Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v13_2/v13_275.txt

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Subject: SPACE Digest V13 #275

SPACE Digest                                     Volume 13 : Issue 275

Today's Topics:
        Re: Value per pound vs. cost per pound
       Re: Saturn V (was: space news from Jan 28 AW&ST
          NASA Headline News - 03/14/91 (Forwarded)
               WX SAT receiver
              Re: MANY QUESTIONS
                  Re: Thrust

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
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----------------------------------------------------------------------

Date: 12 Mar 91 22:17:05 GMT
From: news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Value per pound vs. cost per pound

In article <[e-mail]> [e-mail] (Nick Szabo) writes:
>>Nick's problem here is that he doesn't know much about launcher design,
>>or he wouldn't make ridiculous statements like "already strained to its
>>technical limits".
>
>I certainly know a lot more than you've told us about.

Nick, I'm not going to type in a tutorial on launcher design.  I would
recommend Hunter's "Thrust Into Space", Sutton's "Rocket Propulsion
Elements", and Huzel+Huang's "Design of Liquid Propellant Rocket Engines",
in that order, to anyone who wants to learn about the "technical limits".

>If you look
>at the statistics of jet airplanes vs. rockets, for example fuel per pound
>of payload, structural mass per pound of fuel, maximum speed, etc., you
>will find that chemical rockets are stretched farther to the limits than
>airplanes.

Rockets are different from airplanes; one-to-one comparisons are dubious.
Is a 747 "stretched farther to the limits" because it is built to take
much lower gee-loadings than an F-15?  Well, yes and no; flying in a 747
is unquestionably safer than flying in an F-15, by "the statistics".
Rockets push fuel:payload ratios and fuel:structure ratios harder than
airplanes, but most rockets' operational lifetime is measured in minutes,
so issues like fatigue life are much less significant.  They hit far higher
maximum speeds, but in far thinner air where aerodynamics largely ceases
to be an issue.  The thrust:weight ratios of their engines are much higher,
but that is as much an advantage as a disadvantage, given good design.

Max Hunter, in particular, has stated openly that building airplanes
is a lot harder than building rockets, because high-speed aerodynamics is
far more complex than rocket engineering.  Given his background, I find
his opinion credible.

>The cost of building jet airplanes has flattened out, and I
>expect the cost of building chemical rockets has or soon will do likewise,

What analogy do you see between such vastly different vehicles?  Do you
expect "the cost" of building chemical rockets to level out at current
US/European aerospace-company prices, or at Chinese refrigerator-company
prices?  (Great Wall Industries is not an aerospace company, primarily,
and it shows.)

>>Launcher designers commonly trade off performance for
>>reliability, ease of handling, use of existing hardware, etc.; you would
>>not find such tradeoffs in systems that were stretched to their limits.
>
>All transportation systems have these tradeoffs, including those that have
>reached their economic limits.

Ah, but now the base for discussion has shifted.  All of a sudden we're
no longer talking about a system that is "strained to its technical limits"
in some unique way.  Now economic tradeoffs enter the picture, and technical
issues are resolved in much the same way as for airliners:  change the
economic tradeoffs, and the not-strained-to-their-limits technical tradeoffs
change to match.  Worry about fuel prices, and airliners get less thirsty.
Worry about the ozone layer, and rockets will get less dirty.

>>As a case in point, almost every launcher designer uses 3 or even 4 stages
>>to get to orbit, when Atlas did it with 1.5 over thirty years ago.  There
>>are large margins of performance available if environmental constraints
>>become serious enough to justify major redesign.
>
>It doesn't seem that Atlas has significantly reduced launch costs.

Uh, what does that have to do with what I was saying?  Again, we are
suddenly changing the thrust of the discussion.  Atlas got far higher
performance than current launchers, at a price in manufacturing cost
and handling convenience.  (Balloon tanks are a pain to deal with on
the ground.  Not dangerous, just a hassle.)  Shift the constraints
enough, and that price becomes worth paying to get the performance.
--
"But this *is* the simplified version   | Henry Spencer @ U of Toronto Zoology
for the general public."     -S. Harris |  [e-mail]  utzoo!henry

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

Date: 13 Mar 91 15:01:07 GMT
From: maverick.ksu.ksu.edu!zoot.avgrp.cr.rok.com!aten.cca.rok.com![e-mail]  (Michael L. Cook)
Subject: Re: Saturn V (was: space news from Jan 28 AW&ST

In article <[e-mail]>, [e-mail] (John A. Weeks III) writes:

|>the Saturn V must have been the result of a team of engineers, and was tested
|>and retested innumeral times.  All without the benefit of modern
supercomputers,
|>or even the luxury of a hand calculator.
|>
|>It amazes me that the Saturn V was possible at all, let alone 25 years ago.
|>
|>I wouldn't mind seeing the Saturn V fly again, but I would like to think that
|>we (humans, including those north of the boarder) could do better.

World Wide News should jump on this.  The Saturn V was built for us by
space aliens!!   They knew we could not do it ourselves.  This would explain
all those missing documents, specs, blueprints, etc. making it impossible
for us to build one now.

Michael Cook
Internet: [e-mail]
"Post no bills"

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

Date: 14 Mar 91 16:41:35 GMT
From: elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: NASA Headline News - 03/14/91 (Forwarded)



             Headline News
Internal Communications Branch (P-2) NASA Headquarters

  Thursday, March 14, 1991        Audio Service: 202 / 755-1788

This is NASA Headline News for Thursday, March 14, 1991

Kennedy Space Center technicians are performing final preparations
on Atlantis and its STS-37 stack for rollout to launch pad 39-B.
Atlantis is currently being powered down.  Tile closeout work on the
orbiter has been completed.  First motion in the three-mile move to the
launch pad will begin at 12:01 am tonight.  The vehicle should be at
the pad by daybreak tomorrow.  Atlantis will be powered up again
once the mobile launch system is properly seated on the pad.  Auxiliary
power unit hot fire tests are expected to take place over the weekend or
early next week.  The Gamma Ray Observatory is already in the
payload changeout room, awaiting Atlantis' arrival, and is expected to
be installed into the orbiter's payload bay late this weekend.

The STS-37 terminal countdown demonstration test is set for
next Tuesday and Wednesday, March 19 and 20, with T-0 at 11:00
am on the 20th.  Atlantis' flight crew will arrive this Sunday in
preparation for that test.  The flight readiness review will be held at
KSC one week later, March 26 and 27.

Discovery was demated from its stack yesterday and is presently in
the process of being towed to the Orbiter Processing Facility.  It
should be in the OPF by early this afternoon and will then be
prepared for power-up operations.

Space flight chief Bill Lenoir is visiting the Kennedy Space Center
today and will meet with Florida reporters for an informal
briefing later this afternoon.

                   * * * * * * * * * * * * * * * *

The 22nd annual Lunar and Planetary Science Conference
begins at the Johnson Space Center Monday, March 18.  More than
750 researchers from around the world will present findings on their
latest discoveries during the week-long conference.

On Monday and Wednesday evenings, March 18 and 20, the conference
will present special public sessions focusing on present and future
scientific exploration activities.  The Monday session, "Science
Exploration and the New NASA," will discuss the future
opportunities for exploration and features Space Science Associate
Administrator Lennard Fisk, JSC Director Aaron Cohen, JPL Director
Dr. Edward Stone, and Martin-Marietta Chief Scientist Dr. Noel
Hinners.  The session will be chaired by Dr. Carolyn Huntoon, JSC
space and life sciences director,  and Dr. Michael Duke, JSC Lunar and
Mars exploration program scientist.  The Wednesday session, "Venus,
Earth and Moon: New Views from Magellan and Galileo," will
focus on discoveries made by the two spacecraft in the past year and
will be hosted by Dr. Wesley Huntress, NASA director of solar system
exploration.  Both special sessions begin at 8:00 pm Central time and
will be in the JSC Teague Center Auditorium.


                   * * * * * * * * * * * * * * * *

KSC management will hold a ground-breaking ceremony for the
Space Station Processing Facility on Tuesday, March 26, at
10:00 am.  Center Director Forrest McCartney will preside.


Here's the broadcast schedule for Public Affairs events on NASA Select
TV.  All times are Eastern.  NASA Select TV is carried on GE Satcom
F2R, transponder 13, C-Band, 72 degrees W Long., Audio 6.8,
Frequency 3960 MHz.

Thursday, 3/14/91

        12:00 pm        Taped replay of House Subcommittee on Space
Science and Applications (Committee on Science Space and
Technology) hearing on NASA's Aeronautics, Exploration, and
Technology FY 92 budget.  Arnold Aldrich was the NASA witness.
(Recorded Wednesday.)

        6:00 pm        Taped replay of House Subcommittee on Technology and
Competitiveness (Committee on Science, Space and Technology), and
the House Subcommittee on Research and Development (Committee on
Armed Services) joint hearing on National Aero-Space Plane.
(Recorded Tuesday.)

        7:30 pm        Taped replay of House Subcommittee on Space Science
and Applications (Committee on Science Space and Technology)
hearing on NASA's Aeronautics, Exploration, and Technology
FY 92 budget.  Arnold Aldrich was the NASA witness.  (Recorded
Wednesday.)

Friday, 3/15/91

        12:00 pm        Taped replay of sessions from the American
Astronautical Society 29th Goddard Memorial Symposium being
held in Washington today and tomorrow.

      ___    _____     ___
     /_ /|  /____/ \  /_ /|      Ron Baalke         | [e-mail]
     | | | |  __ \ /| | | |      Jet Propulsion Lab |
  ___| | | | |__) |/  | | |___   M/S 301-355        | Change is constant.
 /___| | | |  ___/    | |/__ /|  Pasadena, CA 91109 |
 |_____|/  |_|/       |_____|/                      |

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

Date: Thu, 14 Mar 91 10:26:46 -0600
From: [e-mail] (Corporate reorgs are like 120mm JHPs, a little too much)
To: "[e-mail]"@skvax1.csc.ti.com
Cc: [e-mail]
Subject: WX SAT receiver

I've seen people asking for information on building WX-SAT receivers, so I'm
sure this will of interest to some of you.

In the latest (March-April) issue of _Ocean Navigator_ this is a short writeup
on receiver from D. F. Crane.  The system consists of a modified Bearcat
scanner, demodulator, software and antenna.  Price is under $650.  You provide
the PC.

This system is setup for the polar orbit satellites, such as TIROS, Meteor and
the Chinese (named??) system.  The data is raw telemetry, so you will have to
interpret it some, but you get it hours quicker than with weatherfax.

D. F. Crane can be contacted at:

710 13th St, #209
San Diego, CA  92101

I really don't know anything more about them, I've just now mailed my letter.
If anyone is interested, I'll post more details when they show up.

Dillon Pyron                         | The opinions are mine, the facts
TI/DSEG VAX Systems Support          | probably belong to the company.
[e-mail]                  |
[phone]                        | "Leopold!  Leopold!!  Leopold!!!"
                                     | - _The Marriage of Bugs_

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

Date: 13 Mar 91 04:54:35 GMT
From: news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: MANY QUESTIONS

[Transliterated to lower case to make it at least semi-readable!  Please
don't post long articles in SCREAMING UPPERCASE.]

In article <[e-mail]> [e-mail] writes:
>4.  more morbid curiosity...since the challenger explosion has there been any
>effort to redesign the shuttle orbiter so that the crew cabin could be used in
>an emergency splashdown?  maybe something like the present crew cabin with its
>own parachute system and heat sheild? ...

The idea is not ridiculous, but it would require massive redesign, and
the extra mass might well wipe out the shuttle's payload entirely.  The
ESA designers working on Hermes came to the same conclusion as NASA:
bringing the whole cabin down is difficult and costly, and probably
not worth it.  (ESA has gone for ejection seats on Hermes, over the
protests of the astronauts, who think the correct solution is not
to fit an escape system at all.)

>5. on the lighter side...are there any shuttle missions planned that call for
>carrying the external tanks into leo? ...   i quess i really want
>to know why this isn't being done already.

The Gamma Ray Imaging Telescope project has looked at the idea, although I
don't believe it is scheduled to fly any time soon.  Putting the tank
into orbit costs payload, it will come down quickly due to air drag unless
precautions are taken, space debris will puncture it quickly, and its own
insulation will crumble and create more debris, so nobody is going to put
up a tank until there is a specific project that wants it and can invest
enough effort to deal with the problems.

>...are there any plans which call for 2 orbiters to be flown at the same time
>and rendevous with each other?

No.  It would serve no terribly useful purpose and would overstrain support
facilities that are only just adequate for a single flight at a time.

>7.  are there any plans for joint missions with nasa's russian counterpart?

There's talk about flying a cosmonaut on the shuttle and an astronaut on Mir.

>... the shuttle
>could rendevous with mir, do some international good-will type stuff, maybe
>even some real science, and then, after some type of eva the astronaut would
>come home with the shuttle.  is there anything preventing such a mission?

Yes:  the shuttle fleet is too busy.  This would have to be a dedicated
mission.  There are also some practical problems with docking adapters
and such, which are not standardized.

> when (or if) we send a manned mission to mars are there any plans to leave
>something like the space telescope there?

Not at present.  It would cost too much and there are too few advantages.
Increasing the baseline for parallax measurements by 50% is not worth it.

>whenever there is a flare alert it makes me wonder what precautions the mir
>cosmonauts take to avoid lethal exposure...

None that I know of, beyond avoiding EVAs and the emergency option of
coming down in the attached Soyuz immediately.  Mir is within the Van Allen
belts and is protected from the worst of a flare.

>... what sort of problem will solar
>flares present to the mars mission and its crew...

Serious.  Some sort of shelter will be needed, although the weight is a
troublesome nuisance.
--
"But this *is* the simplified version   | Henry Spencer @ U of Toronto Zoology
for the general public."     -S. Harris |  [e-mail]  utzoo!henry

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

Date: 12 Mar 91 16:51:24 GMT
From: news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Thrust

In article <[e-mail]> [e-mail] (Glenn A. Serre) writes:
>Another method that has been mentioned is launching water from Earth, then
>using solar energy to convert it to hydrogen and oxygen ...
>...
>I thought that the Space Station (Fred) was at one time going to use this
>scheme.  Has this been abandoned?

Yes.  Fred was going to electrolyze waste water -- humans have a positive
net water output due to chemical breakdown of food, so even a water-recycling
life-support system has a water surplus -- and use the result as maneuvering
fuel.  This got axed in favor of shipping up ton after ton of N2H4/N2O4, to
save development costs.
--
"But this *is* the simplified version   | Henry Spencer @ U of Toronto Zoology
for the general public."     -S. Harris |  [e-mail]  utzoo!henry

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

End of SPACE Digest V13 #275
*******************