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, 11 Oct 1990 03:28:36 -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, 11 Oct 1990 03:27:43 -0400 (EDT) Subject: SPACE Digest V12 #445 SPACE Digest Volume 12 : Issue 445 Today's Topics: Re: Manned/unmanned tradeoffs Magellan Update - 10/02/90 Re: Manned/unmanned tradeoffs Re: Launch cost per pound Re: Time delay (was Re: Manned/unmanned tradeoffs) Re: disposal of N-waste into sun Re: Lifeless interplanetary travellers - where are they now? Article on NASA in Economist Magellan Update - 10/03/90 Magellan Update - 10/10/90 Re: Space GIFs 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: 4 Oct 90 02:58:10 GMT From: media-lab!minsky@EDDIE.MIT.EDU (Marvin Minsky) Subject: Re: Manned/unmanned tradeoffs rbd@neural.tamu.edu (Roger Dubbs) says, > But are you sure about just what kinds of speeds are involved in > space operations? Actually, the overall time constant of the system > is dependent on many factors, not just the speed. The fact is, some > serious analysis of the particular job to be tele-operated is > required. I doubt whether the time constant of the system would be as > large as a tanker or as small as an F-16. This discussion is > meaningless unless you know about the particular system to be > controlled. Yes, I am sure. Generally, the speeds of space-station operation can be lower than any earth operations, unless someone has equipped the lab with things that operate too fast. A few operations cannot be slower than the order of 90 minutes, because some things must be done in orbital time. You're overlooking how many earth-jobs require "real-time" operations like catching things before they fall, only because of gravity. Most Space-lab operations could be done at slower than tanker speeds. Can you really think of station-keeping operations that really must be done in less than seconds? Please remember, I talking about the enormous value of using remotely-manned operation in GEO and lunar operations. Not on Mars or Jupiter. And we're not talking off-hand options, but of doing more with 1 billion dollars this way than with, say, 30 B by using Space Station Freedom with its ill-equipped human crew. > IMHO, the most versatile tool man has is man. We will never really be able to exploit space until we have a permanent manned presence there. Man can adapt to situations that tools could never hope to. The scientists wish that more money could be spent on probes, rather than expensive manned space programs. IMHO, once we have a large presence of humans in space, the probes will be trivial to launch and maintain. Further, when we actually visit places that probes have gone before, we are bound to learn much more about the place than probes could tell us. Nonsense. With a few years R&D, the most versatile tool we'll have is telepresence. Robots can adapt to conditions men can never. Let's be realistic. And stop confusing robotic probes with remotely-manned instruments, which carry the human judgment with them. Think of teleoperators as like shoes. And of space as like walking on ice or on coals. Simple as that. Your brain is still there -- but not your weak, slow, greedy, fragile body. Think of the remote cameras as like microscopes and telescopes attached to your eyes. Let's drop outworn emotional metaphors. The most versatile tools man has are are his tools! ------------------------------ Date: 2 Oct 90 22:48:10 GMT From: elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@decwrl.dec.com (Ron Baalke) Subject: Magellan Update - 10/02/90 MAGELLAN STATUS REPORT October 2, 1990 The Magellan spacecraft has acquired about 125 orbits of Venus radar mapping data since mapping officially began on Sept. 15. When mosaicked, the wedge-shaped area of imagery would cover on Earth a stretch across the southern United States from Los Angeles to nearly the coast of South Carolina, and from the North Pole to almost the South Pole. The DSN (Deep Space Network) acquisition of the radar data has averaged 98.9 percent. A spacecraft anomaly investigation review was held in Denver on September 27. Review board members said additional heartbeat modifications are being studied to facilitate mapping through an AACS (Attitude and Articulation Control Subsystem) glitch. These are planned to be implemented in December. By the end of January 1991, the flight controllers will try to implement an interim fix to the AACS B-side memory to make it usable. The long term memory-B fix is targeted to be completed as early as June 1 of next year, but it could take as long as to the end of the year. The long-term fix also will incorporate software modifications to guard against computer glitches. Most investigations as to the primary cause of the August 16 loss of signal are being closed out. The actual cause has not been found, but several candidates have been eliminated. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ Date: 3 Oct 90 18:24:36 GMT From: wuarchive!cs.utexas.edu!helios!neural!rbd@decwrl.dec.com (Roger Dubbs) Subject: Re: Manned/unmanned tradeoffs jenkins@jpl-devvax.jpl.nasa.gov says, > Trains and tankers have large time constants (in other words, they >don't accelerate quickly), but there's nothing inherently difficult >about controlling such systems ('plants' in control systems jargon). > Time delays in the control input, on the other hand, particularly when >they are not small relative to the dominant plant time constants, can >be destabilizing. > In other words, a 2.5 s delay isn't a problem for a tanker, but you >wouldn't want to fly in an F-16 whose pitch axis control system had >one.... minsky@media-lab.media.mit.edu (Marvin Minsky) responds: >This is confusing different things. Presumably, you could fly an >F-16, in spite of delay -- if you could maintain low speeds. You >can't, because of gravity. The problem of "real-time control", here >is not involved with how FAST you can accelerate, but with how low you >can keep your -- and how SLOW you can accelerate. The issues about >time delay are, thus, much more involved with speeds rather than >accelerations. Planes have minimum speeds, hence each delay implies a >minimum reaction-distance. But that has little to do with spaceships, >or earth-ships. Tankers can be "flown" as slow as you want, hence >have no problems with time delay, for well-trained pilots. But are you sure about just what kinds of speeds are involved in space operations? Actually, the overall time constant of the system is dependent on many factors, not just the speed. The fact is, some serious analysis of the particular job to be tele-operated is required. I doubt whether the time constant of the system would be as large as a tanker or as small as an F-16. This discussion is meaningless unless you know about the particular system to be controlled. IMHO, the most versatile tool man has is man. We will never really be able to exploit space until we have a permanent manned presence there. Man can adapt to situations that tools could never hope to. The scientists wish that more money could be spent on probes, rather than expensive manned space programs. IMHO, once we have a large presence of humans in space, the probes will be trivial to launch and maintain. Further, when we actually visit places that probes have gone before, we are bound to learn much more about the place than probes could tell us. Roger Dubbs ------------------------------ Date: 5 Oct 90 16:18:59 GMT From: news-server.csri.toronto.edu!utgpu!utzoo!henry@rutgers.edu (Henry Spencer) Subject: Re: Launch cost per pound In article <0093DB14.BD2035A0@KING.ENG.UMD.EDU> sysmgr@KING.ENG.UMD.EDU (Doug Mohney) writes: >>Space is expensive because of NASA's and the government's monopoly on the >>facilities. If it became cheap, that would threaten NASA's turf which it >>doesn't want. It suits NASA's purpose to keep space expensive so it should >>be no suprise that it is. > >You make it sound like a conspiracy to keep space expensive. I find THAT hard >to swallow, since it is in NASA's best interest to to DELIVER on their previous >claims of cheap payload-to-orbit, rather than being cheap-shot'ed It's not a conspiracy, just a situation where it's in almost everyone's interest to maintain the status quo. NASA is no longer promising cheap launches and no longer has to worry about being criticized for the lack thereof. I don't think one has to invoke turf protection in quite the way that Allen did, though; it suffices that NASA in particular and the government in general want *control* of space activity, which means they want control of launch operations... and government-controlled operations are never cheap. -- Imagine life with OS/360 the standard | Henry Spencer at U of Toronto Zoology operating system. Now think about X. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 5 Oct 90 15:58:11 GMT From: news-server.csri.toronto.edu!utgpu!utzoo!henry@rutgers.edu (Henry Spencer) Subject: Re: Time delay (was Re: Manned/unmanned tradeoffs) In article <9010041933.AA14633@tilde> pyron@skvax1.csc.ti.com (If Clayton's an Aggie, I'm not!) writes: >As far as training goes, even a trained operator will need to adaptation time >when coming "on shift." And this person could be deadly on the street, trying >to anticipate and react in a different time frame from work. > >Maybe the time delay problem can be licked, but it won't be all that easy. At risk of repeating myself and spoiling a beautiful argument with ugly facts, teleoperation of simple equipment with a 2.5s delay *has been tried* experimentally (by the Space Studies Institute) and *is not that hard*. Mind you, it depends a lot on what sort of work you are trying to do with teleoperation, and this in turn influences how you design missions. Running a bulldozer (which is roughly what SSI tried) is one thing. Assembling electronic equipment is another. Juggling eggs is yet another. :-) There is enough experimental evidence to confidently say that teleoperation for simple tasks, as a *supplement* to manned presence, is feasible at lunar distances: human bulldozer operators need not be on the spot, although the bulldozer repairman may be a different story. Quick response to real-time problems is obviously difficult. The answer is to structure the job so that it isn't necessary. Here again, this has implications for mission design: driving a bulldozer around a base should be okay, but driving a science rover over unknown terrain, with no on-the-spot human help available should trouble develop, will be trickier. -- Imagine life with OS/360 the standard | Henry Spencer at U of Toronto Zoology operating system. Now think about X. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 10 Oct 90 15:21:46 GMT From: voder!dtg.nsc.com!alan@ucbvax.Berkeley.EDU (Alan Hepburn) Subject: Re: disposal of N-waste into sun In article <1361.27121f15@iccgcc.decnet.ab.com> herrickd@iccgcc.decnet.ab.com writes: > >Do the arithmetic on dissolving the "high grade" waste in a suitable >solvent and then dispersing it over a few square miles of ocean. I >think you will find it disappears into the background. It is high >grade only because the ecohysterics have insisted on concentrating >it into minimum volume. > >dan herrick Picture this: a supertanker modified slightly so that the nuclear waste starts out in the bow tank, being diluted 100:1 with sea water. This mix is then pumped to the next tank where it is diluted 100:1 with sea water. And so on till the last tank, which is pumped into the open ocean. You would be unable to detect other than background radiation in the resulting water. -- Alan Hepburn "History is a lie agreed upon." mail: alan@spitfire.nsc.com Voltaire ------------------------------ Date: 10 Oct 90 17:30:24 GMT From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!henry@ucsd.edu (Henry Spencer) Subject: Re: Lifeless interplanetary travellers - where are they now? I wrote: >... Failing that, it would return to Earth's orbit, but the odds are >roughly zero that Earth would be nearby at the time -- Earth's orbit is >half a billion kilometers long. How embarrassing; not half a billion, but a full billion. What's a factor of two between friends? :-) -- Imagine life with OS/360 the standard | Henry Spencer at U of Toronto Zoology operating system. Now think about X. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 10 Oct 90 20:14:07 GMT From: bacchus.pa.dec.com!jumbo!jumbo!ayers@decwrl.dec.com (Bob Ayers) Subject: Article on NASA in Economist The Economist magazine of 29sep-5oct has an excellect article on NASA and its rpoblems. An excerpt: By 1975, NASA's budget was a third of what it had been ten years earlier. NASA responded to starvation the way most creatures do; it lost a lot of weight and developed a monomaniacal interest in its next meal. In the 1970s, the next meal was the space-shuttle programme. ------------------------------ Date: 3 Oct 90 23:49:15 GMT From: sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: Magellan Update - 10/03/90 MAGELLAN SPECIAL REPORT October 3, 1990 A loss of power at the Deep Space Network (DSN) station near Madrid, Spain, resulted in loss of radar data reception of one-half of orbit 490 and all of the mapping data from orbit 491. A bad star calibration on orbit 493 caused a shift in the HGA (High Gain Antenna) pointing of approximately half a degree which severely degraded the downlink during playback of the second half of orbit 493 and the first half of orbit 494. Additionally, radar data was taken on orbit 494 with the HGA mispointed by half a degree. Some or all of that data may be salvaged by special processing. Steps were being taken to limit the size of star calibration updates to prevent bad updates from mispointing the antenna. The orbits are counted from August 10 when Magellan went into orbit around Venus. An orbit takes three hours and 15 minutes and there are seven and a third orbits a day. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ Date: 10 Oct 90 21:39:34 GMT From: swrinde!zaphod.mps.ohio-state.edu!sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: Magellan Update - 10/10/90 Magellan Status Report October 10, 1990 The Magellan spacecraft has now completed 184 mapping orbits, with good radar data received from at least 180 orbits. The seven star calibrations and two desaturations of the reaction wheels in the past 24 hours were successful with nominal attitude updates. Once star calibration was partially successful. The 8 day mapping upload M0283 was sent to the spacecraft yesterday and is now executing. Engineering telemetry shows the radar sensors continue to operate normally. A test image swath from orbit 534 was produced and confirmed satisfactory the end-to-end system performance. Production of standard image products through the SAR (Synthetic Aperture Radar) processor has started. Twelve image swaths covering the reproccessing of orbits 376 through 387 were successfully completed yesterday. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ Date: 10 Oct 90 06:58:58 GMT From: sumax!polari!pv@beaver.cs.washington.edu (Paul Varn) Subject: Re: Space GIFs ------------------------------ From: @polari (Don Wennick) Date: Tue, 9 Oct 90 00:31:56 PDT X-Mailer: Mail User's Shell (6.5.6 6/30/89) To: pv@polari.UUCP In article <2554@polari.UUCP> you write: >Since my orriginal request for a source of space related GIF format pictures, >there has been mail sent to me by others interested in the same thing. Following is a response I recieved from a local user. I've fowarded it in hopes it will help others who seek the same information as myself. There is an e-mail ftp server that I use occasionally. This allows access to any anonymous ftp site, or any other ftp site you have a valid account on. wuarchive.wustl.edu is accessible this way. The server's address is BITFTP@pucc.princeton.edu, and you can get the instructions for it's use by sending e-mail with the command 'help' in the message body. I don't know if a .signature will confuse it, but I never allow mush to sign my messages to any servers. Don. --- Don Wennick | dwennick@polari.UUCP -or- donw@rwing.UUCP "subhuman bloodless leaders fed on lies and fear / and TV anchor news teams trim all we see and hear / use your head / sidestep the traps / snake through the chaos with a smooth noodle map" - Devo -PV- /+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+\ + COMMENTS COMPLIMENTS CONTINOUS COMPLAINTS + " COURTESY: Paul Varn " + UUCP: pv@polari GEnie: p.varn + \+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+/ ------------------------------ End of SPACE Digest V12 #445 *******************