Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_5/V15NO550.TXT

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Date: Wed, 16 Dec 92 05:06:16
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #550
To: Space Digest Readers
Precedence: bulk


Space Digest                Wed, 16 Dec 92       Volume 15 : Issue 550

Today's Topics:
                            Air Force One
                          Apollo Astronauts
             Chicken Guns (was Re: "trivial engineering")
                    Does Sun have magnetic poles?
                       Ephemeris satellite info
           Galileo's Atmospheric Probe Passes Health Checks
                   Galileo Laser Milestone Achieved
            Lunar Exploration Information Available by FTP
                            Saturn history
        Soaring like and Eagle (was Re: Range Safety and DC-X)
                              spacecamp
       Terminal Velocity of DCX? (was Re: Shuttle ...) (3 msgs)
               what the little bird told Henry (2 msgs)

    Welcome to the Space Digest!!  Please send your messages to
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----------------------------------------------------------------------

Date: Tuesday, 15 Dec 1992 08:44:52 CET
From: [e-mail]
Subject: Air Force One
Newsgroups: sci.space

When I understood right the guy in Tucson at the air museum any aircraft of
the air force where the president is still flying is called Air Force One.
So there might not be only one B707 and one or two B747's, but still more.
So even a fighter can wear this name. Correct me if I'm wrong.

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

Date: 15 Dec 92 10:27:09 GMT
From: I F Gow <[e-mail]>
Subject: Apollo Astronauts
Newsgroups: sci.space.shuttle,sci.space

Anyone have addresses of the whereabouts of the surviving Apollo
Astronauts?


Regards,


Iain

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

Date: Tue, 15 Dec 1992 19:50:40 GMT
From: "Michael V. Kent" <[e-mail]>
Subject: Chicken Guns (was Re: "trivial engineering")
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Edmund Hack) writes:

>A former co-worker of mine worked at Pratt & Whitney on the F-100 (?)
>engine program in data acquisition for the test programs.  He said they
>all looked forward to the visit of the Air Force Chicken Cannon with
>both anticipation and dread.  Dead, fully feathered chickens are
>procured and shot into the front at high speed.  He said the noise and
>smell were quite remarkable.

Reminds me of a story I heard circulating MCAIR a few years ago.  They were
performing bird ingestion tests on (I think) the F-15 Eagle.  The engineers
and the technicians got to work and began to set up the test fixture and air
gun.  By the time they were finished, it was about noon, so they decided to hit
the local eatery before performing the tests.  So they get back from lunch,
throw a few remaining switches, and start the test.

"OK Joe -- press the button."

Thwoomp       MEEEOOOOOWWW       <indescribable sound>

Well, at least they know the F-15 can survive feline ingestion.  :)

Mike

You know, ASCII just doesn't do this story justice.

--
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 !!

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

Date: Tue, 15 Dec 1992 19:31:04 GMT
From: Babak Sehari <[e-mail]>
Subject: Does Sun have magnetic poles?
Newsgroups: sci.physics,sci.electronics,sci.space

Recently, an attempt has been made to create electricity using a large
electric loop in the space using earth magnetic force.  However, such thing
should not be a source of energy in the space since it takes energy to
change the flux that passes through wire loop and only a fraction of that
energy would be translated to electric energy. Further more, if the rotation
of satellite itself to be used for this task, the emf back force would change
the speed of the satellite.  That results in altitude drop for satellite.

However, if sun should have magnetic poles and if these magnetic poles
be strong enough, one could use earth rotation around the sun to create
electric energy. This leads to too small a drop in the earth radius, to
be noticeable for all practical purposes.  Could someone give us some idea
about the sun's magnetic field?

                       With highest regards,
                            Babak   Sehari.

--
Recently, an attempt has been made to create electricity using a large
electric loop in the space using earth magnetic force.  However, such thing
should not be a source of energy in the space since it takes energy to
change the flux that passes through wire loop and only a fraction of that
energy would be translated to electric energy. Further more, if the rotation
of satellite itself to be used for this task, the emf back force would change
the speed of the satellite.  That results in altitude drop for satellite.

However, if sun should have magnetic poles and if these magnetic poles
be strong enough, one could use earth rotation around the sun to create
electric energy. This leads to too small a drop in the earth radius, to
be noticeable for all practical purposes.  Could someone give us some idea
about the sun's magnetic field?

                       With highest regards,
                            Babak   Sehari.

--

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

Date: 14 Dec 92 18:44:07 GMT
From: Bruce Watson <[e-mail]>
Subject: Ephemeris satellite info
Newsgroups: sci.space

In article <[e-mail]| [e-mail] (Jape) writes:
|Could someone explain what 'Mean anomoly' is when talking
|about satellite ephemerous information?  How would one
|calculate such a thing?
|
Dan Boulet in his _Methods of Orbit Determination for the Micro Computer_
says:

M _mean anomaly_ A mathematical quantity (just say number, Dan) whose
value relates the position of the celestial body in the orbit to the
elapsed time by means of the Kepler equations. The mean anomaly changes
at a uniform rate equal to the mean motion n.
--
Bruce Watson (wats@scicom) Bulletin 629-49 Item 6700 Extract 75,131

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

Date: Tue, 15 Dec 92 20:00:23 GMT
From: Doug Mohney <[e-mail]>
Subject: Galileo's Atmospheric Probe Passes Health Checks
Newsgroups: sci.space,sci.astro,alt.sci.planetary

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

>     Its incandescent shock wave will be as bright as the sun and
>reach temperatures up to 28,000 degrees Fahrenheit.  After entry,
>the fore and aft heat shields of the deceleration module will be
>shed by deploying a small pilot parachute and then a large main
>chute, exposing the descent module to Jupiter's hydrogen/helium
>atmosphere.

Will entry be observed by the camera on the orbiter?

                    I have talked to Ehud, and lived.
  -- >                  [e-mail]                        < --

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

Date: Wed, 16 Dec 1992 04:09:30 GMT
From: Ron Baalke <[e-mail]>
Subject: Galileo Laser Milestone Achieved
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Dwayne C. Brown
Headquarters, Washington, D.C.                             December 15, 1992
(Phone:  [phone]

James H. Wilson
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone:  [phone])

RELEASE:  92-225

NASA LASER SPACE COMMUNICATIONS MILESTONE ACHIEVED

     A major milestone in space communications was achieved recently when
NASA scientists successfully transmitted laser signals to the Galileo
spacecraft at a distance of 1.3 million miles (2.2 million kilometers).

    "This experiment is part of a program to show that future deep space
missions can use laser beams to send back to Earth larger volumes of space-
acquired data than is currently possible using radio signals", said Dr. James
Lesh, Principal Investigator at NASA's Jet Propulsion Laboratory, Pasadena,
Calif.

    Laser beams were simultaneously transmitted to Galileo from a 24-
inch (61-centimeter-diameter) telescope at Table Mountain Observatory
near Wrightwood, Calif., and a 60-inch (1.5-meter) telescope at the U.S. Air
Force Phillips Laboratory's Starfire Optical Range near Albuquerque, N.M.
The laser beams from both sites were detected by Galileo's onboard camera.

    Called the Galileo Optical Experiment (GOPEX), the experiment began
on Dec. 9 as Galileo flew by Earth on its way to Jupiter.  The experiment will
continue through Dec. 16 when the distance of Galileo will be 3.7 million
miles (6 million kilometers).

    The experiment is operated by the JPL Telecommunications and Data
Acquisition Technology Development Office, with overall management
responsibility by NASA's Office of Space Communications, Advanced Systems
Program, Washington, D.C.
-end-
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Choose a job you love, and
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | you'll never have to work
|_____|/  |_|/       |_____|/                     | a day in you life.

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

Date: Tue, 15 Dec 1992 18:39:38 GMT
From: Graham O'Neil <[e-mail]>
Subject: Lunar Exploration Information Available by FTP
Newsgroups: sci.space,talk.politics.space,sci.astro,sci.geo.geology

                  LUNAR PROSPECTOR FILES AVAILABLE FOR FTP

Lunar Exploration Inc (LEI) organizer of the Lunar Prospector Mission
is establishing a set of reference files on the SPACE ARCHIVES at
ames.arc.nasa.gov.  The purpose is to make information about the

Seleno-mapping mission, and design details on small, simple science
spacecraft available to interested parties. The goal is to establish
an LEI presence on the Internet, and encourage grassroots space
exploration efforts while building public support for space science
missions.

        ftp:      ames.arc.nasa.gov (128.102.18.3)
        user:     anonymous
        password: Your Ident [[e-mail]]
        cd:       pub/SPACE/LEI

For the initial submission, we have identified the following documents
as being of sufficient quality for public access.  Additional
material will be added as progress permits.

1.  Lunar Prospector Mission Requirements Document   [FILENAME: mrd.asc]
2.  Lunar Prospector Mission Operations Document     [FILENAME: mod.asc]
3.  White paper on Lunar Prospectors mission         [FILENAME: white.paper]
4.  References to related lunar science articles     [FILENAME: lei.ref]
7.  Contact information for donations and support    [FILENAME: readme]
6.  Monthly newsletters and status.                  [FILENAME: status]

graham




--
Graham O'Neil    [e-mail]      GONEIL@nasamail
Lockheed  2400 NASA RD 1 Houston, TX 77058  [phone]
----------------------------------------------------------
Practice Random Kindness and Senseless Acts of Beauty

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

Date: 15 Dec 92 20:28:21 GMT
From: Henry Spencer <[e-mail]>
Subject: Saturn history
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>>     Centaur on the Saturn? I think I remember that it was considered
>>     as a fourth stage for Saturn 5 (with early Voyager planning?) but
>>     I believe you're confusing the RL-10 and the Centaur. RL-10
>>     powered the S-IV (predecessor to the J-2 powered S-IVB)...
>
>The Saturn I/Centaur configuration is the original Saturn I multistage vehicle.
>I confirmed this when re-reading General Medaris's book. He specifically
>names the Centaur as the Saturn I upper stage.

Methinks Medaris is confused, or is giving a some early design study
too much weight.  (It would not be unprecedented; Michael Collins, in one
of his books, described an important aspect of the Apollo LM wrong.)

The original Saturn I development effort had no upper stage at all.
Many, many different configurations were studied -- literally dozens --
with particular emphasis on putting an entire Titan or Atlas on top
to minimize development effort.  The confusion about upper-stage choice
lasted long enough to be a serious obstacle to progress.  Stages To Saturn
contains considerable detail on this.

As far as I know, none of those configurations used a Centaur as a
second stage.  It was too small to exploit the first stage properly.
It did show up as a third stage on Saturn-Atlas and Saturn-Titan concepts.

The Saturn I, as built, had two stages, the second being (as Brian noted)
the S-IV.  This was an oddball, never used for anything else.  It was sort
of Centaur's big brother, with six RL10s instead of Centaur's two, but was
not a Centaur derivative in any significant way.  Saturn I never flew with
any other upper stage(s).

>The Centaur was considered as the upper stage (4th) for the Saturn V...
>to support the Grand Tour by the original Voyagers. This little beastie had
>the Nerva as the Third stage with the Centaur as the 4th! Man Talk about
>Delta V or lift capability! I saw this scenario carefully laid out in one of
>the Marshall books on what was called the "Apollo Applications Program". This
>little configuration could lift two Voyager class full up ground tours...

Okay, now here we do have serious confusion.  The original Voyager had
nothing at all to do with the Grand Tour mission.  The first program named
Voyager was Viking's big brother, aiming to send large unmanned orbiters
and landers to Mars in the 1970s.  (Its objectives had originally included
Venus too, before it became clear just how unappetizing a place Venus is.)
It died completely in late-1960s cutbacks, as did the Grand Tour project
a bit later.  The name was re-used for a project originally dubbed
Mariner Jupiter-Saturn, a drastically shrunken reincarnation of Grand Tour
that managed to add Uranus and Neptune on the end as secondary objectives.

Voyager's original launch vehicle was the Saturn IB/Centaur, which was
never built.  It got hit by a double whammy in the mid-1960s:  first,
better data on Mars's atmosphere showed it was much thinner than formerly
thought, which meant major weight growth in Voyager's heatshield/parachute
system, driving Voyager beyond Saturn IB/Centaur's lift limit; and second,
NASA had its first budget squeeze, wanted to reduce the number of launch
vehicles it was involved in, and saw that Voyager was Saturn IB/Centaur's
only customer.

Voyager ended up planned for launch two at a time on a standard Saturn V,
which contributed to its demise by running up its costs.  (The Pasadena
Party Line blames NASA HQ for the launcher switch, but it's hard to see
what else could have been done after the weight growth, especially given
a desire not to get involved in yet more new launcher configurations.)
There wasn't any need for further stages or nuclear stages; the Saturn V
as it stood was really over-large for Voyager.

I haven't been able to find any detail on what launcher was planned for
the original Grand Tour project.  Note, though, that it was not part
of Apollo Applications, which was entirely a manned program.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 15 Dec 1992 20:44:03 GMT
From: Pat <[e-mail]>
Subject: Soaring like and Eagle (was Re: Range Safety and DC-X)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>In article <[e-mail]> [e-mail] (Bill Higgins-- Beam Jockey) writes:
>>Oh, I don't know, Gary.  The thrust-to-weight ratio on DC-X probably
>>compares favorably with an F-15 Eagle...
>
>Yeah, but an Eagle has "wangs" (such as they are). :-)




Okay.

    How many F-15's  have succesfully been dead sticked in under
operational conditions.  Not training,  but real life?

    How many F-15's have been lost due to spin caused by
single engine flame out?

    What is the incidence of total power loss per flying hour?

I would say they would be  a few, several and rare.  hence, what is the
big issue?  if something occurs  infrequently  and has at least as many
fatal modes as recoverable modes, i wouldn't consider it a win.

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

Date: Tue, 15 Dec 1992 19:25:56 GMT
From: Vilkata TDK <[e-mail]>
Subject: spacecamp
Newsgroups: sci.space

In <[e-mail]> [e-mail] (Claudio Egalon) writes:

>As far as I know there are two space-camps one in Huntsville (which
>is the biggeste one) and another in Florida near KSC. I guess that they
>have another one in Kansas but I am not sure.

You're right about Huntsville (Alabama) and Florida--Huntsville is the
original (and, as you said, bigger).  The one in Kansas is (I believe) in
Hutchinson, and I know for a fact it isn't "Space Camp brand".  In other words,
it's not related in any way (legally--obviously the subject matter is similar)
to the Huntsville and Florida ones.  On the other hand, I have heard (my cousin
went to it) that it is very good.  Still, if I had the choice, I'd choose
Huntsville (I've already been twice--VERY good program!).


--
-------------------------------------------------------------------------------
|    V I L K A T A     T . D . K .         [e-mail]------    |
|         If you know what my name refers to, email me!  I forgot!            |
-------------------------------------------------------------------------------

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

Date: Tue, 15 Dec 1992 19:04:59 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

In <[e-mail]> [e-mail] (Gary Coffman) writes:

>That's because you rarely see the prototype engines that blow up in
>testing and are discarded for a different design. Nor do you see the
>engines that worked, but didn't meet the required performance goals.
>A large rocket engine that has to work from sea level to vacuum can't
>be completely debugged on a static stand.

Nothing can be completely debugged on the test stand.  A turbojet
may not have to work from sea level to vaccuum, but it does have
to work from sea level to 35,000 feet.  You need to build a test
chamber in either case.



>What flight articles were they used on? How many went into orbit and
>what was their throttle characteristic? You can't answer because none
>have ever flown.

You deleted your original statement, which said that aerospike
engines had not been tested *even in static tests.*   Are you
deliberately quoting me out of context, or do I need to explain
the difference between a static test and a design article?



>>Oh.  I thought you were talking about the reentry.  No, the controlled
>>powered landing was demonstrated, again in the 1960's, by a vehicle
>>called the LEM.  Which had the additional requirement of landing solely
>>in unprepared fields.

>In 1/6th G in vacuum, single engine, with a vehicle that massed less than
>1/10th of DC. A totally different environment, totally different control
>problem, and totally different scale.

Yes, I'm prepared to assume that engineers can remember to multiple by
6 or 10.  Totally different environment?  But, Gary, you just got through
telling me that the environment of space is much more hostile than the
Earth's atmosphere.  If that's the case, landing on the Earth should be
a cinch compared to landing on the Moon, should it?

And how did we ever manage to design a vehicle that could operate in
that "totally different environment" to begin with?  With all the
problems you say rockets have.  Do you believe the Moon landings were
filmed at a studio on Long Island?

Somehow, the Apollo engineers managed to get the job done, even
though the technology, in those days really *was* "radically new."

Isn't it amazine what you can do when you're "success oriented?"

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

Date: Tue, 15 Dec 1992 19:59:13 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Michael V. Kent) writes:

>>It would include finishing
>>the tests of prototype cryogenic tanks and test the composite structures.

>Are these the same cryo tanks that McDonnell Douglas is building for NASP?

If you mean the tanks for Have Region, no. This would be a new effort.

>>Well we will launch that 400 pound Italian satellite. You remember, the
>>one NASA spent half a billion launching instead of putting it on a $10M
>>Pegasus?

>Could NASA have put the IRIS upper stage on that Pegasus too?

I don't know. If that alternative wouldn't have worked, I'll bet I can
think of others costing a fraction of what NASA paid. Can you?

>While I have
>not heard it stated explicitly, I suspect that launching IRIS was every bit
>as important to the Italians as launching LAGEOS.

So what? How does that justify spending 10 times more than what was needed?

>Was the development effort of integrating Pegasus and IRIS also
>included in that $10 million?

If it wasn't, the additional costs would pale compared to what was
spent.

>What about Mephisto?  The Lambda point experiment?  The United States Micro-
>gravity Payload (which carried the two aforementioned experiments)?

Let's fly them on Mir and use the hundreds of millions saved on some other
worthwhile project.

>Can't you just admit that a lot more happened on STS-52 than the launch of
>LAGEOS so we can put this issue to rest?

I'm sure lots more happened. Now can you demonstrate that it was done in
the most efficient way? Why does the prospect of saving money and getting
more work done bother you so much?

  Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------130 DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: 15 Dec 1992 20:25:53 GMT
From: Pat <[e-mail]>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>In article <[e-mail]> [e-mail] (_Floor_) writes:
>>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>>] always mean higher reliability. A truck engine is usually good for
>>] a million miles while a formula one engine may last 100. They both
>>] put out roughly the same amount of power, but one masses a lot more
>>] than the other.
>>]
>>
>>What?!? What kind of a comparison is that? I don't really think this is
>>an appropriate example of your point. A formula one engine is tortured
>>by blipping rapidly back and forth between 3,000 and 13,000 rpm continually
>>for two hours. It isn't the size that's the factor, is the use! I think
>>a tree trunk versus a twig is a better example of your scale/reliability
>>dependence point.
>
>Actually, both engines have narrow torque bands. Thanks to multi-speed
>gearboxes, both engines are kept near their torque peak at all times
>in service. The RPM levels are grossly different, 1800 for the truck
>and 12,500 for the F1 engine. That's because the smaller engine has
>to wind tighter to make the same power. IE it's stressed harder because
>it has to be small to maintain an acceptable mass ratio in a race car.
>

Okay, we all agree race car engines are more heavily stressed then
trucks.

>Power to weight ratios are critical to good race car performance as they
>are to good SSTO performance, and for the same reason. Light high output
>engines are less reliable than heavy high output engines. The margins
>are thiner in the racecar than the truck. The truck can afford to throw
>away a couple of thousand pounds of payload for a more reliable engine,
>the race car cannot.
>

The truck also takes a huge mass penalty against speed in order to improve
structural reliabilty.  Racing yachts are designed  for max speed and
equipment reliabilty, of exactly one heat.  a freighter or a destroyer
are designed for much tougher conditions.


>An SSTO has to haul all of it's engine and structure mass to orbit so
>these have to be lighter than a staged rocket that can discard engines
>and structure along the way. This is inherent in SSTO design. So a
>staged rocket can be made to have lower stresses than a SSTO for the
>same payload.
>

Certainly, a staged rocket designed with clean sheet approach can carry
more weight to orbit at a better mass ratio then an SSTO.   That does not
mean that you want to take that approach,  if an SSTO CAN!!!  important point
deliver cargo to LEO  for significantly less cost then any staged rocket
then why go with staged rockets for routine access to space?

Gary,  use your brain.    Just because a staged rocket can be built with
greater margins then a SSTO, does not mean that is the way to go.

Right now,  all staged rockets are vintage 60's/50's designs.  they have
absolutely no margin for safety.  neither does the shuttle.  All the
models for rocket costing indicate a major cost item is in the building/
stacking operation related to launch.   The russians turn these guys out
like sausages and still expand thousands of hours on stacking ops.

If a 747 had to change engines every time it flew,  a ticket would
cost 10 times as much.  asirlines are cheap to fly, cuz most items only
need routine maintenance.   literally, you can gas up a 747, clean the
cabin and turn right around.  i've seen it done.

You seem stuck on stress the same way Bi-Plane builders were in the 20's.
Bi-Planes generate the same lift, for half the stress,  yet all
planes are mono-wing.   Why,  because improved materials and design
methods allowed  adequate safety margins.   That's what we need,
adequate margins of 140% of expected load.

Sure,  a NASP, could probably be built with  170% margin of load,  but why?
and if it costs 4 times what DC-1 could deliver, then you are wasting money.

My belief is that the DC-1, will deliver loads to orbit cheaper then anything
else flying.  if it can,  then we are in great shape.


>Shuttle is only high stress because it emphasizes large payload in
>what is essentially a 1.5 stage design. Thus the SSME have to push
>much harder than they otherwise would have to. With a 2 or 2.5 stage
>design, the engines could operate at lower stress levels since they
>would be pushing less dead weight. The wings impose a mass penalty,
>but that's offset by not having to carry landing fuel and it's tankage
>for VTOL operation.
>

Okay,  so lets say we had a staged shuttle,  kinda like Von Braun's
concept.  Winged vehicle on a Saturn S-1, S-2.   Certainly, it would
have been much more reliable.  Certainly it would have carried more
payload.  Wehrner may have been a nazi (Sorry dennis)  but he was a
damn good rocket designer.

So we got werners design.  do you know how much it would cost to fly?
probably on the the order or 2-3 billion per mission.  Saturn missions
were costing NASA around  500 million per shot in 1968.  it's why they
started scrubbing them.

Everyone who has looked at McDac's cost figures,  thinks they are reasonable.
the big question is wether or not the engineers can deliver payload.

I am sure i could really make my truck reliable by changing the suspension,
engine and drive train after hauling every load,  but what for?  it starts
when i stick a key in, so why should i complain?

Gary.  demonstrate how staged rockets can deliver lower costs then SSTO, and
you will have a point.

pat

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

Date: Tue, 15 Dec 1992 19:22:16 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: what the little bird told Henry
Newsgroups: sci.space

In <[e-mail]> [e-mail] (Gary Coffman) writes:

>Success oriented has always been a pejorative phrase in any complex
>developmental program that isn't tolerant of major program slippages
>and that doesn't have practically unlimited funding to fix problems
>as they appear. IE any non-military or commercial program.

Actually, commercial projects tend to be very success oriented,
because (unlike the public sector) failure does not bring in
more money and when the money's gone, the project's over.  The
failure-oriented, "cover your butt" mentality only ensures
failure, and that doesn't go over big with investors and financial
people.


>Any realistic development program *expects* problems along the way
>and plans for alternative approaches if one of the developmental
>technologies fails to live up to it's promise. Apollo took extraordinary
>risks in the Saturn booster program and suffered near catastrophe at
>least twice, either of which could easily have been like the Soviet N-1
>failures instead of the successes they were.

Oh, I see.  You aren't afraid the project will ultimately fail.
You're afraid that someone will get killed along the way.  In
that case, we'd better put an end to all large industrial projects.
Have you ever heard the saying, "every bridge kills a man?"

Better sell your car, too, and put all the money into health
insurance.  Stay home.  But don't go into the bathtub.  Even
that won't ensure perfect safety, however.  There is no absolute
certainty this side of the grave.


>Ask Mary about developmental programs.

Ask Mary yourself.  My family has been in the aircraft business
since the turn of the century.  We ran the *first* success-oriented
development program. :-)

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

Date: Tue, 15 Dec 1992 20:29:35 GMT
From: Brad Whitehurst <[e-mail]>
Subject: what the little bird told Henry
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Edward V. Wright) writes:
>In <[e-mail]> [e-mail] (Brad Whitehurst) writes:
>
>>Promoting the first X-30 as a "real" space-plane was not a good idea.
>>We work on SCRAMjet technology (not the actual engines) and can tell
>>you that there is a lot of work yet to do to really understand the
>>physics of fluid flow and combustion in that environment.  Unless you
>>want to spend seriously painful sums making and breaking engines
>>(these puppies AIN'T easy to test!), we need detailed info on the
>>physics so that what is built has a higher chance of success.
>
>Interesting NASA and the US Air Force were quite ready to test
>a scramjet-powered plane (the X-15C) during the 1960's, except
>that Congress wouldn't appropriate the money.  But today, we
>can't even try without developing a lot of new physics.  Guess
>somebody must have misplaced a lot of data in the last 30 years.
>(Or maybe just misplaced his cajones....)
>
>
    I know about the scramjet test article flown on an X-15, but
I'd never heard of a serious attempt to propel an X-15 with
scramjets.  I've read a fair amount of the NASA papers from '67
forward on scramjet research, and believe me, they had (have) a ways
to go before they could actually propel something.  The diagnostics
were crude in the extreme, and the computational models were in their
infancy.  Aside from issues of ignition and flameholding, mixing and
combustion efficiency, there were more practical issues of chamber
materials.  Plus, if you assume a M=2 flow into the combustor
(representative of conditions in the engine at a flight M of 5-8), 1)
the stagnation air temperature is around 2000 K--before you burn
anything! and 2) the mixing and burning lengths are such that the
combustor/nozzle combination would likely be much longer that the X-15
engine bay.  At those temperatures and Mach number, the inlet air is
moving about 1000 m/sec.  Unless you provide large lower speed areas
in the chamber (which is inefficient and leads to large losses),
you'll need several meters to complete combustion.  This is why there
is so much interest in so-called "external" combustion and nozzles, to
reduce the structure required for the engine (among other things).
    In short, it is not a matter of just "cojones".  That attitude will
get you nothing but dead planes, programs, and pilots.  According to
Yeager, one of the reasons he was successful as a test pilot was his
aptitude for understanding the hardware and why and what it was
doing.  Yes, the pilots need courage to face the unknown, but reckless
bravado will never replace good, careful engineering.  The laws of
physics don't give a shit how much testosterone is flowing in your
veins!  Now, a little intestinal fortitude in the halls of Congress
would be heartily welcome to support this work!
--

Brad Whitehurst    |   Aerospace Research Lab
[e-mail] |   We like it hot...and fast.

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End of Space Digest Volume 15 : Issue 550
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