Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v16_2/v16no231.txt

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Date: Sun, 28 Feb 93 05:00:07
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #231
To: Space Digest Readers
Precedence: bulk


Space Digest                Sun, 28 Feb 93       Volume 16 : Issue 231

Today's Topics:
                        Apollo Moon Missions ?
                  Beamed power transmission on Mars?
              Design Settlement on Mars, Beaming power..
                          Freedom refueling
                  Getting people into Space Program!
          How many RPM's around his own axle can human take?
           How to power the LEO-moon space bus :) (2 msgs)
                  Light Pollution GIF File Available
                    Opening up Space to everyone!
                           PEGASUS QUESTION
                          Refueling in orbit
                       Regulation Space Tosses
                    Spaceflight for under $1,000?
         Spy Sats (Was: Are Landsat Satellites receivable?)
       SSF Resupply (Was Re: Nobody cares about Fred?) (3 msgs)
                      Water resupply for SSF (?)
     X-15 astronauts (was Re: Getting people into Space Program!)

    Welcome to the Space Digest!!  Please send your messages to
    "[e-mail]", and (un)subscription requests of the form
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    (THENET), or [e-mail] (Internet).
----------------------------------------------------------------------

Date: 25 Feb 1993 01:23:36 GMT
From: Tim Thompson <[e-mail]>
Subject: Apollo Moon Missions ?
Newsgroups: sci.space

   I am ignorant, I admit it. My memory has failed. Can someone refresh my
tired brain cells, and tell me (us) which Apollo mission to the Moon was the
last one? There couldn't have been too many.

   Mille Mercis

---
------------------------------------------------------------
Timothy J. Thompson, Earth and Space Sciences Division, JPL.
Assistant Administrator, Division Science Computing Network.
Secretary, Los Angeles Astronomical Society.
Member, BOD, Mount Wilson Observatory Association.

INTERnet/BITnet:    [e-mail]
NSI/DECnet:         jplsc8::tim
SCREAMnet:          YO!! TIM!!
GPSnet:             118:10:22.85 W by 34:11:58.27 N

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

Date: Thu, 25 Feb 1993 02:46:19 GMT
From: Frank Crary <[e-mail]>
Subject: Beamed power transmission on Mars?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry A Worth) writes:
>   You could even vary flux to match activity. Transmitting at a higher
>flux when personnel are in shielded vehicles and on the move (just when
>you have highest demand! -- hey, microwave heated, hot gas blimps!, is the
>Martian atomosphere dense enough?)

Balloons are somewhat more difficult on Mars than on Earth, but they
are very feasible. There will be one on the Russian Mars 94 mission
(or so they say...)

                                                   Frank Crary
                                                   CU Boulder

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

Date: Thu, 25 Feb 1993 02:49:15 GMT
From: Frank Crary <[e-mail]>
Subject: Design Settlement on Mars, Beaming power..
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>This brings up an idea. We need to figure out how the settlement of Mars will
>look like and plan it out.. So that we will make sure that we use the info that
>we have learned about earth and plan for better.. Any ideas??

Historically, most settlers/colonists have been hostile to outside
planning: One of the primary motives is to avoid other people telling
them how to live...

                                                     Frank Crary
                                                     CU Boulder

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

Date: Thu, 25 Feb 1993 00:05:06 GMT
From: Josh Hopkins <[e-mail]>
Subject: Freedom refueling
Newsgroups: sci.space

Newbies take note:  Changing the name of an ancient thread to something that
remotely reflects its content wins you brownie points.

[e-mail] (Allen W. Sherzer) writes:

>>Again, it's not the lack of EVA, it's the fact that you don't want
>>hydrazine all over the EVA crew.

>But the Russians with their backward space program don't find that to
>be a problem. Surely with our better technology we could refuel them
>in orbit possible saving billions of $$ in life cycle cost.

Allen, could you (or perhaps Dennis Newkirk) post a description of just how the
Russians refuel Mir?  It's not imediately obvious to me that they do an EVA to
refuel.  I'm not saying they don't, I'd just like someone to actually explain
what they do before we all take it for granted.

>>|> Maybe we don't need tankage. Maybe we use fuel from the OMS.

>>I don't think the OMS are big enough to fuel both orbiter and SSF.

>Well then maybe they can be refueled with expendables. That will save
>even more money.

Freedom would have weighed roughly five times as much as shuttle and shuttle
needs its OMS fuel to get back home.  In light of this, I can't figure out what
your last comment means.

--
Josh Hopkins                                          [e-mail]

    You only live once.  But if you live it right, once is enough.
            In memoria, WDH

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

Date: Wed, 24 Feb 93 18:58:25 PST
From: Brian Stuart Thorn <[e-mail]>
Subject: Getting people into Space Program!
Newsgroups: sci.space

>>   There were 99 X-15 missions, far fewer that qualified as spaceflight.
>
>There were *199* X-15 missions....

   Oops, caught the typo too late. Sorry!


>---
>Dave Michelson                             University of British Columbia
>[e-mail]                                  Antenna Laboratory
>

-------------------------------------------------------------------------
                                     "Who knows... all this might just be
Brian S. Thorn                     an elaborate simulation running inside
[e-mail]        a little device sitting on someone's table."
                                      -Captain Picard, 'Ship in a Bottle'
-------------------------------------------------------------------------

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

Date: 24 Feb 93 15:54:51 GMT
From: Thomas Gee <[e-mail]>
Subject: How many RPM's around his own axle can human take?
Newsgroups: sci.space,sci.med

In article <[e-mail]> [e-mail] (Adam R. Brody ) writes:
>
>                   The g-levels are small because the moment arms
>are short.  The ear (otolith) senses accelerations, not velocity.
>Once velocity has been achieved, you do not sense the rotation,,,
>until you move your head!

Actually, I suspect it's a combination of the otoliths and the semi-circular
canals.  The semi-circular canals detect rotational acceleration, and the
otoliths detect linear acceleration.  Thus, as you are spun up to speed, you
are aware of the fact that you are rotating on your axis (rotational
acceleration).  Once you have achieved a constant speed (plus a couple of
moments for acclimitization), you lose that sense (provided your only cues
are vestibular).  However, up to this point, your otoliths are still only
detecting the downward force of gravity.  But, when you lean forward, out of
the axis of rotation, you get a strong stimulation of both the semi-circular
canals (because you have suddenly changed your rotational acceleration) and
from the otoliths (because the G vector has rotated and increased due to
increased moment arms).  That's when you get that lovely whirling and
tumbling sensation.

Tom
---
 Thomas Gee      \   altitude      \ Aerospace Physiology Software Development
 [e-mail] \   acceleration  \  DCIEM, CFB Toronto, North York, Ontario
                   \   automation    \   Department of National Defence/Canada

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

Date: Wed, 24 Feb 1993 22:50:58 GMT
From: Henry Spencer <[e-mail]>
Subject: How to power the LEO-moon space bus :)
Newsgroups: sci.space

In article <1993Feb24.005220.15641@bsu-ucs> [e-mail] (Craig Meyer) writes:
>Oxygen (and therefore LOX) looks easy enough.
>The only thing on my list from the World Book that looks "worth
>burning" is Aluminum.  Could it be burned quickly in some kind of powdered
>form?

People have talked quite a bit about LOX-aluminum rockets.  One problem is
that you really want hot *gases* in a rocket exhaust, and aluminum oxide
is a solid at any sane temperature.  The simplest way to get around this
is to run oxygen-rich, but that's a rather harsh environment and there
is little experience with such engines.  Also, the molecular weight of
oxygen is rather high for good performance.  Unfortunately, most all the
gases with lower molecular weight involve hydrogen.

Jordin Kare says that it looks like you could build a lunar laser launcher
using oxygen as propellant.  That might be a better bet.

>When it comes to frieght runs back and forth from LEO to the moon, NUCLEAR
>PROPULSION SYSTEMS look like the way to go.  A few Uranium spheres will take
>you a long way, along with a little hydrogen gas as a working fluid...

Unfortunately, it's more than a little hydrogen, at least with near-future
nuclear systems.
--
C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology
effect since OS/360.                    |  [e-mail]  utzoo!henry

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

Date: Thu, 25 Feb 1993 02:54:06 GMT
From: Frank Crary <[e-mail]>
Subject: How to power the LEO-moon space bus : )
Newsgroups: sci.space

In article <1993Feb24.005220.15641@bsu-ucs> [e-mail] (Craig Meyer) writes:
>"Moon rocks consist chiefly of minerals containing aluminum, calcium, iron,
>magnesium, oxygen, silicon, and titanium.  Hydrogen, helium, and other gases
>are trapped in some of the rocks."

>I've been wondering if, along with building materials, some sort of propellant
>could be extracted from moon dirt.

>Oxygen (and therefore LOX) looks easy enough.
>The only thing on my list from the World Book that looks "worth
>burning" is Aluminum.  Could it be burned quickly in some kind of powdered
>form?

It requires a little bit of work, but oxygen and aluminum are the primary
components in solid rocket fuels.

>When it comes to frieght runs back and forth from LEO to the moon, NUCLEAR
>PROPULSION SYSTEMS look like the way to go.  A few Uranium spheres will take
>you a long way, along with a little hydrogen gas as a working fluid.  As long
>as the thing never came back to earth, radiation wouldn't be nearly as
>much of a problem.

Given the elements available on the surface, oxygen might be a better
option: The specific impulse would drop to 25% of a hydrogen fueled
nuclear thremal rocket, and nasty corrosion problems might crop up,
but refueling on the Lunar surface would be very easy.

                                             Frank Crary
                                             CU Boulder

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

Date: Wed, 24 Feb 1993 22:15:13 GMT
From: Larry Klaes <[e-mail]>
Subject: Light Pollution GIF File Available
Newsgroups: sci.astro,sci.space,sci.misc,sci.environment

        Light pollution in our urban areas has taken away the beauty
    and knowledge of the night sky from many people around the world.
    Improved forms of reduced lighting can solve this problem, while
    still keeping our cities and towns properly lit and saving energy.

        To illustrate the severity of this problem, Geoff Dudley of
    the Astronomical Society of Victoria Light Pollution Subcommittee
    has sent me an uuencoded GIF file of the light pollution over the
    city of Melbourne, Victoria, Australia in early 1991.  I have been
    given permission to offer the image to anyone who is interested.
    Please E-Mail me for a copy.  My net address is below.

        MELBSKY.GIF is an image of Melbourne taken on a moonless evening
    in February of 1991 by ASV member Dr. Tom Richards from his home at
    midnight.  The clouds were at a height of about 4,000 meters (12,000
    feet).  Tom heads the artificial intelligence lab at Latrobe University.

        For more information on the ASV, contact Geoff Dudley at:

        Astronomical Society of Victoria
        Light Pollution Subcommittee
        G.P.O. Box 1059J
        Melbourne 3001
        Australia

        E-Mail addresses:

        [e-mail]
        [e-mail]


        Larry Klaes  [e-mail]
             or - ...!decwrl!verga.enet.dec.com!klaes
                 or - [e-mail]
                     or - [e-mail]

             "All the Universe, or nothing!" - H. G. Wells

        EJASA Editor, Astronomical Society of the Atlantic

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

Date: Thu, 25 Feb 1993 01:18:01 GMT
From: [e-mail]
Subject: Opening up Space to everyone!
Newsgroups: sci.space

: In article <[e-mail]> [e-mail] (Marvin Batty) writes:
: >... Why no disabled people in space? If payload weight is all
: >important, and legs (for instance) are not terribly useful in a low-grav
: >environment...

Henry Spencer ([e-mail]) replied:
: The idea that legs are not terribly useful in free fall is one of those
: superficially-plausible ideas suggested in science fiction that turned
: out to be false.  They're quite important as anchors even though they
: don't get much use as supports.

Besides, legs are particularly useful in almost every launch abort
scenario.  We must plan for off-nominal activities.

-- Ken Jenks, NASA/JSC/GM2, Space Shuttle Program Office
      [e-mail]  [phone]

     "The earth is the cradle of humanity, but mankind will not stay in
     the cradle forever." -- Konstantin Tsiolkvosky

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

Date: Wed, 24 Feb 1993 22:40:27 GMT
From: Henry Spencer <[e-mail]>
Subject: PEGASUS QUESTION
Newsgroups: sci.space

In article <ofVuzca00WB=[e-mail]> Lawrence Curcio <[e-mail]> writes:
>...very minor nit ... Initial velocity isn't *entirely* irrelevant to
>stability in a system that isn't aerodynamically stabilized. A faster
>rocket will be less affected by atmospheric turbulence, whether or not
>it uses fins/wings. Velocity vectors normal to the direction of motion
>are proportionately smaller in a faster rocket...

However, if you're reaching the same final velocity, they have the same
significance to the final result.  The only thing an initial velocity
buys you, in terms of the final results, is the possibility that whatever
supplies the initial velocity may do it more accurately than your rocket
would.
--
C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology
effect since OS/360.                    |  [e-mail]  utzoo!henry

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

Date: Wed, 24 Feb 1993 22:44:53 GMT
From: Henry Spencer <[e-mail]>
Subject: Refueling in orbit
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Brian Stuart Thorn) writes:
>>The Centaur which could have benefitted from on-orbit refueling
>>never had a test program to achieve this mission...
>
>    Centaur is an application, but how many payloads would require
>    this application? Just one: Galileo...

Why do you assume that there will never be another use for it?  I'm
sure the Cassini people, to take one example, would love to be able to
go direct to Saturn rather than batting around the inner solar system
for a while first.  And I expect the Pluto Fast Flyby people wouldn't
mind some extra delta-vee either.

That doesn't even consider potential missions that aren't even being
*planned* because they appear to be impractical within the limitations
of current boosters.
--
C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology
effect since OS/360.                    |  [e-mail]  utzoo!henry

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

Date: Thu, 25 Feb 1993 00:48:18 GMT
From: [e-mail]
Subject: Regulation Space Tosses
Newsgroups: sci.space,sci.space.shuttle

Brian A.Laxson ([e-mail]) wrote:
: Does anyone know what/where to find any regulations that exist for
: astronauts passing objects around in space?  Do they just avoid doing it
: as much as possible?

I don't think there are any Flight Rules about "passing objects
around," either EVA or IVA.  If you really want to check, you might try
to get a copy of the Flight Rules.  They are available to U.S. citizens
via the Freedom of Information Act.  Contact NASA/JSC's Public Affairs
Office through the switchboard at [phone].  (However, your
e-mail address indicates that you are Canadian.  You might be out of
luck.  If you REALLY get stuck, let me know, and I'll have my secretary
paper-mail you a copy.)

There is no reason to "avoid doing it as much as possible."  Passing
objects around in space is part of the normal teamwork which happens on
every manned space flight.  Perhaps I'm not understanding your
question.

-- Ken Jenks, NASA/JSC/GM2, Space Shuttle Program Office
      [e-mail]  [phone]

     Aldrin: "Contact light.  Okay, engine stop.  ACA out of detent."
     Armstrong: "Got it."
     Aldrin: "Mode controls, both auto.  Descent engine command override,
       off.  Engine arm off...."
     CAPCOM: "We copy you down, Eagle."
     Armstrong: "Houston, Tranquility Base here.  The Eagle has landed."

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

Date: Wed, 24 Feb 1993 22:58:48 GMT
From: Henry Spencer <[e-mail]>
Subject: Spaceflight for under $1,000?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Marvin Batty) writes:
>If, therefore, a company got together for the sole purpose of building
>and launching one rocket, presumably the costs would be considerably smaller.
>But does anyone have an idea what would be the minimum cost of putting one
>man in orbit? Presumably the main costs are launchpad, fuel, lifesupport
>and rocket.

If you're fairly optimistic, you might assume launch costs as low as $500/kg.
That's still awfully expensive.  Reductions far beyond that are possible
in principle, but there is no proof that they can be achieved in practice.
There are some fairly major technical challenges involved in achieving
those potential cost reductions.  It's not something you're likely to
manage in your basement.

Remember that good technical people cost you circa $1000/person/week even
if you don't pay them terribly well.

>I heard somewhere that the latest Space Shuttle has five computers
>which combined have less memory than a good PC. Is this really true?

Yes, but those computers and that memory will survive conditions which
would turn your PC into a paperweight.  When you can't get home without
them, you're a bit fussier about computer quality than the MSDOS crowd
usually is.
--
C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology
effect since OS/360.                    |  [e-mail]  utzoo!henry

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

Date: Tue, 23 Feb 1993 21:18:56 +0000
From: Paul Wilson <[e-mail]>
Subject: Spy Sats (Was: Are Landsat Satellites receivable?)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>In article <[e-mail]> [e-mail]
> (Roland Dobbins)  writes:
>>KH-11 is neither the latest nor the greatest "real-time" platform up there.
>
>The ADVANCED KH-11 is... we currently have 2-3 of them up.
>
>OR, are you talking about Lacrosse or Aurora?

I understood that the KH-12 was the major enhancement of the KH-11 in
terms of visible-light imaging (it also carries IR sensors),  and is
used to produce high-resolution pictures.  Lacrosse uses side-scan radar,
and is a very different beast indeed.

BTW,  only a single KH-12 is in orbit at any one time (remember the fuss
when both the Titan and the Shuttle were grounded at the same time,  and
the US didn't have launch capacity to replace the KH-12 which was running
low on manoeuvering fuel?).

------------------------------< Who 'zat? >------------------------------
    Paul Wilson, P-and-S Ltd, P O Box 54, Macclesfield, SK10 5EH, UK
     [Email: [e-mail]]  [Phone: +44 (0) 625 - 503150]
-------------------------------------------------------------------------

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

Date: 24 Feb 1993 16:55 CST
From: [e-mail]
Subject: SSF Resupply (Was Re: Nobody cares about Fred?)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Allen W. Sherzer) writes...
>In article <[e-mail]> [e-mail] writes:
>
>
>>>And if the Shuttle is grounded and the station is forced into
>>>free-drift for lack of replacement thruster modules (which is the same
>>>thing as saying that it ran out of fuel), then where are you?
>
>>What about Titan IV ?
>
>Well I would prefer either Atlas or maybe a Titan III. that would
>save you about $100 million.

Perferable yes, but is there a 14 '' in diameter faring for the above? Maybe
for Titan III but not for Atlas.

>
>But then I forget: the only way to replace the thrusters is with
>Shuttle. NASA designed it so that it can't be done with expendables.
>

No what you forget is that all you need is a faring with the proper diameter.
Titan IV has a Shuttle class payload faring and can carry most payloads that
Shuttle can, although as you point out, not much cheaper.  Kinda shoots your
HLV cost savings idea down for large payloads don't it.

>Now if we bought the Russian docking technology and made a lot of
>modifications we could.
>

Could what? You still have to get the weight up there. You would still have
to completely redesign the system for on orbit refueling. Since you have
this wonderful Shuttle capacity for returning large payloads why not use it?
It is called cutting down on dead head miles in trucker parlance. But I forget
you have said that there is no market for this capability.

>>In addition, it is my understanding that the primary reason for the
>>Fuel on SSF is not for attitude control but for reboost. Now certainly
>>they could live without reboost for a few months or even a year or two.
>
>A few months yes but not a year. About 180 days after missing a firing
>(and there is one every Shuttle flight) it will re-enter.
>

Care to put up any numbers on this? With an altitude of 270 nautical miles, and
the fact that Mir, which has nearly the same frontal area needs reboost less
than the interval that you state, suggests otherwise.

>>Quit making mountains out of molehills. Just because you have not thought
>>of the solution or you have not read it in Space News or seen it on
>>Usnet does not mean that contingencies do not exist.
>
>apparently it also means they may not exist.
>
>  Allen
>

I am truly glad that you put the "may" in there. This suggests that you may
at least think there is a possiblility that everyone in NASA are not flaming
idiots who only think about their paychecks.  An interesting thing about
paycheck philosophy here. NASA budget under this assumption is based upont the
fact that the more they do successfully, the more money they get to do more.
Does this not suggest that from pure self preservation alone, they would want
to do a good job?

Dennis, University of Alabama in Huntsville

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

Date: Thu, 25 Feb 1993 02:27:55 GMT
From: Frank Crary <[e-mail]>
Subject: SSF Resupply (Was Re: Nobody cares about Fred?)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>>But then I forget: the only way to replace the thrusters is with
>>Shuttle. NASA designed it so that it can't be done with expendables.

>No what you forget is that all you need is a faring with the proper diameter.
>Titan IV has a Shuttle class payload faring and can carry most payloads that
>Shuttle can, although as you point out, not much cheaper.  Kinda shoots your
>HLV cost savings idea down for large payloads don't it.

I think the point was, NASA didn't have to design the thrusters in
this way. They could have made the system servicable from a different
launch vehicle. The only driving need for a large diameter system
seems to be giving the Shuttle a job...

>>Now if we bought the Russian docking technology and made a lot of
>>modifications we could.

>Could what? You still have to get the weight up there.

However, you would no longer need a 14' wide payload, nor would
you have to launch the supplies in high mass packages (i.e. you
would have the flexability of several smaller launches.)

>...You would still have
>to completely redesign the system for on orbit refueling.

Perhaps that should have been done from the start.

>...Since you have
>this wonderful Shuttle capacity for returning large payloads why not use it?

Because you shouldn't count on that Shuttle capacity. The Shuttle
isn't exactly famous for keeping schedules reliably, nor is it
immune to long down times. Worse, the station's design lifetime
is 30 years. I don't think anyone seriously thinks the Suhttles
will still be flying in 2025. Their expected lifetime, at the
current launch rates, is expected to last no later than 2010.
Since the resupply of the station is dependent on the Shuttle,
how will it be resupplied after 2010? If the station is expected
to remain on orbit, there can't be more that a year or so delay
before a new Shuttle replacement is flying. Given the delays in
the Shuttle's first flight, I don't think that's very realistic.
There isn't anything wrong with using the Shuttle's orbit-to-Earth
payload capability, but there is a problem with being absolutely
dependenton it.

>>A few months yes but not a year. About 180 days after missing a firing
>>(and there is one every Shuttle flight) it will re-enter.

>Care to put up any numbers on this? With an altitude of 270 nautical miles, and
>the fact that Mir, which has nearly the same frontal area needs reboost less
>than the interval that you state, suggests otherwise.

Last time I checked, 200 not 270 nm was the operational altitude of
Freedom. Also, as I recall, Mir reboosts every month or so as a
general rule. Freedom would require replacement of its station keeping
motors after 180 days of normal operations. However, there are
things that can be done, in extreme emergency, to increase this:
Using all available fuel to boot to a high orbit, and putting
the solar arrays into a minimum drag cross section pointing would
extend the station's life to a year or two without resupply. However,
that would have very serious consequences: A roughly fifty percent
reduction in power (is that even enough to keep life support and
housekeeping running?) and the station would be inaccessable to
the Shuttle until it's orbit had decayed (I'm not a ACRV could
make an emergency crew return from such a higher orbit, either.)

                                                  Frank Crary
                                                  CU Boulder

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

Date: Thu, 25 Feb 1993 02:35:55 GMT
From: Frank Crary <[e-mail]>
Subject: SSF Resupply (Was Re: Nobody cares about Fred?)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (tomas o munoz 283-4072) writes:
>There are a couple of problems to this recommendation:
>Titans can't deliver/retrieve humans if the scenario occurs during
>permanent manned operations [although the ACRV is already there].

A Titan IV should be able to deliver an extra ACRV. I also don't
see why you couldn't put a few people in that extra ACRV, and
thereby both deliver and retrieve humans.

>How do you perform the actual payload transfer from the expendable
>to the SSF if the SSF is unmanned? - You really need IVA for this
>operation.

Which sort of unmanned: After MTC, you just need to get people to
the station, and there are only a few launches (low risk) before
MTC.

>This is true at almost any place along SSF assembly.  In the PMC
>phase, you have the ability to fully feather the PV arrays and have
>orbital lifetime ranging up to ~1.5 years.

At the price of almost complete (complete? What exactly do you
mean by "fully" feather?) loss of power.

                                               Frank Crary
                                               CU Boulder

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

Date: Wed, 24 Feb 1993 22:46:16 GMT
From: Henry Spencer <[e-mail]>
Subject: Water resupply for SSF (?)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (BAIRD) writes:
>....Everyone is complaining about the cost of the space station's resupply
>through the shuttle or HOPE or Hermes.  WHy not just NOT use these vehiciles?
>I have heard of a number of proposals to drag ice from the outer system and
>refine it in orbit or get it from the asteriod belt.  Using a set of robotic
>systems, using either electric propulsion(EP) or light sails(LS), in conjunction
>with a few robotic mining platforms shouldn't it be feasible to resupply the
>space station using either the belt or the outer planets' moons?

Someday.  Not today.  This is *far* beyond what can be done with current
robotic systems.
--
C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology
effect since OS/360.                    |  [e-mail]  utzoo!henry

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

Date: 24 Feb 1993 23:29:57 GMT
From: CLAUDIO OLIVEIRA EGALON <[e-mail]>
Subject: X-15 astronauts (was Re: Getting people into Space Program!)
Newsgroups: sci.space

There were 199 flights of the X-15. Among those, 13 flights were flown above the
atmosphere or beyond the limit where we today call space (which is 80 km). The
guys who flew above this limit were

1. Bob White (USAF) (once)
2.  Joe Walker (NASA) (three times)
3.  Bob Rushworth (USAF) (once)
4. Joe Engle (USAF) (three times)
5. John McKay (NASA) (once)
6. Bill Dana (NASA) (twice)
7. Bill Knight (USAF) (once) and
8. Michael Adams (USAF) (once)

Michael Adams was killed during the flight that  he  got to go over 80 km and the X-
15 that he was flying (the number 3) was desintegrated. The "Astronaut Wings"
were awarded ONLY to the USAF pilots so the civilian guys did not qualify. But,
according to Thomas Wolf (The Right Stuff), Joe Walker was indeed awarded the
"ASStronaut Wing".

The Proceedings of the X-15 First Flight 30th Anniversary Celebration and the book
X-Planes by Jay Miller, have a table sumarizing all X-15 flights as well as their pilots
dates, altitude etc...

[e-mail]

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End of Space Digest Volume 16 : Issue 231
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