Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v15_1/v15no184.txt

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Date: Fri, 11 Sep 92 05:02:42
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #184
To: Space Digest Readers
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Space Digest                Fri, 11 Sep 92       Volume 15 : Issue 184

Today's Topics:
                         3 booster questions
                        farthest Laser signal
         Is NASA really planning to Terraform Mars? (5 msgs)
                    NASA/Rice information request
          One Small Step for a Space Activist... Vol 3 No 9
                   Pluto Direct Propulsion Options
               QUERY Re: Pluto Direct/ options (5 msgs)
                                 SPS
                       SSTO Mailing List Formed

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

Date: 10 Sep 92 22:08:51 GMT
From: Josh 'K' Hopkins <[e-mail]>
Subject: 3 booster questions
Newsgroups: sci.space

[e-mail] (Brett Vansteenwyk) writes:

>[2].Atlas still goes *boom* a lot?  Is this inherent to the design of having
>two of the engines fall off and the difficulty in shutting off the fuel flow
>to these engines?

Actually, the most recent problem has been the upper stage.  Another recent
failure was due to a lightning strike.  Going through my data, it looks like
the booster stage has been a significant cause of failures in the last 20 years
bt it's hard to tell if it's caused more problems that first stages  of other
systems.

>[3].It seems, like it or not, that the Shuttle will be flying for at least 10
>more years.  Perhaps developing an LRB for the Shuttle will not be justified
>on its own.  Perhaps developing an HLV will not be justified on its own.
>However, if you have an HLV whose first stage will also serve as an LRB
>you could amortise development costs pretty fast.  Is there something wrong
>with this idea?
>    For example, a single engine "Baby Saturn" based on the F1A may qualify.
>If modifying the External Tank design for 3 boosters instead of 2 is not
>difficult, and if there is no particular reason that you cannot ride the
>Shuttle on "top" of the stack instead of the the bottom (angle of attack
>considerations would force this change), then you would have a ready use
>for 25-30 of these vehicles per year.  Why not?

Changing the layout that drastically would require redoing the VAB, the crawler
and the two launch complexes among other things.  A single engine booster also
wouldn't be suitable for the first stage of an HLV as you suggest.  Plus,
putting the orbiter on top of the ET means you're sending exhaust straight at a
tank of LH2/LOX, which is not a great safety feature.


>            --Brett Van Steenwyk

--
Josh Hopkins           "If you are sitting in an exit row and you cannot read
                       this card or cannot see well enough to follow these
               instructions, please tell a crew member."
[e-mail]                       -United Airlines safety instructions

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

Date: 11 Sep 92 05:32:04 GMT
From: Ron Baalke <[e-mail]>
Subject: farthest Laser signal
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (David Knapp) writes...
>
>Ron, would you be interested in posting some of your planetary probe inormation
>to alt.sci.planetary?

Sure, I'll post something tonight.

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Anything is impossible if
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | you don't attempt it.
|_____|/  |_|/       |_____|/                     |

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

Date: Thu, 10 Sep 92 17:29:00 GMT
From: Doug Mohney <[e-mail]>
Subject: Is NASA really planning to Terraform Mars?
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (David Knapp) writes:

>You mean ignoring any possible consequences of ozone loss and maybe even
>global warming? Let's even completely ignore increasing risks of nuclear
>war (from non-NATO develpment) or from nuclear disaster.  We can also ignore
>steady expansionism of the populace.

Hey, and I bet you were kvetching about the Evil Stockpiles of Nuclear War
between the United States and the Soviet Union a couple of years ago.
It's gone, so there's something else to blow up, er, INFLATE as a "threat"
to civilization as we know it.

It's also laughable to look at "global warming" when a single volcanic eruption
kicks enough enough ash to DROP temperatures despite our many years of
unregulated environmental engineering, hmm?

We also don't have enough of a dataset on our world to show what the "real"
temperature should be. I kid you not. Would you like to average in the ice ages
and the time before the DinosaurKiller impacted?

>Even if you ignore all the globe-threatening issues, *population* growth,
>which you can *count on*, will still be one of our greatest challenges.  It
>will keep growing until it simply *can't* and that only happens when world
>resources, particularly in food stuffs, become steadily taxed. Don't
>kid yourselves, this is *going* to happen whether you like it or agree with
>it.

I didn't know we had gone to world goverment. Now, who in the third world is
going to come and tax US, hmm?

Besides, population growth is self-correcting. People who have nothing better
to do start little piss-ant wars and end up killing themselves off.

>Even after you look at the population curve and make some simple extrapolations,
>keeping in mind things like fossil fuel depletion in the next 50 years,
>shifting agricultural zones, you do not see this?

Another Club of Rome member. <yawn>

We've been running out of fossil fuels for 100 years. Before that, there was a
fear of a great shortage of whale oil, due to overhunting.

Could you tell me what the current demand for whale oil is?

Furthermore, the Club of Ignorance also ignores little things like A)
Technological Innovation is not static, B) Free-market economies stimulate the
development of more efficient use of resources and substitutes.

>You do not know there is no life on Mars or anywhere else other than Earth.
>I don't see the relevance of arguing over the label of 'back yard'.  I don't
>think as a society, or even a planet, we have yet learned how to manage our
>*own* planet, not even a *little*.  Because of this I don't think we are
>qualified to begin applying our ignorance to anther planet.
>
>Luckily, this will not be an issue for many years.

Naw, you'd better line up now to put Saturn's rings off-limits to Szabo's Ice
Mining, Inc. And then prepare to go out there and enforce your law, hm?

                 Support U.N. military force against Serbia

  -- >                  [e-mail]                        < --

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

Date: 10 Sep 92 18:27:02 GMT
From: Don Roberts <[e-mail]>
Subject: Is NASA really planning to Terraform Mars?
Newsgroups: sci.space

In article <[e-mail]>
[e-mail] (David Knapp) writes:

>You mean ignoring any possible consequences of ozone loss and maybe even
>global warming? Let's even completely ignore increasing risks of nuclear
>war (from non-NATO development) or from nuclear disaster.  We can also ignore
>steady expansionism of the populace.

Yep. Ignore it. Contrary to Chicken Little Opinion, we don't understand
global warming very well and unless you're planning to move to Antarctica,
I wouldn't get in a tizzy about the "ozone hole." [see Physics Today, Dec
'91 for a discussion of the polar stratospheric cloud mechanism for ozone
depletion by CFC's].

As for the "increasing risk of nuclear war" due to nuclear proliferation,
Nonsense. The threat of all-out thermonuclear war *is gone* (huzzah!). The
threat of despotic countries seeking to develop nuclear weapons *is* real,
and requires more stringent efforts in UN inspections, non-proliferation
research, and development of both a defense against limited strikes and
the abililty to disable a "terrorist bomb."  Complaining about the "global
threat" won't make it go away.

>Even if you ignore all the globe-threatening issues, *population* growth,
>which you can *count on*, will still be one of our greatest challenges.  It
>will keep growing until it simply *can't* and that only happens when world
>resources, particularly in food stuffs, become steadily taxed. Don't
>kid yourselves, this is *going* to happen whether you like it or agree with
>it.

Haven't we had about enough of this in the last 200 years?? Ever since
Malthus first came up with the idea, we've been in Imminent Peril of
choking the planet with people. Fortunately, there have been enough people (!)
cleverer than ol' Tom that we've managed well enough. Try telling the
people in Singapore, Japan, or Taiwan that high population densities
guarantee abject poverty and starvation. Ever stop to think there might be
more to it than that?

--
 Dr. Donald W. Roberts
   University of California                                      Physicist
   Lawrence Livermore National Laboratory         Recreational Bodybuilder
   [e-mail]                                           Renaissance Dude

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

Date: 10 Sep 92 12:55:04 GMT
From: Richard Nickle <trystro!rick>
Subject: Is NASA really planning to Terraform Mars?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (David Knapp) writes:
>In article <[e-mail]> [e-mail] (Richard Nickle) writes:
>>In article <jvrnh5#[e-mail]> [e-mail] (Thomas H. Kunich) writes:
>>>Without references it is difficult to remember, but isn't there
>>>water, water vapor and possible liquid water along the interface of
>>>the Martian north pole?
>>>
>>>If so, shouldn't this represent a possible seeding area for life forms?
>>>
>>>I also seem to remember that the upper atmosphere of Venus was
>>>mostly water vapor even though the bulk of the atmosphere was
>>>sulphuric acid.
>>>
>>>Perhaps I didn't make myself clear enough. I don't believe that
>>>Venus could ever be made earthlike. I see the chance, however,
>>>of seeding life there and letting it make it's own way.
>>>
>>>The same with Mars. All of the grandiose plans aside I can't see
>>>the bulk of the necessary machinery being transported to Mars to
>>>terraform it and then the project continued for thousands of years.
>>I never understood this machinery bit though...my understanding of
>>Martian terraforming was that the timescale would be large, but the
>>steps taken would be rather simplistic:  slamming large ice blocks
>                      ^^^^^^^^^^^^^^^^^^
>>from the belt or Saturn's rings (though why anybody would want to
>>throw away all that nice water, I don't know...maybe they could just
>>send the low-grade ore towards mars), using orbiting mirrors to melt
>>the poles, or covering the poles with dark matter to assist in raising
>>the surface temperature.
>
>I think you and I have different ideas of what is 'simplistic'

It's you're not transporting megatons of machinery to Mars, and you
don't have to worry about the problems of soft-landing anything on the
surface.  Adding water requires small robot probes to go retrieve ice
and move it to mars.  The robots would attach themselves to the appropriate
piece of ice, and use the ice itself as reaction mass to move them from
wherever you got them (Saturn, the belt) to Mars, whereupon they would
fall onto mars and release tons of water.  You just set up your ice-retriever
robot factory someplace convenient:  Lunar orbit?  And begin mass-producing
the things.  Now, Luna doesn't have any water, right?  So, well, you pay for
the cost of the robot factory by using the robots principally to move water
to Luna, not Mars.  Once you've paid off all your creditors and are making
a steady profit, the factory owner makes the magnamonious gesture of diverting
a certain percentage of his ice-retrieval robots to moving ice to Mars as well.

If the robots are reusable (they can retrieve their payload and steal enough
water to propel themselves back to where they got the ice), it's even better.
Your number of robots working on the project continually increases, and water
delivery to Mars begins to skyrocket.  Add any potential colonies on Mars who
actually need the water for immediate use, delivered to a specific spot, and
it's even better, they'll be willing to pay for the delivery system.

>Do you understand how many 'mirrors' would be required to raise the polar
>caps one degree centigrade?

Use solar sails to transport cargo to Mars orbit: (sensing gear, microbe
packages (when needed), the dirt for covering the poles to help it absorb
heat, gear for colonies....and just leave them there.

Have you worked out the mirror surface area for a one-degree centigrade
rise in a cap?  Any pointers where I could find the data?

>David Knapp                                      University of Colorado, Boulder
>Perpetual Student                                   [e-mail]


--
richard nickle        [e-mail]    617-625-7155 v.32/v.42bis

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

Date: 10 Sep 92 18:44:03 GMT
From: Sam Warden <[e-mail]>
Subject: Is NASA really planning to Terraform Mars?
Newsgroups: sci.space

[e-mail] (Gary Coffman) writes:

>In article <samw.715971213@bucket> [e-mail] (Sam Warden) writes:
>>Were Venus ever to cool off, I would expect ferocious amounts of
>>oxidation/carbonation weathering to occur, for example.

>Remember that chemical reactions like oxidation proceed at a rate
>proportional to temperature.
>... a hell of battery acid and acidic complexes. Nearly every member of
>the metal group is bound to be fully oxidized. Venus is a natural
>toxic waste dump.

The surface is above the decomposition temperature of most sulfates,
carbonates, and some oxides.  That's why all that stuff is in the
atmosphere.

--

[e-mail] (Sam Warden) -- and not a mere Device.


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

Date: Thu, 10 Sep 92 21:18:21 GMT
From: "Thomas H. Kunich" <[e-mail]>
Subject: Is NASA really planning to Terraform Mars?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Richard Nickle) writes:
>
>It's you're not transporting megatons of machinery to Mars, and you
>don't have to worry about the problems of soft-landing anything on the
>surface.  Adding water requires small robot probes to go retrieve ice
>and move it to mars.  The robots would attach themselves to the appropriate
>piece of ice, and use the ice itself as reaction mass to move them from
>wherever you got them (Saturn, the belt) to Mars, whereupon they would
>fall onto mars and release tons of water.  You just set up your ice-retriever
>robot factory someplace convenient:  Lunar orbit?  And begin mass-producing
>the things.  Now, Luna doesn't have any water, right?  So, well, you pay for
>the cost of the robot factory by using the robots principally to move water
>to Luna, not Mars.  Once you've paid off all your creditors and are making

It's always nice to see people write refreshing things like, "All you have to
do is move Mars several thousand miles into a closer orbit." Or some such.
Do you remember that lunatic that was interviewed on 60 Minutes about
the Soviet antiballistic missle system -- the one where he said, "All
you have to do is, first, contain a nuclear explosion. Then ---", I
sort of turned off at that point.

Here we are, with great difficulty even getting antennas to point in the
correct direction and this guy suggests that we can throw jillions
of tons of matter at a planet accurately. Yes indeed, really refreshing.
>
>If the robots are reusable (they can retrieve their payload and steal enough
>water to propel themselves back to where they got the ice), it's even better.
>Your number of robots working on the project continually increases, and water
>delivery to Mars begins to skyrocket.  Add any potential colonies on Mars who
>actually need the water for immediate use, delivered to a specific spot, and
>it's even better, they'll be willing to pay for the delivery system.

How do we build these water recovery robots in the first place? Hwo
do these martian colonists get to Mars? How are they supported while
you are throwing enough mass at the planet to cause cataclismic damage?

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

Date: 10 Sep 92 19:52:31 GMT
From: Paul Havlak <[e-mail]>
Subject: NASA/Rice information request
Newsgroups: talk.politics.space,sci.space,bit.listserv.space,tx.general,houston.general,rice.general

    I'm forwarding this request from Jim Kelly at the Houston Press:
*****
    I'm working on a piece for Sallyport, the Rice University alumni
magazine, centering on the Rice/NASA relationship over the last 30
years.  For example, I'd like to hear about Rice astronauts (alumni
and faculty), NASA-sponsored Rice research, and the Rice/Humble Oil
(now Exxon)/NASA land deal that brought Johnson Space Center to Clear
Lake.  In particular, I'm interested in the role of U.S. Rep. Albert
Thomas (D-Houston, Rice '20) in the deal.
    Any other connections between Rice and NASA are also of interest.

Please send mail to [e-mail], attention Jim Kelly.
Thanks
*****
    Jim doesn't have Usenet access, and I'll be out of town, so he
won't be able to use any information you don't send directly.  You can
also reach him by fax [phone]) or snailmail:

    Jim Kelly
    Houston Press
    P.O. Box 540167
    Houston, TX 77254-0167

Thanks,
Paul
--
Paul Havlak            Dept. of Computer Science
Graduate Student        Rice University, Houston TX 77251-1892
PFC/ParaScope projects        [phone] x2738     [e-mail]

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

Date: 10 Sep 92 21:49:00 GMT
From: Josh 'K' Hopkins <[e-mail]>
Subject: One Small Step for a Space Activist... Vol 3 No 9
Newsgroups: talk.politics.space,sci.space

[e-mail] (Michael V. Kent) writes:

>In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>>On the plus side, station supply will mean placing a lot of
>>mass into LEO, and this could make the market for launch
>>services a LOT bigger, which could help reduce launch
>>costs. But the way things currently are, NASA intends to use
>>only the Shuttle (with its high cost) for resupply. Not only

>NASA intends to use only the Shuttle for resupply ONLY until something
>better comes along.  Also, one of the design missions of the Delta Clipper
>is station resupply.

ESA has also done studies of an Ariane Transfer Vehicle to do logistics for
Freedom.  It has two advantages I see over either of the above suggestions.
First, its launched on a vehicle that, while still vaporware, is looking to be
done one time and inexpensive to launch.  Second, if ESA does the resupply, we
don't have to pay anything.

--
Josh Hopkins           "If you are sitting in an exit row and you cannot read
                       this card or cannot see well enough to follow these
               instructions, please tell a crew member."
[e-mail]                       -United Airlines safety instructions

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

Date: 11 Sep 92 05:13:41 GMT
From: Ron Baalke <[e-mail]>
Subject: Pluto Direct Propulsion Options
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] ("Phil G. Fraering") writes...
>Henry Spencer, net.authority, pontificates:
>/You really cannot do a Pluto
>\orbiter in a reasonable amount of time with 1960s propulsion technology,
>/which is what all currently-planned missions use.

>Just out of curiosity, is there a way to convince them to use post-early-
>1960's technology, like an ion drive of some sort?

JPL is currently studying the stationary plasma thrusters that the
Department of Defense recently obtained from the Soviets.  These plasma
thrusters perform better than ion thrusters and are in a small package about
10 times smaller, and they weigh only 4 kg.  The plan is to build scaled-up
versions of the Soviet thrusters that would provide the primary propulsion for
spacecraft for transfer to geosynchronous orbit.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Anything is impossible if
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | you don't attempt it.
|_____|/  |_|/       |_____|/                     |

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

Date: Thu, 10 Sep 92 17:36:54 GMT
From: Doug Mohney <[e-mail]>
Subject: QUERY Re: Pluto Direct/ options
Newsgroups: sci.space

References: <[e-mail]> <[e-mail]> <[e-mail]>,<[e-mail]> <[e-mail]>,<[e-mail]>
Reply-To: [e-mail]
Sender: [e-mail]
Source-Info:  Sender is really [e-mail]

In article <[e-mail]>, [e-mail] (Ron Baalke) writes:
>In article <[e-mail]>, [e-mail] (Doug Mohney) writes...
>>In article <[e-mail]>, [e-mail] (Henry Spencer) writes:
>>
>>>It is extremely difficult to combine a reasonable payload and a manageably
>>>short trip time with an orbiter mission.  Pluto is *a long way away*; to
>>>get there in under a decade, the probe has to be fast.  Killing all that
>>>velocity is inordinately expensive in mass.
>>
>>Aerobrake?
>>
>
>We don't have that much practical experience with aerobraking into orbit
>capture - it has never been attempted before.  If given the chance, Magellan
>will perform a number of aerobrake maneuvers through the atmosphere of
>Venus to circularize its orbit, but the uncertainty is so great that we
>can only estimate that it will take from 100 to 300 days.  Pluto does have a
>tentative atmosphere, but we know so little about it.  A flyby mission will
>help to enlighten us.  If you haven't noticed already, the basic blueprint
>for planetary exploration is to do a flyby first, then follow it up with
>an orbiting mission, and then follow that up with a lander.

Wouldn't we find out more if we tried to dip the probe INTO the atmosphere?
After all, we'd get much better close-up pictures :-). As well some better feel
for the composition of the atmosphere upon entry.

I suppose for imaging purposes, a flyby makes more sense, but if the
seat-of-the pants aerobrake worked, you get more imaging time, plus some data
on atmosphere density, etc.

OK, it would be impolite to dump the RTGs on Pluto's surface if it doesn't
work...minor details...


                 Support U.N. military force against Serbia

  -- >                  [e-mail]                        < --

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

Date: 11 Sep 92 01:55:53 GMT
From: Ron Baalke <[e-mail]>
Subject: QUERY Re: Pluto Direct/ options
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Doug Mohney) writes...
>Wouldn't we find out more if we tried to dip the probe INTO the atmosphere?
>After all, we'd get much better close-up pictures :-). As well some better feel
>for the composition of the atmosphere upon entry.

Actually, the radio science experiment will tell us a lot about the
atmosphere.  As the spacecraft flies by, the radio signal will be
transmitted through the atmosphere to Earth.  How the radio signal is
affected by the atmosphere will tell us its density and composition.
This is a common technique already performed with all of the other planets.
I believe from what we do know about Pluto's atmosphere is that it
quite thin and extends out quite a ways, even encompassing Charon.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Anything is impossible if
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | you don't attempt it.
|_____|/  |_|/       |_____|/                     |

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

Date: 10 Sep 92 18:05:09 GMT
From: Dave Jones <[e-mail]>
Subject: QUERY Re: Pluto Direct/ options
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>
>Wouldn't we find out more if we tried to dip the probe INTO the atmosphere?
>After all, we'd get much better close-up pictures :-). As well some better feel
>for the composition of the atmosphere upon entry.
>
>I suppose for imaging purposes, a flyby makes more sense, but if the
>seat-of-the pants aerobrake worked, you get more imaging time, plus some data
>on atmosphere density, etc.
>
>OK, it would be impolite to dump the RTGs on Pluto's surface if it doesn't
>work...minor details...
>
Err, like not being able to get the stored pictures sent back to you.
Remember these things aren't done in real time.  There was a mention of
several weeks playback time for data in a previous posting.  You can't
blame mission designers for avoiding the risk of losing the entire craft
by staying well away from the planet's surface.



--
||)) Those who wallow in ignorance      ))) Policemen are numbered in case))|
||)) must dwell in Limbaugh for a time  ))) they get lost - S. Milligan   ))|
||))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))|
||Dave Jones ([e-mail]) | Eastman Kodak Co. Rochester, NY   |

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

Date: 10 Sep 92 20:09:20 GMT
From: Nick Janow <[e-mail]>
Subject: QUERY Re: Pluto Direct/ options
Newsgroups: sci.space

[e-mail] (Henry Spencer) writes:

> In article <[e-mail]> [e-mail]
> writes:
>+> ... Pluto is *a long way away*; to get there in under a decade, the probe
>+> has to be fast.  Killing all that velocity is inordinately expensive in
>+> mass.
>+
>+ Aerobrake?
>
> In what? :-)  Pluto does have an atmosphere of sorts at the moment, but I'd
> guess it's too thin to do much aerobraking in, even if we knew its properties
> well enough to plan an aerobraking mission, which we don't.

Would it be possible to aerobrake at Uranus or Neptune, perhaps also using the
atmosphere to change trajectory significantly?  This would provide a fast
flight for much of the journey and have the remaining part at a speed slow
enough for aerobraking in Pluto's atmosphere, or at least a much slower pass by
Pluto.  It would also allow a mission at Uranus or Neptune.

I can see lots of problems with this, but sometimes wild ideas are workable.

--

[e-mail]

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

Date: 10 Sep 92 21:29:49 GMT
From: Gerald Cecil <[e-mail]>
Subject: QUERY Re: Pluto Direct/ options
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>Wouldn't we find out more if we tried to dip the probe INTO the atmosphere?
>After all, we'd get much better close-up pictures :-). As well some better feel
>for the composition of the atmosphere upon entry.
>I suppose for imaging purposes, a flyby makes more sense, but if the
>seat-of-the pants aerobrake worked, you get more imaging time, plus some data
>on atmosphere density, etc.

You're skimming the atmosphere at 20 km/s!  In an aerobrake, your speed roughly
halves each time you sweep up atmospheric mass equal to your own (drops
somewhat faster if you radiate heat).  Use even the *surface* pressure of the
Pluto atmosphere (I don't have that # at hand) and you're sure to require more
than the few 10's of kms that are available.  So, Lithobreak it is!
--
Gerald Cecil  [e-mail]  919-962-7169   NC 27599-3255 USA
   If we don't succeed, we run the risk of failure. -- Chairman of US Space
    Council.    ** Be terse: each line cost the Net $10 **

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

Date: Thu, 10 Sep 92 20:31:12 BST
From: [e-mail]
Subject: SPS

> Actually, you don't have to fool around with aluminum-oxygen (which
is
> a hassle as a rocket fuel, because both the aluminum and the
aluminum
> oxide are solids, where you'd really like liquid and gas
respectively).
>


Henry:

Not really. The way the fellow I know was doing it in a way that was
quite hassle free.

The fuel consists of, roughly speaking, tightly wrapped aluminum
foil. The oxidizer is water that is introduced to a lithium igniter.
The resulting heat causes the H20 to dissociate. The O2 and the Al
then react and release supply enough heat to continue to dissociate
the water as it is introduced. Specific impulse is okay but not
wonderful. But it hardly matters because the engine is so cheap and
safe. The reactions are self sustaining (until you turn off the
spigot). The plume is quite nice (I've seen a photo of an engine
firing on a test stand in the middle of a farm in Somewhere, USA).

I've not spoken to him in several years. He was talking about going
to a different igniter. A fairly standard one whose name escapes me
at the moment. Don't know if he has used it yet or not. Or even if he
has gone any farthur at all. But from what I know of the person, I
suspect he is still moving ahead.

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

Date: Thu, 10 Sep 1992 20:44:18 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: SSTO Mailing List Formed
Newsgroups: sci.space,talk.politics.space

                    SSTO Mailing List Charter

This group is for people interested in promoting the development of
Single Stage to Orbit vehicles in general and the current SDIO Single
Stage Rocket Technology (SSRT) program (DCX and DCY) in particular.
The group will disseminate technical and political information on the
project and promote discussions on both the technology and how best
to promote this technology to the government and general public.

Members are expected to be ACTIVE supporters who will be willing do
work in their communities and with their elected representatives to
publicize this program. If you sign up you WILL be expected to help
(writing to and perhaps meeting with your representatives at the very
least). If you simply want to read about it, stick to sci.space or
space-tech.

How to sign up:

Send mail to [e-mail]. In the message include:

1. Your name
2. Address
3. Phone number
4. New congressional district (if known)
5. New congresscritter's name (if known)

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "If they can put a man on the Moon, why can't they     |
|  [e-mail]     |  put a man on the Moon?"                               |
+----------------------226 DAYS TO FIRST FLIGHT OF DCX----------------------+

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End of Space Digest Volume 15 : Issue 184
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