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Subject: SPACE Digest V12 #58

SPACE Digest                                      Volume 12 : Issue 58

Today's Topics:
       Re: Free Space Station - Spacious but needs work
             Re: Bush Approves Cape York
            BRIGHT TIDINGS FOR THE FUTURE
       Re: Free Space Station - spacious but needs work
            Re: NASA's lobbying on the net
              Re: Big Rock Watch
              Galileo Update - 07/12/90

Administrivia:

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

Date: 12 Jul 90 13:28:16 GMT
From: eagle![e-mail]  (Dave McKissock)
Subject: Re: Free Space Station - Spacious but needs work

In <[e-mail]>,
[e-mail] (Vincent Cate) writes:

>Todays New York Times had an article about how the maintenance
>for the space station was going to be much higher than even the
>recent higher estimate.  There is so much work to do that the
>current design is out of the question.  The maintenance problems
>seem to be due to micrometeors, the extreme high/low temperatures,
>and radiation in general.


Mr. Cate needs to go back and re-read the article in the Times. Mr.
Broad reported in the article that
"In the 30-year history of the American space program,
astronauts have logged a total of 400 hours in space walks, which
are considered dangerous BECAUSE OF RADIATION RISKS AND POSSIBLE
INJURY OR DEATH FROM SPEEDING DEBRIS AND MICROMETORITES." (Emphasis
added by me).

The article is saying the problem with radiation &
micrometeoroid / debris is that it presents a danger to the astronaut
performing EVA to replace a failed Orbital Replacement Unit on
Freedom.

The majority of the article is discussing the problem of Freedom
maintenance. The fundamental problem is that estimates of EVA time
to replace failed ORUs is quite a bit larger than allocation for
EVA time. The Times article says NASA allocated 130 hours each year
to EVA. I don't know the source of that number, recent NASA allocations
were one EVA per week (so 52 per year), with each EVA involving two
crew members providing a nominal six hours of productive EVA time
per crew member. So 52 x 6 x 2 = 624 hours per year. The Times
article says Fisher-Price team prior estimates were 2,200 hours
of maintenance, and the final report (due next week) has 3,800
hours. Since the article says "NASA will have no official
comment on the report" until it is released, I guess
I'm not supposed to comment on the report at this time.

>The idea of using the external tank as a space station platform
>has been around for a long time (I first heard it at a talk at NASA
>Ames about 9 years ago).  Does anyone know why this idea (which seems
>so fantastic) has not been incorporated into the station design?

I also recall this idea being tossed around during Phase B of the
program. One bad thing about the idea is the problem of refurbishing
the tanks to be habitable on-orbit. This would talke alot of, guess
what, EVA TIME, which we are having a problem with in the first place.

I'm doing a little bit of apples/oranges mixing here. The EVA times
mentioned above (624 hrs per year allocated) are for the assembly
complete configuration (i.e. after finisning the assembly of the
Station, NASA allocates 624 hours per year to maintain the thing).
NASA is still in the process of addressing EVA time during the
assembly of Freedom. During assembly, there are two kinds of EVA:
Shuttle based EVA & Station based EVA. Shuttle based EVA is
used to put Freedom together, & change out failed ORUs before
Station based EVA is available.

The current design of the HAB/LAB modules requires zero EVA time
(I believe) for assembly. Just launch 'em in the Shuttle, use the
Shuttle arm to hand them off to the Station arm (being built by Henry
Spencer's friends up north), & plug them in place.
--
-----------------------------------------------------------------------
Dave McKissock              [e-mail]
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
NASA LeRC: Responsible for the remarkable & ingenious Space Station
           Freedom Electrical Power System
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Opinions expressed herein probably bear absolutely no resemblance to
the official NASA position.
-----------------------------------------------------------------------

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

Date: 12 Jul 90 17:39:47 GMT
From: mojo![e-mail]  (Doug Mohney)
Subject: Re: Bush Approves Cape York

In article <[e-mail]>, [e-mail] (Rev Phil Skinque, DD (Ret.)) writes:

>>I guess they wouldn't want to put up a com-sat or an observation sat (spy
>>sat just doesn't fit the Aussie frame of mind), huh?

>Other than that, we can always
>acquire elint from our allies the USA (whom you will recall have a
>number of satellite bases here).

Somehow, I don't think the U.S. would bend over backward to run a KH-11/12
mission in your part of the world unless it was REALLY needed. Most of the
coverage is (probably, but Henry will correct me, of course) in the Northern
Hemisphere.

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

Date: 12 Jul 90 15:29:04 GMT
From: swrinde!zaphod.mps.ohio-state.edu!rpi!crdgw1!gecrdvm1![e-mail]
Subject: BRIGHT TIDINGS FOR THE FUTURE


   BOY, WHAT A BUNCH OF PESSIMISTS YOU GUYS ARE:  HST IS DEAD!
NASA IS WASHED UP!  SHUTTLE IS TRASH THAT SHOULD BE JUNKED!
YOU READ LIKE A BAD SUPERMARKET TABLOID (WHICH I ADMIT HAS ITS
ENTERTAINMENT VALUE).  MAYBE IT'S JUST MY OPINION, BUT I DON'T
THINK ANY OF THE ABOVE ARE TRUE.  THEY ALL HAVE FLAWS, YES, BUT
DOWN AND OUT, NO.
  I'LL LEAVE THE HST ALONE, SINCE MANNED SPACE EXPORATION IS MY
BAG, AND I WOULDN'T WANT TO BS ABOUT SOMETHING WHICH I AM NOT
SOMEWHAT VERSED.

  NASA:  OVERSTAFFED BUREAUCRATS WHO CAN'T BRING ANYTHING IN ON
TIME, OR ON BUDGET.  EXAGERATED, BUT THERE MAY BE SOME TRUTH TO
THIS STATEMENT, BUT THEN, WHAT DO EXPECT FROM A GOVERNMENTAL
AGENCY CREATED WITH THE MOTTO 'WASTE ANYTHING BUT TIME' (TO GET US
TO THE MOON).  THE MAIN STATEMENT  IS NOTWHETHER NASA CAN DO
SOMETHING, BUT WHETHER THEY CAN DO IT WITHOUT WASTING TONS OF OUR
MONEY.  WHAT WE NEED, BESIDES A BIG CIVILIAN SPACE AGENCY TO GIVE
THEM SOME COMPETITION, IS A NEW FUNDING PROCESS SO THEY DON'T HAVE
TO OVERPROMISE IN ORDER TO SELL AN IDEA, SO THEY DON'T HAVE TO HEAP
MORE PROMISES ON IN ORDER TO SELL IT AGAIN WHEN A NEW CONGRESS OR
ADMINISTRATION ROLLS IN.  THE FUNDING PROCESS IS WHAT FORCES THEM TO
PROMISE GOLD, WHEN THEY ONLY HAVE LEAD.  THE OTHER PROBLEM, RELATED
TO THIS PR OVERSELL, IS US, THE CITIZENS OF THE USA (OR AT LEAST THOSE
OF US THAT LOOK UP FROM WATCHING BIG TIME WRESTLING LONG ENOUGH TO
CHECK OUT THE WORLD).  WE DEMAND SPECTACULAR SUCCESSES. DOING SOMETHING
IS NOT GOOD ENOUGH FOR US, WE NEED TO DO IT BIGGER, BETTER, ORDERS OF
MAGNITUDE ABOVE THE REST.  ANYTHING LESS IS FAILURE.  THUS NASA, IN
ORDER TO LOOK GOOD AND GET OUR APPROVAL AND OUR MONEY (INDIRECTLY,
OF COURSE), MUST GO FOR THE BLOCKBUSTER INSTEAD OF INCREMENTALLY
ADVANCING (WHICH BY THE WAY, IS HOW THE SOVIETS GOT TO WHERE THEY ARE-
SLOW AND STEADY WINS THE RACE).  WELL, THE BUBBLE HAS BURST, THE NEWS
IS OUT:  NASA HAS SOME PROBLEMS!  DOES THIS MEAN THEY ARE DEAD? NO!!
THEY ARE MERELY (OR SHOULD BE) IN THE SHOP FOR REPAIRS. THERE IS
PLENTY OF COMPETITION FOR THEM IN THE WORLD, AND IF THE USA WANTS
TO REMAIN COMPETITIVE IN MANNED SPACE (AND OF COURSE WE DO, OUR EGOS
WON'T ALLOW ANYTHING ELSE) THEY ARE GOING TO HAVE TO MAKE SOME COURSE
ADJUSTMENTS.  NOW THAT EVERYONE KNOWS THERE ARE PROBLEMS WE CAN
CORRECT THEM (AFTER ALL, HOW DO YOU KNOW YOU HAVE HEMORRHOIDS UNTIL
YOU FEEL THE ITCH).
  NOW, ON TO THE SHUTTLE.
    A LOT OF PEOPLE APPARENTLY THINK THAT THE SHUTTLE IS JUNK.  PERHAPS
IT COULD HAVE BEEN BUILT BETTER AND SMARTER, BUT TO SAY IT HAS NO USES
IS FOOLISH.  I SAY, FINISH UP LAUNCHING THOSE ITEMS CONFIGURED SPECIFI-
CALLY FOR THE SHUTTLE AND THEN ELIMINATE IT FOR THAT PURPOSE.  IF YOU
CAN SHIP SATELITES CHEAPER AND FASTER WITH EXPENDABLES THEN DO SO (BUT
FIRST PROVE THAT THIS IS FACT, NOT FANTASY PROMISES).  RESERVE THE
SHUTTLE FOR MANNED EXPERIMENTATION.  THINK OF IT AS A RE-USEABLE SPACE
STATION.  DO  THOSE ADD-ONS THAT WILL KEEP IT UP FOR A MONTH AND USE IT
MORE SPARINGLY (DRIVES COSTS UP PER FLIGHT, BUT THEN YOU'RE SAVING MONEY
BY LAUNCHING PAYLOADS ON EXPENDABLES).  FROM THE LOOKS OF IT, WE'RE NOT
GOING TO HAVE FREEDOM OR ANY OTHER SPACE STATION ANYTIME SOON, SO THE
SHUTTLE IS ALL YOU'VE GOT.  I DON'T THINK YOU CAN DO QUITE THE AMOUNT
OF WORK IN A CRAMPED CAPSULE THAT YOU CAN IN SPACELAB.
I THINK THE QUESTION NOW IS, WHERE DO WE GO FROM HERE?  I BELIEVE
EXPENDABLE CAPSULES IS A STEP BACKWARDS, AT LEAST UNTIL YOU GET A STATION
UP THERE, AND MAYBE EVEN THEN (BY THE BY, I DON'T THINK LIVERMORE IS
GOING TO PUT UP THEIR BLOW-UP STATION TOO QUICKLY EITHER, OR FOR AS
CHEAP AS THE 500 MIL FIGURE I HEAR BANDIED AROUND THIS NEWSGROUP).
I WOULD RATHER SEE A WHOLE NEW AVENUE TAKEN:  AN AIR LAUNCHED MANNED
PLANE BIGGER THAN PEGASUS/X-15 (ALONG THE LINES OF SAENGER BY MBB)
SERVICING A SMALL EXPANDABLE STATION.
   OR MAYBE WE CAN KEEP ON BICKERING AND THEN BEG A RIDE ON HERMES OR
HOPE.

THESE OPINIONS ARE MINE AND DO NOT REPRESENT ANYONE BUT ME.  THEY
ARE NOT INTENDED TO INSULT ANYONE.
                                 PETE

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

Date: 12 Jul 90 16:23:05 GMT
From: news-server.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Free Space Station - spacious but needs work

In article <[e-mail]> [e-mail] (Vincent Cate) writes:
>If external tanks were used as shells for the space station modules
>these problems would be solved.  The ET walls must be fairly
>thick because the fuel is rather heavy at launch (3 inches thick?).
>Thus the ET should do a good job of providing thermal insulation and
>protecting against radiation or micrometeors!

Nope, sorry, the ET walls are quite thin.  They have to be, or the thing
would be too heavy to fly.  They are thin enough that the folks looking
at converting one into an orbiting gamma-ray telescope figure they will
need to put some kind of outer "meteor bumper" shield around the ET or
it will be punctured fairly quickly by debris.  A contributing reason
for doing this is that it will keep the ET's sprayed-on insulation *in*;
apparently the stuff will "popcorn" in vacuum, worsening the space-debris
problem.

>While currently the external tank does not go into orbit it would
>actually take less fuel if they did put the external tank in orbit.
>They currently get to orbital speed and then do an extra maneuver to
>send the ET back down...

Sorry, not so, not any more.  They did that in the early days, but they
now use "direct ascent" trajectories that avoid this.  There is a cost
for getting the ET up.  A worse problem, actually, is keeping it up,
since it's a big light object and is badly affected by air drag.  You
have to do something with it quickly.

>The idea of using the external tank as a space station platform
>has been around for a long time (I first heard it at a talk at NASA
>Ames about 9 years ago).  Does anyone know why this idea (which seems
>so fantastic) has not been incorporated into the station design?

Partly because there are real problems with it; see above.  Partly
because NASA has a phobia of trying to do in-orbit assembly work, and
fitting tanks out as a station would take a lot of it.  Partly because
it carries just a tiny bit of risk, which NASA is averse to nowadays.

>PS  Maybe if lots of us call NASA and tell them about this idea
>    (like many votes) they will really think about it.

Save your breath; they *have* heard about it, and the "Outreach" program
is *not* a popularity poll.
--
NFS:  all the nice semantics of MSDOS, | Henry Spencer at U of Toronto Zoology
and its performance and security too.  |  [e-mail]   utzoo!henry

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

Date: 13 Jul 90 01:11:10 GMT
From: unmvax!nmt.edu![e-mail]  (Daniel Briggs)
Subject: Re: NASA's lobbying on the net

In article <[e-mail]>
   [e-mail] (Nicholas J. Szabo) writes:
>
>   Look, I am not trying to be a grinch here, I just want to point out...
>   [In spite of good intentions, he does a reasonable job of grinching.]

In article <[e-mail]>
    [e-mail] (Mary Shafer) writes:
>
>   Fine.  That's it, I'm out of here.

In article <[e-mail]>
    [e-mail] (Lee Mellinger) writes:
>
>   Although I don't post very often (NASA/JPL work to do you know), I
>   vote with Mary.  It's been nice (sometimes).

Whoa, people!  Let's not speak too hastily.  I'll admit, I have stayed
out of this one because I thought if I ignored it, the issue would
eventually go away.  Obviously, I was wrong.  I'd sure hate to see
anyone drop the group, just because of one *stupid* issue.

First, Nick: Will you please let this issue die?  In the interests of
group harmony, if for no other reason.  While I personally don't agree
with you, I'm not going to press my opinions into the fray here.  It
*isn't* worth the friction that it would cause!  Consider that the
issue is obvious contentious.  You are obviously not going to change
the mind of a significant number of NASA personel, yet you may well
hurt the feelings of many of them.  What good will that
accomplish?  The fact is, arguing about this issue is not going to
change a bloody thing, but will make a lot of people angry and
unhappy.  Like civilized people, let's just agree to disagree and
leave it at that.

Second, Mary & Lee & anyone else feeling a bit stepped on: You really
*are* wanted here.  I'm sorry that more of us with positive feelings
towards the NASA crowd didn't speak up sooner.  I know that *I* find
it very hard to speak about what I do without getting rather worked
up.  I can't see how anyone could possibly work at a place like NASA
and not feel at least somewhat the same.  I certainly don't feel like
I'm lobbying when I talk enthusiastically about some new telescope or
several that we are building.  Why should I make that assumption about
you?  I don't!  It's hard to ask someone to stick around, and put up
with inevitable and significant bashing of their employer.  But know
that if you do, it is effort that is greatly appreciated by many of
us!

Everyone: In a group like sci.space, it is easy to get lost in the
rivets and forget that there are *people* on the other side of the
postings.  It's just as important to remember the other guy when you
post here as it is when you post to something like alt.callahans.  We
just talk about different stuff here.  We are all in the group for
basically the same reason: love of space.  The only real differences
between us are that we don't agree how to get there.  That shouldn't
be a reason for bashing each other, should it?  Let's leave the flaming
on news.groups, where it belongs, OK?

--
This is a shared guest account, please send replies to
[e-mail] (Internet)
Dan Briggs / NRAO / P.O. Box O / Socorro, NM / 87801  (U.S. Snail)

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

Date: 12 Jul 90 14:36:25 GMT
From: thorin!homer![e-mail]  (Jonathan Leech)
Subject: Re: Big Rock Watch

In article <telnet.647782493@blackjack> [e-mail] (Michael Hart) writes:
>>It is going 22,000 mph relative to Earth, and as a WAG (+- 200%)
>>masses 13 million tons.   Such a collision with Earth would
>>release 1.5e17 (150 thousand trillion) calories of energy.
>Can anyone give an approximation of what would happen if a rock
>this size were to impact the earth, releasing the above mentioned
>amount of energy?

    About a 2.5km diameter crater, if I didn't drop any decimals (ref
Shoemaker, Ann.  Rev.  Earth & Planetary Science 1983, 11:461-94).
This one seems to be moving pretty slowly, which would be to our
advantage.
--
    Jon Leech ([e-mail])    __@/
    "Why do you suppose we only feel compelled to chase the ones who run away?"
    "Immaturity."
    _Dangerous Liasons_

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

Date: 12 Jul 90 16:48:00 GMT
From: swrinde!zaphod.mps.ohio-state.edu!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Galileo Update - 07/12/90


                     GALILEO MISSION STATUS
                          July 12, 1990

     The Galileo spacecraft is 87.7 million miles from Earth
(round-trip communication time 15 minutes 43 seconds) and 114.6
million miles from the Sun.  It has travelled 450 million miles
in space since launch last October 18, and its heliocentric speed
is now just over 52,000 mph.

     The flight team has developed and reviewed the design of
next week's trajectory correction maneuver.  It calls for 228
pulses using the axial thrusters (toward the Sun) and 160 lateral
pulses (at nearly a right angle to the Sun-line) for a total
velocity change of less than one meter per second (about 2 mph).
The command sequence will be sent to the spacecraft next Monday,
and the maneuver operation will begin about 11 a.m. (PDT)
Tuesday, July 17.

     Meanwhile, at the spacecraft, things are relatively quiet.
Routine science observations of the interplanetary environment
continue, with data readouts about every 4-5 days; there are also
regular scheduled engineering calibrations and system maintenance
activities.  Galileo's performance continues to be excellent.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

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

End of SPACE Digest V12 #58
*******************