Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_1/V15NO143.TXT

Internet Message Format | 1993-07-13 | 32KB

Date: Wed, 26 Aug 92 04:59:59
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #143
To: Space Digest Readers
Precedence: bulk


Space Digest                Wed, 26 Aug 92       Volume 15 : Issue 143

Today's Topics:
            BuckyStalks (was Re: Beanstalks in Nevada Sky)
                        Global positioning sys
                       GOP space platform text
             Need GIF (JPG, whatever) of Shuttle Landing
                       Opinions on NLS (2 msgs)
                   Private space ventures (4 msgs)
     Saturn class (Was: SPS feasibility and other space (3 msgs)
                 Spot Images Corp and EOSAT addresses
                       TOPEX Update - 08/24/92
                            Venus orbiters
     With telepresence, who needs people in Earth orbit? (3 msgs)

    Welcome to the Space Digest!!  Please send your messages to
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----------------------------------------------------------------------

Date: 24 Aug 92 16:34:54 GMT
From: Dani Eder <[e-mail]>
Subject: BuckyStalks (was Re: Beanstalks in Nevada Sky)
Newsgroups: sci.space

>Seriously, since I'm posting this anyway, does anyone know of any
>cleverer (or at least easier) ways to get a beanstalk built than
>the extrude-it-from-Geosynch approach? Specifically, anything that would
>let us keep the factory on the ground?

Sure.  Two approaches to building a beanstalk: literal bootstrapping
and gun-launch.  In the first:  You have a small vehicle (maybe 10
ton takeoff mass) that is designed to take a small payload (like
1 ton) to a high suborbital speed (like 5 km/s).  This vehicle would
use LOX/H2 rockets.  At this speed you dump a 1 ton payload consisting
of solid rocket motor plus spool of tether material.  The rocket
motor kicks you up to orbit and delivers maybe 200 kg tether stuff
to orbit.

As you collect these spools of tether and build down from LEO, you
run an electrodynamic engine and raise the tether system, keeping
the bottom end just above the atmosphere.  As you build up the tether,
the bottom end moves slower with respect to the ground.  Eventually,
you are moving slow enough that the vehicle can fly directly to the
bottom of the tether, continuing to deliver cable sections (and also
payloads for paying customers).  As the tether grows, the vehicle
can deliver larger and larger payloads since it is flyinbg to a slower
velocity, theus the construction rate goes up (in terms of kg of
tether delivered per flight).

Given a strong enough material, you eventually get the bottom end
to stop, and attach it to a tower you have built up from the ground
to meet it.

Method 2:  Use a gas gun on the ground to fire cannisters of cable
to Earth orbit.  The cannisters may be as small as 20kg and still
be effectively launched from the ground.  This saves you from having
to build the cryogenic vehicle until later.  Meanwhile, you can
get revenue from carrying customer spacecraft from LEO up to the
top of the developing tether and releasing them, giving them a boost
on their way.  After that, you continue as in method 1.

Once you have a large tether that has the span you want, you can
increase it's payload by hauling up parallel strands, literally
lifting by your own bootstraps.

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: 18 Aug 92 19:22:47 GMT
From: Keith Stein <[e-mail]>
Subject: Global positioning sys
Newsgroups: sci.space

Jeff you'll need to contact the Air Forc for GPS information.

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

Date: Tue, 25 Aug 1992 13:05:52 GMT
From: Stephen J Kenny <[e-mail]>
Subject: GOP space platform text
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Tom Nugent       ) writes:
>Does anybody have the Democratic platform on space?
>
They're in favor of it..
-------------------------------------------------------------
"Away..we go...so fast...."  | [e-mail]
            - Autosexual | [e-mail]
           Be Bop Deluxe | Stephen J. Kenny
-------------------------------------------------------------

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

Date: 25 Aug 92 21:17:56 GMT
From: Dennis Bruggink <[e-mail]>
Subject: Need GIF (JPG, whatever) of Shuttle Landing
Newsgroups: sci.space

Maybe someone can save me some hunting:  I've checked a number of sites
w/ GIFs for an image of the shuttle landing; I've found one in the Hubble
series (hubble24.gif) which is exactly the view I'm after, but it's not
very sharp.  Basically the shuttle has just touched down, and is seen
as from a side view.

Going through various achives has taken a lot of time, and the directory
listings are usually not at all specific (e.g., shuttle1, shuttle2, ...).

So ...    doesn't anyone have a pointer to this image, or recall coming
across it anywhere??

thanks,

-dennis bruggink

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

Date: 25 Aug 92 11:45:14 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Opinions on NLS
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>the bottom line on NLS is that it will not reduce costs but will
>actually raise costs if you factor in development costs. On the other
>hand, we have proposals out there for Delta and Titan derived HLV's
>which WILL reduce costs by a factor of two even if development costs
>are included (assuming they work).

NASA's primary mission is air and space flight R&D. It's secondary mission
is operational support of pure science missions and waving the flag. The
primary mission means that development costs are not an expense, they are
an opportunity to perform the primary mission. The secondary mission means
that spacecraft should have the lowest possible operational costs consistent
with mission support, development cost of the vehicle isn't important if it
is done in house as part of the primary mission. If it's an out of house
commercial purchase, then R&D costs must be charged against operations,
raising secondary mission costs.

Failure to understand mission accounting rather than life cycle accounting
leads to dependence on old technology when the primary mission is to push
new technology.

Gary

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

Date: 25 Aug 92 16:54:25 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Opinions on NLS
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:

>NASA's primary mission is air and space flight R&D.

Since NLS is not R&D but rather operations this is another excellent
reason for dropping NLS.

>primary mission means that development costs are not an expense, they are
>an opportunity to perform the primary mission.

For operational vehicles, like NLS, development costs ARE an expense. Since
NLS is intended to be a simple operational vehicle it does not support
NASA's mission.

>Failure to understand mission accounting rather than life cycle accounting
>leads to dependence on old technology when the primary mission is to push
>new technology.

Failure to understand the difference between research and operations leads
to money going to operations when it would be better spent on research.

The goal of NLS is not to conduct research; it is to replace existing
launch vehicles with more expensive alternatives. People ask why there
is no Bill Gates for space. The answer is right here: so long as we
make a virtue out of wasting money and paying more then we need to
we aren't going anywhere.

  Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "If they can put a man on the Moon, why can't they     |
|  [e-mail]     |  put a man on the Moon?"                               |
+----------------------241 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 25 Aug 92 13:51:14 GMT
From: "Frederick A. Ringwald" <[e-mail]>
Subject: Private space ventures
Newsgroups: sci.space

(attribution lost in the shuffle)
> [It bugs me that there are people like H Ross Perot, who
> themselves have enough cash to finance their own space
> programs, but that none, so  far, has underwritten one.]

Don't worry about it, I'm sure something like it will happen, sooner
than you think.

For practical uses of space technology, private investors have for
years been able to buy stock in aerospace companies such as Boeing and
Lockheed.  Howard Hughes had many millions worth of shares in, ahem,
Hughes Aircraft.

Since it's been brought up, if space technology is so useless for the
Third World, then how come Mexico, India, and Indonesia are acquiring
their own communications satellites?  Meteorological satellites can see
typhoons heading toward Bangladesh as well as they can hurricanes for
Florida, and the list goes on.  When space technology and services look
like good investments to these countries, for the amount of capital
they can afford, they do invest, just like everyone else.

(Also, it bothers me to hear arguments about how "the Third World
doesn't bother me at all, they're overpopulated anyway." This strikes
most people as very callous.  You wouldn't think this if you were in
this situation: for an interesting perspective on the dubious notion of
"surplus population", re-read "A Christmas Carol," by Charles Dickens.
Space should be helpful, not hurtful, and it certainly can be helpful,
as many other technologies can be.)

For the more abstruse uses of space technology, promising no immediate
payback, a modest level of effort still gets funded, sometimes, because
people value it.  People enjoy learning about the Universe; if people
think a project is interesting enough to warrant the funding requested,
the project gets funded.  Sometimes there turn out to be paybacks, but
I think it's dishonest to claim there certainly shall be immediate
practical applications when they are still only speculative, and may
appear really only in the long term (some of which turn out to be very
important, but you can't know in advance which ones).  The main
objective of such projects is the science, to learn about nature.

Of course this decision process can be involved.  Physicists are having
trouble funding the Superconducting Super Collider, at a cost of over
$8 billion, in today's weak economy.  It certainly does not help this
project that most people find the science involved difficult to
understand: how familiar are you with experimental tests of Standard
Model 1-2-3 electroweak theory? (Beam jockeys excepted.;-))

The W.M. Keck foundation has donated over $70 million to build the 10-m
Keck telescope in Hawaii.  This is now the largest telescope in the
world: its size will make it able to see unprecedentedly faint objects.
The value of this to astronomical research is easy to understand.
All the mirror segments are in, testing is underway, and so far it
looks to be a first-class telescope.  Astronomy has benefited from
private funding since the time of Lord Rosse, continuing through the
telescopes on Mount Wilson and Palomar, not to mention my favorite, the
1.3-m McGraw-Hill telescope on Kitt Peak.

So, I think it's just a matter of time before some private individual
or venture funds a similar project in space.  A good candidate will be
a replacement for the International Ultraviolet Explorer satellite,
which has revolutionized nearly every field of astronomy (see Exploring
the Universe with the IUE satellite, ed. by Y. Kondo).  IUE is still at
it, after 14 years, and even despite its much-larger successor, the
Hubble Space Telescope (which is a nightmare to try to get telescope
time on).  Now, IUE originally cost about $25 million, about 1% of HST.
With inflation and an advanced detector, a successor might cost about
$100 million: not too unlike the Keck telescope.

I am quite sure my friends in planetary science and space physics will
have no trouble thinking up interesting projects in their own fields:
we're looking at a price range of a-few-to-100 million dollars.
Face it, $1 billion is a mighty big piece of pocket change,
even for Ross Perot or Bill Gates!

Fred

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

Date: 25 Aug 92 14:03:14 GMT
From: [e-mail]
Subject: Private space ventures
Newsgroups: sci.space

In <[e-mail]> Frederick A. Ringwald writes:
>(Also, it bothers me to hear arguments about how "the Third World
>doesn't bother me at all, they're overpopulated anyway." This strikes
>most people as very callous.
   I'll pick this up, since it was my comment you are objecting to.
Firstly, I was responding to the poster who whinged about spending
money on a space program instead of feeding the starving millions.
Most moderately sentient beings will recognise this as a piece of
fin de siecle western angst. My response was designed deliberately to
be excessively callous, in an attempt to highlight the stupidity of
the original append.
>You wouldnUt think this if you were in this situation:
  Perhaps not, however I would hope that were I in such an unfortunate
situation, I would have sufficient vision to recognise that the best
way out for all, was wealth creation (access to extra resource in space)
rather than redistribution.
>Space should be helpful, not hurtful, and it certainly can be helpful,
>like many other technologies.)
  Space can indeed be helpful, however if we have too many fools
screaming about it being a waste of resource, we will never have the
chance to prove it.
  As an aside, I will point out that most of those starving in Africa
are doing so because their family and countrymen think it more
important to kill each other than feed each other. Against a climate
such as this, it is difficult to see how diverting finance from space
into Africa is going to be of any lasting benefit.

 -----------------------------------------------------------------
               ** Of course I don't speak for IBM **
Greg Nicholls ... [e-mail] or [e-mail]
                  voice/fax: [phone]

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

Date: 25 Aug 92 19:40:16 GMT
From: "Frederick A. Ringwald" <[e-mail]>
Subject: Private space ventures
Newsgroups: sci.space

In article <[e-mail]>
[e-mail] writes:
>   Space can indeed be helpful, however if we have too many fools
> screaming about it being a waste of resource, we will never have the
> chance to prove it.

I wouldn't worry about it.  During the Apollo project, everyone and his
brother was complaining about it being just a stunt, a waste, "a
boondoggle for scientists", while the money could have been used to
feed the "whole of India."  But no one says that about communications
or weather satellites today, except the extreme fringe (and I know one
of them: he's the only person I know who couldn't read after graduating
from high school).

Space benefits are obvious, in ways they weren't in 1972: how many
people did you know back then who owned their own satellite dishes?  If
and when GPS receivers for cars are mass-marketed, the effect on
people's attitudes will be interesting.  Especially interesting may be
the effect of space-manufactured goods, particularly ones that aren't
microscopic (like microspheres) or indistinguishable from similar items
made on the ground (a bottle of medicine looks like a bottle of
medicine).  (Two-way wrist TVs would be interesting, too, but they may
not need satellites.)

Also, in the past, I have heard disturbingly many space enthusiasts
using words quite like your ironic statement, and sounding sincere!
Not only is this mean, it's positively harmful to the space field.  On
the other hand, trickle-down economics doesn't really work: any
benefits that accrue from space to the poor have to be in the hands of
the poor in the first place.  But many are, already. Your proof exists,
and becomes more obvious all the time.

P.S. It is still perfectly possible to waste money in space, as one can
waste money at any activity, no matter how beneficial or appealing it
may seem. Avoiding waste requires careful examination of just what one
wants to do with that money...

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

Date: 25 Aug 92 20:30:55 GMT
From: Henry Spencer <[e-mail]>
Subject: Private space ventures
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Frederick A. Ringwald) writes:
>...If and when GPS receivers for cars are mass-marketed, the effect on
>people's attitudes will be interesting...

It won't help.  The belittlers will just redefine the "space program"
they are criticizing to exclude these obviously-useful things.
--
There is nothing wrong with making      | Henry Spencer @ U of Toronto Zoology
mistakes, but... make *new* ones. -D.Sim|  [e-mail]  utzoo!henry

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

Date: 25 Aug 92 16:06:50 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: Saturn class (Was: SPS feasibility and other space
Newsgroups: sci.space

In <[e-mail]> [e-mail] (Nick Szabo) writes:

>Heavy-lift vehicles from Saturn to Energiya to NLS have
>not and do not have any sort of commercial market, despite $dozens of
>billions spent in them. Even the Titan IV has only a dwindling military market.

If the Saturn V can be built for the same cost as the Titan III/IV
and has better reliability, the extra payload capacity won't stop
customers from using it. If necessary, they'll add water tanks for
ballast.


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

Date: 25 Aug 92 17:19:59 GMT
From: Josh 'K' Hopkins <[e-mail]>
Subject: Saturn class (Was: SPS feasibility and other space
Newsgroups: sci.space

[e-mail] (Edward V. Wright) writes:

>In <[e-mail]> [e-mail] (Nick Szabo) writes:

>>Heavy-lift vehicles from Saturn to Energiya to NLS have
>>not and do not have any sort of commercial market, despite $dozens of
>>billions spent in them. Even the Titan IV has only a dwindling military market.
>If the Saturn V can be built for the same cost as the Titan III/IV
>and has better reliability, the extra payload capacity won't stop
>customers from using it. If necessary, they'll add water tanks for
>ballast.
>

    Sure, _if_ you can build _and_ operate a Saturn class vehicle for the
price of a Titan it might be competitive with a Titan.  However, seeing as
there are no non-government customers for Titans and considering that the first
launches are going to have to pay for development costs, I think Nick is right
in saying that HLVs have no commercial relevance in this decade.
    If we could launch Saturn size payloads for the price of a Titan III,
that might get a government SEI program going.  However, industry won't
build this rocket, and government won't buy it without an SEI program (which
it won't start until a big cheap rocket works).  So we seem to be at an
impasse until the equation changes.
--
Josh Hopkins                    Friends don't let friends derive drunk
             [e-mail]

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

Date: 25 Aug 92 21:03:14 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Saturn class (Was: SPS feasibility and other space
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Josh 'K' Hopkins) writes:

>I think Nick is right
>in saying that HLVs have no commercial relevance in this decade.

SS Freedom construction and supply IS a viable commercial market for
HLVs this decade.

  Allen
--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "If they can put a man on the Moon, why can't they     |
|  [e-mail]     |  put a man on the Moon?"                               |
+----------------------241 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 25 Aug 92 18:01:13 GMT
From: "Philippos A. Peleties" <[e-mail]>
Subject: Spot Images Corp and EOSAT addresses
Newsgroups: sci.space

I would appreciate it if anyone out there could e-mail me the complete
address (FAX+phone) of Spot Images Corporation (Reston, VA?) and EOSAT
(the company who's marketing EOSAT satellite pictures.)

Thanks in advance


Philip Peleties
--


I speak for myself, I think for myself, I work for myself ... but I don't want
to play by myself ... so bring your toys and let's share ...

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

Date: 25 Aug 92 23:49:20 GMT
From: Ron Baalke <[e-mail]>
Subject: TOPEX Update - 08/24/92
Newsgroups: sci.space,sci.astro

Forwarded from:
PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. [phone]

                  TOPEX/POSEIDON STATUS REPORT
                         August 24, 1992

          The TOPEX/Poseidon satellite is healthy and performing
nominally.  The attitude control computer, batteries,
telecommunications and on-board computer are all functioning
properly.

          Tape recorder playback has occurred as planned since
last Friday.

          The Centre National d'Etude Spatiales' Solid State
Altimeter (SSALT) is in a four day check out period.   CNES is
processing the data in Toulouse and engineers there report all
looks good.  The NASA altimeter will be commanded to the track
mode after the CNES altimeter is turned off.

          The TOPEX Microwave Radiometer is working well.

          An inclination maneuver is planned for Thursday to
boost the satellite to its 66 degree inclination toward the
Earth.
                             ######
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Optimists live longer
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | than pessimists.
|_____|/  |_|/       |_____|/                     |

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

Date: 25 Aug 92 21:40:41 GMT
From: Jeff Bytof <[e-mail]>
Subject: Venus orbiters
Newsgroups: sci.space

Is the Pioneer Venus orbiter still functioning?  Besides Magellan,
what other spacecraft (Russian?) may be still functional?

Jeff Bytof
[e-mail]

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

Date: Tue, 25 Aug 1992 11:56:43 GMT
From: Rui Sousa <[e-mail]>
Subject: With telepresence, who needs people in Earth orbit?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:

   Not the same thing at all. Except for the Viking landers, *none* of the
   spacecraft that ventured beyond the Moon have been able to manipulate
   their environment. They have been mere sensor platforms. The common
   usage of robot is more specialized than automation. It requires the
   ability to manipulate the environment. The term robot also ordinarily
   means autonomous to a large degree, capable of on the spot decisions.
   This is in contrast to teleoperated devices that require distant super-
   vision at the detail level in near real time.

   There have been no robots in space with the autonomy of a fruit fly or
   the manipulative ability of a mouse as yet. Nothing approaching the
   capability of a man has even been designed, let alone successfully
   tested, on Earth as yet. Earthlings have sent out glorified box brownies
   to snap pictures, but nothing designed to turn over a rock.

   Gary

You are forgetting the Luna series and the Viking landers. Though not
autonomous they certainly could turn rocks over...

Rui Sousa
--
*** Infinity is at hand!                               Rui Sousa
*** If yours is big enough, grab it!                   [e-mail]

                All opinions expressed here are strictly my own

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

Date: 25 Aug 92 13:05:42 GMT
From: Gary Coffman <ke4zv!gary>
Subject: With telepresence, who needs people in Earth orbit?
Newsgroups: sci.space

In article <[e-mail]> jenkins@fritz (Steve Jenkins) writes:
>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>>Not the same thing at all. Except for the Viking landers, *none* of the
>>spacecraft that ventured beyond the Moon have been able to manipulate
>>their environment.
>
>Why except Viking?  It *was* able to manipulate its environment.  I'd
>argue that Voyager has no environment to manipulate.  What did you have
>in mind?

Why except Viking? Because the landers did have the limited ability
to manipulate their environment by taking a soil sample and analysing
it, and it travelled beyond the Moon, the other parameter of the statement.
Voyager doesn't qualify as a robot because it is only a sensor
platform with no way to modify it's environment. It's true that it's
environment isn't very dense with matter, but irrelevant to whether
it's a robot or an automated sensor platform.

>>This is in contrast to teleoperated devices that require distant super-
>>vision at the detail level in near real time.
>
>Current planetary spacecraft are not operated that way.  The one-way
>light time to Voyager 2 at Neptune encounter was on the order of four
>hours.  That's stretching my notion of "near real time" a bit.  Even
>nearby Magellan does its thing mostly on its own;  the routine
>commanding is mostly housekeeping stuff of a noncritical nature.
>Sometimes we give 'em the whole weekend off. :-)

It's true that these sensor platforms have some autonomous self safing
capability, but mission critical actions are commanded from the ground.
These commands are almost completely open loop in that they don't depend
on any immediate environmental feedback resulting from their actions
toward their objective to close the loop, only delayed reaction commands
from ground stations. Note that I don't count starcals because they aren't
the objective of the mission sensor systems. That may be arbitrary, but
they are simple navigational servo systems rather than systems that react
to mission objectives. Robots need servos, but servos aren't the robot
if you get my meaning.

>>There have been no robots in space with the autonomy of a fruit fly or
>>the manipulative ability of a mouse as yet. Nothing approaching the
>>capability of a man has even been designed, let alone successfully
>>tested, on Earth as yet. Earthlings have sent out glorified box brownies
>>to snap pictures, but nothing designed to turn over a rock.
>
>Except Surveyor 7, Luna 16, Luna 17, Luna 20, and Vikings 1 and 2,
>depending on what counts as a rock.

As noted in the first paragraph, I am referring only to non-lunar missions
and listed Viking as the (limited) exception. Even Viking's action was
an open loop pre-programmed action in a spot determined solely by the
way the lander faced when it touched down. A real robot would say, "Gee
that's an interesting pile of dirt, think I'll dig there." (Metaphorically
of course.) That's why I said that robots in space don't yet have the
autonomy of a fruit fly or the manipulative ability of a mouse.

>No one claims that highly autonomous, highly intelligent robots have
>been sent to explore space.  That doesn't make all exaggerated
>statements to the contrary true.

Nick, the astronaut basher, seems to think so. He's the one to which I
was replying.  The sensor platforms sent to the outer solar system have
been impressive achievements. I don't denigrate their importance even
while calling them box brownies. Getting them there, getting them to
snap pictures in the right direction, and getting the pictures back is
a monumental achievement mainly because *competent AI doesn't exist* and
everything had to be done open loop over long delay command links.

Jupiter probes didn't notice the Red Spot and say, "hmmmm that's interesting"
and zoom in for a closeup. Ground calculations had to be done to open
loop aim the probe's camera to capture a known feature of Jupiter. I'd
even accept a system that could be told, "find a big red spot and get
me a picture of it", to be somewhat robotic, but Jupiter probes haven't
been able to do this. Io's active volcano was an after the fact discovery
from a picture taken that included it by chance. A competent AI system might
have zoomed in and gotten pictures of that interesting feature in real time,
assuming a zoom lens of course. But no such image recognition capability has
been included on any sensor platform in deep space to date.

Some kind of self direction based on the results of environmental sensing
is a requirement of a competent robot, but not the only one. It must also
be able to modify it's environment in a closed loop feedback. None have so
far been launched into space. So I maintain that Nick's claim that all work
beyond the Moon's orbit has been done by robots is false since no robots
have been sent beyond Lunar orbit, except a pair of very primitive Vikings
and a couple of Veneras. I don't consider them to be robots in any real sense,
however, because they lacked mission oriented self direction modifiable
by closed loop feedback from sensor discoveries.

Gary

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

Date: 25 Aug 92 13:31:34 GMT
From: Gary Coffman <ke4zv!gary>
Subject: With telepresence, who needs people in Earth orbit?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Bill Higgins-- Beam Jockey) writes:
>
>Henry Spencer, I expect, would agree fully with Matthew's statement, but
>insist that to engineer all this stuff, you've got to fly it, try it,
>take it home and fix mistakes, then fly again-- as he recently
>advocated during the Tethered Satellite System discussion.   Frequent
>and simple access to orbit is the key.   What NASA has now is "We're
>only gonna get one chance this decade to fly our gadget, and if it
>doesn't work our careers are shot, so it must be super-reliable and
>gold-plated."

One of the reasons that missions only fly once per decade is that
they *are* super-reliable and gold plated. Launch costs are usually
a small fraction of payload costs. They are still a significant cost,
however. One way to shorten the build, fly, try, recover, fix, iterate
cycle, however, is to plan to fix the problems on the spot. NASA didn't
do that with the tether experiment, but they could have, and they have
done so with other experiments on other flights. Manned flight does
have significant advantages because competent robotics don't exist.
It also has significant expenses of course.

It seems to me that the arguments center on what is the right mix
of cheap "try it" missions and more expensive "try it and fix it
if necessary" missions. I tend to think the latter can be more
productive right now. Dirt cheap and frequent launches could change
that, but I don't see any indication that's about to happen, SSTO
wishful thinking not withstanding.

Gary

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End of Space Digest Volume 15 : Issue 143
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