Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V15_2/V15NO249.ZIP/V15NO249

Internet Message Format | 1993-07-13 | 34KB

Date: Sat, 26 Sep 92 05:01:33
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #249
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat, 26 Sep 92       Volume 15 : Issue 249

Today's Topics:
                       Clinto and Space Funding
                  Clinton and Space Funding (2 msgs)
                                HL-20
                   Hypersonic test vehicle proposed
                   Mars Observer Launched (3 msgs)
             Mars Observer Update - 09/25/92 (Launch Day)
              No large worlds in Lagrangian pts (2 msgs)
                   Pegasus/Conestoga update anyone?
  PUTTING VENUS IN AN ORBIT SIMILAR TO THE ORBIT OF THE EA (2 msgs)
                     Robot Rovers: Big or Small?
                   Tether Thesis available via FTP

    Welcome to the Space Digest!!  Please send your messages to
    "[e-mail]", and (un)subscription requests of the form
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    (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle
    (THENET), or [e-mail] (Internet).
----------------------------------------------------------------------

Date: 25 Sep 92 13:27:33
From: Steinn Sigurdsson <[e-mail]>
Subject: Clinto and Space Funding
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:


   > This is where that military money can and should be spent. However,
   the typical
   > Reagan/bushist freemarketeers are completely against this
   government
   > intervention in the marketplace, and, it seems from here, bury any
   attempt at a
   > US Industrial policy. The frequent cries that 'goivernment
   intervention doesn't
   > work' are plainly wrong. Look at Japan. Look at the EEC even, where
   > technological programmes seem to be coming together.

   they built their companies on the toehold in electronics, and got
   into building cheap but reliable small cars, as did the Germans with
   the Volkswagen. In the 70's they careful business approach began to
   pay off, as the companies kept plowing profits back into R&D. And in
   particular they adopted Deming and TQA at a very early level. They
   were still largely copying technology, but going into the 80's they
   picked up on the Video Tape Recorder and made it a household item. No
   magic government intervention involved there. Just a lot of market
   savvy and good quality at low prices.

Not quite true, take a look at Japanese patent law and figure
out why TI is only getting IC royalties now after Sony and Matsushita
can pay them out of discretionary funding rather than 20 years
ago when the royalties could have been make-or-break for these
companies... also vtr, autofocusing and a couple of others...

|  Steinn Sigurdsson    |I saw two shooting stars last night        |
|  Lick Observatory    |I wished on them but they were only satellites    |
| [e-mail] |Is it wrong to wish on space hardware?        |
| "standard disclaimer"    |I wish, I wish, I wish you'd care - B.B. 1983    |

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

Date: 25 Sep 92 20:57:00 GMT
From: [e-mail]
Subject: Clinton and Space Funding
Newsgroups: sci.space,sci.astro,talk.politics.space,alt.politics.bush,alt.politics.clinton

In article <[e-mail]>, [e-mail] (Gary Coffman) writes...
>In article <[e-mail]> [e-mail] (Rob Healey) writes:
>>    What I want to know is why everybody WANTS government involved
>>    with ANY of the space exploration? Government is what generally
>>    messes up perfectly good ideas. Doesn't matter whether it's
>>    a Republican or a Democrat in office, space utilization suffers
>>    because its at the spending whim of a government. B^(.
>>
>>    Government is OK at doing initial exploration, i.e. Christipher
>>    Columbus, but things don't get rolling till private enterprise get's
>>    involved, i.e. the colonies were usually paid for by investors who
>>    expected the colonies to pay for themselves.
>>
>>    What we REALLY need to do is convince investors that starting
>>    a colony on the moon in our time is as good of an idea as
>>    starting a colony in the new world was back in the 17th
>>    century.
>Let's see, ole Chris landed in the New World in 1492, the first viable
>colony landed in 1620. Apollo landed on the Moon in 1969. So we should
>expect private enterprise to land a commercial colony on the Moon about
>2097. Let's call it New Plymouth. In the meantime, I guess we'll have
>to let the great navigators be funded by the government. The maps have
>to be filled in in those spaces that now say "Here there be dragons."
>
>Gary

Chris's mission was government financed. So were most of the other
early "missions" to the new world by other governments.  The difference is
that the missions were not to investigate scientific principles but to
icrease the wealth of the mother countries.  This was also true in Roman
times with Roman colonies supported by the state after the legions killed
all the oppostion.  This also happened in the Ionian settlements of Athens
in what is now Turkey.  Also happened in Sicily.  The Carthigenians and
their Phonecian Ancestors also applied this logic.

Funny how the space program is stalled because of the insistance on
Scientific missions as opposed to development oriented missions.  Why do
I say this? Look at the record. Since 1972 we have visited every planet in
the solar system plus most of their moons with Gaspra thrown in as a bonus.
How many Lunar missions have we had in that time period?  How many asteroid
only misions have we had? Actions speak far louder than words on this subject.

Lunar Prospector tried to overcome this with a private effort but was
plagued with difficulties not related to the spacecraft effort.  Why not
all of us smart boys here on the net start designing a basic lunar mission
and think about raising the bucks.  Anybody out there have the guts?
The obvious retort is why don't you do it. Well well well........:-)

Dennis, University of Alabama in Huntsville

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

Date: 25 Sep 92 22:45:39 GMT
From: StarOwl <[e-mail]>
Subject: Clinton and Space Funding
Newsgroups: sci.space,sci.astro,talk.politics.space,alt.politics.bush,alt.politics.clinton

[e-mail] writes:

: Scientific missions as opposed to development oriented missions.  Why do
: I say this? Look at the record. Since 1972 we have visited every planet in
: the solar system plus most of their moons with Gaspra thrown in as a bonus.

We've made it to Pluto, and whatever that thing is they just discovered
a couple of weeks ago (a 120-mi diameter "planet", reported in the NYT a
few weeks ago)?  That's news to me.

--
Michael Adams (aka StarOwl)             "Republicans understand the
Internet:  [e-mail]             importance of bondage between
Bitnet:    FREE1217@UIUCVMD             parent and child."
Anonymous: [e-mail]            -- Dan Quayle
UUCP:      ...!uiucuxc!uiuc.edu!StarOwl

Marrou/Lord in '92

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

Date: Fri, 25 Sep 1992 21:22:22 GMT
From: Dave Rickel <[e-mail]>
Subject: HL-20
Newsgroups: sci.space

I was looking through the August issue of Spaceflight--they had a couple of
pages on the HL-20.  I was surprised to see that it was apparently designed
to use Hydrogen/Oxygen engines.  Any idea why?  It doesn't seem like
performance would be that critical.  Something more traditional like UDMH/NTO
would seem to be less troublesome.

Pretty mockup.  I like flying bathtubs.


david rickel
[e-mail]

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

Date: 26 Sep 92 00:29:52 GMT
From: Josh 'K' Hopkins <[e-mail]>
Subject: Hypersonic test vehicle proposed
Newsgroups: sci.space

I saw an interesting article on p 27 of the September 14 AW&ST.

Apparently Ames has proposed a Mach 10 class manned research aircraft as a
more conservative approach to building NASP.  The idea would be to collect data
on hypersonic flight before trying to build a full orbital vehicle.

The Hypersonic Air Launch Option (HALO) would be a piloted vehicle that would
be launched from an SR-71 at Mach 3 and 70,000 ft.  It would use a LH2/LOX
rocket to reach Mach 9, then test variations on a scramjet engine at speeds up
to Mach 10-12.  It would be designed to fly 50-100 flights over a period of
several years.

Proponents say it is a more rational approach to building NASP and more
fiscally acceptable.  Opponents say that it's an unnecessary sidetrack that
will delay NASP and end up costing more money.

Personal Opinions:
   I tend to agree with the proponents.  I'm not sure if that's because it
sounds like better engineering technique or becuase I like the idea of stapling
a scramjet to the top of a Blackbird :-)  I don't know enough about the current
state of the art in NASP technology to know if it's needed though.

   Followers of "Black" programs should also note that the relative ease with
which this could be done says a few things about what may have already been
done.

--
Josh Hopkins                 Of course I'm a solipsist - Isn't everybody?
[e-mail]

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

Date: 26 Sep 92 04:56:08 GMT
From: Ron Baalke <[e-mail]>
Subject: Mars Observer Launched
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Just wanted to let you know that Mars Observer was successfully launched
at 17:05:01 UTC.  Will give more details later....
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Quiet people aren't the
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | only ones who don't say
|_____|/  |_|/       |_____|/                     | much.

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

Date: 25 Sep 92 21:04:06 GMT
From: Steve Masticola <[e-mail]>
Subject: Mars Observer Launched
Newsgroups: sci.space

From National Public Radio:

Mars Observer is in low Earth orbit as of 3 PM EDT. Electronics
problems in the Titan booster delayed launch for about 30 minutes;
some difficulty was experienced in establishing communication with the
spacecraft once it was in orbit. The trouble may have been related to
the transfer orbit stage (TOS), which is being used for the first
time.

Congratulations to the members of Team Mars! (Knock wood :-)


        M A R S   O B S E R V E R   1 9 9 2   T O U R

          Pasadena * Hightstown * Cocoa Beach * Mars


- Steve ([e-mail]).

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

Date: 25 Sep 92 23:29:47 GMT
From: "Phil G. Fraering" <[e-mail]>
Subject: Mars Observer Launched
Newsgroups: sci.space,sci.astro,alt.sci.planetary

[e-mail] (Ron Baalke) writes:

>Just wanted to let you know that Mars Observer was successfully launched
>at 17:05:01 UTC.  Will give more details later....
>     ___    _____     ___
>    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
>    | | | |  __ \ /| | | |     Jet Propulsion Lab |
> ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Quiet people aren't the
>/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | only ones who don't say
>|_____|/  |_|/       |_____|/                     | much.



Yeah!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! (*)

Hip hip horray!

(*) even if it doesn't have ion drive.




--
Phil Fraering [e-mail] where the x is a number from 1-5.
Phone: [phone] SnailMail: 2408 Blue Haven Dr., New Iberia, La. 70560
"NOAH!"
"Yes Lord?"                          - Bill Cosby
"HOW LONG CAN YOU TREAD WATER?"

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

Date: 26 Sep 92 09:24:58 GMT
From: Ron Baalke <[e-mail]>
Subject: Mars Observer Update - 09/25/92 (Launch Day)
Newsgroups: sci.space,sci.astro,alt.sci.planetary

                         MARS OBSERVER STATUS REPORT
                                 Launch Day
                            September 25, 1992

     The Mars Observer spacecraft was launched today after a 38 minute delay.
At 17:05:01 UTC, the Titan III solid rocket boosters burst to life and
leaped off the launch pad at a 98 degree flight azimuth.  The Titan III
then proceeded to to deliver Mars Observer into Earth orbit.  At one minute,
48 seconds after launch (+01:48), the Titan core vehicle ignited, as planned,
and could easily be verified with the long range cameras tracking the launch.
This was quickly followed by the solid rocket booster jettision at +01:56.
At +04:28, the second stage on the Titan ignited and the first stage
separation then followed.  The second stage continued to burn until
it shutdown at +08:05, as planned.  A trim velocity burn started at +09:22
and continued for 36 seconds.  In less than 10 minutes, Mars Observer was now
in an Earth parking orbit.  At +15:00, the Titan III separated from Mars
Observer.  The Titan III had completed its part of the launch effort
flawlessly.

    The next step at this point was that the two ARIA planes supporting
the launch were to acquire the S-band signal from the TOS (Transfer Orbit
Stage) upper stage.  After several minutes, neither plane reported receiving
any signal from TOS.  Did something happen?  Did the TOS malfunction, or was
it still functioning properly, but was just not transmitting any telemetry
back to Earth?  We did not know.  This was the maiden flight of the TOS, and
some doubts began to creep forth.  At +39:51, the TOS was to ignite its solid
rocket boosters to send Mars Observer from an Earth parking orbit onto a
trajectory to Mars.  The time came and went, and still no signal from TOS.
We don't know if the burn occured or not, or if the spacecraft was still in
Earth orbit.  At +51:03, DSS-46 (26 meter antenna at Canberra) was in position
to acquire the TOS signal.  Still more silence from TOS.  Then a report came
in that the ARIA planes visually saw a red glow in the sky at the time that
the TOS burn was to have occured, and this was encouraging news.  At +53:31,
the Mars Observer spacecraft was scheduled to separate from the TOS, but we
could not confirm this without any feedback from TOS.  The TOS was then
scheduled to perform a small delta burn at +57:31 to move itself away from
the spacecraft.  Still no signal acquisition from TOS.  Canberra was scheduled
to acquire the X-band downlink from Mars Observer at +01:24:00, but that was
still a good 30 minutes away at this point.  We just had to sit and wait.

     Three of the Canberra antennas were being used to acquire Mars Observer's
signal.  We brought up the Canberra's telemetry displays on our monitors.
What Canberra saw, we would see at the same time here at JPL.  We waited
for +01:24:00 to arrive.  As +01:11:30 went by, Mars Observer was supposed to
deploy its High Gain Antenna, solar arrays and Magnetometer.  Fifteen more
minutes to go.  Since I've worked on the telemetry subsystem being used for
Mars Observer, I was very familiar with all of the fields on the displays
what they meant.  The displays were showing red "OUT-OF-LOCKs", and if we get
a signal from Mars Observer then they would turn to green "IN-LOCKs".
As +01:24:00 approached, we could hear the commentary on NASA Select
mentioning that they were waiting for confirmation of spacecraft acquisition
from Canberra.  We all turned our eyes to the displays waiting for our
telemetry subsystem to acquire a signal from Mars Observer.  Then the DSA
field on the display went to a green IN-LOCK followed quickly by green IN-LOCKs
in the Frame Synchronizer and Reed Solomon fields.  We've acquired the signal
from the spacecraft!  The DSA SNR (signal-to-noise ratio) was over 20 with
the Reed Solomon SNR at 40.  We were receiving a strong and clean signal.
TOS has done its job.  Word of the signal acquisition was quickly relayed to
Kennedy Space Center, and we watched the mission controllers celebrate on
NASA Select.  Mars Observer was OK and on its way to Mars.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Quiet people aren't the
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | only ones who don't say
|_____|/  |_|/       |_____|/                     | much.

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

Date: 25 Sep 92 18:48:11 GMT
From: "Frederick A. Ringwald" <[e-mail]>
Subject: No large worlds in Lagrangian pts
Newsgroups: sci.astro,sci.space

In article <[e-mail]>
[e-mail] (Martin Connors) writes:

> Summary: I feel Lagrange points should be checked more thoroughly. Earth's
> would be relatively easy to check. Mars seems to have at least one Trojan.

There was a photographic search by Frank Valdes (at NOAO), with
Burrell-Schmidt telescope on Kitt Peak, for objects in the stable
orbits about the Earth-Moon L4/L5 libration points, as well as the
potentially stable nonplanar orbits near L1/L2, Earth-Moon L3, and
Sun-Earth L2. The results were published in:
     Valdes, F., and Freitas, Jr., R. A. 1983, Icarus, 53, 453.

An earlier, less-sensitive search was described in:
     Freitas, Jr., R. A., and Valdes, F. 1980, Icarus, 42, 442.

They found no libration objects. With the limiting magnitude in V of
17-19 for L3, L4, and L5, this excludes anything with a lunar albedo
(i.e., dark) and a diameter larger than 1-3 meters. With a CCD, it
should be possible to extend this search to V = 20-22, and probably
much fainter.

Read these papers, if you like, the detection methods are very clever.
They involve both taking a time exposure and searching for streaks from
moving objects, and tracking the telescope at the rate expected of the
libration objects, to make them look like points and everything else
look like streaks. These searches really didn't require so much
telescope time: the major effort was searching the images thoroughly,
afterwards. Then again, modern software might work wonders here - but
beware, it might also put horse blinders on you.

One of the funkier implications of this is for SETI: if a spacecraft
just like Pioneer 10 were at Earth/Moon L4/L5, it would have been seen.
(Don't harangue me, look at the papers!)

Dust in Earth-Moon L4/L5, backscattering sunlight, may have been
detected by the Rutgers Zodiacal Light Analyzer on OSO-6, reported by:
     Roach, J. R. 1975, Planet. Space Sci., 23, 173.

An upper limit to a search for forward-scattered sunlight from L4/L5
dust, from the white light coronagraph on Skylab, is in:
     Munro, R. H., et al. 1975, Planet. Space Sci., 23, 1313.

Avenues for future research might include trying to light this dust up
with the Arecibo radar, which I've calculated might just be able to do
it. Since the dust is moving rapidly through the sky (same rate as the
Moon, after all), however, this poses a challenge. Using one of the new
infrared array cameras, particularly in the 10-micron region, might
also be worth looking into, as might the COBE data. Some years ago,
maybe 1985, I saw a blurb by Rob Staehle (at JPL) on a preliminary
design for a simple spacecraft to buzz through the Earth-Moon L4/L5
points, armed with a dust detector. Say...they might be interesting
targets for any spacecraft on its way to a comet, especially if you're
using one of these intricate trajectories by Bob Farquar to pump up
your spacecraft speed. Such a spacecraft would be well-instrumented for
this, after all.

As a curious note, none other than Gerry O'Neill helped me with this,
who faxed me what must have been one of his last pieces of professional
correspondence, about a week before he died. Maybe one of these days
I'll get around to it, but I'm emigrating to a first-class scientific
opportunity - not too many of those on this continent these days, you
know - so I should be pretty busy. If *you* want to do this, let me
know, and I'll send you my notes. Frank Valdes might be interested,
too, and he sure knows software, being one of the main architects of
IRAF.

Fred Ringwald
Department of Physics & Astronomy
Dartmouth College
Hanover, NH 03755-3528 U.S.A. (for the time being, at least)

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

Date: 25 Sep 92 23:17:06 GMT
From: "Frederick A. Ringwald" <[e-mail]>
Subject: No large worlds in Lagrangian pts
Newsgroups: sci.astro,sci.space

In article <[e-mail]>
[e-mail] (Martin Connors) writes:

> Summary: I feel Lagrange points should be checked more thoroughly. Earth's
> would be relatively easy to check. Mars seems to have at least one Trojan.

There was a photographic search by Frank Valdes (at NOAO), with the
Burrell-Schmidt telescope on Kitt Peak, for objects in the stable
orbits about the Earth-Moon L4/L5 libration points, as well as the
potentially stable nonplanar orbits near L1/L2, Earth-Moon L3, and
Sun-Earth L2. The results were published in:
     Valdes, F., and Freitas, Jr., R. A. 1983, Icarus, 53, 453.

An earlier, less-sensitive search was described in:
     Freitas, Jr., R. A., and Valdes, F. 1980, Icarus, 42, 442.

They found no libration objects. With the limiting magnitude in V of
17-19 for L3, L4, and L5, this excludes anything with a lunar albedo
(i.e., dark) and a diameter larger than 1-3 meters. With a CCD, it
should be possible to extend this search to V = 20-22, and probably
much fainter.

Read these papers, if you like, the detection methods are very clever.
They involve both taking a time exposure and searching for streaks from
moving objects, and tracking the telescope at the rate expected of the
libration objects, to make them look like points and everything else
look like streaks. These searches really didn't require so much
telescope time: the major effort was searching the images thoroughly,
afterwards. Then again, modern software might work wonders here - but
beware, it might also put horse blinders on you.

One of the funkier implications of this is for SETI: if a spacecraft
just like Pioneer 10 were at Earth/Moon L4/L5, it would have been seen.
(Don't harangue me, look at the papers!)

Dust in Earth-Moon L4/L5, backscattering sunlight, may have been
detected by the Rutgers Zodiacal Light Analyzer on OSO-6, reported by:
     Roach, J. R. 1975, Planet. Space Sci., 23, 173.

An upper limit to a search for forward-scattered sunlight from L4/L5
dust, from the white light coronagraph on Skylab, is in:
     Munro, R. H., et al. 1975, Planet. Space Sci., 23, 1313.

Avenues for future research might include trying to light this dust up
with the Arecibo radar, which I've calculated might just be able to do
it. Since the dust is moving rapidly through the sky (same rate as the
Moon, after all), however, this poses a challenge. Using one of the new
infrared array cameras, particularly in the 10-micron region, might
also be worth looking into, as might the COBE data. Some years ago,
maybe 1985, I saw a blurb by Rob Staehle (at JPL) on a preliminary
design for a simple spacecraft to buzz through the Earth-Moon L4/L5
points, armed with a dust detector. Say...they might be interesting
targets for any spacecraft on its way to a comet, especially if you're
using one of these intricate trajectories by Bob Farquar to pump up
your spacecraft speed. Such a spacecraft would be well-instrumented for
this, after all.

As a curious note, none other than Gerry O'Neill helped me with this,
who faxed me what must have been one of his last pieces of professional
correspondence, about a week before he died. Maybe one of these days
I'll get around to it, but I'm emigrating to a first-class scientific
opportunity - not too many of those on this continent these days, you
know - so I should be pretty busy. If *you* want to do this, let me
know, and I'll send you my notes. Frank Valdes might be interested,
too, and he sure knows software, being one of the main architects of
IRAF.

Fred Ringwald
Department of Physics & Astronomy
Dartmouth College
Hanover, NH 03755-3528 U.S.A. (for the time being, at least)

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

Date: 25 Sep 92 14:55:04 GMT
From: [e-mail]
Subject: Pegasus/Conestoga update anyone?
Newsgroups: sci.space

Ron Baalke's handy space calendar (dated 29 July 1992) shows launch dates
for Conestoga and Pegasus this month (actually, the 24th). Since these are not
likely to be high-profile events in the general community, could some cognizant
person(s) provide a status update for these launches?

Inquiring minds want to know...

   .
   |
   |
  .|.
  |||
  * * MCDONNELL | Layne Cook
 ** **  DOUGLAS | Advanced Products Design & Technology           My own time
*** ***   SPACE | [e-mail]                     My own ramblings

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

Date: Fri, 25 Sep 92 17:28:50 GMT
From: Dave Jones <[e-mail]>
Subject: PUTTING VENUS IN AN ORBIT SIMILAR TO THE ORBIT OF THE EA
Newsgroups: sci.space

Alan Barclay ([e-mail]) wrote:
: In a previous message you said that mars' gravity was too light to hang on the
: lighter gasses, thus the atmosphere is thin.  Titan, a moon of Saturn is
: slightly smaller than mars and has an atmospheric density twice earths at the
: surface.  How do you explain that? :)
:
: Alan

Titan is a damn sight colder than Mars, for one thing!  Its a question
of gravity, temperature and the molecular weight of the gases in the
atmosphere.  Venus is hot and lost most of its hydrogen but kept oxygen
and heavier stuff (Question: where is Venus's nitrogen?).  Mars is
colder but lost most everything because of its size.  Titan is much
colder and has free nitrogen in the atmosphere.  I'm not sure if the
other local materials - methane and ammonia - are frozen out or have
been lost.

--
||)) There is no truth to the rumor that:)))))))))))))))))))))))))))))))))))|
||)) Lotus are suing Apple for copying the look and feel of their lawsuits )|
||))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))|
||Dave Jones ([e-mail]) | Eastman Kodak Co. Rochester, NY   |

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

Date: 25 Sep 1992 17:03:38 GMT
From: Jeff Bytof <[e-mail]>
Subject: PUTTING VENUS IN AN ORBIT SIMILAR TO THE ORBIT OF THE EA
Newsgroups: sci.space


>...Titan, a moon of Saturn is
>slightly smaller than Mars and has an atmospheric density twice Earths at
>the surface.  How do you explain that?

Surface gravity, atmospheric temperature and composition are all factors
in determining a planet's atmospheric density and pressure.

Jeff Bytof
[e-mail]

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

Date: 25 Sep 92 14:36:10 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Robot Rovers: Big or Small?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Karl Altenburg) writes:
>I would like to know peoples ideas on which types of robots should be
>used in possible, future Lunar and Mars missions.
>
>Some support the traditional large rover.  An example would be Carnegie
>Mellon's Ambler, which has 6 legs legs (non-traditional), complex vision
>system, stands around 14 feet tall, and weighs a ton (I think?).
>It would be launched and work as a solitary rover.
>
>Others support the non-traditional, small (insect-like), multiple,
>cooperative rovers.  An example of this type of robot would be JPL's
>Rockey III, at has six wheels, 24 X 20 X 16 inches, and weighs about
>60 pounds (the proposed Rocky IV will weigh less than 20 pounds.)
>Several of these would be launched and work collectively.
>
>I realize there are many issues involved, but I would like informed
>opinions on the different views to exploring space.

The key questions are:

1) What's the mission?

2) How much money can you spend?

3) How much mass can you launch?

2) How many launches do you get?

3) How frequently can you launch?

A) If the mission requires long distance travel and/or deep core samples,
   then the big rover is the only way to go. 2 and 3 have to meet the
   rover requirements, or you don't go at all. Likely for Moon, possible
   for Mars.

B) If money is tight and/or launch mass is low, you launch one
   little rover. A likely situation for distant targets. A possible
   situation for all space science under current budget pressure.

C) If money is tight, but continues for many years, and you can
   launch often, you launch several little rovers one after the
   other. Possible for the Moon and likely for Mars.

D) If money and launch mass are available *once*, you launch many
   little rovers on one vehicle and let them disperse via a carrier
   which can be a big rover. Big science mentality, typical of the
   NASA way of selling grand projects. Chance of total loss of
   mission due to budget overruns or launch failure is high.

E) If money and launch mass are available frequently, you launch
   *men* and explore to your heart's content. Unlikely in the
   foreseeable future.

Gary

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

Date: 25 Sep 92 21:08:03 GMT
From: "P. Douglas Reeder" <[e-mail]>
Subject: Tether Thesis available via FTP
Newsgroups: sci.space

Beacause of the recent interest in tethers, I have made my senior
thesis available for anonymous FTP.  The beginning and the end of the
paper contain a short summary of the tether concept and some of its
uses.  The main body is an analysis of the dynamics of an orbiting
mass barbell.  It is not a general introduction to tethers.

The FTP location is the space-tech archive site:

daisy.learning.cs.cmu.edu

The paper is in the directory

public/space-tech/reeder.thesis


The files in the directory contain my senior thesis: "Tethers for
Space Propulsion Without Reaction Mass" in two formats.

The file "reeder.thesis.dvi" is a TeX device independant file
containing the complete text of the thesis.  You must ftp it in BINARY
mode.  Consult your local documentation for information on printing
".dvi" files.

The file "reeder.thesis.ps" is a PostScript file containing the
complete text of the thesis.  You must ftp it in ASCII mode.  Consult
your local documentation for information on printing PostScript files.

--
Doug Reeder                                 USENET: ...!tektronix!reed!reeder
Internet: [e-mail]                   BITNET: [e-mail]

I am actively seeking scientific programming contracts.

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From: Dani Eder <[e-mail]>
Newsgroups: sci.space
Subject: Re: overpopulation
Message-Id: <[e-mail]>
Date: 24 Sep 92 20:52:33 GMT
References: <[e-mail]> <[e-mail]> <[e-mail]> <[e-mail]>
Distribution: na
Organization: Boeing AI Center, Huntsville, AL
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Source-Info:  Sender is really [e-mail]

[e-mail] (Nick Szabo) writes:

[about population growth rates behavior]

Of course, in any long term, you have to consider the effects of a
sub-populations (like the Mormons) for whom large families are an
imperative.  In the long run they will tend to overrun the rest of
the population by producing more offspring.

Another effect is the cost/benefit ratio for children.  In Africa,
children are seen as a net benefit.  In the US they are seen as
a major cost, despite which people have them because they want them.
What if in 20 years automation has reduced the cost of supporting
children and changes the equation again?  For example, housing is
the largest single cost of raising a child (that extra bedroom
in your house).  If housing construction costs drop dramatically,
then what cost children.  Another possibility is extended lifespans
making having sequential children more affordable than having to
have them all at once in your 20's and 30's.  Finally, in 40 years
or so I expect human-capability computers to be in production.
If you are liberally minded and not a carbon-chauvinist, you would
count the silicon baed intelligences along with the old-style humans.
We are cranking out PCs at around 20 million per year now, in the
next century the silicon population may outstrip the carbon population
in absolute numbers.

Dani Eder

--
Dani Eder/Boeing/Advanced Civil Space/[phone](w)/232-7467(h)/
Rt.1, Box 188-2, Athens AL 35611/Member: Space Studies Institute
Physical Location: 34deg 37' N 86deg 43' W +100m alt.
***THE ABOVE IS NOT THE OPINION OF THE BOEING COMPANY OR ITS MANAGEMENT.***

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

Date: Fri, 25 Sep 92 20:44:59 PDT
From: [e-mail] (Ross Borden)

however, someone with a bit less of a (hmm, twisted isnt quite the right word)
homocentric perspective might see it like this:

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End of Space Digest Volume 15 : Issue 249
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