Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V12_4/V12_444.TXT

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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:

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----------------------------------------------------------------------

Date: 5 Oct 90 16:27:41 GMT
From: news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Manned/unmanned tradeoffs

In article <[e-mail]> [e-mail] (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.  |  [e-mail]   utzoo!henry

------------------------------

Date: 10 Oct 90 13:42:55 GMT
From: mcsun!ukc!icdoc!syma![e-mail]  (Andy Clews)
Subject: Re: Ulysses Update - 10/06/90

From article <[e-mail]>, by
[e-mail] (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: [e-mail]   BITNET: [e-mail]

------------------------------

Date: 10 Oct 90 23:43:14 GMT
From: usc!elroy.jpl.nasa.gov!euclid.jpl.nasa.gov![e-mail]  (Peter Scott)
Subject: Re: Beta Testers Needed

In article <5A0A080E09090128-MTASATURN*[e-mail]>, [e-mail] writes:
> > From:         Leonard Abbey <[e-mail]>
>
> > 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?    |    ([e-mail])

------------------------------

Date: 11 Oct 90 04:22:12 GMT
From: agate!garnet.berkeley.edu![e-mail]  (James Wilbur Lewis)
Subject: Re: Ulysses Update - 10/06/90

In article <[e-mail]> [e-mail] (Andy Clews) writes:
>From article <[e-mail]>, by
>[e-mail] (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![e-mail]  (Brian or James)
Subject: Re: atmosphere on earth's moon.  atmosphere and tide/gravity

In article <[e-mail]> [e-mail] (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![e-mail]  (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                              [e-mail]
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![e-mail]  (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         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

------------------------------

Date: 9 Oct 90 17:32:00 GMT
From: mcsun!i2unix!sixcom![e-mail]  (Joe Giampapa)
Subject: Re: Manned/unmanned tradeoffs

In article <[e-mail]> [e-mail] (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. ....
>
>[e-mail]

   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  ([e-mail])

------------------------------

Date: 10 Oct 90 11:09:13 GMT
From: zaphod.mps.ohio-state.edu!samsung!munnari.oz.au!uhccux![e-mail]  (David Tholen)
Subject: Re: Pluto mission?

In article <[e-mail]>, [e-mail] 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
*******************