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 03:10:45 -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 03:09:51 -0400 (EDT) Subject: SPACE Digest V12 #444 SPACE Digest Volume 12 : Issue 444 Today's Topics: Re: Manned/unmanned tradeoffs Re: Ulysses Update - 10/06/90 Re: Beta Testers Needed Re: Ulysses Update - 10/06/90 Re: atmosphere on earth's moon. atmosphere and tide/gravity Re: Manned/unmanned tradeoffs Galileo Update - 09/27/90 Re: Manned/unmanned tradeoffs Re: Pluto mission? 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: 5 Oct 90 16:27:41 GMT From: news-server.csri.toronto.edu!utgpu!utzoo!henry@rutgers.edu (Henry Spencer) Subject: Re: Manned/unmanned tradeoffs In article <6298@uceng.UC.EDU> dmocsny@uceng.UC.EDU (daniel mocsny) writes: >Another way to go about it is to accept higher equipment losses, which >you may be able to afford because human life is not at stake. > >In a manned mission, losing a crew member would look like a disaster. This is a problem of mindset, not a fundamental obstacle. Few class it as a disaster when an Antarctic expedition loses a crew member, or for that matter when a member of the test-stand crew at Edwards is killed by a falling crane (which happened recently). >On another note, has anyone seriously considered mounting a >*one-way* manned mission to Mars? This would of course mean >suicide for the crew, but it would save a lot of money. Could >qualified volunteers be found? I don't think anyone has seriously considered a suicide mission, although in a lunar context, there have been serious proposals for both a mission with no immediate possibility of return (in the 1960s, as a way to get a man up there quickly before the Soviets) and a mission that is one-way by intent (starting a lunar colony rather than a base). Starting a Mars colony is not a ridiculous idea, although it would probably cost *more*, not less, than a minimum one-shot mission. It might, however, cost less than a serious program of exploration conducted by expeditions that all end up returning to Earth. I don't think you're going to get many volunteers for a mission that is definitely certain death. You would get quite a few if there were a reasonable chance -- it need not be 99.9% -- of long-term survival. -- 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 13:42:55 GMT From: mcsun!ukc!icdoc!syma!andy@uunet.uu.net (Andy Clews) Subject: Re: Ulysses Update - 10/06/90 From article <1990Oct9.034919.25903@jato.jpl.nasa.gov>, by baalke@mars.jpl.nasa.gov (Ron Baalke): > The closest Ulysses will ever > get to the sun in its lifetime is when it was on Earth. Shome mishtake, shurely? What about when Ulysses was in the orbiter payload bay in orbit around Earth? Or even after deployment as it floated gently away from Discovery, on the side of the Earth facing the sun and before its boosters were fired to send it off on its merry way? I mean c'mon guys, let's have some accuracy here! :-) :-) -- Andy Clews, Computing Service, Univ. of Sussex, Brighton BN1 9QN, England JANET: andy@syma.sussex.ac.uk BITNET: andy%syma.sussex.ac.uk@uk.ac ------------------------------ Date: 10 Oct 90 23:43:14 GMT From: usc!elroy.jpl.nasa.gov!euclid.jpl.nasa.gov!pjs@ucsd.edu (Peter Scott) Subject: Re: Beta Testers Needed In article <5A0A080E09090128-MTASATURN*Chip.Olson@UCS.umass.edu>, Chip.Olson@ucs.umass.edu writes: > > From: Leonard Abbey > > > Wanted.....beta testers for sun/moon rise/set program. > > It's been running just fine for 4.5 billion years; why bother beta-testing > it now? :-) It's being put under government contract. You'll need a license in the future to access it. :-) -- This is news. This is your | Peter Scott, NASA/JPL/Caltech brain on news. Any questions? | (pjs@aristotle.jpl.nasa.gov) ------------------------------ Date: 11 Oct 90 04:22:12 GMT From: agate!garnet.berkeley.edu!jwl@ucbvax.Berkeley.EDU (James Wilbur Lewis) Subject: Re: Ulysses Update - 10/06/90 In article <3602@syma.sussex.ac.uk> andy@syma.sussex.ac.uk (Andy Clews) writes: >From article <1990Oct9.034919.25903@jato.jpl.nasa.gov>, by >baalke@mars.jpl.nasa.gov (Ron Baalke): >> The closest Ulysses will ever >> get to the sun in its lifetime is when it was on Earth. > >Shome mishtake, shurely? What about when Ulysses was in the orbiter payload >bay in orbit around Earth? Or even after deployment as it floated gently >away from Discovery, on the side of the Earth facing the sun and before its >boosters were fired to send it off on its merry way? > >I mean c'mon guys, let's have some accuracy here! :-) :-) It got closer to the sun sitting on Earth when we were at perihelion than it ever did in Earth orbit at this time of the year. You asked! :-) -- Jim Lewis ------------------------------ Date: 2 Oct 90 13:56:57 GMT From: att!watmath!maytag!watdragon!watyew!jdnicoll@ucbvax.Berkeley.EDU (Brian or James) Subject: Re: atmosphere on earth's moon. atmosphere and tide/gravity In article <1990Oct2.015310.11508@unicorn.wwu.edu> n9020351@unicorn.wwu.edu (james d. Del Vecchio) writes: >If enough air ( nitrogen, oxygen ) was somehow brought to the moon to >equal one sea-level earth atmosphere, how fast would it dissipate? >For example, would it drop to 1/2 pressure in months, centuries or >how long? There's a discussion that pertains to this in 'Habitable Planets for Man' by Stephan Dole, published in the 1960s, by a company whose name I utterly forget. Any reasonably well stocked science, mathematics and engineering library would have a copy :) >Would most of this dissipation be from the earth's pull skimming it away, >or would the spin of the moon versus it's gravity be a bigger factor? Low escape velocity vs speed of air molecules on the Moon plays the important part, I suspect. At the temperature of the Moon, most of the air molecules will be moving fast enough to cause a fairly rapid loss of atmosphere [centuries, if I remember the math right]. The rest I'll leave for Mr. Spenser. James Nicoll PS: Does anyone know if utzoo has a person named 'Hawk' registered :)? ------------------------------ Date: 9 Oct 90 16:45:06 GMT From: visix!news@uunet.uu.net (Amanda Walker) Subject: Re: Manned/unmanned tradeoffs Another thing to keep in mind when thinking about time delays is programmability. Even though humans have a closed-loop cycle time of about 200ms, they can still perform tasks that require greater than 200ms precision. If a task (or subtask) can be performed ballistically (open loop), or locally (closed loop but without having to go through remote processing, such as a spinal reflex), the overall time delay is less relevant. I think it is naive to assume that teleoperated robots can't have the equivalent of motor skills and reflexes. The operator doesn't have to be consciously "in the loop" for every action, any more than they are *with their own body*. I think that biological information-handling systems can offer a lot of insight into approaches for remote operation. After all, neurons aren't that fast for the scale in which they operate, either... -- Amanda Walker amanda@visix.com Visix Software Inc. ...!uunet!visix!amanda -- "In this age, the mere example of nonconformity, the mere refusal to bend the knee to custom, is itself a service." --John Stuart Mill, "On Liberty" (1859) ------------------------------ Date: 3 Oct 90 04:16:53 GMT From: elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@decwrl.dec.com (Ron Baalke) Subject: Galileo Update - 09/27/90 GALILEO MISSION STATUS REPORT September 27, 1990 As of noon (PDT) Thursday, September 27, 1990, the Galileo spacecraft is 41,661,100 miles from the Earth and was traveling at a heliocentric speed of 51,260 miles per hour; distance to the Sun is 115,924,200 miles (1.24 AU). The downlink telemetry rate is at 40 bits/second through the LGA (Low Gain Antenna), and the spacecraft is spinning at 3.15 rpm. Round trip light time is 7 minutes, 32 seconds. A NO-OP command was sent on September 24 to reset the Command Loss Timer to 264 hours, the planned value for this mission phase. A second North/South delta Differential One-way Ranging (DOR) using the 70 meter antennas in Goldstone and Australia was successfully conducted on September 21. This delta DOR activity was the fourth of 17 delta DOR data gathering activities planned prior to the Earth closest approach. Delta DOR is an additional navigation data source in addition to doppler and ranging data. When the delta DOR signal is modulating the downlink carrier spacecraft telemetry data from the TMU (Telemetry Modulation Unit) is interrupted; no spacecraft telemetry is transmitted during this interruption. The next delta DOR activity is scheduled for October 8 using the same two 70 meter antennas. A set of 8 DACs (Delayed Action Commands) were sent on September 24. The DACs included commands to properly configure the transponder in the RFS (Radio Frequency Subsystem) in preparation for the planned GSOC (German Space Operation Center) uplink compatibility test later on September 24 and 26. The two GSOC/Weilheim Uplink Compatibility Tests were successfully completed this week. During each test 16 NOP (No operation) commands were transmitted to the spacecraft from the German Weilheim tracking station under control of the German Space Operation Center. The two tests were identical except that ranging modulation was on the uplink for the second test. The Galileo Flight Team in the MSA (Mission Support Area) at JPL used downlink telemetry via the DSN (Deep Space Network) Madrid tracking station to confirm proper command acceptance and execution by the spacecraft. GSOC will support the cruise science phase of the Galileo mission starting in September 1991 by tracking the spacecraft 5 passes each week, generating EDRs (Experiment Data Records) and transmitting non-interactive commands for the F&P (Fields and Particles) LRS (Low Rate Science) instruments. Cruise Science Memory Readouts (MROs) were successfully performed for the EUV (Extreme Ultraviolet Spectrometer), DDS (Dust Detector) and MAG (Magnetometer) instruments on September 25 and 27. Near the beginning of the Australian 70 meter track on Sunday, September 23, the sixth occurrence of the despun CDS (Command Data Subsystem) CRC A (Critical Controller A) POR (Power on Reset) was observed in CDS telemetry. The signature was the same as that observed in the previous occurrences in February, April, July and September of this year. Recovery actions to reset the telemetry indication were taken about 27 hours later. Due to the non time critical nature of resetting this indicator and the very short tracking pass on Sunday, it was decided to implement the recovery actions on September 24. After the recovery actions, a NO-OP command was set to properly reset the Command Loss Timer in both halves of the CDS. There is no concern for the health of the spacecraft as a result of these telemetry indications. The despun CDS POR telemetry indication is a latched signal generated by electronic circuitry normally used to inhibit Despun Critical Controller commanding when a real POR signal is present. However, problems in the electronic circuitry or in the telemetry latch device could produce an anomalous telemetry indication. The circuitry used in this application is simple, has few components and responds in 50-100 microseconds. The time duration of the "signal" triggering the anomalous spacecraft event is unknown. In all occurrences recovery from the POR telemetry indication was completely successful indicating the anomalous event was not caused by a permanent failure in the CDS. The CDS personnel are in process of developing a method to determine whether the telemetry latch device is "faulty" or the circuitry is actually detecting a transient "POR signal" on the interface. A report to the Project is planned for mid-October 1990 to discuss the value/risk of this CDS effort. Another USO (Ultra Stable Oscillator) test was conducted on September 25. This test provides continuing trend information characterizing the performance of the ultra-stable RF downlink frequency source. The AC/DC bus imbalance measurements exhibited some activity. The AC measurement dropped about 12DN from 48.6 volts to 46.1 volts; the DC measurement increased 2 DN to 18.8 volts. These changes occurred during a quiescent period with no spacecraft activity. All other power-related and subsystem telemetry measurements are normal. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ Date: 9 Oct 90 17:32:00 GMT From: mcsun!i2unix!sixcom!garof@uunet.uu.net (Joe Giampapa) Subject: Re: Manned/unmanned tradeoffs In article <6324@uceng.UC.EDU> dmocsny@uceng.UC.EDU (daniel mocsny) writes: >While we are on the subject of dealing with time delays, I >wonder if anyone has considered hiring whales to teleoperate >bulldozers on the Moon. > >The speed of nerve signal propagation is not very high in >biological systems. .... > .... >The longest animals which have lived (the sauropods) apparently >coped with propagation delays by off-loading a portion of their >control to a large nerve ganglion located about halfway back >along the spine. .... > >dmocsny@uceng.uc.edu Isn't this the description of the reflex arc? A human may touch a hot object and pull away very rapidly before the temperature stress signal reaches the brain. The input signal only travels to the spinal cord (analogous to Daniel Mocsny's "large nerve ganglion") before the output "retraction" signal is emitted. It is not completely uncontrollable either. A person may suppress this reflex as well. The 2.5sec time delay should not figure prominently as a protest to the remote-controlled lunar robot. Design it with autonomous locomotion and detect mechanisms, which will function until they encounter a situation which warrants remote guidance. The rover need not rely on any one particular method of locomotion either (ie. mix of caterpillars, legs, etc.). Genetic learning algorithms have demonstrated some impressive results for robots learning coordination, and are certainly relevant to this. [cf. work done by VUB AI Lab head, Luc Steels; student Patti Maes; etc.] For what regards human perception of delayed response: hasn't anyone every played "rogue", "nethack", or other 'action' games via modem w/ or w/out error correction? Many times the delays are quite a few seconds. Or better yet, try doing full screen editing (1200bps modem <--> X.25 <--> Internet), with an average command-response loop of 15_minutes_ (Milano <--> Boston), with lots of noise and retransmission delays. One learns very quickly what are some efficient "safety" command sequences to execute. 2.5seconds is a luxury! [Still, I love it that there are people who talk about response times in order of magnitude of seconds! :-D] That is all for my soap box stand. -Joe Giampapa (garof@sixcom.uucp) ------------------------------ Date: 10 Oct 90 11:09:13 GMT From: zaphod.mps.ohio-state.edu!samsung!munnari.oz.au!uhccux!tholen@tut.cis.ohio-state.edu (David Tholen) Subject: Re: Pluto mission? In article , MJENKIN@OPIE.BGSU.EDU writes: > Back in August '89 when the press was patiently explaining to people > that no, Voyager COULDN'T go to Pluto, I heard a comment to the effect > that someone had plans for a Pluto mission sometime in the early 2000's > or 2010's, and that it could be a small probe launched "piggyback" from > something else. Was this moonshine, or is there really a plan to that > effect? (If there is, I'd like to get in on the ground floor and > suggest "Orpheus" as a name!) NASA is indeed studying various options for sending a spacecraft to Pluto. The piggyback approach is one that has been suggested, although I do not know if NASA has studied this particular option in depth. The most recent rumor I have heard is that some people are suggesting that flight spares from the CRAF and Cassini spacecraft be assembled into a third spacecraft that could be sent to Pluto (that is, the spacecraft would be virtually free of cost). Unfortunately, the current budget compromise has trimmed 50 million dollars from the 148 requested for the CRAF and Cassini projects, and one way they would weather the cutback would be to do away with the construction of flight spares. ------------------------------ End of SPACE Digest V12 #444 *******************