Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_5/V15NO507.TXT

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Date: Sat,  5 Dec 92 18:04:50
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #507
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat,  5 Dec 92       Volume 15 : Issue 507

Today's Topics:
                   Mars Observer Update - 12/04/92
                       NASA employment outlook
                         NSSDC Data on CD-ROM
                 Rush Limbaugh and the SAUCER PEOPLE
    Rush Limbaugh says problems with HST are a DoD hoax! (2 msgs)
                     Shuttle replacement (7 msgs)
                      Space probe to pass Earth
           Terminal Velocity of DCX? (was Re: Shuttle ...)
                          unpowered landings
             Voyager's "message"... What did it *say*?!?

    Welcome to the Space Digest!!  Please send your messages to
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    (THENET), or [e-mail] (Internet).
----------------------------------------------------------------------

Date: Sat, 5 Dec 1992 02:26:45 GMT
From: Ron Baalke <[e-mail]>
Subject: Mars Observer Update - 12/04/92
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Forwarded from the Mars Observer Project

                      MARS OBSERVER STATUS REPORT
                           December 4, 1992
                             10:00 AM PST
                           Launch +70 Days

Flight sequence C4 remains active through December 14.  The Mars
Observer Camera bakeout is continuing through December 28.  The Gamma
Ray Spectrometer and Magnetometer instruments are powered on, but are
in a quiescent state.  The spacecraft is transmitting in the Mission Mode at
a data rate of 250 bits per second.  It will remain at this rate/mode until
High Gain Antenna activation, currently planned for January 4, 1993.

Today marks ten weeks since launch.  The Mars Observer Spacecraft and
Instrument Teams report that all spacecraft subsystems and instruments
are performing nominally.

In-flight activities this week were minimal.  The primary activity was
uplink and activation on Tuesday of a new Star Catalog/Ephemeris which
affected spacecraft attitude to provide optimal low gain antenna Earth
pointing while keeping the solar array at a desired sun incidence angle to
protect against excessive electrical power build-up.

Command files for the recently proposed Magnetometer and Electron
Reflectometer Geotail experiment are in the development, approval, and
generation process in anticipation of the 8 - 12 December Geotail
measurement opportunity.

A "Power-In" maneuver Preliminary Design Review will be held Friday, 11
December.

As of today, the spacecraft is 21,918,495 km (13,619,521 miles) from
Earth, traveling at a velocity of 5.6069 kilometers per second (12,542
miles per hour) with respect to Earth. One way light time is approximately
73 seconds.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | The 3 things that children
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | find the most fascinating:
|_____|/  |_|/       |_____|/                     | space, dinosaurs and ghosts.

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

Date: Fri, 4 Dec 92 21:19:56 EST
From: John Roberts <[e-mail]>
Subject: NASA employment outlook

-From: [e-mail] (Mary Shafer)
-Subject: Re: NASA employement outlook
-Date: 4 Dec 92 15:52:34 GMT
-Organization: NASA Dryden, Edwards, Cal.

-There are absolutely no conditions under which a foreign national can
-work for NASA or any agency of the US gov't.  A green card is the
-absolute minimum and even then, it's not straightforward.  Quite a bit
-of our work, particularly on joint programs with the Department of
-Defense, is NOFORN, for example.  (NOFORN = no foreign access).

-Besides, we're in a hiring freeze right now.

-However, foreign national, particularly students, can be affiliated
-with NASA through various research institutes.  This includes the NSF.

At least some government agencies (I don't know about NASA) have a guest
researcher program, in which foreign nationals come to the US to work
on a specific project for a few months to perhaps a year. It appears
generally to be a deal worked out between the agency and some foreign
organization such as a government or a university.

I believe the pay isn't all that great - less than an American doing the
same job would make. It's viewed mainly as a chance to live in the US
for a few months (many of the participants take some time off to travel
for a while), to learn from working on the project, and in many cases,
to improve skills in conversational English. I believe some US citizens
work as guest researchers in other countries, for corresponding reasons.

(And that's *all* I know on the subject, so please don't ask me for more
information! :-) People might check to see whether their own countries
have organizations that participate in guest researcher programs.

John Roberts
[e-mail]

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

Date: Fri, 4 Dec 1992 16:59:18 GMT
From: Martin Connors <[e-mail]>
Subject: NSSDC Data on CD-ROM
Newsgroups: sci.space

In article <[e-mail]>
[e-mail] (E. V. Bell, II - NSSDC/HSTX/GSFC/NASA -
[phone]) writes:
>     I also feel obligated to point out that right now we are out
>     of stock on two of the Voyager CD-ROMs, so if you request a
>     whole set right now, you'll be told to check back with us
>     (probably in three months). (We are out of the Saturn and
>     Jupiter CD-ROMs which contain the browse images. Although we
>     *did* have a few complete sets of the Uranus and Neptune
>     images, my guess is that they will be depleted shortly, too.)

This may be a useful place to point out that CDROM, Inc., in Golden
Colorado, sells these sets at not much more than NSSDC does. If you need a
whole set (and you NEED these if you are going to have a truly fulfilled
life!) try 1-800-555-1212 to get their 800 #. It's about $100 for the set
(although that may be just 7 not 12 disks if I recall correctly but it
does include the useful browse disks). By checking popular astronomical
publications you can also find outfits selling these (same I presume) CD
sets for as much as $500. I don't know if that is legal....
--
Martin Connors         |
Space Research         | [e-mail]  [phone]
University of Alberta  |

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

Date: Fri, 4 Dec 92 17:53:30 -0600
From: [e-mail] (Phil G. Fraering)
Subject: Rush Limbaugh and the SAUCER PEOPLE

\Could someone who actually pays some attention to Mr. Limbaugh
/tell us whether he has previously displayed any serious interest in
\stories of Saucer People?


I didn't hear his statement but Mr. Limbaugh, when I listened
to him many years in the past, frequently engaged in satire.
Since he is known to be on computer networks, where the SAUCER
PEOPLE find an EASY OUTLET for their UPPER-CASE rantings, I
suppose that might be where he got the idea.

I have seen the statement many times on the SAUCER-ORIENTED
NEWSGROUPS, which I have SEEN WITH MY OWN EYES. I've tried
crossposting material here and there, but the MEN IN BLACK,
as seen in the short film THE INTERVIEW, speeded to SILENCE
ME and the inews here has NEVER BEEN THE SAME SINCE, and the
censorship has reduced me to POSTING BY MAIL.


More seriously, I think that Jim Bowery (!) is right in that
someone who usually gets described as a "highly placed source"
deceided to see what sort of stuff they could get the general
public to believe.

What would you believe? It's been 20 years since Apollo stopped,
we've spent >200 billion dollars on space (combined military and
civilian government space dollars), and we haven't gone anywhere
except for piddling little expensive trips to leo.


\     O~~*           /_) ' / /   /_/ '  ,   ,  ' ,_  _           \|/
/   - ~ -~~~~~~~~~~~/_) / / /   / / / (_) (_) / / / _\~~~~~~~~~~~zap!
\ /       \                          (_) (_)                    / | \
/ |       |     Bill Higgins   Fermi National Accelerator Laboratory
\ \       /     Bitnet:     [e-mail]
/   -   -       Internet:  [e-mail]
\     ~         SPAN/Hepnet:      43011::HIGGINS

Help save the 4-line .sig before it's too late!

Phil

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

Date: 4 Dec 92 19:33:56 GMT
From: Ray Swartz <[e-mail]>
Subject: Rush Limbaugh says problems with HST are a DoD hoax!
Newsgroups: sci.space

[e-mail] (Ryan Korniloff) writes:

> The popular American radio personality Rush Limbaugh stated today that the
> problems with HSTs mirror are a Department of Defense hoax. He says that
> the DoD took over control of the HST program so they could study a strange
> radio source that could possibly be another civilization's radio
> emmisions. And that the DoD cooked up the story of the faulted mirror to
> cover up there actions.
> Rush has over 13 million listeners and has may connections into the goings
> ons of many behind-the-scenes happenings. I don't think that he would make
> such a statment without a reason to believe it is true.


    If anybody would have listened clostly to what he said, they wouldn't
make statements like this.  He said specifically that this was a rumor that was
going around (indeed, I heard it here on the net several days before he said it)
and, although he didn't like to report rumors, he thought this one was funny
enough to talk about.  ONLY AFTER SAYING ALL THIS did he "report" the rumor.

    He never said that he thought it was true, nor did he say that he had
any sort of (whisper here) inside story.  Keep in mind that the man considers
himself a humorist, albeit a conservative one.

Ray Swartz

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

Date: Fri,  4 Dec 1992 18:21:56 -0500
From: Kevin William Ryan <[e-mail]>
Subject: Rush Limbaugh says problems with HST are a DoD hoax!
Newsgroups: sci.space

>The popular American radio personality Rush Limbaugh stated today that the
>problems with HSTs mirror are a Department of Defense hoax. He says that
>the DoD took over control of the HST program so they could study a strange
>radio source that could possibly be another civilization's radio
>emmisions. And that the DoD cooked up the story of the faulted mirror to
>cover up there actions.

    Riiiiiight... The HST is an _optical_ telescope, not a radio
telescope. This does make a difference. Said story is entirely bogus.

>Rush has over 13 million listeners and has may connections into the goings
>ons of many behind-the-scenes happenings. I don't think that he would make
>such a statment without a reason to believe it is true.

    I've seen his late night TV show. He's a sensationalist media guy,
not a serious reporter or anything. Note the 'radio personality' title
you give him rather than 'journalist'. He certainly doesn't know
anything about astronomy if he thinks co-opting the HST will help
investigate radio transmissions.

>Could some NASA insiders shed some light on this!? This is a rather
>radical statement. I have followed the developments closely enough to know
>that there is a repair mission due next year and an instrument will be
>replaced with COSTAR to correct the mirrir flaw. And what about the
>investigations into the contractor who made the mirror? Was NASA wsting
>it's time!? This can't be and with 13 million listeners how come nobody
>else said anything about this??

    One of the mirrors in the test apparatus, only a few inches across,
was installed (as I understand it) backwards. Since this was the
measurement of mirror alignment the mirror was ground with extreme
accuracy: to the wrong curvature. The COSTAR has optics intended to
correct the spherical abberation.

    The mirror manufacturer is _hideously_ embarrassed, and will likely
not be doing any more mirror making without _carefully_ checking the
alignment apparatus.

    And nobody said anything about the DOD faking the problem because it
makes no sense whatsoever.

                                                    kwr

Internet: [e-mail]

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

Date: 4 Dec 92 11:16:07 EST
From: "John F. Woods" <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

[e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Brian Stuart Thorn) writes:
>>I was wondering if anyone else was going to mention that gaffe.
>>I mean, TEN PEOPLE???
>>Okay, you've crewed the fire truck... now who's going to fuel the DC? :-)
>How many people does it take to connect a couple of hoses and push the
>buttons to start the pumps?

Hey, it takes at *least* ten people just to sign off the paperwork for EACH
of those steps, right?  Can't fly a rocket without paperwork, can we?

And then, of course, it requires another twenty USENET posters to argue about
it :-).

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

Date: 4 Dec 92 18:25:24 GMT
From: Pat <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Brian Stuart Thorn) writes:
>
>>>Total turnaround is expected to cost around $10 million. I have seen figures
>>>for ground crew size and from memory is was on the order of 10 people.
>>>
>>        I'd be REAL skeptical of this.  Even if they cut the manpower
>>by an order of magnitude over the shuttle, I'd guess we're still
>>talking 100+ personnel (pretty good, all things considered).
>
>>Brad Whitehurst    |   Aerospace Research Lab
>
>I was wondering if anyone else was going to mention that gaffe.
>I mean, TEN PEOPLE???
>Okay, you've crewed the fire truck... now who's going to fuel the DC? :-)
>
>-Brian



Brian,  i think you miss the point.  the Mindset of the DC-1 is to build
an operational spacecraft capable of cohabitating with Long Haul Airliners
or Military aircraft.  The ground crew for an F-15 does not normally
include the fire truck.  Sure,  there is a fire truck at an air base or
air port, but it sits in a hangar waiting for a call.

The design, hope, philosophy of DC-1 will be to use aircraft maintenance
and procedures to fly.

What if someone says,  I want to fly to japan, packages faster then currently available.

Kelly johnsons Avatar says use hydrogen fuel.  they build and they get an
SST going flying on hydrogen.  and LOX.  and it's capable of landing at
ohare, miami and john wayne.

Would you insist that it only land at White sands, even after a rigorous
test suite.  would you scream about crashing rocket fuel in Disneyland???

Would you insist that everyone at the airport be counted as ground crew?????

the DC will only count as ground crew, those people who are needed to
touch the craft or to drive and operate the support vehicles.

Firemen, tower personnel, porters, ticket attendants.  they dont count.

747's take off with a ground crew of only 3.  if DC-1 can get to an operational
status,  it should be able to do similiar things.  we will see.

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

Date: 4 Dec 92 19:24:00 GMT
From: [e-mail]
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Ralph Buttigieg) writes...
>Original to: [e-mail]
> [e-mail] (Henry Spencer), wrote:
>
> h> Generally correct.  There's no obvious upper limit.  People have
>proposed

There are obvious upper limits that have to do with the overhead necessary
to support the weight of a really large SSTO. Look in Serways Fresman Physics
book for an explanation that is somewhat relevant.

> h> some really huge SSTO designs in the past; most things get easier at
>large

Which ones? I've never seen an SSTO design larger than DC, though that dosen't
really man much. Bob Truax's Sea Dragon is the largest launcher I have ever
seen put on paper in a serious manner. It was 768 feet tall and only had one
engine, BUT it still was a multistage bird.

> h> size.  (You can theoretically build a *solid-fuel* SSTO if you make it
> h> big enough, I'm told.  Although why you'd want to...)
>
You would not gain anything at all really. The largest All solid that I know
of is the Minuteman series of missles. The minuteman I that I worked with many
years ago could put 3,000 lbs into LEO for a cheap (1978 price of 10 million)
price. Look for the AIAA paper on the Aries IV by Richard Rasmussen circa 1978
from the Conference at Ajacco Corsica.

> Its worth remebering that a heavy lift version of SSTO would, if
> refueled in orbit be capable of interplanetery travel. I think GD did
> research on such a craft in the early 70's (ROMBUS?).
>

Its worth pointing out something that JR Thompson, former Associate Administrator
for NASA once pointed ot to congress and NASA. If you refueled the ET in LEO
the Shuttle could go anywhere in the solar system.

Dennis, University of Alabama in Huntsville

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

Date: Fri, 4 Dec 1992 18:02:47 GMT
From: Pat <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Michael V. Kent) writes:
>In article <[e-mail]> [e-mail] (Pat) writes:
>>In article <[e-mail]> [e-mail] (Michael V. Kent) writes:
>
>>we'll have to wait for the DC-X.
>
>DC-X, even if successful, will do nothing to reduce the uniqueness of the
>Shuttle.  It will prove some important concepts for the SSTO program and will
>hopefully pave the way for a full-scale manned prototype, but it will not
>replace the Shuttle.
>
I thooroughly agree.  DC-1,2  may make the shuttle a limited ops system
or even totally obsolete.  DC-X is just a research vehicle.  i've
seen what happens when research lab prototypes get shoved into real
production situations.

>What I'm trying to say here is that the SSRT program is doing some get-your-
>hands-dirty engineering the way it used to be done in this country -- by
>building X-planes to do the impossible.  It desperately needs to be done.
>But when you have all of your eggs in one basket (like the Shuttle) you don't
>throw away that basket, even if someone shows you a picture of a real pretty
>basket meant to replace it.
>

Goldin's plans are to fly shuttle until 2006, then build a replacement.
but all posited plans to date are NLS.  Hell, i'd rather see us go with
Dennis's ideas of the Baby Saturns.  known technology and it's scalable
to HLV.
>>I dont know,  while we went distance x with shuttle,  the russians
>>using their aging protons and those goofy soyuzes went 10X.
>
>Oh?  That is very much a debatible point.  The Russians launch a LOT of rock-
>ets, which is good if you're a rocket scientist.  But what do they accomplish?
>Their satellites last weeks to months, while ours (Western) last years to
>decades.  They have a space station with a permanent two-man crew.  We have a
>Shuttle flying eight 10-day missions per year with a seven-man crew.  It's
>two different approaches, really.  Many simple things vs. a few complex, and
>there are benefits and drawbacks to each.
>

Remember  we have only hit 8 after 12 years.  we went three years down.
The average launch rate was 4 for over ten years.  And we spend 3 times
as much per mission as they do on a proton.  sure different capabilites
but i am not sure we are getting good value.


>Which approach is better?  Well, they've gone head-to-head twice.  The first
>was Apollo, the second was Desert Storm.  Draw your own conclusions.
>
Well,  Apollo is now aging space junk.  Saddam is still in Baghdad.

I'll discuss the gulf war in sci.military.

>>who holds the records for manned spaceflight.  who has the record
>>for spacewalks.
>
>The Russians, on both, for total time.  But considering 70% of everyone who
>has ever gone to orbit has done so in the Shuttle, the Americans have
>certainly put more people up more times.
>
I dont know if that is that important.  they have a cadre of highly experienced
astronauts.  we have a large corps of less experienced guys.

>>who understands more LEO lifescience.
>
>The Americans.  Mir is not very useful for life science research, other than
>for sitting around and breaking records.  The medical data from Mir has been
>of very low quality.  NASA learned more life science on one Shuttle mission
>(SLS 1) than the Soviets did during four years of Mir operations.
>
I am not so sure.  I would be very wall eyed of NASA guys trying to justify
SSF by claiming the russian stuff is crap.  did anyone do a cost study
on how much it would cost to improve russian life sciences data.
send an american and a bunch of gear up on a soyuz and get all the high quality
data you could desire.


>As I understand it, however, Mir does good work in the materials research area.
>
>>We took one path, the stuck to the old one.  i bet they think they
>>made the better choice.
>
>They do (as far as aerospace is concerned :) )  A few months ago a delegation
>from Russia (aerospace professionals) were given a tour of some American
>facilities.  They were surprisingly unimpressed with our computational and
>manufacturing capabilities.  It's not that they could do better, it was that
>they just didn't think it was very useful.
>
>Mike
>
>--
>Michael Kent                                   [e-mail]
>Flight Test Engineer                           Tute-Screwed Aero '92
>McDonnell Douglas                              Rensselaer Polytechnic Institute
>These views are solely those of the author.    Apple II Forever !!


I guess you got a job?  good.  someone needs to help pay the national debt;-)

i think the russians arent terribly impressed by Computational modeling
because they do pretty good math themselves or just build hardware and
take test data.  why simulate, when you can create.

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

Date: 4 Dec 92 19:39:00 GMT
From: [e-mail]
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Richard A. Schumacher) writes...
>In <[e-mail]> [e-mail] writes:
>
>Nonsense. It will never cost less than $500 million to launch a shuttle.
>Are you claiming otherwise?
>
Well by golly I think I am. Is it so difficult to believe that they cannot
reduce the costs of Shuttle operations? I can think of s number of things
that can be done to accomplish this. I will let you know more later. I am going
to to KSC to deliver a payload we built for SpacHab later this month. I will
be working and loading the payload into the SpaceHab module and working around
the orbiter, so I will get an idea of the reality down there. Any of you
armchair Shuttle haters ever do that?

>
>>Got any idea what you mean by this remark? You sure as heck could not have
>>gotten HST up to that altitude with anthing less than NLS II or Shuttle
>
>Nonsense. How did the Air Force get all those KH-11s, every bit
>as big as Hubble, into orbit?
>
As has been posted before, you must greatly reduce the payload delivered  to
the final orbit for the Titan. There ain't no way to get an HST sized payload
to 330 nautical miles with Titan III or 34D or IV for that matter.

[stuff deleted]

>Having identified better uses for the money, why keep pissing
>it into the hole called Shuttle? NASA should not be a welfare program
>for aero engineers and bureaucrats.
>

Having built, test flown and then certified for normal operations, this is the
time to stop "pissing money" away on the Shuttle and not before. This is the
crass mistake we made with the loss of the Saturn series of vehicles, let us not
make this mistake again. Does anyone here remember that the Saturn IB put the
same amount of payload to LEO as the Titan IV? For a cheaper price? If we had
maintained even this capability we would have a straight path to returning the
full Saturn system to service.

>
>>You have not even addressed the other end, the HLV end of the spectrum. IT too
>>will depend on the influx of government cash until we develop a commercial
>>space industry, either in products or raw materials.
>
>This can only be done incrementally. No one can identify a commercial
>need for an HLV in the forseeable future. Recall that Columbus did not ask
>Isabella for the "Queen Mary".
>

You are absolutey right here and this is what I have been saying. Junk the
Titan IV with its polluting SRM,s bring into existence the Baby Saturn that
in its MINIMUM configuration out lifts the Titan IV. Then as the market develops
incrementally upgrade to the Baby Saturn II which ups the lift to 120,000 to LEO
then make the jump to Saturn III, IV and V. to get us the heck off of this dirt
ball and help us to begin to develop the solar system not just go out and take
pretty pictures that only serve to grace magazine covers and rust at the NSSDC.
(And provide fodder for Usnet armchair Einstein's)

Dennis, University of Alabama in Huntsville.

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

Date: 30 Nov 92 16:28:02 GMT
From: Ralph Buttigieg <[e-mail]>
Subject: Shuttle replacement
Newsgroups: sci.space

Original to: [e-mail]
 [e-mail] (Henry Spencer), wrote:

 h> Generally correct.  There's no obvious upper limit.  People have
proposed
 h> some really huge SSTO designs in the past; most things get easier at
large
 h> size.  (You can theoretically build a *solid-fuel* SSTO if you make it
 h> big enough, I'm told.  Although why you'd want to...)

 Its worth remebering that a heavy lift version of SSTO would, if
 refueled in orbit be capable of interplanetery travel. I think GD did
 research on such a craft in the early 70's (ROMBUS?).

 ta
 Ralph

--- Maximus 2.01wb
 * Origin: Vulcan's World-Sydney Australia 02 635-1204 (3:713/635)

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

Date: 4 Dec 92 19:41:19 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Pat) writes:
>
>Actually how many instances of total power loss have their been?
>The brits lost one after an engine fire on a 757 and the pilot
>then shut down the remaining good engine.  Their was Gimli and
>and an incident when a US airliner lost all engines when a mechanic
>forgot an o-ring on all foour engines.   there was also the avianca?
>(Columbian airline)  that ran out of fuel enroute to JFK.
>Have their been any other isntances?  i am sure the military has lost a
>few this way also.

Southern Airways DC9 lost both engines to water ingestion over North
Georgia. Due to controller error initially giving vector in wrong direction,
failed to make dead stick into Dobbins and crashed near New Hope. (Actually
made a nice landing on the highway, but clipped the pump island at a gas
station and went up in flames.)

Gary

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

Date: Fri, 4 Dec 1992 10:32:21 GMT
From: Ben Burch <[e-mail]>
Subject: Space probe to pass Earth
Newsgroups: sci.space

Re: Space probe to pass Earth

In article <[e-mail]> ,
[e-mail] writes:
>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)

Well, your almost answered this one yourself, but also imagine the
delta-vee that this "aerobraking" maneuver would produce.  The reason
that the spacecraft had to do so many flybys is that we couldn't give
it enough velocity to get to its destination with rockets, and had to
borrow some of the orbital energy of the planets.  Even if this would
pop the antenna open, there would be no mission left to save.

-Ben Burch

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

Date: 4 Dec 92 17:57:02 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>>The proposed DC *is* a rocket, it *is* a low margin system as any
>>SSTO has to be, and it has exactly *zero* flight history. It will
>>use throttleable engines with variable geometry *based* somewhat
>>on RL-10 technology at first, but radically new and never flight
>>tested. Later it intends to use aerospike engine designs that have
>>*never* been tested, even on the ground. It will be difficult for
>>it to live up to rocket standards of reliability, much less airliner
>>standards of reliability. This is radically new engine and control
>>technology being pioneered on a very marginal flight article. The
>>cost and reliability levels being bandied about have no basis other
>>than wishful thinking.
>
>Gary, why do you insist on confusing the experimental prototype (DC-Y)
>with the hoped-for commercial spaceship (DC-1)?  By the time people are
>seriously interested in certifying this thing as an airliner, there
>will be *lots* of flight experience with the technology, we will know
>whether payload margins are sufficient to allow adequate safety margins
>(as others have pointed out, these are two different things), and the
>engine and control technology will not be new.  Nobody is suggesting
>airliner-level certification of DC-Y.
>
>The whole point of building DC-X and DC-Y is to move the concept out
>of the paper-concept stage and into the hard-engineering-data stage.
>Nothing less than functioning prototypes will suffice, given the novelty
>of the approach.

Hold on Henry. I fully support the X tests. It's you and Allen who
are talking airliner reliability, costs, and certification of a
system that hasn't even been designed yet, much less tested. I'm
pointing out that what's being attempted in the X and Y tests is
edge of the envelope high risk stuff that's not going to lead to
airliner type vehicles any time in the near future, unless the
tests are wildly more successful than we have any right to believe.
Airliner type certification requires a degree of testing and proof
of low risk way beyond *anything* that has ever flown in space.
To hear Allen tell it, we should *immediately* scrap our current
*working* systems because Paradise is just over the hill. What
I've been saying is that it's a mighty long and steep hill.

Gary

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

Date: 4 Dec 92 18:20:19 GMT
From: Gary Coffman <ke4zv!gary>
Subject: unpowered landings
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>
>Total power loss is extremely rare in multi-engine turbine aircraft.  It
>also appears to be quite rare in multi-engine rockets.

Yes, the usual failure mode is a nasty explosion near or on the pad.
Current rockets of DC size and larger have a failure rate of about
1 in 100, and that's with a standing army doing zero defects preparation
and inspection. Flight testing may reduce that in DC by as much as one or
two orders of magnitude, or it might not reduce it at all, we have
no experience to guide us. If the failure rate of DC drops to 1 in
1000, or even 1 in 10,000, optimistic I think, that's still *wonderful*
for a *spacecraft*. However, that's still orders of magnitude worse than
airliner reliability rates. There's no credible evidence that DC will
approach airliner reliability rates with airliner grade servicing and
at airliner costs.

Overselling of this program is dangerous in a way that even the most
aggressive overselling of Shuttle was not. That's because one failure
of your *airliner safe* system will likely kill it dead, dead, dead.

Gary

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

Date: 4 Dec 92 12:49:08 EST
From: "John F. Woods" <[e-mail]>
Subject: Voyager's "message"... What did it *say*?!?
Newsgroups: sci.astro,sci.space

[e-mail] (Rick Miller, Linux Device Registrar) writes:
>
>Does anyone know (or know who knows, or where to find out) what the heck
>the "message" on Voyager's gold plate was supposed to 'mean'?

"Help, I'm being held prisoner in a satellite factory!"

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End of Space Digest Volume 15 : Issue 507
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