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Subject: SPACE Digest V13 #561

SPACE Digest                                     Volume 13 : Issue 561

Today's Topics:
              Re: Why the space station?
      Re: 14 Astronauts have died for space exploration?
             Re: LIGO (was Re: IT'S OVER)
     University of Surrey Satellite Engineering Division
              Re: Why the space station?
          Re: SPACE STATION FREEDOM WOUNDED
             Re: Space Station Cancelled

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
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Date: 15 May 91 12:10:43 GMT
From: dog.ee.lbl.gov!hellgate.utah.edu!caen![e-mail]  (Ken Sheppardson)
Subject: Re: Why the space station?

[e-mail] (George William Herbert) writes:
>[e-mail] (Ken Sheppardson) writes:
>
>>If I understand you correctly, you're saying that we should design a space
>>station that looks like Mir because it would take X Titan launches instead
>>of Y shuttle launches, right? I suppose I can't argue with you there. If
>
>        There are vaild reasons to question the whole truss-layout concept,
>number one being still-unanswered (as far as I've seen in trade press)
>questions about the repair EVA efforts.

  I agree with you 100%. I think very few folks in NASA wouldn't.

>        Another problem with Freedom is the 'station per pound' tradeoff.
>We're going to fly 17 shuttle missions to lift and assemble Freedom, and at
>25 tons each this is about 425 tons-equivalent to orbit.  If instead we
>were to build it in a plug-cans-together manner (no truss, etc) we could
>very likely get the same capability for a lot less weight to orbit.  I.E.
>5 to 10 Titan launches (100-200 tons).  This is the approach that MIR was
>built under.

  That 'same capability' question is important. Hold that thought.

>        Freedom's design concept just hasn't been demonstrated to be
>effecient.

  And just how would you have us go about proving the 'efficiency' of a
  design? What are your criteria?

>If we're not planning to put microgravity experiments on it and
>if we can't afford to expand it then there's no need for the truss, which is
>going to cost us how much?

  I'll have to look it up. Considering they haven't yet sized the PIT
  members, I'm not sure exact costs are available.

>Can we build/resupply/refurbish lunar or martian
>transver vehicles with Freedom? yes.  Can we do it with a can-based Mir-oid
>station? yes.  Which would be cheaper?  Probably not Freedom.

  Is that just a gut feeling or do you have numbers? We certainly don't.

>
>[If someone in the Freedom team would like to change my mind, please do.
>Source material that indicates Freedom will be more effecient than possible
>alternatives would be particularly appreciated, if it exists.]

  'Efficiency' has very little to do with it. Let's get back to that point
  you raised about Mir having the 'same capabililty' as Freedom.

  Let my pose a purely hypothetical situation to you. You're designing a
  space station. It's over budget. You're asked to 're-st...' er... I
  mean 'descope' your station to fit budget constraints. You're given the
  following set of requirements.

     1) Reduce cost
     2) Use existing designs wherever possible
     3) DO NOT reduce available power
     4) fully utilize all hardware you launch (i.e. don't launch any
        unused capability)

  The existing designs call for sun tracking photovoltaic arrays placed out
  on the ends of long booms to provide clearance for them to rotate 360 deg
  and to reduce/eliminate shadowing. Alright, now propose a configuration
  which meets the above requirements. I challenge you to come up with a
  configuration which doesn't put the PV arrays out on the ends of long
  booms where they can fully track the sun.

  Now let's say we wantet our station to look at an existing station,
  oh, say, Mir. Mir has PVs sticking out all over the place from (almost)
  every module. I believe the PV arrays have at most one degree of freedom
  each. Not only can the arrays not track the sun 100%, but the layout of the
  modules causes severe shadowing problems. Mir therefore violates
  Requirement #4 as stated above.

  Of course, if this where a real-life situation, you'd have non-technical
  issues to deal with, but as I said, this is only a HYPOTHETICAL situation.

===============================================================================
 Ken Sheppardson                                  Email: [e-mail]
 Space Station Freedom Advanced Programs Office   Phone: [phone]
 NASA Langley Research Center, Hampton VA         FAX:   [phone]
===============================================================================

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

Date: 15 May 91 14:05:23 GMT
From: prism!mailer.cc.fsu.edu!geomag![e-mail]  (Joe Cain)
Subject: Re: 14 Astronauts have died for space exploration?

In article <Added.sc=[e-mail]> [e-mail] (Bob Rehak Ext. 3-9437, AIS Central Services  -  Swen Parson 146) writes:
>>
>>
>>The Astronauts Memorial, honoring the 14 U.S. astronauts who
>>have given their lives in the exploration of space, will be unveiled
>
>14 astronauts?  Last time I counted there were only 10.
>
>Could someone correct me on this and tell me who the other 4
>were who died for space exploration...?
>
My wife and I attended the dedication and will add from the handout
the additional information in it:

Roger Chaffe, Ed White, Gus Grissom: Jan 27, 1967 flash fire in O2
atmosphere during countdown simulation

Greg Jarvis, Christa McAuliffe, Ron McNair, Ellison Onizuka, Judith
Resnik, Dick Scobee, Michael Smith: STS 51L 1 min 13 sec after launch
at 11:38:00 EST Jan 28, 1986

Charles Bassett and Elliot See: Feb 28, 1966 during an instrument
landing approach at McDonnell Aircraft plant in St. Louis

Theodore Freeman: October 31, 1964 on landing attempt in T-38 at
Ellington AFB near Houston

Cliff Williams, Jr. : T-38 accident on October 5, 1967.

In addition to the above 14, a name is to be added for Sonny Carter,
Jr. who was killed April 5, 1991 in a plane crash while on official
travel for NASA. He was to be a mission specialist on STS-42
(International Microgravity Lab)

    The program included a 50 State Flag team, Walt Disney chorus
(not bad), A Navy Band, and remarks by a number of VIPs including
Richard Truly with some subtle comments welcoming the vice President.
Mr. Quayle understandably stuck precisely to his script even including
the erroneous comment about the last Shuttle landing at Edwards
(better be safe than sorry!). I understand that Carter would have
participated in the T-38 flyover if he had not been killed.  All in
all, an impressive and moving ceremony.  I would recommend a stop at
the memorial if you happen to be at the Cape and is worth a quick
sidetrip from Orlando if you want to escape from Disney for
a while.


Joseph Cain        [e-mail]
[e-mail]        scri::cain

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

Date: 15 May 91 16:34:49 GMT
From: swrinde!zaphod.mps.ohio-state.edu!cis.ohio-state.edu!pacific.mps.ohio-state.edu!linac!unixhub!slacvm![e-mail]  (Jon J Thaler)
Subject: Re: LIGO (was Re: IT'S OVER)

In article <[e-mail]>, [e-mail] says:
>
>
>One thought that occured to me is that since there is no natural "resonance"
>to a LIGO arm, that a laser beam 6 million miles long will be no more
>efficient that a laser arm 1 mile long if the gravity waves being detected
>are only a few meters in length. I throught that a better design would entail
>the laser beams re-intersecting the SAME region of space/time multiple times
>to increase the apprent effect.

A wavelength of a few meters corresponds (just as with radio waves) to a
frequency of a hundred megaHertz, or so.  No GW sources are expected to
radiate at this frequency.  The current crop of interferometers are
planned to be sensitive to the 10-1000 Hz regime.  They do plan to bounce
the light back and forth many times to amplify the effect, as mentioned
above.  The reason for proposing to go into space is to be able to see very
*LOW* frequency gravitational radiation.  The noise level on Earth is
intractable at 1E-3 to 1E-5 Hz, where GR produced during the big bang
becomes important.

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

Date: Wed, 15 May 91 13:55:22 EST
From: Somers_PW <@BITNET.CC.CMU.EDU:[e-mail]>
Subject: University of Surrey Satellite Engineering Division

   Could someone provide an E-mail address of the University
of Surrey Satellite Engineering Division?  Thanks.

[e-mail]

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

Date: 15 May 91 20:24:32 GMT
From: agate!lightning.Berkeley.EDU![e-mail]  (Frank Crary)
Subject: Re: Why the space station?

In article <[e-mail]> [e-mail] (Ken Sheppardson) writes:
> [e-mail] writes:
>>        Freedom's design concept just hasn't been demonstrated to be
>>effecient.
>
>  And just how would you have us go about proving the 'efficiency' of a
>  design? What are your criteria?
>
I would suggest the following:

 1: manpower efficience: ratio of man-hours of available (e.g. non-
    mantainance and support) time to total man-hours of work available

 2: Operational cost: dollar cost of sppplying the station per year.
    (Note, this is only valid for compairing stations of equal capabitity)

 3: Gracefull failure modes: Can the station operate if something goes
    wrong? This includes, for example a grounding of the shuttle should
    annother accident occur.

 4: Construction costs: dollars to build and fly the station. (Like #2,
    this is only valid for stations of equal capibility.)

 Given these criteria, Freedom is "inefficient" because:

 1: At 400 man-hours of EVA/year (This is a figure I heard the head of
    the station program say maintanance could be "keep down to".) for
    maintanance, and assuming that 6 hours of EVA every other day is a
    full time job (based on Soviet experience and the US experience of
    Astronauts needing a day off after EVAs, which are very tiring.)
    Freedom will require at least 0.37 crewmen for EVA maintanance
    alone. Interior such work will probabibly (a guess) account for the
    remaining 0.63 crewman. As such Freedom's "manpower efficiency" will
    be 0.75 (with four crewmen). This could be better.

 2: The station will be supplied by the space shuttle. Assuming only
    two filghts/year. (assuming a 6 month tour on-orbit.) While I
    don't have cost numbers handy, two shuttle flights boils down to
    <50 tonnes and 8 passengers (the 4-man crew twice). This load
    could be met with expendable vehicles (four should do it) and a
    capsule-type manned craft (say derived from the Assured Crew Return
    Vehicle which is being designed for the station.)

 3: Failure modes: Since the shuttle may suffer a two or greater year
    grounding during the station's lifetime, and since the station will
    be up until 2027 (30 year lifetime starting in 1997 ) and since the
    shuttle will not be around after, say 2010... The station's lack of
    an alternate supply vehicle is a serious weakness.

 4: Construction costs: 17 shuttle filghts is VERY expensive, and somewhat
    risky (at 97.5% reliability, there is a 35% chance of a shuttle
    accident during construction.) While no other designs of similar
    capability exist currently, I feel such a station could be built
    more cheaply. In any case, I am sure that Freedom could be redesigned
    to be partially launched on less expensive expendable launchers.
    (The shuttle would still be needed for manpower during construction,
    but not 17 flights worth.)


>>Can we build/resupply/refurbish lunar or martian
>>transver vehicles with Freedom? yes.  Can we do it with a can-based Mir-oid
>>station? yes.  Which would be cheaper?  Probably not Freedom.
>
>  Is that just a gut feeling or do you have numbers? We certainly don't.
>
I think there is a misunderstanding here. If I understood your earlier
post, the work you are doing at Langley assumes, as a baseline, the NASA
90 day study for the type and scope of on-orbit construction required.
However, this is not necessarily the work needed to "build/resupply/
refurbish lunar or martian transfer vehicles." There have been LOTS
of manned Mars archetectures suggested that require very much less on-orbit
construction. A Mir-type station might not be able to support NASA's
Moon/Mars construction requirements, but it could easily support a
plausable Lunar base or Mars mission of a different design.

>  oh, say, Mir. Mir has PVs sticking out all over the place from (almost)
>  every module. I believe the PV arrays have at most one degree of freedom
>  each. Not only can the arrays not track the sun 100%, but the layout of the
>  modules causes severe shadowing problems. Mir therefore violates
>  Requirement #4 as stated above.

Correct, Mir's pannels have only one degree of freedom, and are often in
the shadow of other pannels or station modules.

While I agree that a station redesign should use as much of the old, money
already spent on it, hardware as is possible, there is a limit. If using
existing systems does not solve the problem (e.g. your design does not
meet whatever requirement called for a redesign) then the use of existing
systems is going to far. (A redesign that changed nothing would make total
use of existing hardware, but would not be much of a redesign.)
Further, There is a diference between using existing hardware and using
existing designs. The solar pannels are existing hardware. Mounting them
on a pivoted truss so that they have greater freedom of motion (or th
need for this freedom of motion) are part of the old DESIGN. In a redesign
the existing HARDWARE should be used, not the existing design and/or
existing design philosophy.

                    Frank Crary
                    UC Berkeley

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

Date: 16 May 91 00:33:38 GMT
From: agate!bionet!uwm.edu!zaphod.mps.ohio-state.edu!mips!news.cs.indiana.edu!widener!hela![e-mail]  (Allen W. Sherzer)
Subject: Re: SPACE STATION FREEDOM WOUNDED

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

>>... They zeroed out ALL station funding...
>>
>>looks like the space science people who lobbied had an effect.

>Sigh, the politics of envy...  They're dreaming if they think it will have
>more than a momentary effect on their own financial problems.

But they will get the short term monetary benifit. I agree however, that
its a pity the space science people don't support the creation of a better
infrastructure. I can't think of anything which do more to promote science
that the reduced costs we would see.

The next step however, is to turn this into an advantage. If Freedom
is killed we need to push for a real station. This would be a good time
to tell your Congresscritters about projects like the Commercially
Developed Space Facility or ideas from the SSI External Tank Study.
Push to get them funded.

If Freedom survives we need to make sure that this puts the 'fear of
God' into the program managers. The worst possible result would be
for the Senate to approve funding and have some survive in Conference.
That way Freedom would die a slow and painful death.

This vote is a good thing for space. The Freedom station just wasn't
panning out. It was getting smaller and smaller with no reductions in
cost.

   Allen

--
+---------------------------------------------------------------------------+
|Allen W. Sherzer |        Allen's tactics are too tricky to deal with      |
|   [e-mail]   |             -- Harel Barzilai                           |
+---------------------------------------------------------------------------+

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

Date: 16 May 91 00:39:41 GMT
From: pacbell.com!iggy.GW.Vitalink.COM!widener!hela![e-mail]  (Allen W. Sherzer)
Subject: Re: Space Station Cancelled

In article <[e-mail]> [e-mail] (Jim Bowery) writes:
>The VA, HUD and Independent Agencies Subcommittee of the House
>Appropriations Committee canceled Space Station Freedom

They didn't cancel it, they zeroed out the funding. It won't be
cancled until the full house and Senate agrees. This was a bit of
a suprise move for the house and it's likely the Senate will
move to restore funding. This could be the worst possible scenario:
low level funding so it limps on for years without dying or
building anything. The Senate markup will be critical.

  Allen

--
+---------------------------------------------------------------------------+
|Allen W. Sherzer |        Allen's tactics are too tricky to deal with      |
|   [e-mail]   |             -- Harel Barzilai                           |
+---------------------------------------------------------------------------+

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End of SPACE Digest V13 #561
*******************