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Date: Tue,  9 Jan 90 16:04:37 -0500 (EST)
Subject: SPACE Digest V10 #402

SPACE Digest                                     Volume 10 : Issue 402

Today's Topics:
            Re: Nuclear Reactors in Space
               Re: Simpler space suits?
      New data on the difficulties with Soviet N-1 lunar rocket
             Reactors in space II
         Re: Payload Status for 01/05/90 (Forwarded)
            Re: Nuclear Reactors in Space
               Reminders for Old Farts
            Re: Nuclear Reactors in Space
            Re: Nuclear Reactors in Space
               Re: Simpler space suits?
----------------------------------------------------------------------

Date: 9 Jan 90 05:37:19 GMT
From: cs.utexas.edu!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Nuclear Reactors in Space

In article <[e-mail]> [e-mail] (Loren Petrich) writes:
>    I wonder if anyone has evaluated any solar power source that
>is radiation-proof, such as some thermal cycle? How much progress has
>been made in attempting to make photovoltaic cells resistant to
>radiation degradation?

Solar-thermal cycles have been evaluated for a long time, but nobody has
yet flown one.  Low-performance types are not hard to build in principle,
but performance and weight are not as good as solar cells.  High-performance
ones are of interest for a lot of applications, including the space station,
but tend to have moving parts and fluid loops.  Any solar scheme also suffers
when eclipses are involved, because batteries are heavy and unreliable.
(Voyager has no batteries of any kind -- there was no big need, given RTGs,
and the desire to maximize spacecraft life encouraged finding alternatives
for the few places where they would have been useful.)  A fancy solar-thermal
scheme might be able to store energy as heat to keep its turbogenerators
running, although heat storage is another one of those fun technologies
that isn't as easy as it looks.

>    I have a feeling that the likes of the Christic Institute
>enjoy tying up big organizations like NASA with lawsuits, and that's
>why they do stuff like that.

Looking for rational reasons for the Christics' behavior is pointless.
--
1972: Saturn V #15 flight-ready|     Henry Spencer at U of Toronto Zoology
1990: birds nesting in engines | uunet!attcan!utzoo!henry [e-mail]

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

Date: 8 Jan 90 18:49:26 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Re: Simpler space suits?

In article <[e-mail]> [e-mail] (bill davidsen) writes:
>  I would like more information on this... why is the man made stuff
>such a problem? Things in the same orbit have the same velocity, or they
>wouldn't be in the same orbit. Now some stuff may be in an eliptical
>orbit, and cross the path of the EVA, but is likely to have a fairly
>small closing speed, since highly eliptical orbits which cross LEO tend
>to cross the atmosphere, too.
>
>  Looking at what has been launched in terms of number of items, and the
>volume of LEO, the term "empty space" still doesn't seem too far wrong.
>
>  Could someone come up with some explanation of why the man-made junk
>is an issue (or even confirm my gut feeling that it's not all that bad)?

Look to your left, look to your right, look both ways before crossing,
as the school safety patrol lady sez...

The enemy is inclination, not eccentricity.  Most Cape launched
"equatorial" orbits are inclined 28 degrees; over time, the entire band
of space +/- 28 degrees from the equator in LEO is filled with debris.
Consider the N-S component of orbit velocity.  Anything in one of these
orbits covers 56 degrees of latitude per half-orbit, for an average N-S
speed of around 2,000mph, peaking at the equator (the nodes) at about
4,000mph.  If you cross the equator on your ascending node and meet a
Delta booster paint chip crossing on its descending node, it hits from
the NORTH at 8,000mph!  That'll put a ding your bumper all right.

--
US out of North America, NOW!!   /:   Tom Neff
           -- Richard O'Rourke   :/   [e-mail]

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

Date: Tue, 9 Jan 90 11:32:23 EST
From: <@ll-vlsi.arpa:glenn@vdd> (Glenn Chapman)
To: [e-mail], [e-mail],
        [e-mail], [e-mail],
        [e-mail], [e-mail]
Subject: New data on the difficulties with Soviet N-1 lunar rocket

     The booster area this month generated some interesting Soviet
announcements. First the production rate of the Proton booster is being cut
from the current 13 per year to 8. The Proton, which first flew in 1965 and
was their largest operational booster (20 Tonnes to orbit) before Energiya,
is probably being partially replaced by the newer, and cheaper to produce,
Zenit booster (15 Tonnes to orbit). Current Zenit launch rate is about 6
per year, half the Proton level, but the combination of the two would put
nearly the same mass in orbit. The attempt to sell the spare Proton
production to the western satellite companies have been blocked by
Washington hence this change. In addition the Soviet satellites lifetime
has been improving lately making less launches necessary to maintain their
current systems. Energiya is suffering a cutback which puts the next launch
in early 1991 using the shuttle Buran as its payload. Currently they have
an Energiya ready to launch but the cargo has been delayed. The Soviets are
doing tests to cool the liquid hydrogen/oxygen propellants, thus decreasing
their volume. This raises the cargo capacity of Energiya by 1 Tonne (1% of
its 100 Tonne capacity). (AW&ST Dec. 11)
     The Soviet/French Granat gamma ray observatory was successfully
launched by a Proton on Dec. 1 into the required 2000 x 200,000 Km (1200 X
124,000 mi.) orbit. Currently it is being tested in orbit. (AW&ST Dec. 11)
     More information has come out about the ill fated Soviet Saturn class
booster called N-1 of the 1960's. It appears that there was a battle
between Sergei Korolyov, the "grand designer" of the Sputnik and manned
program, and Valenta Glushko, the "Chief Designer of Rocket Engines".
Korolyov wanted to use Liquid Hydrogen/Oxygen while Glushkvo felt the
resulting low fuel density would make the booster mass too high. For the
first stage Korolyov wanted a large cluster of Lox/Kerosene small engines
to meet the time demands of the space race, while Glushkvo wanted a small
number of big engines using storable fuels. The disagreement resulted in
Korolyov turning to the N.D. Kuznetstov design bureau which built the jet
engines for the Tupolev aircraft. Korolyov's death in Jan. 1965 further
complicated the problem. Since the Kuznetstov bureau had never built
rockets, let alone a complicated cluster of synchronized power plants,
significant problems occurred. Note that previous reports have stated that
in all four launch attempts the first stage engines failed. Kuznetstov in
1976 stated that the N-1 engines had been tested for 14,000 sec. while only
140 were required for the launch. However, by that time (1974) the booster
had been cancelled, though two N-1's were assembled at that time.
Apparently the only real remnant of the N-1 booster is the odd roof of the
bandstand at Baikonur built from the fuel tanks of the launcher.
(Spaceflight Dec. 1989)
     In reguar to this it is interesting to note (as has been stated in
other postings) that Soviet officials reveal a copy of their lunar lander
to five MIT professors who were visiting the Moscow Aviation Institute. The
Russians had planed to use a lunar rendezvous style system similar to that
of the Apollo. Initially their large N-1 booster would lift the lunar
lander and service rockets into earth orbit. Then a Proton would lift a
modified Soyuz capsule (similar to the Zond 7) with two cosmonauts into
earth orbit, where it would dock with the lander. Probably this was so that
the N-1 would not need to be man rated. The combined system leave earth
orbit and enter Lunar orbit where one cosmonaut to transfer to the lander,
descend to the surface, then return to the orbital portion. This would be
followed by a return to earth, probably involving a reentry pattern that
would skip through the upper air to reduce the G force on entering the
earth's atmosphere. Pictures of the lander, and the description of flight
plan, reveal it to be very similar to the speculations of Charlie Vick and
David Woods. The lander was ready to go in 1978 but the problems with the
N-1 prevented it from flying.  (MIT Press Release, Boston Globe, Dec. 14)
      Finally the last pieces of the puzzel of the Soviet lunar program are
coming into place.  Hopefully we will get some books now writen by workers
in that program detailing the problems that lead to their failure there,
and the lessons they learned.

                                             Glenn Chapman
                                             MIT Lincoln Lab



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

Date: 8 Jan 90 18:41:00 GMT
From: [e-mail]
Subject: Reactors in space II


Regarding nuclear reactors in space --

Someone suggested a Uranium/Plutonium breeder for power on the moon.  As
an alternative, how about Thorium-232/Uranium-233 breeder for that purpose
(i.e., power).  Various designs have been suggested (a couple tested) and
there has been a laboratory demonstration of in situ reprocessing of the
fuel for extraction of rad-waste.  Might make a good approach down on
old terra firma.

--paul hager        [e-mail]

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

Date: 9 Jan 90 01:07:55 GMT
From: ogicse!littlei!nosun![e-mail]  (David Schneider)
Subject: Re: Payload Status for 01/05/90 (Forwarded)

In article <[e-mail]> [e-mail]
(Peter E. Yee) writes:
>Daily Status/KSC Payload Management and Operations 01-05-90
>
>- STS-35 ASTRO-1/BBXRT (at O&C) -
>
>Cite testing continues.

After reading the many reports Peter has been kind enough to forward,
I feel foolish that I don't know what "cite" testing is.  Could someone
explain or elucidate?  Thanks.

                    Dave Schneider
                    Mon, Jan 8

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

Date: 9 Jan 90 03:41:45 GMT
From: ccncsu!handel.CS.ColoState.Edu![e-mail]  (michael vincen conca)
Subject: Re: Nuclear Reactors in Space

In article <[e-mail]> [e-mail] (Paul Dietz) writes:
>missions, another possibility hasn't been mentioned.  A spacecraft in
>orbit around Jupiter is moving rapidly through a strong magnetic
>field.  It should be possible to generate power with an electrodynamic
>tether, especially when very near the planet.  Now, this will slow the
>spacecraft, but the available kinetic energy is very large (Jupiter
>has a very deep gravity well), and the orbit could be pumped up again
>by slingshoting off Jupiter's moons.
>
>    Paul F. Dietz
>    [e-mail]

Here at Colorado State, were are currently designing a shuttle experiment
to test the feasibility of this.  It involves the use of plasma contactors.

Basically, you run a strong, insulated wire down from the shuttle towards
the planet so that as the Shuttle moves, the wire intersects the magnetic
field lines at right angles.  At each end of the wire is a plasma contactor.
As the shuttle moves through the magnetic field, an electrical current is
generated (see Physics 101) with electrons going from the plasma surrounding
the planet, up the wire, and then exiting back out into the plasma.

You pointed out that doing this will slow the spacecraft (and hence lower
its orbit). One of our graduate students thought of a unique way to counter
this problem.  Since the spacecraft will orbit the planet about the center
of mass between the actual craft and the plasma contactor at the end of the
wire, you make the wire short so that the center of mass is as near
the spacecraft as possible.

Now, as the spacecraft slowly loses altitude, you reel the plasma contactor
out a little, and voila!, the spacecraft gains some altitude
and you are back where you started.

Obviously, the tether can only be so long, so eventually, some
sort of action will be necessary to restore the spacecrafts orbit.


-=*=--=*=--=*=--=*=--=*=--=*=--=*=--=*=--=*=--=*=--=*=--=*=--=*=--=*=--=*=-
Mike Conca, Computer Science Dept.   *  [e-mail]
Colorado State University            *  conca@129.82.102.32
                 'Back off man - I understand computers!'

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

Date: Tue, 9 Jan 90 04:01:13 PST
From: Eugene Miya <[e-mail]>
Subject: Reminders for Old Farts

Hints for old users (subtle reminders) You'll know these.

Minimize cross references, [Do you REALLY NEED to?]
Edit "Subject:" lines especially if you are taking a tangent.
Send mail instead, avoid posting follow ups. [1 mail message worth 100 posts.]
Read all available articles before posting a follow-up. [Check all references.]
Cut down attributed articles.  Summarize!
Put a return address in the body (signature) of your message (mail or
article), state institution, etc. don't assume mail works.
Use absolute dates.  Post in a timely way.  Don't post what everyone will
get on TV anyway.
Some editors and window systems do character count line wrapping:
please keep lines under 80 characters for those using ASCII terms (use <CR>).

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

Date: 8 Jan 90 23:00:21 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Re: Nuclear Reactors in Space

In article <[e-mail]> [e-mail] (D Gary Grady) writes:
>Moreover, RTGs are not useful for the power levels required by SDI; for
>that you need a nuclear reactor.  And, in case you're unaware of it, RTG
>research is essentially irrelevant to nuclear reactors in space.

This has been said twice now in the past couple of days, and I can't let
it sit.  By 'required for SDI' people seem to mean 'required to pump huge
lasers' or the like.  There is a lot more to SDI than this.  Detection and
deflection stations have power requirements well below the Doc Emmett
Brown Flux Capacitor levels envisioned for the big lasers.

Last I checked, RTGs were easier to harden against laser attack than
solar arrays, although neither is impossible (but the SA protection
is pretty bulky).
--
'We have luck only with women -- not spacecraft!'     \\  Tom Neff
 -- R. Kremnev, builder of failed Soviet FOBOS probes //  [e-mail]

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

Date: 9 Jan 90 05:30:17 GMT
From: cs.utexas.edu!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Nuclear Reactors in Space

In article <[e-mail]> [e-mail] (Paul Dietz) writes:
>... another possibility hasn't been mentioned.  A spacecraft in
>orbit around Jupiter is moving rapidly through a strong magnetic
>field.  It should be possible to generate power with an electrodynamic
>tether...

One issue with electrodynamic tethers is expected lifetime of the tether.
This is a real problem in low Earth orbit, given the growth of the space
debris belt around Earth.  The outer planets don't have *that* problem,
but they do have substantial dust belts in their ring planes, out well
beyond the visible rings.  I don't know how the numbers would work out,
but this might be a limitation.

(Fortuitously, it turned out that the Voyager plasma-wave/radio-astronomy
experiment can detect a dust-particle impact almost anywhere on the
spacecraft [!] -- the hypervelocity impact creates a plasma cloud that
makes a bit of electrical noise when it hits the PW/RA antennas.)
--
1972: Saturn V #15 flight-ready|     Henry Spencer at U of Toronto Zoology
1990: birds nesting in engines | uunet!attcan!utzoo!henry [e-mail]

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

Date: 9 Jan 90 05:16:54 GMT
From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Simpler space suits?

In article <[e-mail]> [e-mail] (bill davidsen) writes:
>| ... My guess,
>| made without checking the numbers, is that natural debris is not much
>| of a concern, but in low orbit the man-made junk is a real issue.
>
>  I would like more information on this... why is the man made stuff
>such a problem? Things in the same orbit have the same velocity, or they
>wouldn't be in the same orbit...

The trouble is, there is lots of it, in all kinds of different orbits.
Long-standing design defects in certain boosters (like paint that flakes
too damned easily on the Delta) have put a *lot* of debris into low
orbits.  Satellite explosions, both deliberate and accidental, have made
things worse.  There is now starting to be some attention to the issue,
and none too soon.  People were startled at the number of micro-craters
on modules brought back from Solar Max a few years ago, and I imagine
LDEF is pretty well pock-marked by now too.  One of the shuttle orbiters
got an outer window pane cratered by something -- probably a Delta paint
flake -- a few years ago.  NASA routinely runs a giant collision analysis
for a shuttle mission, matching the shuttle orbit against all debris with
known orbits... but the worst of the debris is too small to be tracked
with current systems.
--
1972: Saturn V #15 flight-ready|     Henry Spencer at U of Toronto Zoology
1990: birds nesting in engines | uunet!attcan!utzoo!henry [e-mail]

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

End of SPACE Digest V10 #402
*******************