Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_4/V16NO446.TXT

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Date: Sat, 10 Apr 93 05:08:18
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #446
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat, 10 Apr 93       Volume 16 : Issue 446

Today's Topics:
              Clementine Science Team Selected (2 msgs)
                 Magellan to Start Aerobraking in May
                      Magellan Update - 04/09/93
                   Mars Observer Update - 04/09/93
                             NASA "Wraps"
                            nuclear waste
                    Plans, absence therof (2 msgs)
                  Portable Small Ground Station?dir
                            Protectionism
                 Question- Why is SSTO  Single Stage
         Weekly reminder for Frequently Asked Questions list

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

Date: 9 Apr 1993 19:52 UT
From: Ron Baalke <[e-mail]>
Subject: Clementine Science Team Selected
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Paula Cleggett-Haleim
Headquarters, Washington, D.C.                                April 9, 1993
(Phone:  [phone])

Major Mike Doble
Department of Defense, Washington, D.C.
(Phone:  [phone])

RELEASE:  93-66

CLEMENTINE MISSION SCIENCE TEAM SELECTED

    NASA today announced the selection of the science team for the
Clementine mission to orbit the moon and to visit an asteroid.

    The team will be headed by Dr. Eugene Shoemaker of the U.S. Geologic
Survey, Flagstaff, Ariz., who has been very active for many years in both lunar
and asteroid research.

    Clementine, sponsored by the Strategic Defense Initiative Office
(SDIO), will launch a small spacecraft in January 1994 to orbit the moon for
several months, then de-orbit the moon in early May 1994.  The spacecraft
would then fly by the near-Earth asteroid 1620 Geographos on Aug. 31, 1994,
when the asteroid is several million miles away, its closest distance to the
Earth.

    The goals of the mission are to test new, lightweight sensors in a
space radiation environment and to demonstrate autonomous navigation and
spacecraft operation.  Lightweight and innovative spacecraft components also
will be tested, including a lightweight star tracker, an inertial measurement
unit, lightweight reaction wheels for attitude control, as well as a
lightweight nickel hydrogen battery and a lightweight solar panel.

    The science team will plan for the acquisition of the scientific
measurements, the archiving of all science data in a form easily accessible to
the planetary science community and initial analyses of the data.

    Geographos is one of the earliest discovered Earth-crossing asteroids.
It was discovered in September 1951, in a sky survey sponsored by the National
Geographic Society.  Most Earth-crossing asteroids are thought to be fragments
produced by collisions between asteroids in the main belt between Mars and
Jupiter, which are later perturbed into Earth-crossing orbits.

    Radar images recently obtained of the asteroid 4179 Toutatis suggest
that the shape of Geographos and other Earth crossers might be much more
complex than previously suspected.

    The sensors will be trained on the moon and on the asteroid.  Also,
mutispectral science measurements at ultraviolet, visible and infrared
wavelengths will be made and played back to Earth.  The specific filter
wavelengths were selected in consultation with NASA scientists, to both meet
SDIO objectives and maximize the scientific data return.

    The science team members selected and their affiliations are:

        Charles Acton, Jet Propulsion Laboratory, Pasadena, Calif.
        Daniel Baker, Goddard Space Flight Center, Greenbelt, Md.
        Jacques Blamont, CNES (France)
        Bonnie Buratti, Jet Propulsion Laboratory, Pasadena, Calif.
        Merton Davies, Rand Corp., Santa Monica, Calif.
        Thomas Duxbury, Jet Propulsion Laboratory, Pasadena, Calif.
        Eric Eliason, U.S. Geologic Survey, Flagstaff, Ariz.
        Paul Lucey, University of Hawaii, Honolulu
        Alfred McEwen, U.S. Geologic Survey, Flagstaff, Ariz.
        Carle Pieters, Brown University, Providence, R.I.
        David Smith, Goddard Space Flight Center, Greenbelt, Md.
        Paul Spudis, Lunar and Planetary Institute, Houston

    The Naval Research Laboratory, Washington, D.C., is responsible for
mission design, providing the spacecraft and for mission operations.  The Jet
Propulsion Laboratory will be responsible for tracking the spacecraft radio
signal using NASA's Deep Space Network and  will be responsible for accurately
locating Geographos using its Near Earth Object Center in preparation for the
flyby.

- end -
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Being cynical never helps
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | to correct the situation
|_____|/  |_|/       |_____|/                     | and causes more aggravation
                                                  | instead.

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

Date: 9 Apr 1993 16:20:15 -0400
From: Matthew DeLuca <[e-mail]>
Subject: Clementine Science Team Selected
Newsgroups: sci.space,sci.astro

In article <[e-mail]> [e-mail] (Ron Baalke) writes:

>    Clementine, sponsored by the Strategic Defense Initiative Office
>(SDIO), will launch a small spacecraft in January 1994 to orbit the moon for
>several months, then de-orbit the moon in early May 1994.

Um, where do they plan to land the moon? :-)
--
Matthew DeLuca
Georgia Institute of Technology, Atlanta Georgia, 30332
uucp:      ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!matthew
Internet: [e-mail]

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

Date: 9 Apr 1993 20:17 UT
From: Ron Baalke <[e-mail]>
Subject: Magellan to Start Aerobraking in May
Newsgroups: sci.space,sci.astro,alt.sci.planetary

From the "JPL Universe"
April 9, 1993

Magellan will change orbit, attempt aerobraking in May

     The Magellan spacecraft, which has mapped the surface of
Venus with imaging radar, will be put into a near-circular orbit
in a process called "aerobraking" beginning in late May, said
Magellan Project Manager Doug Griffith.
     Griffith explained the process in a noontime lecture in von
Karman Auditorium March 26. The essence of the aerobraking
process requires the spacecraft"s lowest orbital point,
periapsis, to be placed in the upper Venus atmosphere. That
allows atmosphere-induced "aerodynamic drag" to reduce the
spacecraft velocity and circularize the orbit.
     It will be the first time a NASA spacecraft has been
aerobraked at a distant planet, and the experiment is expected to
provide valuable information for future missions.
     Magellan, which completed mapping the planet last September,
is making gravity observations in its fourth 243-day cycle around
Venus. At the end of the cycle, on May 25, spacecraft controllers
will perform an orbit trim maneuver to lower Magellan's periapsis
altitude. Aerobraking operations will then start, and the process
is expected to take about 70 days.
     The near-circular orbit would be from 200 kilometers to 300
kilometers (124 to 186 miles).
     After circularization has been accomplished, Griffith said,
the project will perform high-resolution gravity studies, pending
NASA approval, through October 1994. Funding has been requested
to extend the mission for that period, he said.
                              ###
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Being cynical never helps
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | to correct the situation
|_____|/  |_|/       |_____|/                     | and causes more aggravation
                                                  | instead.

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

Date: 9 Apr 1993 19:53 UT
From: Ron Baalke <[e-mail]>
Subject: Magellan Update - 04/09/93
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Forwarded from Doug Griffith, Magellan Project Manager

                      MAGELLAN STATUS REPORT
                           April 9, 1993

1.  The Magellan mission at Venus continues normally, gathering
gravity data which will be correlated to surface topography.
Spacecraft performance is nominal.

2.  Magellan has completed 7173 orbits of Venus and is now 46 days
from the end of Cycle 4 and the start of the Transition Experiment.

3.  The Project has completed the current phase of office
consolidation to assist in the collocation of the MESUR Project on the
230-2nd floor.

4.  Preparations for aerobraking continue to go well.  As presently
planned, the Transition Experiment will begin with a 785-second Orbit
Trim Maneuver (OTM) on May 26, 1993 during orbit #7626 at about 10:40
AM PDT.  This will lower the periapsis from 170 km to 147 km above the
surface of Venus.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Being cynical never helps
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | to correct the situation
|_____|/  |_|/       |_____|/                     | and causes more aggravation
                                                  | instead.

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

Date: 9 Apr 1993 19:55 UT
From: Ron Baalke <[e-mail]>
Subject: Mars Observer Update - 04/09/93
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Forwarded from the Mars Observer Project

                       MARS OBSERVER STATUS REPORT
                             April 9, 1993
                              11:20 AM PDT

The spacecraft was commanded to the 4 kbs Science and Engineering
downlink data rate this morning.  This was the first step in a series of
activities affecting Gamma Ray Spectrometer, Electron Reflectometer,
and Pressure Modulator Infrared Radiometer instruments planned for
today.

While at the 4k downlink rate, the GRS team will be examining the GRS
Ram load to verify content, the MAG/ER team is performing instrument
calibration activities, and the PMIRR team is using the opportunity to
update an  auxiliary heater state indicator time tag.  Upon completion of
these activities, the spacecraft will be commanded back to the 2k
downlink Engineering data rate.

MO participation in the Gravity Wave Experiment ends at 1:20 AM Monday,
April 12.  The active Flight Sequence, C8, will then execute steps to begin
further Magnetometer instrument calibrations to allow the instrument
team to better characterize the spacecraft-generated magnetic field and
its effect on their instrument.  This information is critical to Martian
magnetic field measurements which occur during approach and mapping
phases.  Magnetometer calibrations performed Monday through Wednesday
(April 12 through 14) will require the sequence to command the spacecraft
out of Array Normal Spin state and perform slew and roll maneuvers to
provide the MAG team data points in varying spacecraft attitudes and
orientations.  The sequence will perform the transition back to Sun Star
Init at 7:21 on Tuesday, April 13.  With Inertial Reference reestablished,
the spacecraft will be commanded to slew to Array Normal Spin at 10:31 AM.

Concurrent with MAG Calibration activities, the Mars Observer Camera
team will power on their instrument and take Wide Angle and Narrow
Angle images.  Wide Angle imaging will be performed while the spacecraft
is in the Inertial Slew Hold mode.  Narrow Angle imaging will be performed
after the Spacecraft has been returned to ANS, and the planet Jupiter is in
the Narrow Angle field of view.  These activities are executed by non-
stored sequence commands and will be closely coordinated between
Instrument, Spacecraft, and Ground Operations Teams.

Verification Test Laboratory testing of Flight Software Build 8.0 began on
Tuesday, March 23 and is scheduled to be completed May 5.  An earlier
report erroneously stated the completion date to be April 5.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Being cynical never helps
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | to correct the situation
|_____|/  |_|/       |_____|/                     | and causes more aggravation
                                                  | instead.

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

Date: 9 Apr 93 12:20:51
From: Steinn Sigurdsson <[e-mail]>
Subject: NASA "Wraps"
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:


   In article <[e-mail]> [e-mail] (David M. Palmer) writes:

   >>I believe that at all the National Labs, there is a Director's Fund,...

   >It is also good for faster, cheaper, better projects.

   Agreed. I don't mean to say that wraps are always bad. Just here they
   are costing too much money. What I think is hapenning is that people

For comparison the JPL Director's disgressionary fund is 0.3% of the
JPL budget - and apparently Goldin feels this is much too little.

(Ref: E&S Winter 1993).

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

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

Date: 9 Apr 93 16:55:17 GMT
From: Kenneth Ng <sugra!ken>
Subject: nuclear waste
Newsgroups: sci.space

In article <[e-mail]: [e-mail] (fred j mccall 575-3539) writes:
:I was under the impression that the Japanese plutonium was more
:'enriched' than this; however, that was from press coverage of the
:transshipment, and we know what the gentlemen of the Press can be like
:when it comes to strict factuality on issues like this.

I can understand this impression.  One of the advertisements I've read has
so many mistakes, misleads, and downright lies that it was laughable.
Constantly they were infering that 'plutonium' means 'nuclear bomb'.  But
I must say that to this day, I have yet to read the isotope concentration
of the plutonium shipment.  Since the target is a nuclear reactor, I would
imagine that it would not have a high amount of pu239.

--
Kenneth Ng
Please reply to [e-mail] for now.
"All this might be an elaborate simulation running in a little device sitting
on someone's table" -- J.L. Picard: ST:TNG

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

Date: Fri, 9 Apr 1993 17:22:28 GMT
From: Mary Shafer <[e-mail]>
Subject: Plans, absence therof
Newsgroups: sci.space

On Thu, 8 Apr 1993 17:38:07 GMT, [e-mail] (Allen W. Sherzer) said:

Allen> In article <[e-mail]>
Allen> [e-mail] (Mary Shafer) writes:

>[Descussing the Hatch Act]
>This is both for our protection and for the protection of the parties;  we
>can't be pressured to make "voluntary" donations of time  and money and
>incumbents can't have an army of ready-made campaign workers.
Allen>  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Allen> That only applies to the executive branch. Congress, in its
Allen> wisdom, has seen fit to exempt itself from this law. This gives
Allen> every Represntative and Senator his or her own personal crew of
Allen> campaign workers paid for by you and I.

You're quite right about Congress.  They've also exempted themselves
from the various equal opportunity, nepotism, handicapped hiring,
workplace safety, whistleblowing, et cetera laws, regulations, and
orders.

They're not Civil Service and I should have made that clear.
--
Mary Shafer  DoD #0362 KotFR NASA Dryden Flight Research Facility, Edwards, CA
[e-mail]                    Of course I don't speak for NASA
 "A MiG at your six is better than no MiG at all."  Unknown US fighter pilot

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

Date: 9 Apr 93 12:27:57
From: Steinn Sigurdsson <[e-mail]>
Subject: Plans, absence therof
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Mary Shafer) writes:

   On Thu, 8 Apr 1993 17:38:07 GMT, [e-mail] (Allen W. Sherzer) said:

   Allen> In article <[e-mail]>
   Allen> [e-mail] (Mary Shafer) writes:

   >[Descussing the Hatch Act]
   >This is both for our protection and for the protection of the parties;  we

   Allen> That only applies to the executive branch. Congress, in its
   Allen> wisdom, has seen fit to exempt itself from this law. This gives

   You're quite right about Congress.  They've also exempted themselves
   from the various equal opportunity, nepotism, handicapped hiring,
   workplace safety, whistleblowing, et cetera laws, regulations, and
   orders.

Just remember there's a real reason why they do that - it can be
quite important for the legislature to be immune from executive
interference and a "by the book" enforcement of a lot of the
et cetera laws and regulations could cripple a select sub-group
of legislators if a determined executive wanted to go after them.

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

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

Date: Fri, 9 Apr 1993 15:45:58 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Portable Small Ground Station?dir
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>In article <[e-mail]>
>[e-mail] (Gary Coffman) writes:
>>The DSN stations are different, and aren't used to monitor Shuttle.
>>These stations use huge antennas to gather in the very faint signals
>>from distant probes. They use advanced LNAs, low noise amplifiers,
>>and computer enhancement to pick up signals that are so faint that
>>a flea scratching himself at 2000 km would have more power. You have
>>no hope of duplicating them on an amateur budget.
>>
>I would not be quite so extreme in my statements about DSN.  The Low
>Noise Amps (LNAs) are quite expensive but you can do some significant
>enhancement on any PC if you know the encoding schemes and are willing
>to run significantly less than real time.

Actually, nitrogen cooled HEMT preamps might do all right. They're
getting very close to MASER performance and you can put one together
for a couple hundred dollars. But to do non-realtime processing you have
to have recorders that will capture the signals in real time. That's not
simple when you have to preserve the phase coherence of the signal in order
to postprocess it out of the incoherent noise. You almost need atomic
references for your LO and tape recorder. You might trick that out of
a GPS receiver if you're clever.

>You can also create an antenna field (small cheap antennas) and rebuild
>the signal using amplitude and phase combining.  The theory actually
>allows an awful lot from spacial diversity and block coding.  Your targets will
>be significantly limited by your system and receiver noise, but above a
>certain threshold I think you could scrape up the energy and recover bits.

You can do a lot of beam convergence with a field of antennas, but unless
you have a way of shielding each antenna's individual pattern from the Earth,
they'll have a noise temperature of 290 K, and that sets a mean floor on
receiver noise figure that your very quiet preamp can't repair. Dipoles
would be out, but a whole bunch of home satellite dishes might work. Getting
them to all track would be fun.

We talked about a continental network of amateur radio astronomy stations
here a few months ago. Each would have it's own home satellite dish and
share a common reference via a GPS satellite. The received data would
be concentrated via the network and post processed. I suspicion it just
might work if the scanned bandwidths were kept limited enough.

Gary
--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244     |                     |

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

Date: Fri, 9 Apr 1993 16:47:19 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Protectionism
Newsgroups: sci.space,sci.econ

In article <[e-mail]> [e-mail] (Nick Szabo) writes:
>[e-mail] (Gary Coffman) writes:
>
>>there's a 15% tax break to companies exporting raw logs from the
>> Pacific Northwest to Japanese furniture factories.
>
>Wrong.  Another popular myth making the rounds.  There's a
>15% tax break on any export, including high-value-add wood
>products like furniture, because we want to cut the trade deficit.

What I said was not wrong. There is a 15% tax break on raw log export.
The tax break applies to other things as well, but doesn't negate my
statement.

>The reason Japanese buy raw logs is straightforward: they have
>important, exacting standards unique to their culture which U.S.
>mills have been unable or unwilling to meet.  These standards range
>from the simple (cutting in metric dimensions) to the complex
>(Japanese archictectural traditions & standards, including unique
>designs for earthquake protection).

Add in the factor of predatory home market protectionism. I can buy
metric 3.8cmX8.57cm milled lumber from Georgia Pacific, so can the
Japanese. GP'll even sell you 4cmX9cm stock if you request. A 2X4
by any other name is just a tweak of the plane away.

>BTW, there is now a strong statist incentive _against_ raw log exports:
>such exports of logs from state & federal lands are now illegal,
>another stupid measure that protects low-skill, low-wage jobs (eg
>raw log lumbering) and discourages high-skill, high-wage jobs (eg
>building finished wood products for the Japanese market).

What kind of contradiction is this? The Greenpeacers, and other
tree huggers, have stopped much of the logging on Federal lands.
That's true. But it hurts logging jobs, not millworking jobs, to
restrict raw log exports. Such exports are more profitable than
selling to domestic mills who find little export market for their
products. So the exports benefit loggers, not millworkers.

>Of course, it's much easier to claim to be patriotic and Japan-bash
>than to try to learn something about another culture so that one
>can do business with them.  It's much easier to make up and propagate
>myths about "subsidizing raw log export" than to admit and correct
>our own shortcomings that have caused the problem.

We *do* subsidize raw log export. That's a fact. Most of those
exports *do* go to Japan. That's a fact. The Japanese *do* practice
predatory home market protectionism. That's a fact. Try selling beef,
citrus, or rice in the Japanese market. It won't matter that your
quality is higher and your prices lower, they won't buy. They have
their reasons, we have ours. That's a fact. It's not Japan bashing.
It's a statement of how Pacific Rim trade works.

Gary
--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244     |                     |

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

Date: Fri, 9 Apr 1993 15:09:45 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Question- Why is SSTO  Single Stage
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>
>People built two-stage airliners once.  Nobody bothers any more.  It's
>just not worth the extra performance.

I must have missed this, tell us about two stage airliners.

In article <[e-mail]> phoenix.Princeton.EDU!carlosn (Carlos G. Niederstrasser) writes:
>>... However, we pay a very high penalty on
>>payload capability.
>
>*SO* *WHAT*???
>
>This is the big mistake that almost every launch system currently in
>existence has made:  shooting for maximum performance instead of minimum
>operational cost.

Shooting for minimum operational cost doesn't necessarily mean throwing
away all hint of performance, otherwise we'd still be using sticks and
wire to support the wings of our biplanes. A craft that must burn 800 klb
of cryogenic fuel to deliver 10 klb of payload to orbit isn't necessarily
of lesser cost than one that needs 400 klb of fuel to deliver 40 klb of
payload to orbit. You can do that without overstressed engines and
complex and tedious assembly stacking. You just have to design your
system with adequate margins and easy assembly from the start. The
advantages of staged vehicles are too great to throw away just because
we haven't designed one to be easy to maintain and use *yet*. That's
never been the primary design goal before.

>If you don't like the size of the payload, either scale up the vehicle
>(this is not a military missile that has to fit in a predefined silo)
>or fly it more often and assemble in orbit (the largest payload that
>absolutely must go up in one piece is a human with life support).

But you have to look at cost of assembly in orbit versus cost of launching
preassembled from the ground. The latter looks cheaper due to the high
labor cost of on orbit work, and that high cost isn't all transport cost
either.

>>    I would think that by applying all the concepts of SSTO to a double
>>stager we would get nearly the same price and time performance, but with
>>higher payload capabilities.
>
>Developing two different vehicles is going to be nearly as cheap as one?
>I have my doubts.

It's one vehicle, it's just that not all it's pieces are permanently
attached. It would seem that a first stage built like an airplane, and
operated like an airplane, that carried an orbital stage, built like
an airplane and operated like an airplane, with an easy mate design would
make orbital flight cheaper and more effective than a SSTO requiring
ultralight structures and finicky maneovers just to get to orbit and
back. MX has been launched from a C5, and neither system was designed
for that. A F16 has carried an orbital ASAT rocket. And of course there's
Pegasus. Systems designed from the ground up to be used together routinely
and cheaply would seem to be even easier to do than systems thrown together
to take advantage of existing hardware. I'm not saying either has to have
wings, only that the systems have to be easily mated and easily recovered
and reused without major rebuilds. We've never done that either, but we
likely could with little more effort than required for SSTO, and with a
much larger payoff in terms of payload to orbit.

As a hypothetical, suppose we build a new first stage using F1 engines
modified to be throttlable and designed to softland under radio
control after separation. The top stage could be DC-1/2, a system
similar to the proposed DC-1, but with it's launch cradle replaced
by a docking adapter fitted to the nose of the F1 stage, and a four
times larger payload bay. When it re-enters and lands all you need to
do is set it on top of the F1 instead of it's launch cradle, fasten
some explosive bolts, fuel, and launch again. It constrains takeoffs
and landings to the same field until you start operating a fleet, but
once you do, every field will have F1 stages sitting around waiting
for an incoming DC-1/2 to relaunch.

Note that the combined F1-DC-1/2 could do a landing abort if there
were a problem during boost. And if you were clever with some heat
shielding, the DC-1/2 stage could bring all it's engines up to idle
before separation, so engine out failures at separation would become
a viable abort situation. Of course Von Braun thought of all of this
long ago, but it's still a great idea.

Gary
--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244     |                     |

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

Date: 9 Apr 1993 14:09:08 -0400
From: Jon Leech <[e-mail]>
Subject: Weekly reminder for Frequently Asked Questions list
Newsgroups: sci.space,sci.astro,sci.space.shuttle

    This notice will be posted weekly in sci.space, sci.astro, and
sci.space.shuttle.

    The Frequently Asked Questions (FAQ) list for sci.space and sci.astro is
posted approximately monthly. It also covers many questions that come up on
sci.space.shuttle (for shuttle launch dates, see below).

    The FAQ is posted with a long expiration date, so a copy may be in your
news spool directory (look at old articles in sci.space). If not, here are
two ways to get a copy without waiting for the next posting:

    (1) If your machine is on the Internet, it can be obtained by anonymous
FTP from the SPACE archive at ames.arc.nasa.gov (128.102.18.3) in directory
pub/SPACE/FAQ.

    (2) Otherwise, send email to '[e-mail]'
containing the single line:

help

    The archive server will return directions on how to use it. To get an
index of files in the FAQ directory, send email containing the lines:

send space FAQ/Index
send space FAQ/faq1

    Use these files as a guide to which other files to retrieve to answer
your questions.

    Shuttle launch dates are posted by Ken Hollis periodically in
sci.space.shuttle. A copy of his manifest is now available in the Ames
archive in pub/SPACE/FAQ/manifest and may be requested from the email
archive-server with 'send space FAQ/manifest'. Please get this document
instead of posting requests for information on launches and landings.

    Do not post followups to this article; respond to the author.

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


Received: from leibniz.CS.Arizona.EDU by optima.cs.arizona.edu (5.65c/15) via SMTP
    id AA03811; Fri, 9 Apr 1993 13:26:08 MST
Date: Fri, 9 Apr 1993 13:26:07 MST
From: "Richard Schroeppel" <[e-mail]>
Message-Id: <[e-mail]>
Received: by leibniz.cs.arizona.edu; Fri, 9 Apr 1993 13:26:07 MST
To: [e-mail]
Subject: Biosphere 2, In Praise of

I think public opinion is much too harsh on Biosphere 2.  They are
being criticized as "not doing real science".  This is silly: they
are gathering information about how to live in a mostly self-contained
ecology.  Naturally, this involves a lot of tinkering.  So does any
laboratory.  Most tinkering is unpublishable.  B2 are being jumped
on for not being open.  BFD- Kodak & IBM certainly don't tell all,
but are nevertheless considered serious science.

Instead of bitching about what real science is or isn't, we should credit
B2 with bringing up some inconvenient problems that space colonists will
have to deal with:

(1) You must have bigger reserves of food & O2 than you would expect.
    You must provide for too much CO2, and disappearing O2.  You must
    stabilize pO2, and total pressure.
(2) Food variety is virtually mandatory.  People will subsist on junk
    without going crazy only in wartime.
(3) Pests are REAL trouble.  California can't even keep out medflies,
    and we weren't planning to keep visitors out of our colony.  At the
    minimum, they will bring the latest flu, dust mites, tiny insects,
    mold, and fungi in their clothing & luggage.
(4) Crop failures happen.  I'm no treehugger, but the decision to use
    DDT etc. in a closed colony is not going to be taken lightly.
    You must keep a lot of different plants growing; & maybe a seed bank.
(5) Provide extra crew time for maintenance of things that aren't
    supposed to break.  Murphy lives in space.

Rich Schroeppel  [e-mail]

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End of Space Digest Volume 16 : Issue 446
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