kit (Forwarded) |> Date: Sat, 18 Apr 1992 19:56:05 GMT |> |> STS-49 PRESS KIT |> MAY 1992 |> |> ... |> IMPROVED FEATURES OF SPACE SHUTTLE ENDEAVOUR |> The advanced general purpose computers (GPCs) are now in the |> process of being incorporated into the entire orbiter fleet and will be |> installed and used on Endeavour for its first space flight. The |> updated computers have more than twice the memory and three times the |> processing speed of their predecessors. Officially designated the IBM |> 10-101S, built by IBM, Inc., they are half the size, about half the |> weight and require less electricity than the first-generation GPCs. |> The central processor unit and input/output processor, previously |> installed as two separate boxes, are now a single unit. |> |> The new GPCs use the existing Shuttle software with only subtle |> changes. However, the increases in memory and processing speed allow |> for future innovations in the Shuttle's data processing system. |> Although there is no real difference in the way the crew will operate |> with the new computers, the upgrade increases the reliability and |> efficiency in commanding the Shuttle systems. The predicted Rmean time |> between failuresS (MTBF) for the advanced GPCs is 6,000 hours. The |> flight computers are already exceeding that prediction with an MTBF of |> 18,500 hours. The MTBF for the original GPCs is 5,200 hours. |> |> New GPC Specifications |> Dimensions: 19.52S x 7.62S x 10.2S |> [I wonder what an "S" is? From context, I'd guess "inches". - JR] |> Weight: 64 lbs. |> Memory Capacity: 262,000 words (32-bits each) |> Processing Rate: 1.2 million instructions per second |> Power Requirements: 550 watts 64 lbs? What's it made of? Lead? 1 Mb? 1.2 MIPs? 0.5 kW? They want to put these in all the shuttles? Why not give them 3lb 20Mb 25 MIPs 0.25W 0.5 Gb hard drive laptops? Doesn't Compaq make laptops that can double for speed bumps? Just cross compile everything. You can probably buy a hundred computers for each of these heavyweights. Henry Choy choy@cs.usask.ca ------------------------------ End of Space Digest Volume 15 : Issue 423 ------------------------------