Date: Thu,  3 Dec 92 05:40:46    
From: Space Digest maintainer <digests@isu.isunet.edu>
Reply-To: Space-request@isu.isunet.edu
Subject: Space Digest V15 #497
To: Space Digest Readers
Precedence: bulk


Space Digest                Thu,  3 Dec 92       Volume 15 : Issue 497

Today's Topics:
                             Autorotation
                       figuring comet's orbits
          NASA lawn ornaments (was Re: Shuttle replacement)
                         physiology in zero-G
                         Shuttle replacement
                  Space probe to pass Earth (2 msgs)
                             swift finder
           Terminal Velocity of DCX? (was Re: Shuttle ...)
            What is the SSTO enabling technology? (2 msgs)

	Welcome to the Space Digest!!  Please send your messages to
	"space@isu.isunet.edu", 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 space-REQUEST@isu.isunet.edu (Internet).
----------------------------------------------------------------------

Date: 3 Dec 92 00:05:53 GMT
From: Ian Ameline <ameline@vnet.ibm.com>
Subject: Autorotation
Newsgroups: sci.space

In article <BynG3r.1sp.2@cs.cmu.edu>,
lindsay+@cs.cmu.edu (Donald Lindsay) writes:
>
>>In that case, there must be an awful lot of ghosts walking around.
>>Every helicopter pilot is requried to practice and demonstrate
>>autorotation in order to get his license.
>
>Hah. It works nicely under certain well-known circumstances, and
>the practice is carefully done in just such circumstances.
>
>In real life, the pilot doesn't get to choose when his problem will
>occur. For example, helicopters which spend a lot of flight time
>lifting construction materials (towers and such) are unlikely to be
>able to autorotate.
>--
>Don		D.C.Lindsay	Carnegie Mellon Computer Science
>

   Don, I take it you're a pilot? Or an aeronautical engineer? You're
speaking with such certainty that it might help if we knew what
experience you have with aeronautical activities that would justify
that certainty. As a pilot, I'm always interested in learning from the
experiences of others.

Regards,
Ian Ameline,

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

Date: 3 Dec 92 00:52:58 GMT
From: Earl W Phillips <ephillip@magnus.acs.ohio-state.edu>
Subject: figuring comet's orbits
Newsgroups: sci.space,sci.astro

Can anyone give me the equations necessary to
determine a comet's orbit, given the necessary
parameters readily available in S&T, here on
the net, etc?

*****************************************************************
*                                    | ====@====      ///////// *
* ephillip@magnus.ircc.ohio-state.edu|     ``________//         *
*                                    |       `------'           *
*                 -JR-               | Space;........the final  *
*                                    | frontier...............  *
*****************************************************************

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

Date: 3 Dec 92 00:54:42 GMT
From: gawne@stsci.edu
Subject: NASA lawn ornaments (was Re: Shuttle replacement)
Newsgroups: sci.space.shuttle,sci.space

In article <1992Dec2.015805.4724@nuchat.sccsi.com>, 
rkolker@nuchat.sccsi.com (Rich Kolker) writes:
 
> I checked this out a while back.  The Apollo 19 Saturn is at KSC, the Apollo
> 20 Saturn is at JSC (I could check out the actual SV designations in Starges
> to Saturn, but you get the idea).  The Saturn V at MSFC is the Engineering
> test model, not a flight article.

Think of all the pink plastic flamingos they could have bought instead.

Those Saturn V's do look nice out there on the lawn, but I'd sure prefer
to have seen them _fly_.  I still get thrills watching old films of Apollo
launches.  Nothing like watching the engines light up at T-6 and just BURN.

Oh well, nice to know my country once had a lunar exploration capability.
Now we get LEO, ...with feeling.  (As Arlo Guthrie said in Alice's Resturant)
And Saturn V lawn ornaments.

-Bill Gawne,  Space Telescope Science Institute

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

Date: Thu, 3 Dec 92 01:55:01 EST
From: John Roberts <roberts@cmr.ncsl.nist.gov>
Subject: physiology in zero-G

Caution: the following is somewhat explicit, but not enough to drool over.
Readers outside the discussion might consider not reading further. Magnus
was upset about my post, so I thought it merited further explanation, which
is *slightly* relevant to space.

-From: magnus@planck.thep.lu.se (Magnus Olsson)
-Subject: Re: physiology in zero-G
-Date: 1 Dec 92 10:05:35 GMT
-Organization: Dept. of Theoretical Physics, Lund University, Sweden

-In article <ByKI34.4FG.1@cs.cmu.edu> roberts@cmr.ncsl.nist.gov (John Roberts) writes:
->>From: magnus@thep.lu.se (Magnus Olsson)
->Newsgroups: sci.space
->Date: 29 Nov 92 23:17:18 GMT
->Organization: Theoretical Physics, Lund University, Sweden

->-[General discourse on why it's a good idea to wear clothing while operating
->-a blender or a circular saw.]

-John, if you're going to flame someone (albeit flippantly),

That's an important "albeit" - I didn't intend it as a flame.

- you should at
-least observe the common courtesy of getting your attributions right, and not

-deliberately distort what people say. 

OK, in the interest of no distortion, here are the two previous postings
on the topic under the name Magnus Olsson, exactly as they appeared:
----- beginning of message 1 -------
|Path: cam!dove!uunet!sun-barr!cs.utexas.edu!zaphod.mps.ohio-state.edu!cis.ohio-state.edu!news.sei.cmu.edu!fs7.ece.cmu.edu!crabapple.srv.cs.cmu.edu!thep_t@garbo.sunet.se
|From: thep_t@garbo.sunet.se (MAGNUS OLSSON)
|Newsgroups: sci.space
|Subject: Breasts in zero-g
|Message-ID: <Bxwr4s.AJ5.1@cs.cmu.edu>
|Date: 18 Nov 92 10:38:20 GMT
|Sender: news+@cs.cmu.edu
|Distribution: sci
|Organization: [via International Space University]
|Lines: 7
|Approved: bboard-news_gateway
|X-Added: Forwarded by Space Digest
|Original-Sender: isu@VACATION.VENARI.CS.CMU.EDU


|I know this may sound like a weird kind of question, but we were discussing
|a comment in an SciFi book about the effect of zero-gravity on a female 
|characters breasts, and started wondering what really happens to womens 
|breasts in space.  Do women astronauts need to wear bras, for example?

|/M
----- end of message 1 -------------
----- beginning of message 2 -------
|Path: cam!dove!uunet!mcsun!sunic!lth.se!pollux.lu.se!magnus
|From: magnus@thep.lu.se (Magnus Olsson)
|Newsgroups: sci.space
|Subject: Re: Breasts in zero-g
|Message-ID: <1992Nov29.231718.7513@pollux.lu.se>
|Date: 29 Nov 92 23:17:18 GMT
|References: <Bxwr4s.AJ5.1@cs.cmu.edu> <roelle.722116771@uars_mag> <1992Nov26.231358.2257@r-node.gts.org>
|Sender: news@pollux.lu.se (Owner of news files)
|Distribution: sci
|Organization: Theoretical Physics, Lund University, Sweden
|Lines: 36
|Nntp-Posting-Host: leif.thep.lu.se

|In article <1992Nov26.231358.2257@r-node.gts.org> taob@r-node.gts.org (Brian Tao) writes:
|>In article <roelle.722116771@uars_mag> roelle@uars_mag.jhuapl.edu (Curtis Roelle) writes:
|>>
|>>The use of a brazier is
|>>still required, although the flight version differs from the
|>>terrestrial standard in that instead of lifting the breasts upward it
|>>pulls them downward, keeping them out of the face.

|I recall reading somewhere (I think it was in the Omni Space Almanac)
|that NASA was completely unisex: the only difference between the
|clothing of male and female astronauts was that the women wear bras to
|keep their breasts in place. 

|One would think there'd be some more or less official NASA policy on
|this, and that they would have put some effort into research on this
|topic before sending women into space (I wouldn't be too surprised if
|there really were a special "flight version" as mentioned above).
|Would anybody at NASA care to comment? 

|>Speaking of spaceflight attire, don't the jumpsuits have some
|>sort of built-in "support"?  I know they are supposed to be form-fitting
|>so no baggy ends can accidentally snag a control switch or get caught
|>on a corner.  With a properly designed jumpsuit, would a bra be
|>superfluous in zero g?

|Probably, if it were really form-fitting, like the uniforms in Star
|Trek... But don't the astronauts wear trousers and short-sleeved
|shirts most of the time nowadays? A guess would be that a shirt made
|to such specifications would be so revealing that NASA's image would
|be jeopardized :-)

|              Magnus Olsson                | \e+      /_
|    Department of Theoretical Physics      |  \  Z   / q
|        University of Lund, Sweden         |   >----<           
| magnus@thep.lu.se, thepmo@seldc52.bitnet  |  /      \===== g
|PGP key available via finger or on request | /e-      \q
----- end of message 2 -------------

Based on your reaction in this (third) post, I'm beginning to wonder
whether you are the person who posted the first message. It is attributed
to a Magnus Olsson in Sweden, but it doesn't use your usual address, and
doesn't have your usual .sig at the end. Perhaps it's a forgery, or perhaps
it's just a different Magnus Olsson (for all I know, Magnus Olsson is as
common in Sweden as Jim Smith or Bill Jones in the US).

-I hope I'm wriong, but I get the
-feeling that you're trying to make it seem as if I had written
-something highly inappropriate. If that is so, then *please tell us*
-what is inappropriate, and why, don't just imply it.

If you only posted the second of the two messages above, then I don't 
consider it particularly inappropriate - it's merely a somewhat lighthanded
treatment of a subject that had already been brought up. If you posted
both of them, then I would be inclined to consider the combination, in this
context to be slightly (not extremely) objectionable. Please do not take
this to be a call for censorship - I believe censorship is mainly 
overapplied and otherwise misused (in the US). But I believe that certain
topics are more appropriate in their proper environment than elsewhere.
(For instance, just because I like sugar doesn't mean I want it dumped
on my steak.) There are *plenty* of newsgroups dedicated to the discussion
of sex - sci.space in primarily intended for discussion of space exploration.
Now it would be incorrect to claim that sex is irrelevant to space
exploration - it's vital for long-term colonization of space, and can be
expected to be a significant part of the lifestyle of future space colonists.
I myself have posted a summary of an article on the subject. But the
combination of the two above posts - the first bringing up the subject,
and the second making light of it, suggests that the topic was introduced
with the main objective of making crude remarks, or out of prurient interest -
and as I said, I feel that these are more appropriate to the sex newsgroups.

I might also point out that there are a large number of female participants
in sci.space, and while I am sure that many of them are not at all offended
by the discussion, and perhaps most of them don't mind occasional mention
of the subject (after all, if females want to go into space, the related
health concerns must be addressed), there is still the risk that a
significant number might eventually get the impression that sci.space is
a forum in which a bunch of males (I don't recall any female contributors
to the topic) sit around and exchange crude jokes about female anatomy,
and I would hate to lose their participation in the important general topic
of space exploration.

-For new readers: I don't know really *what* John is trying to imply
-that I meant, but somebody else had been speculating about the need
-for female astronauts to wear supportive clothing (bras or special
-jump suits) in zero-g, and I made a HHOS ("ha ha, only serious")
-comment that NASA probably had done speical research on this. 

->I presume you've read "Rendezvous with Rama".

-Yes, I have, several years ago. What has that got to do with it?

If you are the person who posted the first message, and if you recall
the beginning of Chapter 11, then you will realize that this is a
relevant answer to one of the questions posted. Arthur C. Clarke has
been proven correct in so many of his predictions concerning space
exploration, that I would expect him to be pretty close in his guesses
on the responses of the female anatomy to microgravity. I doubt you're
going to find an official NASA publication on the subject.

There was also a practical reason for my question. You (or whoever posted
the first message) never gave the reason for needing to know the answer
to the question. I come across a tremendous volume of obscure space-related
material, only a fraction of which is ever posted to sci.space. If you
have some serious scientific reason for needing to know it (for instance,
a concern over possible long-term health effects of repeated oscillations), 
then I might come across something that would be helpful. If the reason is
only prurient interest, then I'm not likely to bother.

For the record - female astronauts in the Shuttle use essentially the same
clothing and health supplies as they would on the ground, and no significant
problems have ever arisen to make it noteworthy. The questions of 
pregnancy and childbirth in humans under microgravity have not been addressed.
Some experiments have been performed using animals, most recently the in-orbit
fertilization and early development of tadpoles (which worked so well that 
it at least sounds an encouraging note for eventual human reproduction in
space).

The topic of sanitary facilities for females in space suits is very seldom
discussed by NASA officials, but from occasional remarks I gather that what
is used is basically the "adult diaper" that is sold in drug stores everywhere
for people who suffer from incontinence. It's not a very dignified solution,
and I can't imagine female astronauts being anxious to talk about it to the
press, but it seems to work. (I'm not entirely sure that this isn't also
used for male astronauts.)

->So - when is Sweden going to buy a Shuttle flight and make some of the
->movies it's famous for, but in zero-G? And is your research the groundwork
->for such an undertaking? :-)

-You know, we Swedes are getting sick and tired of hearing that kind of
-remarks, even with smilies attached. I can assure you that they have
-long since lost any relevance. 

I'm sorry if you are offended. I guess that was a little out of line. 
But I'm somewhat concerned. Sweden has been admired for many years for 
having a free and open society. Are you saying that this is no longer 
the case - that the puritannical censors have taken over and halted the 
production of such films? I can see the merits of not broadcasting such
material to all age groups - but to outlaw it entirely seems a little
heavy-handed.

-Nowadays, they must be said to belong
-to the same kind of ethnic slurs as stories about sausage-eating,

Hey - I resent that. I'm very fond of German sausage.

-war-mongering 

Don't forget war-mongering Swedes. Not everybody has forgotten the days
of the Vikings, and the Swedish empire of the 1600s. (One of the national
exhibits at Epcot makes much of the high adventure of the Viking lifestyle,
without quite getting around to mentioning what they did for a living.)
And of course the war-mongering Americans are another popular stereotype.
(Just because we like to stomp on some little country every few years, how
could anybody get that impression? :-)

-Germans with scars and heavy Prussian accents. But it's
-of course very easy for you Americans - who, if one were to judge by
-American pop. culture, and the postings here on Usenet, seem to be
-the most sexually obsessed people on Earth - to have somebody to point
-your fingers at, isn't it? 

If that's an example of the truth of national stereotypes, then the Swedish
stereotype must be true, because the American one sure is. Actually, that's
not the whole story - a large fraction of the US population is obsessed both
with sex *and* the repression of sex. One of the most popular US television
program formats is one in which shocking stories are told, and shocking
excerpts are shown, and the viewers cluck their tongues in condemnation of
such wickedness, while keeping their eyes firmly glued to the screen. It is
said that a television station once accidentally broadcast an adult film
(that much, at least, is documented), and there were hundreds of complaints
phoned in, but not a single one until the movie was over! Another highly
popular format is the fictional portrayal that's loaded with suggestion,
but with no body parts actually shown, which confuses foreign viewers, who
are unsure whether anything is supposed to have taken place.

-Sheesh. 

-(Oops - I seem to have made an ethnic slur myself. Sorry for that -
-please note the wording "if one were to judge by ... seem", and that I
-certainly don't mean *all* Americans)

I'm sorry you were offended by what you perceived as a national slur. Tell
you what - next time I remark that Sweden is a backward country because
one can't get a good taco there, you are authorized to reply "Ha! Typical
American self-centered selfishness!".

-              Magnus Olsson                | \e+      /_
-    Department of Theoretical Physics      |  \  Z   / q
-        University of Lund, Sweden         |   >----<           
- magnus@thep.lu.se, thepmo@seldc52.bitnet  |  /      \===== g
-PGP key available via finger or on request | /e-      \q

If you didn't post the first message, then I apologize profusely - it was
all a case of mistaken identity. If you did post both, then please don't
be so offended - I only meant a mild criticism.

My opinions.

John Roberts
roberts@cmr.ncsl.nist.gov

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

Date: Thu, 3 Dec 1992 00:01:02 GMT
From: Josh 'K' Hopkins <jbh55289@uxa.cso.uiuc.edu>
Subject: Shuttle replacement
Newsgroups: sci.space

gary@ke4zv.uucp (Gary Coffman) writes:

>(Allen W. Sherzer) writes:
>>
>>I believe current plans are to put weels on it after it lands and tow it
>>to a hanger or the launcher. Empty weight is only 80K pounds so this isn't
>>hard.

>What's the height/width of the projected DC? What I'm asking is how
>stable is this thing on just wheels? Would a bracing structure be
>helpful or required when moving it over ordinary rough concrete surfaces?

One of my promotional sheets shows DC-Y as 127' tall and a quick guestimate with
a ruler suggests that its maybe 40' wide depending on just what they counted
in that height.  You'd want to be careful of course, but I think you could
move it without a bracing structure.  This is the kind of thing that playing
with hardware would help clear up.

>Are the payload/pallet integration costs included in DC flight costs,
>or are they offloaded onto the customer?

Just to be a twit, I have to say "Both" since that is a fundamental concept of
profit making enterprise.  To get at what you really mean however, I think I 
should point out that anybody who tells you the answer is probably wrong anyway.
The types of payloads DC flies (in the future conditional tense of course) 
will change over time and will probably be less fragile and pampered that 
current payloads and the interface will of course be standardized.  In short,
The cost of integration and who pays for it directly will change with time and
are dependant on things we don't yet know.

>Also, I'd expect a mobile gantry platform would be better than
>having a ten ton pallet swaying on the end of a crane cable. Costs
>for a ten ton mobile gantry platform shouldn't be that high, just
>a glorified forklift.

The drawing of DC flight ops I saw had a big truck with an elevating platform
like they use for loading the in flight meals onto jets.  Again, the exact
device used for loading probably isn't and shouldn't be determined yet, but it
won't be a multi million dollar million ton gantry.

-- 
Josh Hopkins                                          jbh55289@uxa.cso.uiuc.edu

	"Why put off 'til tomorrow what you're never going to do anyway?"

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

Date: 3 Dec 92 00:51:01 GMT
From: Josh 'K' Hopkins <jbh55289@uxa.cso.uiuc.edu>
Subject: Space probe to pass Earth
Newsgroups: sci.space

moroney@ramblr.enet.dec.com writes:

>In article <1992Dec2.010418.19960@Princeton.EDU>, phoenix.Princeton.EDU!carlosn (Carlos G. Niederstrasser) writes...
>>190 miles ?!?!  Isn't that even closer than the normal shuttle orbit?  Are they  
>>missing a few zeroes?  I mean, at 190 miles I would expect air resistance  
>>(considering the high speed) to be quite detrimental.

>I do believe it is 190 miles.

>Hmm.  Me just had crazy idea.  Aim the spacecraft so the air resistance
>will attempt to force the stuck HGA open (like an umbrella or parachute)
>while trying to crank it open at the same time.  Perhaps this will free
>it?  Or tear it apart? (I'd guess not, as it was expected to be fully
>open now)

I always like to encourage free thinking and figuring things out for yourselves,
but lets take that a little farther fellas.   190 miles is low, but not _that_
low.  Sattelites can stay up there for a while.  In addition, we know that
Galileo will be moving fast ('cuz that's the whole point of a planet swingby).
We can therefore assume that Galileo will be down that low for a very short
amount of time (I'm guessing tens of minutes below a given moderately low 
altitude).  Now if satellites (which aren't exactly standing still) can hang
around for weeks or months at that altitude before worrying about drag, I think
we can safely assume that air won't put major loads on Galileo.  I'd hope the 
calculations have been done, but I doubt they had very exciting results.     

-- 
Josh Hopkins                                          jbh55289@uxa.cso.uiuc.edu

	"Why put off 'til tomorrow what you're never going to do anyway?"

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

Date: 2 Dec 92 23:46:12 GMT
From: Hunter Scales <hunter@oakhill.sps.mot.com>
Subject: Space probe to pass Earth
Newsgroups: sci.space

baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes:

>190 miles is correct, with an accuracy of about +/- 4 miles.  This is no 
>suprise, the VEEGA trajectory was planned out 5 years ago.  A trajectory
>correction was performed over the weekend, and the spacecraft is right 
>on course with no further corrections needed.  All we have to do right now is 
>sit back and collect the science data.  Even thought the closest approach for 
>the Earth isn't until December 8, the Earth encounter has already started.
>The science instruments are already on and sending back data.

	Will this be visible from North America (at night, of course).
	If so, where and when should we look?


-- 
Hunter Scales                                      Motorola Semiconductor Inc.
hunter@prometheus.sps.mot.com                      Austin, Texas
"The opinions expressed in this posting do no necessarily reflect
those of the management"

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

Date: 3 Dec 92 01:35:58 GMT
From: Earl W Phillips <ephillip@magnus.acs.ohio-state.edu>
Subject: swift finder
Newsgroups: sci.space,sci.astro

January's S&T has a finder chart for comet P/Swift-Tuttle.
I scanned it to a .gif, uuencoded it & posted it here. I
didn't test it, so let me know if it's ok!
----------------cut here--------------------
begin 0666 swiftcht
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9->QA$9M8Q2Z6L8UU[&,A&UG)3E8:!0  .U?G
 
end

---------------cut here----------------------
it should uudecode to swiftcht.gif

*****************************************************************
*                                    | ====@====      ///////// *
* ephillip@magnus.ircc.ohio-state.edu|     ``________//         *
*                                    |       `------'           *
*                 -JR-               | Space;........the final  *
*                                    | frontier...............  *
*****************************************************************

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

Date: 3 Dec 92 01:07:18 GMT
From: Josh 'K' Hopkins <jbh55289@uxa.cso.uiuc.edu>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

gary@ke4zv.uucp (Gary Coffman) writes:

>To shut me
>up, all you need to do is agree to launch and land this thing away from 
>major population centers. It's not an airliner, and it likely can never be
>an airliner. If it's a cheap launcher that ocasionally crashes or goes
>boom in an uninhabited spot, that's good enough for me.

DC isn't an airliner with wings and jets, but it's not a rocket with low
margin engines and flight history of zero either.  It's something in between.
To shut us up, you're going to have to show us why, given reasonable estimates
of vehicle reliablity, you require it to live up to rocket standards and not 
airliner standards.  I think most of us agree that the RSO for a rocket is an
important job, but that the current accident rate of airliners doens't 
necessitate them.  Just why can't a launcher be an airliner anyway?

-- 
Josh Hopkins                                          jbh55289@uxa.cso.uiuc.edu

	"Why put off 'til tomorrow what you're never going to do anyway?"

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

Date: 2 Dec 92 23:56:23 GMT
From: Henry Spencer <henry@zoo.toronto.edu>
Subject: What is the SSTO enabling technology?
Newsgroups: sci.space

In article <GNB.92Dec1140531@baby.bby.com.au> gnb@baby.bby.com.au (Gregory N. Bond) writes:
>My understanding is that an SSTO project has only just crossed the
>line of possible, hence the interest in the DC-X & followon.  What is
>the main changing technology that makes an SSTO possible?  

Lighter structural materials are the big development in recent times.

However, SSTO has been possible for a long time.  The recent change is
that development risks have gotten low enough to make it very hard to
claim that the project is doomed to failure.  That is, the threshold
has been political, not technical.  Serious SSTO proposals existed 20
years ago, and if we'd tried five of them, probably at least two would
have worked.  But greater doubts could be raised about them more easily,
and Congress has never really grasped the notion that gambling with the
taxpayers' money can be a smart thing to do.
-- 
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  henry@zoo.toronto.edu  utzoo!henry

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

Date: Thu, 3 Dec 1992 00:21:46 GMT
From: Brad Whitehurst <rbw3q@rayleigh.mech.Virginia.EDU>
Subject: What is the SSTO enabling technology?
Newsgroups: sci.space

In article <1992Dec2.174115.18860@iti.org> aws@iti.org (Allen W. Sherzer) writes:
>In article <1992Dec2.151242.10249@murdoch.acc.Virginia.EDU> rbw3q@rayleigh.mech.Virginia.EDU (Brad Whitehurst) writes:
>
>>>RL-10s seem to do just fine.
>
>>	But are they reused?
>
>Each RL-10 is tested with something like 20 starts and stops. There is
>nothing in their design which prevents starting and stopping  an arbitrary
>number of times.
>
>RL-10's have been started, stopped, and re-started in space several times.
>There is no reason they can't be re-used.
>
	However, the duty cycle of interest is how many full throttle
launch profiles IN SERVICE (i.e., subject to vibration, weather,
whatever) can the engine endure before some specified wear criterion
is reached, requiring overhaul/junking.  There is ALWAYS something in
every mechanical design which defines a lifetime (i.e., the number of
cycles is NOT arbitrary!).  Since these engines have not been used as
reusable launch motors before, I would suggest that a sound
"commercial" engineering approach would be to construct several test
articles and launch and relaunch them repeatedly...unto destruction,
or some specified wear limit.  This would seem a likely job for
something small/cheap (i.e., DC-X) before the construction of bigger
units.  
-- 

Brad Whitehurst    |   Aerospace Research Lab
rbw3q@Virginia.EDU |   We like it hot...and fast.

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

End of Space Digest Volume 15 : Issue 497
------------------------------