Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V11_4/V11_416.TXT

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Subject: SPACE Digest V11 #416

SPACE Digest                                     Volume 11 : Issue 416

Today's Topics:
         space news from Dec 18/25 1989 AW&ST
          space news from Dec 11 1989 AW&ST
             Terra-forming Venus
            Re: Terraforming Venus
             Re: Manned mission to Venus
Carnegie Mellon University develops planetary robot for NASA (Forwarded)
            Re: Deep Space Relay Satellite
    Re: Earth Orbits (was: space news from April 9 AW&ST)
----------------------------------------------------------------------

Date: 17 May 90 02:46:30 GMT
From: mcgill-vision!clyde.concordia.ca!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: space news from Dec 18/25 1989 AW&ST

[Yes, I know, this is a lot out of sequence.  Given that I'm more or less
caught up on current issues -- I consider running a month behind to be
normal, given Post Office, reading the things, etc. -- I'm going back for
quick summaries of the issues I missed due to the subscription foulup.
My thanks to Alex Sim of Dryden and to the Dryden library, for supplying
the issues I missed, and to Mary Shafer for arranging it.]

Discussion of the rumors about the "Aurora" hypersonic spyplane, successor
to the SR-71, asking whether the USAF's ambivalence about the Aerospace
Plane is because similar technology is already being developed in secret.

Some grumbling about silly secrecy in military space operations.  For
example, AW&ST had considerable difficulty finding out the details of
the engine-gimballing problem on the first Titan 4 flight.  The USAF
didn't even admit there was a problem until prodded about it (after
informal reports from "friendly sources").  After the investigating
team produced its final report, a request for a copy was ignored.
"It was not secret, it just was not any of my business."  A request
under the Freedom Of Information Act was denied on the grounds that
it would "reveal the deliberative process of the Air Force". [!!]

USAF Space Systems Division has been ordered to terminate design work
on ALS, disband the program office, and scale back the program to a
technology-research effort, ALTP (Advanced Launch Technology Program).
The decision apparently was because full-scale development, starting
in 1992, would have involved a sharp jump in spending, and the SDI
launch requirements that have been driving the program have been
shrinking of late.  NASA is disappointed, and hopes to continue work
leading to a prototype new-technology rocket engine, at the very least.

Kvant 2 is now in place on Mir.
--
Life is too short to spend    |     Henry Spencer at U of Toronto Zoology
debugging Intel parts. -Van J.| uunet!attcan!utzoo!henry [e-mail]

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

Date: 17 May 90 03:02:12 GMT
From: mcgill-vision!clyde.concordia.ca!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: space news from Dec 11 1989 AW&ST

[Yes, I know, this is a lot out of sequence.  Given that I'm more or less
caught up on current issues -- I consider running a month behind to be
normal, given Post Office, reading the things, etc. -- I'm going back for
quick summaries of the issues I missed due to the subscription foulup.
My thanks to Alex Sim of Dryden and to the Dryden library, for supplying
the issues I missed, and to Mary Shafer for arranging it.]

Iraq claims successful launch of a rocket capable of launching satellites.
People are concerned, not about Iraq launching satellites but about Iraq
having long-range-missile technology.

USSR cancels planned 1990 Energia launch, due to tight budgets.  "There
is a launcher ready but we no longer have a payload for it."  The nature
of the cancelled payload was not specified.  The next flight is now set
for early 1991 carrying a Buran orbiter (unmanned).  Energia development
work continues, however, including successful preliminary tests on using
supercooled fuels to increase fuel density and therefore payload; a 1-ton
payload increase has been achieved by unspecified cooling technologies.

Kvant 2 docking operations at Mir being completed after a solar-array
deployment problem was solved.

Diagram of the approach maneuvers planned for the LDEF retrieval.

Solar Max reenters and burns up Dec 2, over the Indian Ocean.

Sonic boom from the Columbia landing Aug 13 caused a "mini-earthquake"
in downtown Los Angeles, shaking office buildings slightly, since the
dominant component of the shock waves had a period matching the
resonant frequency of the ground there.

Letter from Allen Thomson, observing that there are at least six
unclassified radarsats set for launch in the next five years, none
of them American:  ERS-1 (ESA), JERS-1 (Japan), Radarsat (Canada),
two Almaz platforms (USSR), and the radar system on the planned
remote-sensing module for Mir.  "One wonders how a nation that
pioneered orbital radar imaging with Seasat (sadly, it was once
called Seasat-A) in 1978 finds itself seventh in line at the end
of the century."
--
Life is too short to spend    |     Henry Spencer at U of Toronto Zoology
debugging Intel parts. -Van J.| uunet!attcan!utzoo!henry [e-mail]

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

Date: 15 May 90 18:45:10 GMT
From: crash!orbit!pnet51![e-mail]  (S Schaper)
Subject: Terra-forming Venus


 What sort of Delta-V would be required to take a smaller moon of Saturn and
send it on a Hohmann-type intercept with Mars? Refine it in process to get rid
of cyanides, etc, and make ice-cubes, and larger chunks to connect Mare Hellas
with Mare Borealis?, Likewise, send a Ni-Fe asteroid to Venus on a tangent to
increase durineal speed :-) (may be totally impossible!) and blast away a lot
of atmosphere.
   Else anitmatter bombs to reduce atmos pressure, or better yet engineered
critters to return the SO2, and CO2 to water and carbonate and sulfates?
Major problems with this, but what are some calculations?

UUCP: {amdahl!bungia, uunet!rosevax, chinet, killer}!orbit!pnet51!schaper
ARPA: crash!orbit!pnet51![e-mail]
INET: [e-mail]

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

Date: 17 May 90 17:37:19 GMT
From: usc!cs.utexas.edu!uwm.edu![e-mail]  (Russ Brown)
Subject: Re: Terraforming Venus

From article <[e-mail]>, by [e-mail] (Commander Krugannal):
>
>       Umm, in a word NO!  Think about it next time, perhaps its
>    the space or vacumn between the pieces of glass in your stove
>    window that keeps the heat in.  Or better yet, take a look
>    at a thermos bottle someday.
>       Perhaps you were thinking of UV radiation?


Glass is a very effective barrier to infrared RADIATION. you're mixing
up conductive heat loss (which you insulate against) with heat lost through
radiation. But I agree that the oven door is not a good example of this
effect.

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

Date: 17 May 90 14:16:47 GMT
From: usc!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!IDA.ORG!pbs![e-mail]
Subject: Re: Manned mission to Venus

In article <[e-mail]>, [e-mail] (Mark SOKOLOWSKI) writes:
> (deleted)
> Kennedy wanted a man on the Moon in 10 years, and we will remember it
> forever because it was done. Nobody cares about the lunar missions after
> Apollo 11, nobody cares about Skylab, Mir. The only thing HUMANITY
> remembers now is that a man was on the Moon. And it will never care about
> Moon colonies and space stations because all of these are now banal things
> for imagination. We have to be original, Venus is so terribly harsh, such
> a strange and unknown place....
>
> Mark S.
> -------
Maybe the average person does not care about Moon colonies now because they ARE
just imaginary.  But a real colony on the Moon that has grown large enough to
be visible from Earth will have a profound impact on humanity.  Imagine looking
up at the Moon some evening and noticing the glow of manmade lights and other
indirect signs of human activity up there.  It is sometimes said "Out of sight
... out of mind."  No activity on any of the other planets in the solar system
will be noticible to the unaided eye and perhaps the man in the street would
 care less what happens way out there, but big active moon colonies would be
 hard to ignore and will have a definite cultural impact we underestimate now.

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

Date: 17 May 90 18:31:18 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: Carnegie Mellon University develops planetary robot for NASA (Forwarded)

Mary L. Sandy
Headquarters, Washington D.C.                        May 17, 1990
(Phone:  [phone])                               10 a.m. EDT

Anne Watzman
Carnegie Mellon University, Pittsburgh
(Phone:  [phone])


RELEASE:  90-69

CARNEGIE MELLON UNIVERSITY DEVELOPS PLANETARY ROBOT FOR NASA


     The "Ambler," a six-legged, 12-foot-tall, prototype,
autonomous robot with the "brains" and motor skills to explore
rugged terrain, is being developed for NASA by Carnegie Mellon
University's Robotics Institute, Pittsburgh.

     NASA officials and university researchers say the Ambler's
technology could bring an important new dimension to solar system
exploration.  Because the robot literally walks, it can traverse
rough terrain by stepping over crevices and large boulders.
Future operational rovers, based on the Ambler design, could
reach areas on the Moon and Mars inaccessible to wheeled vehicles
or too dangerous for humans.

     Since October 1987, three teams of researchers including
Carnegie Mellon graduate and undergraduate students have been
developing the algorithms, hardware and software necessary for
the Ambler's locomotion, perception and planning capabilities.
The Ambler represents an integrated, self-sufficient system that
will be used to provide NASA mission managers with the confidence
that legged vehicles are a realistic alternative to wheeled
rovers for lunar and martian exploration.

     The aluminum Ambler has two sets of stacked legs, with three
legs per stack.  These legs separately lift, advance and
circulate to their original positions, much like an egg beater.

     "The body is propelled in a motion similar to cross-country
skiing," said Carnegie Mellon's William L. "Red" Whittaker, one
of three Ambler project principal investigators.  "A single leg
reaches out in front of the others, places itself firmly on the
ground like a ski pole and then pulls the machine forward."

     Because the drive motors that support the Ambler's body are
separate from those that propel it, the robot remains level
whether it's walking on flat or rugged ground.  The design
provides a stable platform for sensors, scientific equipment and
sample acquisition tools.

     Above the legs, on the stacks, are boxes containing the
machine's electronics.  Above that, a cross bar connects the two
sections.  The electrically-powered Ambler will be energy
efficient and can retain its ability to walk even if it loses
mobility in two legs.

     The Ambler requires a set of sensors for its vision
system.  With input from this system, the robot creates three-
dimensional maps of the surrounding topography and objects it
might be interested in sampling.  After studying the maps, it
decides in which direction to move and where to place its feet.
Future versions deployed on Mars could combine the current laser
sensing system with cameras, sonar and other sensors to provide
the full spectrum of information needed for sampling and
navigation.

     "These machines will have to contend with rugged and soft
terrain, low temperatures, high winds, dust and equipment
failure," said principal investigator Takeo Kanade.  "For
autonomous operation under such conditions, a good vision system
is critical."

     The Ambler's unique software control system, called Task
Control Architecture, enables the Ambler to plan for the
selection of stable and safe steps.  "The system is designed for
robots that operate in dynamic and uncertain environments,"
explained principal investigator Thomas Mitchell.  "It uses a
variety of sensors with different ranges and resolutions to know
where it is and see where it's going."

     The Ambler recently took its first steps at the Carnegie
Mellon University's Robotics Institute.  The next step is
integration of its perception, planning and control capabilities.

     The Ambler represents a new generation of robots to explore
and work in natural terrains.  The technology also has
implications for Earth-bound activities such as construction,
mining, timbering, hazardous waste management and emergency
response.

     The Ambler is one of the concepts being evaluated under
NASA's Planetary Rover program, which is developing robotic and
manned technology to explore lunar and planetary surfaces.  The
program initially is focused on unmanned rover technology with
both legged and wheeled options being studied.

     Planetary rovers must be able to make autonomous decisions
because of the long transmission times for commands between Earth
and planetary surfaces -- about 45 minutes one way to Mars.  "The
intent for the vehicles being designed is for them to be capable
of operating on their own with just a very general set of
directions," notes David B. Lavery, manager of NASA's Planetary
Rover Program.

     "Robots are not susceptible to temperature changes or
radiation exposure on the long flights required to reach the
planets," added Whittaker.  "They can spend protracted time on a
mission that would be impossible for an astronaut who requires
close proximity to his or her space ship."


                             - end -



     A video clip and still photographs are available to media
organizations to support this release and can be requested from
NASA Headquarters by calling 202/453-8375.

     Photo numbers are:

     color   90-HC-305
     B/W     90-H-320

     The 8-minute video clip will be broadcast on NASA Select
television at noon EDT, Thursday, May 17.  NASA Select may be
accessed via Satcom F2R, transponder 13, frequency 3960 MHz,
position 72 degrees West longitude, polarization vertical, audio
monaural 6.8 MHz.

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

Date: Thu, 17 May 90 14:58:22 EDT
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Re: Deep Space Relay Satellite


>From: mojo![e-mail]  (Doug Mohney)
>Subject: Deep Space Relay Satellite

>What's the feasability of getting a mid-point "relay" station put into
>place to support transmissions of deep space probes such as Voyager and
>future missions? Seems a waste for them to collect all that data and
>not be able to get access to it because either A) the 70 meter Deep Space
>Tracking network here on Mother Earth wasn't available or B) The wattage
>coming out of 'em in future years will be too low to be heard by anything
>sitting on the ground.

Sounds like it might be useful under certain specific conditions. For instance,
it could reduce weather-related loss of data. I can think of a few problems
you'd have to consider:
 - Space is not linear, with everything "out there" in the same direction.
   For instance, suppose Jupiter and Saturn at some point are on opposite sides
   of the sun, and you want links to both? In practice, you'd need several
   relays (i.e. in a ring), and pay a lot for each one.
 - The DSN receivers are extremely precise, sensitive, huge pieces of
   equipment which can be repaired if they break. The reduction in distance
   would relax the performance requirements of space-based relays only slightly.
   It might be more worthwhile to just build more ground-based receivers.
   Perhaps some could be built on the moon to augment the current DSN.
 - If the distances and signal strengths are such that a relay is *necessary*,
   you add a failure point to the system. It might be safer just to augment the
   capabilities of the ground-based equipment.

If you can think of a way around these problems, it would be a neat system -
sort of like a super-TDRS network.

>Alternately, we'll end up designing probes which drop off three or four
>football-sized relays (like a high-tech trail of bread crumbs :-) which
>can pass back clear data from way-way out.

Since probes spend most of their time coasting, the relays would just follow
the probes closely. You could drop one off before the final positioning for
each slingshot maneuver - since each relay would be somewhat off course, I
don't know how well this would work.
        John Roberts
        [e-mail]

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

Date: 17 May 90 16:59:53 GMT
From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Earth Orbits (was: space news from April 9 AW&ST)

In article <[e-mail]> [e-mail] (Bruce W. Mohler) writes:
>Just curious.  Where can I learn more information about the three types
>of orbits Henry mentions in the above segment? ...

Hmm, didn't expect to have to repost this so soon:

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

End of SPACE Digest V11 #416
*******************