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Subject: SPACE Digest V10 #310

SPACE Digest                                     Volume 10 : Issue 310

Today's Topics:
  Wanted: Unix based satellite prediction program - source preferred
             Mars Mission Agenda
        Re: Manned vs Unmanned Mission to Mars
     Re: Greenhouse Effect (was NASA Headline News 11/29)
             Mars Mission Agenda
           Re: Why NASA wants to go to Mars
 Science vs Exploration (was Re: Manned vs Unmanned Mission to Mars)
        Re: Manned vs Unmanned Mission to Mars
        Re: Manned vs Unmanned Mission to Mars
----------------------------------------------------------------------

Date: 4 Dec 89 17:56:23 GMT
From: mailrus!cs.utexas.edu!asuvax!anasaz![e-mail]  (John Moore)
Subject: Wanted: Unix based satellite prediction program - source preferred

I would like to get hold of a satellite tracking program that I can
run on my 386 Unix System-V. Does anyone have source of such that
I can have? How about tracking equations for:
(1) predicting satellite position from standard element sets
(2) calculating range, bearing, and doppler from any point on earth?

Thanks in advance.
--
John Moore (NJ7E)           mcdphx!anasaz!john asuvax!anasaz!john
[phone] (day or eve) long palladium, short petroleum
7525 Clearwater Pkwy, Scottsdale, AZ 85253
The 2nd amendment is about military weapons, NOT JUST hunting weapons!

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

Date: 4 Dec 89 10:56:10 GMT
From: mentor.cc.purdue.edu![e-mail]  (Eric C. Garrison)
Subject: Mars Mission Agenda

All this talk about which is better, manned or unmanned, is getting worn.
Let's try a new game.  Let's suppose that we were designing a mission to Mars.
We have THREE options: A manned mission, An Unmanned Mission, and a partially
robotic mission(a mixture of both technologies, for the people who don't want
commit either way)

The object is to design a Mars landing/sample return mission, with minimum cost
and maximum results.  There is a soft limit on the Budget at $200 billion, and
a hard limit at $400 billion.  Keep the three headings seperate in your posting
(I would suggest using _manned_mars_, _unmanned_mars_, and _hybrid_mars_ to
prevent confusion.)  The agenda should include mission goals, what hardware
is needed(this includes Earth bound equipment), and some realistic pricing
on the hardware/support.  The rest is up to however you want to organize.
Don't worry about having multiple projects under the same catagory, just try
not to get them confused.  Let's put April 20, 1990 as a date to have a basic
proposal ready.

This is not a contest.  I'm not giving out any prizes.  I want to know what you
people out there can put together.  Enough criticism has been bantered about
concerning all manner of things.  Let's see if you can work as a design team,
instead of just criticizing each other's and the government's proposals.

       -A. Hasara

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

Date: 4 Dec 89 16:48:34 GMT
From: zaphod.mps.ohio-state.edu!swrinde!dpmizar!dptspd![e-mail]  (John Arft)
Subject: Re: Manned vs Unmanned Mission to Mars

In article <[e-mail]> [e-mail] (Nichael Cramer) writes:
>
>  4] To give a base for discussion, can someone name me *anything*
>     that Apollo accomplished that could not have been done by remote
>     probes?  Was it worth the enourmous extra cost?
>
>NICHAEL

It caught the attention of nearly every human on the planet.
When was the last time JPL did that?

Seriously, I have the highest respect for JPL's work, and
scientifically speaking, there is little to be gained by
sending men any farther than Earth orbit.  However, man
does not live on science alone.

Abdul.

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

Date: 5 Dec 89 03:34:58 GMT
From: [e-mail]  (JOHNSON RICHARD J)
Subject: Re: Greenhouse Effect (was NASA Headline News 11/29)

In article <[e-mail]> [e-mail] (Will Martin) writes:
>I seem to be confused. I thought the ozone depletion due to
>chloroflurocarbons was the cause of increased levels of ultraviolet
>radiation making it to the surface, thus producing higher levels of skin
>cancer and related effects, and didn't have anything to do with global
>warming.

Many CFCs (most?), in addition to destroying ozone, are also greenhouse
gasses.  It's called the old double whammy.

CFCs absorb infra-red radiation in different bands than CO2.  The
atmosphere is more nearly opaque in the bands absorbed by CO2 than it is
in the bands absorbed by CFCs.  That means you need lots more CO2 to
produce the same net additional energy retention as you can with a smaller
increase in CFCs.  In other words, a little CFC goes a long way.  Of course,
as more CFCs are added to the atmosphere, such differences will lessen.

No, I don't have numbers on the relative effectiveness, or even the
wavelengths.  Perhaps someone else who reads sci.environment saved the
thread...

>Regards, Will
>[e-mail] OR [e-mail]


| Richard Johnson                           [e-mail] |
|    CSC doesn't necessarily share my opinions, but is welcome to.     |
|  Power Tower...Dual Keel...Phase One...Allison/bertha/Colleen...?... |
|   Space Station Freedom is Dead.  Long Live Space Station Freedom!   |

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

Date: 4 Dec 89 14:18:06 GMT
From: helios.ee.lbl.gov!pasteur!sting.Berkeley.EDU![e-mail]  (Scott Silvey)
Subject: Mars Mission Agenda


> All this talk about which is better, manned or unmanned, is getting worn.
> Let's try a new game.  Let's suppose that we were designing a mission
to Mars.
> We have THREE options: A manned mission, An Unmanned Mission, and a partially
> robotic mission ...
>
> The object is to design a Mars landing/sample return mission, at minimum cost

Well, for the sake of rough comparison, does anyone know what the cost of the
  Viking program was?

And, can anyone perhaps estimate what the same program would cost if we were to
  realize it today?  (I'm not sure if there would be a significant difference.)

-Scott

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

Date: 4 Dec 89 18:04:44 GMT
From: zaphod.mps.ohio-state.edu!wuarchive!cs.utexas.edu!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Why NASA wants to go to Mars

In article <[e-mail]> [e-mail] (Jim Bowery) writes:
>>>... If you want to develop a propulsion system you do propulsion R&D.
>>Except that if you don't have a specific mission to use that R&D on, the
>>funds for it tend to get cut off.
>
>Uh.... Henry...  if you don't have a use for the propulsion R&D other than
>the mission it is supposed to "spin off" from...  where is it supposed to
>"spin off" to?

The missions that can be flown *once the propulsion system is known to be
available*.  There is a big difference between a system that seems to work
in laboratories and one that has been proven in space.  This is why you
still see ambitious, highly weight-constrained space missions designed
with hydrazine monopropellant propulsion systems, twenty years after
better systems were running successfully in labs.  One objective of the
Lunar GetAway Special proposal was to *finally* prove that solar-ion
rockets are a workable way to propel spacecraft, so that space-probe
propulsion can be brought into the 1970s.

There are always uses for better propulsion, once people are prepared
to consider it a viable alternative.
--
Mars can wait:  we've barely   |     Henry Spencer at U of Toronto Zoology
started exploring the Moon.    | uunet!attcan!utzoo!henry [e-mail]

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

Date: 5 Dec 89 05:24:35 GMT
From: rochester![e-mail]  (Brian Yamauchi)
Subject: Science vs Exploration (was Re: Manned vs Unmanned Mission to Mars)

In article <[e-mail]> [e-mail] (Nichael Cramer) writes:
>In article <[e-mail]> [e-mail] (Henry Spencer) writes:

[quoting somebody else...]

>>>  4] To give a base for discussion, can someone name me *anything*
>>>     that Apollo accomplished that could not have been done by remote
>>>     probes?  Was it worth the enourmous extra cost?
>>Apollo probably did not do anything that could not have been done by
>>remote probes, assuming we are speaking strictly of science returns.
>
>Which I am...
>
>>(As noted elsewhere, space is more than just science.)
>
>Perhaps, but Science is a far better reason for this --or anything-- else
>than just because we think it's really neat.
>
>Particularly if we're expecting someone else to pay for it.

I think the last sentence represents a fundamental misconception that
has been repeated a number of times in this newsgroup.

It goes something like this:

"As space enthusiasts, we may support space exploration because we are
attracted to the vision of mankind exploring the universe, but this is
a democracy and if we want the public to pay for this, we must justify
it on the basis of reasons that are attractive to the public.  And as
everyone knows, the American public has a passion for scientific
knowledge which far outweighs their desire for spectacular human
adventures."

Well, there may be some evidence to support the latter statement.

Nova definitely gets higher ratings than Star Trek: The Next
Generation, and many more people watched Voyager 2's encounter with
Neptune than saw Apollo 11 land on the moon.  True, a few people may
have watched Apollo 11 for the excitement of seeing a man walk on the
moon, but when the later flights became "routine", it was the chemical
analyses of the lunar samples which kept the public's interest riveted
on the space program. :-) :-) :-)

Seriously, though, I think the public will be more willing to spend
billions to see humans explore Mars than they will to find out the
chemical composition or geological history of Mars.

Of course, eventually robots may advance to the point where humans
will recognize them as individuals, and at that point sending a robot
another world may be as attractive to the public as sending a human.

(Actually, this day may not be too far away, especially since the NASA
adjective for describing space probes and satellites seems to have be
officially determined to be 'plucky'. :-)

_______________________________________________________________________________

Brian Yamauchi                University of Rochester
[e-mail]        Computer Science Department
_______________________________________________________________________________

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

Date: 5 Dec 89 03:30:13 GMT
From: bbn.com![e-mail]  (Nichael Cramer)
Subject: Re: Manned vs Unmanned Mission to Mars

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>>Yes people can improvise.  But maintaining them on a long mission is a
>>highly expensive, bulky, dangerous proposition.  Voyager suffered several
>>major system malfunctions and is *still* working...
>The Voyagers were extremely lucky.  Remember that one of Voyager 2's command
>receivers died shortly after launch, and the other one got sick and stayed
>sick (fortunately, not quite sick enough to disable it).  Voyager 2 came
>within a hairsbreadth of going the same way Seasat and Phobos 1/2 went.
>There have been several nail-biting problems, fortunately all fixable.

Similarly, one of the camera arms stayed jammed because of rapid,
repetitive overuse during the Jupiter (Saturn?) flyby until JPL managed to
get it unstuck after N months.  There were other parts of the mission that
were simply scrapped because of various system problems.

But this is, of course, exactly the point.  Voyager's *overall* mission
can, and did, survive problems like this.

It means something else altogether, however, to a manned flight to have the
primary oxygen supply go down and have the backup operate at 10%
efficiency.  You can't have the water filtration system stop working for 18
months until you figure out how to fix it.  Systems, which I would further
argue, are vastly more difficult to keep working *at the necessary level*
than the analagous systems on the Voyager.

And, most importantly, you can't lose the human crew and say "Oh well, I
guess we just can't do that part of the mission; we'll have to make do with
the rest".

>>It's not at all clear that the *net* robustness of the system is improved
>>by having humans on board.
>How would you feel about flying on the first remotely-piloted airliner?
>How about the first airliner whose engines were maintained by robots?

This analogy is not valid.

Look, obviously humans are better at, say, improvising a solution to a
particular problem.  No one is arguing any different.  But you've missed
the critical phrase: "*net* robustness".  Again, you've neglected the
enormous overhead and difficulty of keeping a human crew alive and healthy
for a *very* long time.

A more apt analogy would be flying on an airliner:

  o whose pilots were hermetically sealed in their cabin, and all of whose
    life support systems were not replenished for a number of years...

  o which had a *fixed* number of spare engine parts available for the
    lifetime of the airplane.

  o which flew with a crew who had no way of communicating its condition
    to the passengers,

  o and which was *required* to continue making flights regardless of
    any of the above.

>>  4] To give a base for discussion, can someone name me *anything*
>>     that Apollo accomplished that could not have been done by remote
>>     probes?  Was it worth the enourmous extra cost?
>Apollo probably did not do anything that could not have been done by
>remote probes, assuming we are speaking strictly of science returns.

Which I am...

>(As noted elsewhere, space is more than just science.)

Perhaps, but Science is a far better reason for this --or anything-- else
than just because we think it's really neat.

Particularly if we're expecting someone else to pay for it.

>... However, the
>pricetag would probably have been similar, if not worse...

Well, I, for one, am going to need a lot of convincing about this...

>...The Soviet
>sample-return missions probably cost an order of magnitude less than
>Apollo, but they accomplished two or three orders of magnitude less.
>We are talking about quantitative results here:  a few grams of soil
>are not the same as hundreds of kilograms of samples selectively
>collected over substantial areas....

... and this doesn't do it.

One more time: take the money involved in keeping the human alive for N
missions, fly 5N missions and bring back several thousand kilos of fairly
well selected samples... (etc. etc. etc.)

>As has been mentioned before, nobody uses robots to explore Antarctica,
>even though supporting humans there is decidedly expensive.
Oh, come on Henry, you're reaching here... I expect better of you than
this.  ;)

>Mars can wait:  we've barely   |     Henry Spencer at U of Toronto Zoology
>started exploring the Moon.    | uunet!attcan!utzoo!henry [e-mail]

N

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

Date: 4 Dec 89 15:58:28 GMT
From: attcan!utgpu!utzoo![e-mail]  (Kieran A. Carroll)
Subject: Re: Manned vs Unmanned Mission to Mars

[e-mail] (Nichael Cramer) writes:
>
> >If you define the range of interesting activities for space missions as
> >those that unmanned probes do best -- remote sensing -- then of course
> >unmanned probes are better.
>
> Well, let's say I certainly believe that remote sensing can accomplish the
> vast majority of interesting, real science that a manned flight can
> accomplish.  Furthermore, I'd argue that if what we're interested in is the
> science per cost ratio --and keeping this on a per-mission basis-- the
> advantages of remote sensing flights are overwhelming.

And if you were to argue that what we're interested in is the goal of space
colonization, then manned missions have something of an advantage over
unmanned ones :-)

Seriously, Nichael, your response illustrates one of the big unstated
assumptions underlying the manned-vs-unmanned debate: if you >assume< that
science-per-cost is your goal, then of course unmanned missions win out.
However, do we have to wait until all the interesting science results have been
squeezed out of the solar system, before we're allowed to start spending money
on occupying it?

I might also point out that "while "science-per-cost" makes a good assumption
for justifying unmanned over manned spaceflight, it is a two-edged sword: the
science-per-cost efficiency of space science is much less than that of
>ground-based< science...
--

     Kieran A. Carroll @ U of Toronto Aerospace Institute
     uunet!attcan!utzoo!kcarroll [e-mail]

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

End of SPACE Digest V10 #310
*******************