Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_6/V16NO618.TXT

Internet Message Format | 1993-07-13 | 32KB

Date: Mon, 24 May 93 05:05:35
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #618
To: Space Digest Readers
Precedence: bulk


Space Digest                Mon, 24 May 93       Volume 16 : Issue 618

Today's Topics:
                      About the mercury program
                           Adaptive Optics
             Boeing TSTO concept (sort-of long) (2 msgs)
        ELEVEN G-forces during atmospheric reentry??? (3 msgs)
               Hey Philly! Re: Why Government? (2 msgs)
             Hey Sherz! (For real!) Cost of LEO (3 msgs)
                          Moon Base (2 msgs)
                    Post Doctoral Position at NASA
                    Soyuz and Shuttle Comparisons
               Why Government? Re: Shuttle, "Centoxin"

    Welcome to the Space Digest!!  Please send your messages to
    "[e-mail]", and (un)subscription requests of the form
    "Subscribe Space <your name>" to one of these addresses: listserv@uga
    (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle
    (THENET), or [e-mail] (Internet).
----------------------------------------------------------------------

Date: Mon, 24 May 1993 00:40:13 GMT
From: Leigh Palmer <[e-mail]>
Subject: About the mercury program
Newsgroups: sci.space

In article <[e-mail]> Gary Coffman,
[e-mail] writes:
>I think it's wrong to blame the astronaut for this failure, at least not
>totally. Instead the PI screwed up in mechanical design. A look at his
>3 year old's Jack in the Box would have showed him how to make a box with
>a hand crank that even the clumsiest little vandal couldn't easily break.

A real apologist for the astronaut!

Do you suppose he broke the handle in rehearsal? Is it possible he didn't
rehearse? Would it have been wise for him to have rehearsed?

Leigh

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

Date: Sun, 23 May 1993 18:48:27 GMT
From: Frank Crary <[e-mail]>
Subject: Adaptive Optics
Newsgroups: sci.space,sci.astro

In article <Bob_Hearn-180593110809@192.35.50.165> [e-mail] (Robert Hearn) writes:
>> Instead of using natural reference stars, could lasers be used
>> by scattering the beam off of the sodium layer in the upper
>> atmosphere, etc. , to act as an artifical reference star?

>I thought that was how professional adaptive optics systems worked.
>Could someone familiar with the techniques please post a general
>description of them?

They usually switch to a bright, near-by reference star (usually by
moving the secondary mirror very slightly...), calculate
the corrections necessary to resolve the reference as a point, then
switch back to the dim object to be observed. For the near IR
the reference star has to be re-observed and the corrections re-calculated
at least every tenth of a second. As you move to shorter wavelengths
more frequent cycling is required and therefore the reference star
has to be closer to the observed object. At some point this falls
apart, since you can't count on finding a sufficiently bright reference
star within (say) ten or twenty arc seconds of whatever you want
to observe.

Artificial guide stars let you create a reference where ever you like.
Unfortunately, for large telescopes, the artificial reference is
relatively close to the telescope (i.e. not in the far-field) and
the required calculations become more difficult...

>There's actually an adaptive optics system available to amateurs: the
>AO-2.  It steals half the light going to the eyepiece with a beam-
>splitter, and adjusts the angle of a lens or prism to keep the
>brightness equal in all four quadrants, thus keeping the image of
>a planet or bright star centered.  Doesn't work for deep-sky objects,
>though.  Also, I get the impression that it doesn't really correct for
>atmoshpheric turbulence, just telescope instability.

It doesn't correct for blurring due to turbulance, but if you have really
poor seeing, the large-scale turbulance can also move the image around.
However, for the big, professional telescopes this isn't a very usefull
technique: They generally have very good seeing...

                                                       Frank Crary
                                                       CU Boulder

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

Date: Sun, 23 May 1993 22:23:24 GMT
From: Henry Spencer <[e-mail]>
Subject: Boeing TSTO concept (sort-of long)
Newsgroups: sci.space

In article <1to6bu$[e-mail]> [e-mail] (Pat) writes:
>>... a better trick:  inject liquid hydrogen (I think
>>it was) into the bypass ducts of the regular 747 engines, and burn it...
>
>I guess that makes Nitrous injection look pale :-)  How would this
>differ from a conventional afterburner? ...

The main difference is that the air stream in question has not gone through
the engine core; this is its only exposure to fuel.  The boundaries are
admittedly rather fuzzy, since there are afterburning turbofans that use
both the core flow and the duct flow in their afterburners (although they
generally have rather low bypass ratios, hence are a different sort of
animal).

>If they seriously boost thrust,  did they have to rre-design
>the thrust pylons?

I'd expect so, but I didn't see technical details.
--
SVR4 resembles a high-speed collision   | Henry Spencer @ U of Toronto Zoology
between SVR3 and SunOS.    - Dick Dunn  |  [e-mail]  utzoo!henry

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

Date: Sun, 23 May 1993 22:25:57 GMT
From: Henry Spencer <[e-mail]>
Subject: Boeing TSTO concept (sort-of long)
Newsgroups: sci.space

In article <1to6kj$[e-mail]> [e-mail] (Pat) writes:
>|The B-58 wasn't capable of Mach 3 even in a dash, and neither the SR-71
>|nor the X-15 was made of aluminum...
>
>How about the XB-70?

The XB-70 forward fuselage was titanium, and the main body and wing were
stainless-steel honeycomb (an excellent material, but fearfully expensive
to make and use -- the two XB-70s cost their weight in gold).
--
SVR4 resembles a high-speed collision   | Henry Spencer @ U of Toronto Zoology
between SVR3 and SunOS.    - Dick Dunn  |  [e-mail]  utzoo!henry

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

Date: 23 May 1993 20:01:28 GMT
From: Claudio Oliveira Egalon <[e-mail]>
Subject: ELEVEN G-forces during atmospheric reentry???
Newsgroups: sci.space

A friend of mine has written that  Gus Grinson, during his
suborbital flight of the Mercury program, was subjected to
acelerations from 0 to ELEVEN g's, within 32 seconds,  when
he was reentring the atmosphere!!! Although I can not recall
the phisiological tolerance to g-forces 11 g's seems darn too
 high for me. Most likely it is well above the value that
anyone can tolerate. So my questions are:

1) What is the g interval that a human being can tolerate and

2) What was the maximum acceleration that a Mercury
astronaut was subjected to.

[e-mail]

Claudio Oliveira Egalon

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

Date: Sun, 23 May 1993 22:58:15 GMT
From: Henry Spencer <[e-mail]>
Subject: ELEVEN G-forces during atmospheric reentry???
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Claudio Oliveira Egalon) writes:
>A friend of mine has written that  Gus Grinson, during his
>suborbital flight of the Mercury program, was subjected to
>acelerations from 0 to ELEVEN g's, within 32 seconds,  when
>he was reentring the atmosphere!!!

Yup.  The suborbital trajectories of the Mercury-Redstone flights involved
rather higher decelerations than the orbital flights, because the capsule
entered thicker atmosphere sooner.  Ham took 14.7G, and both Shepard and
Grissom took nearly 12.  The Mercury seat design was tested to 20, in a
centrifuge, by Carter Collins.

(Although the Mercury, and later, orbital flights generally involved no
more than 6-7G on reentry, some classes of mid-launch aborts could have
involved rather higher decelerations.)

>1) What is the g interval that a human being can tolerate and

It depends on duration, direction, support, training, etc.  Also on whether
it is necessary for the human to continue functioning and/or stay conscious
during the acceleration.  "Bioastronautics Data Book" (NASA SP-3006) has
a number of graphs showing various possibilities.  Notably, if you're
willing to pick a good case -- highly-motivated test pilots with major
high-G experience, on their backs, well supported -- then two minutes
at 14G is neither dangerous nor incapacitating.

With extreme measures (water immersion), over 30G is tolerable for maybe
fifteen seconds.

And we're still talking about what people will *voluntarily tolerate*,
as opposed to surviving in a life-threatening emergency... although in
fact the numbers above are pushing close to the "probable injury" levels,
so accelerations much beyond these are dangerous.

(Impact accelerations -- endured for only a fraction of a second -- are
a very different story, with much higher limits.  The limit of survival
for impact is circa 175-200G.)
--
SVR4 resembles a high-speed collision   | Henry Spencer @ U of Toronto Zoology
between SVR3 and SunOS.    - Dick Dunn  |  [e-mail]  utzoo!henry

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

Date: Mon, 24 May 1993 02:38:32 GMT
From: Dave Michelson <[e-mail]>
Subject: ELEVEN G-forces during atmospheric reentry???
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>>A friend of mine has written that  Gus Grinson, during his
>>suborbital flight of the Mercury program, was subjected to
>>acelerations from 0 to ELEVEN g's, within 32 seconds,  when
>>he was reentring the atmosphere!!!
>
>Yup.  The suborbital trajectories of the Mercury-Redstone flights involved
>rather higher decelerations than the orbital flights, because the capsule
>entered thicker atmosphere sooner.  Ham took 14.7G, and both Shepard and
>Grissom took nearly 12.  The Mercury seat design was tested to 20, in a
>centrifuge, by Carter Collins.
>
>(Although the Mercury, and later, orbital flights generally involved no
>more than 6-7G on reentry, some classes of mid-launch aborts could have
>involved rather higher decelerations.)

During the Soyuz 18-A abort in April 1975, Lazarev and Makarov pulled
about 15 g's.  Since the flight lasted 21 minutes and 27 seconds, the
Soviets now hold the record for the longest suborbital mission flown.

--
Dave Michelson  --  [e-mail]  --  University of British Columbia

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

Date: Sun, 23 May 1993 16:41:46 GMT
From: "Phil G. Fraering" <[e-mail]>
Subject: Hey Philly! Re: Why Government?
Newsgroups: sci.space,talk.politics.space

[e-mail] (Ken Hayashida) writes:

>[e-mail] (Phil G. Fraering) writes:

>I had originally posted:
>>>BTW, I'm not republican (as someone seemed to infer).  I'm a conservative
>>>democrat.  Don't misconstrue my arguments, I'm for space shuttle because
>>>its the most sophisticated and best example of American technology in the
>>>air-space field.

>Philly wrote:
>>Tell a lie often enough, and maybe someone will beleive it...

>I hope you aren't calling me a liar, but then again you probably would
>resort to name-calling instead of focusing on issues.   This only
>shows how weak your arguments are.

Uh, no.

Let me put it this way: the shuttle, as a system, is composed
of subsystems: the propulsion system, thermal protection system,
life support system (including power), guidance system... any
major systems that I've missed?

I will now jot down the sub-subsystems, prior to listing the
"lineage" and technological development in each of them.

Propulsion system: three subsystems here: solid rocket boosters,
SSME's, and OMS/RMS system.

Thermal protection system: tiles and thermal blankets

Guidance systems: no subsystems here...

life support: LiOH cartriges, food, toilet, fuel cells (for power
and water).

Okay, now the detailed criticism:

1. Propulsion:

   A. Solid Rocket Boosters: these aren't really advanced technology.
      They are a simple scale-up of the segmented boosters used on
      the Titan well before the Shuttle came along. The fact that they
      are segmented, along with their high vibration loads, would be
      proof that they shouldn't be used further in any advanced launch
      system.

      i. The Titan III was once considered for use as a manned booster,
         but the vibration caused by the SRB's was considered to be
         counterproductive to man-rating.

         (Hey, anyone have a source for this? I remember reading it
          somewhere...)

     ii. The nature of the segmented boosters is such that they are
         not only expensive to build and/or refurbish, but they remain
         of dubious safety. They have caused the only loss of life and
         orbiter to date (unless you want to count the Enterprise, but
         that's another story where I have heard conflicting stories from
         people I trust. Maybe someday I'll ask Mary Shafer about it).
         And NASA's safety inspection procedures haven't improved much
         since then, if you believe the story about the pliers.

    iii. Attempts to "fix" the SRB's with a new design are turning out
         to be of such expense that it is surviving on pure pork-barrel
         momentum. The ASRM (sort of a contradiction in terms) will
         allow, after some 12 years of operation, the STS system to
         finally carry its design payload, but only if in the case
         of an emergency landing you plan to rebuild the orbiter or
         write it off, because it's over the max recommended safe
         landing weight.

   B. Space Shuttle Main Engines: in _"What do *You* Care What Other
      People Think?"_ (book titles should be underlined, but said title
      already includes an underline and quotes, so it looks awkward)
      by Richard Feynmann, in the chapter "Fantastic Figures." A lot
      of the criticisms of the shuttle program in that book unfortunately
      still seem to be relevant. Like the pliers, which according to the
      signatures of three separate people, had been removed.

      Perhaps more relevant is the fact that of launcher designs currently
      being proposed, they are either not using the SSME or are using
      a derivative with greatly downgraded performance in the hope that
      it will be reliable.

   C. OMS/RCS system: It just works. But aside from slightly better
      electronics, there's nothing really different about this than
      the one on the Service Module... other than the different
      thruster configuration needed to accomodate the aerodynamics of
      the shuttle. While it's a good workhorse system, it isn't very
      advanced compared to the Hubble's attitude control system.

      Perhaps this is a good lesson: the "least advanced" system is
      giving Yeoman sevice...

2. Guidance systems: these were just upgraded; hardware considered by
   NASA as being "cleared" for space use are usually much less powerful
   or up-to-date than those in other fields, or many computers flying in
   space right now (I think the Hubble has more advanced computers; its
   guidance needs, though, are much more demanding).

3. Life support:

   A. The LiOH cartridges are I believe much the same (except for minor
      improvements) as those used in Apollo, and different from those
      planned for the station. (At one point they were going to use
      something really advanced for the station, but they backed down;
      maybe this'll change in the redesign process _or_ after they get
      a couple modules up and find out it doesn't take hundreds of
      millions of dollars to install a couple lab racks with recycling
      equipment).

   B. Food: I don't think this is much different from Skylab food.

   C. Toilet: same design as Skylab, except more costly and less reliable.

   D. Fuel cells: these don't really do much that the Apollo ones didn't,
      except for the need to provide power to control the aerodynamic
      surfaces on the way down. They have _no_ relevance to the future needs
      of space exploration because they're just an expendable short-time-
      period power source. If the shuttle had good solar cells, that would
      be a different story; but since it's meant to be a launcher and not
      a station, this is beginning to get ridiculous.

I will now procede to the rest of Ken's article.

>I had written:
>>>shuttle is the best piece of hardware we've got.  If shuttle haters get
>>>their way, we'll be out of the manned space business for the rest of the
>>>century.  boy (smirk), that'd be a great legacy wouldn't that?
>>>Back to the days of 1976-1979 when skylab fell and shuttle couldn't fly.
>>>Carter administration II...hope not!

>>We're out of the manned space exploration business now; have been since
>>1973. Where the hell were you?


>Gee, need I write more folks? I must've hit pretty close to home or
>something...

No, I'd just like to point out that the last lunar mission that
the U.S. has launched, and the last manned space exploration mission,
was launched on Dec. 7, 1972. (I guess I was wrong about 1973).
Since then, we've just been screwing around in Low Earth Orbit.

Maybe this is grounds for letting December 7 reclaim the title of "day
of infamy" from November 7.

You did cut close to the bone about manned exploration there, because it
does cause me great pain that we haven't done anything for so long.

> have a nice day philly.

Try writing a long reply at 1200 baud in emacs that the original poster
won't read and see how fun your day gets. But don't worry, dear, I'll
try to have a nice day anyway. The least you could do to help is to read
and re-read this post all the way through a couple times. It was tedious
to write.

And the next time you go home to visit your Ma, try making a side trip
up to the Keck telescope and look at it for a while.

And also look at the pricetag while you're at it.

Can you think of any single shuttle mission that's provided as much science
return as the Keck is likely to?

(Yes, I'm comparing apples and oranges, but when oranges cost a hundred
times as much as apples, you learn to make do with apples and the occasional
pinch of lemon juice for vitamin C).

I wrote that to impress on you the difficulty I've had trying to convince
people much smarter than me about the validity of the space program itself.
The Shuttle program has apparently convinced them that there's really nothing
there.

I'm sure you're a nice, interesting boy, but you don't know how absurd
some of your arguments have sounded. Such as the one where the shuttle is
a better system than others because it used _more_ manpower than other
alternative systems. This is close to the inverse of the definition of
efficiency in engineering (although I may have to bring Dan Stephenson in
on this argument before I'm through).

That's all I have to say for now, but if I have to say it again I may
just repost this again.

Unless you can really answer the points outlined above. Which you
haven't yet.

Later,

Phil

--

+-----------------------+---------------------------------------+
|Phil Fraering          | "...drag them, kicking and screaming, |
|[e-mail] | into the Century of the Fruitbat."    |
+-----------------------+-Terry Pratchett, _Reaper Man_---------+

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

Date: Sun, 23 May 1993 18:38:27 GMT
From: "Phil G. Fraering" <[e-mail]>
Subject: Hey Philly! Re: Why Government?
Newsgroups: sci.space,talk.politics.space

And I forgot to comment on the thermal protection system. Part of the
pitfalls of the narrow window I'm looking through as I'm writing this.

Anyway, most if not all currently proposed launch systems that
have a return element don't rely on shuttle technology for their
thermal protection. Although the HL-20 might use it...

(I'd like to comment that although it seems to be a dead end,
the tile system on the Shuttle has given the least problem of
any of its components, even though Sixty Minutes was running
reports that the tiles were all going to unzip upon re-entry or
something like that).



--

+-----------------------+---------------------------------------+
|Phil Fraering          | "...drag them, kicking and screaming, |
|[e-mail] | into the Century of the Fruitbat."    |
+-----------------------+-Terry Pratchett, _Reaper Man_---------+

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

Date: 23 May 1993 14:42:56 -0400
From: Pat <[e-mail]>
Subject: Hey Sherz! (For real!) Cost of LEO
Newsgroups: sci.space

Ken, you are mixing  your measures, for cargo.

For the saturn,  the point was to deliver the S-IV,  the CSM/LM
to stable orbit.

Look at the skylab mission.  THe S-V,  delivered the WOrkshop
to Stable  High ORbit.  Other proposed Apollo applications
were to deliver Large quantities of stuff to orbit.

In the SHuttle,  you can only count,  the Payload Cargo,  and the MidDeck,
flight compartment mass  plus the RObot Arm, as delivered Payload.

If you want count abou;t 10 % of the Orbiter weight as useful
payload to orbit.   THe return system, is not useful orbital payload.

Now in Shuttle C,  the entire Canister payload is working cargo,
or in the SSF option C baseline,  the worksop is cargo.

For a return system,  it's not.   Think of it as a semi-trailer.
the trailer is canister,  the Cargo is weight,  the tractor is
necessary to get from A to B.  If you intend to climb steep terrain,
you need a much different  tractor, but the useful payload is
still just the cargo delivered.

Look at a train, or a ship.    If a ship has to cross a shallow harbor,
it can only carry a reduced cargo.  No matter if it's a ULCC, if it can only
draft 27 feet,  that's the useful cargo delivered.

Look at a shuttle TDRSS mission,  sevarl million pounds at the pad,
go to putting appx 2 K lbs to GEO.  that's the delivered useful
cargo.   Or in LEO terms, it's a TDRSS and a PAM?

A Delta will meet that same cargo lift.

pat

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

Date: 23 May 1993 14:54:06 -0400
From: Pat <[e-mail]>
Subject: Hey Sherz! (For real!) Cost of LEO
Newsgroups: sci.space

>In article <1tn3f7$[e-mail]> [e-mail] (Ken Hayashida) writes:
>>(although some still refuse to acknowledge
>>the feats performed by the shuttle).

Ken

    I know a guy who's so flexible he claims he can auto-fellate
himself.  Now while this is a truly amazing feat,  I don't see
how relevant it is.   Many of the things you point out as
Amazing are essentially technical side shows.  The Main Event is
still the Three ring circus.  What we need is Rapid, Reliable,
Economical Medium lift to LEO.

And for all the money the SHuttle has eaten,  we have lost
capcbility.  Where is the money for Basic High speed Research?
Advanced Suit Technology?  Closed Cyucle Life SUpport?
Methane fuel production?  Advanced Propulsion?  Engineering
Qualification programs?   Relative to the money spent, the
catalog of Space QUalified hardware is pathetic.

Your'e a doctor.  How would you feel if NIH and the Entire
Bio-medical establishment with all the research and commercial
dollars poured in,  only delivered 1 new procedure a year,
and one new drug,  and that procedure costs more then the
old procedure and is more dangerous, and the drug is
more expensive,  and you have to request an ampoule
6 months in advance?

pat

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

Date: Sun, 23 May 1993 21:05:49 GMT
From: Josh Hopkins <[e-mail]>
Subject: Hey Sherz! (For real!) Cost of LEO
Newsgroups: sci.space

[e-mail] (Ken Hayashida) writes:

>My calculation was:
>>>STS/shuttle mass to orbit:
>>>Mass of the orbiter plus payload in the bay.

>Allen sez:
>>The mass of the orbiter is a pointless thing to consider. A launcher which
>>lifted a million pounds to LEO but only one ounce of payload would win
>>your contest but would be a pretty useless operational launcher.
>...
>>The only figures of merit are capability and cost.

>I agree that capability and cost are important.  but, I disagree with
>your methodology.
...
>If I really wanted to limit the discussion to payload, I could
>have counted the Command Module as the ultimate payload of the Saturn V!
>Clearly that is incorrect. so, the basis of my decision to include the
>orbiter's mass in the mass to LEO calculation is based on inclusion of the
>total mass injected into orbit by the launch system in question.

What I believe you should be trying to measure is payload.
This has nothing to do with the mass of the vehicle.  A one million pound
experimental SSTO with no payload would, under your accounting scheme,
have a huge mass to orbit and a huge mass returned.  It would not, however,
be any use to anyone.

In addition, to do an accurate calculation of the type you are considering is
going to be very complex.  Many ELVs leave an upper stage in orbit, often
partially fueled.  To calculated the total mass thrown into space you are going
to need to track down lots of numbers.

>The S-V vehicle put up the whole S-IV-B stage plus the LEM-CSM-escape tower.

The escape tower was ejected a little more than three minutes after launch. It
cannot be considered payload to orbit.

>If all of those pieces are gonna get talleyed into the S-V mass to orbit
>figure, why shouldn't the orbiter's mass be talleyed in to LEO calc?

The question is slightly complicated by the fact that the S-IVB stage was fired
to finish orbit insertion, but was also used to leave orbit.  If you want
payload capability, I would use the mass of Skylab.  If you want actual mass
inserted into orbit, you are going to have a very messy calculation on your
hands, as you will need to take into account part of the mass of the S-IVB
stage and different masses of the lunar vehicles.

--
Josh Hopkins                                          [e-mail]
    "This Universe never did make sense; I suspect it was built on
              government contract."
                -RAH

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

Date: Sun, 23 May 1993 21:25:24 GMT
From: Nick Janow <[e-mail]>
Subject: Moon Base
Newsgroups: sci.space

[e-mail] (Henry Spencer) writes:

> The main reason for going back to the Moon is to start a sustained program
> of space exploration.

Well, that supports the case for an aluminum-oxygen extraction plant on the
moon.  It supports further projects, and the officials who approved it would
try to encourage use of it, to justify their decision.  :)

The R&D in automation/remote-operation would be applicable to civilian use on
Earth too.  It could greatly increase industrial productivity.

--

[e-mail]

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

Date: Mon, 24 May 1993 00:00:36 GMT
From: Nick Janow <[e-mail]>
Subject: Moon Base
Newsgroups: sci.space

[e-mail] (Gary Coffman) writes:

> I've been on the other side of this with Nick, but comets and Earth
> crossing asteroids may offer much higher commercial rewards. And open space
> offers commercial potential for communications, manufacturing, and perhaps
> even power. What's Luna offer? Maybe He3, some light metals and oxygen
> buried in yet another gravity well. Not very appealing.

The moon offers easily available metal and oxygen ores and a gravitational
field, and is nearby (short communication times and within manned reach).  It
would probably be cheaper and easier to develop a resource extraction
facility there than to develop zero-g facilities for extracting water from
near-Earth asteroids.

The technology and facilities developed with a lunar base project would
greatly reduce the cost of developing open-space projects.  It would be a
more gradual development; technology in small steps, rather than one risky
leap.

A mining company would probably choose a lower-grade ore body in a temperate,
developed area rather than a higher-grade one in Antarctica, where they'd
face new problems (redesigning equipment for extreme cold) and the hassle of
time delays (no FedEx overnight delivery).  For similar reasons, I do think
that although asteroids will eventually be a cheaper source of resources than
the moon, they would not be at this time. Lunar bases don't make economic or
> scientific sense, and they aren't *necessary* stepping stones to the more
> interesting targets.

They aren't *necessary*, but they could make economic and scientific sense.
Studying "dead bones" provides a lot of critical information for studying
living animals.  Without the study of fossilized remains, scientists might
still be studying existing life forms from an incorrect perspective.
Likewise, studying the "fossilized bones of the solar system" (the moon),
might provide useful insights into processes on Io, Venus, etc.  BTW, can you
provide a list of "interesting" targets in a list that everyone can agree on?
:)


To put it simply, the moon project might be feasible to get money for.  The
asteroid one--needing more money and requiring more new technology--might not
be.

--

[e-mail]

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

Date: 23 May 1993 20:24:19 GMT
From: Claudio Oliveira Egalon <[e-mail]>
Subject: Post Doctoral Position at NASA
Newsgroups: sci.space

> on the possiblity of an overseas post-doc position at NASA
> (or other US  space related research centre).

That is not the first or second time that such a question comes
along... Shouldn't  we write a FAQ about that???

The National Ressearch Council, NRC,  has  a Post-Doc
fellowship that you can use at any NASA Center as well as
many other companies and, I guess, even Universities. Try
contacting the NASA Center that you are interested to work
 for they have all the information that you need to apply for
this Post-Doc fellowship. Non-citizens are require to come
to work under a "J" VISA, but if you already have a green-card
(which is no longer "green" but "pink"), you do not have to
worry about that...

[e-mail]

Claudio Oliveira Egalon

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

Date: 21 May 93  13:43:00
From: [e-mail]
Subject: Soyuz and Shuttle Comparisons
Newsgroups: sci.space

In your message you stated that:

 The Soyuz-TM spacecraft is lifted into orbit by PROTON, which
has some fairly impressive heavy-lift capabilities. The PROTON
was used to loft the MIR main core module, which weighed 21
tons, the KVANT 1, KVANT 2, and KRISTAL modules into orbit.

Here are the specs:

First Stage
      Engine                  RD-253
      Propellants             Nitrogen Tetroxide/UDMH
      Thrust                  167 tons

Actually, the Soyuz TM is launched by a rocket called the Soyuz rocket. The
Proton is about three times more powerful than the Soyuz rocket, and was
originally used to launch a satellite called the Proton.

BTW, the Rd-253 engines were uprated to 178 tons of thrust about 10 years
ago.....

--- Maximus 2.01wb

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

Date: 23 May 1993 23:04:02 GMT
From: Timothy Banks <[e-mail]>
Subject: Why Government? Re: Shuttle, "Centoxin"
Newsgroups: sci.space,talk.politics.space

In article <1tiqpo$[e-mail]> [e-mail] (Pat) writes:
>
>New Zealand, Australia,  and the Philippines did not pay for
>their defense either,  but their economies are in the  S***TEr.
>

    Pat - go read a history book, will you? The above statement
    betrays terrible ignorance....and is insulting to the many
    who died. A little bit of current affairs might be nice too.





--
  Timothy Banks, Physics Department, Victoria University of Wellington, NZ.
       bankst@kauri|rata|matai.vuw.ac.nz, [e-mail].
    "He's dead, Jim!" "OK, you take the tricorder, I'll take the wallet!"

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

End of Space Digest Volume 16 : Issue 618
------------------------------