Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_4/V13_464.TXT

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Subject: SPACE Digest V13 #464

SPACE Digest                                     Volume 13 : Issue 464

Today's Topics:
               Re: Saturn V and the ALS
        Space camp -- thanks for the resposes
          Re: Atlas Centaur bites the big one, 4/18
          Re: Energia (was Re: Saturn V blueprints)
               Re: Saturn V blueprints
       Re: Shuttle Reliability (was: Re: Saturn V and the ALS)
               Re: Gas Guns and Tethers
           Re: Uploading to alpha Centauri
               Re: Saturn V blueprints

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

Date: 25 Apr 91 16:42:48 GMT
From: mentor.cc.purdue.edu!noose.ecn.purdue.edu!en.ecn.purdue.edu![e-mail]  (/dev/null)
Subject: Re: Saturn V and the ALS

In article <[e-mail]>, [e-mail] (Glenn A. Serre) writes:
>    Not magically appear, I think NASA has been committing(sp?) resources
>    to the shuttle at the expense of other systems.  Now that they can, we
>    have ALS!
>
> This last sentence isn't too clear.  Are you saying that NASA can move
> resources from the Shuttle to ALS developement?

Not exactly, I'm sorry is I was not clear.  I meant to say that there}i is a
stirring of political will to look into cheaper alternatives to the shuttle.
NASA has also shown some will by allocating some money to ALS.

>
>    I think the stagnation of launcher technology is more of a refusal
>    of NASA to use anything other than the shuttle for launches. (Until
>    recently)
> Air Force launch technology is pretty stagnant, too.  I'd have to agree with
> Henry that it's due more to the fact that all launches are operational.
>
I am uncertain by what you mean in the last sentance.  I'll try to reply.

Sure its *partly* due to that, but NASA has been pretty insistant that
the shuttle be used a lot, and has booked flights for both military and
civilian uses.  I believe that NASA pressured a lot of military to
sign on.  In the post Challenger world, we are trying to find alternatives
to the shuttle and see that we have long neglected disposible launchers.

Another point is that there is such an over capacity of relatively expensive
launchers in the world ($2000+ /lb) that until prices drop a lot, there
probably will be no reason to bring in yet anxDother super-costly
($2000+/lb) launcher, and thus, more stag~rnation.

>    > *not* have to debug the design significantly.  For example, we know the
>    > engines run reliably without serious combustion instability... and that
>    > is several years' development bypassed right there.
>
>    BUT, engines could be made that burn less fuel and therefore lift
>    even more to orbit.  Maybe rocketdyne could modify the F-1 to
>    bring it up to date.
>
> This is how we got the SSMEs.  Increasing performance does not decrease
> cost, nor does it increase reliability (neccessarily).  The Saturn V could
> lift plenty of weight (mass, whatever) to orbit: 265,000 pounds.
>
Okay, I see what you mean.  The bonus that making it stronger/lighter
is allowing even more to be boosted making the pound to orbit decrease
to a reasonable level.  I'll agree that 265,000 pounds is great, but
if we could do better for similar costs, it would be worth looking into!
(And, please don't claim that it would cause the costs to skyrocket,
no one knows until it is technically examined in detaiL.)

>
>    > >You just said that you'd need to revise the drawings and retest, etc.
>    >
>    > No I didn't.  Please read what I wrote.  We have to figure out how to make
>    > it again; we don't have to figure out what to make.
>    >
>    Unfortunately, this can be just as expensive.


>
> I disagree completely.  The materials do NOT need to be made lighter.  The
> Saturn V worked as designed.  The F-1 engines were low-pressure, high-thrust,
> and they worked reliably.  Maybe if we had been building and using F-1s since
> the Apollo days, they would now be somewhat improved, but we scrapped the
> tried and true Saturn for the complex, high-performance Shuttle and its
> SSMEs.
>
So what is the best solution : resurrect the F-1 technology or use
Our current capability to make reliabile engines?


You know, maybe there could be a program to drop launch costs below these
really expensive per pound costs!  I think that is the real enemy of
would-be space utilizers!  If launch costs drop, then perhaps more
resources could be concentrated towards what we are going to do in space
and less on how we are going to get there (and 'oh my ghod look at that
bill!').

--
+-----------------------------------------------------------------------+
| Brent L. Irvine     |            These are MY opinions   |
| Malt Beverage Analyst     |            As if they counted...:) |
+-----------------------------------------------------------------------+

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

Date: 25 Apr 91 16:07:54 GMT
From: oravax![e-mail]  (Douglas Harper)
Subject: Space camp -- thanks for the resposes

I'd like to thank everyone who emailed me about Space Camp.  Apparently
email from this site isn't always reaching its destination.

The responses were all very encouraging and helpful, and I appreciate
them very much.  My daughter will be going to Space Camp this summer.

--
Douglas Harper    [e-mail]
        oravax![e-mail]

Are there any David N. White, SFS or KCA alumni reading this?

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

Date: 25 Apr 91 08:58:57 GMT
From: mcsun!ukc!icdoc!syma![e-mail]  (Nick Watkins)
Subject: Re: Atlas Centaur bites the big one, 4/18

From article <[e-mail]>, by [e-mail] (Fraering Philip):
> In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>>Sounds like you didn't look back far enough. :-)  Centaur's development
>>was a memorable horror story, although it has been very reliable in
>>recent times.
Most memorably, *both* the maiden flight of Atlas Centaur, May 8,, 1962
(also my debut :-) ), *and* the maiden flight of Titan IIIE Centaur were
failures. Former *may* be the spectacular explosion at end of Geoffrey
Reggio's film Koyannisqatsi (sp?), it certainly *was* an Atlas Centaur
exploding. Mariner 8 was also lost to an Atlas Centaur failure on 8 May
1971, but not an explosion. It has, as they say, been "the soul of
virtue in its later years", but I was still rather glad to hear that
CRRES was in orbit after the first commercial Atlas launch.

Nick


--

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

Date: 25 Apr 91 17:02:04 GMT
From: mojo![e-mail]  (Doug Mohney)
Subject: Re: Energia (was Re: Saturn V blueprints)

AIn article <[e-mail]>, [e-mail] (Charles Frank Radley) writes:
>whether or not NASA "likes" to buy launches from other people
>is moot.   Federal law PROHIBITS NASA from purchasing foreign
>launch vehicles.

As Henry so eloquently pointed out, Congress could pass one-time exceptions to
the "law" to allow NASA to purchase other launch vehicles. And if A) It saved
money and B) Provided some "laundering" of financial aid to the Soviet Union,
they'd do it in a New Yark minute.


     Signature envy: quality of some people to put 24+ lines in their .sigs
  -- >                  [e-mail]                        < --

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

Date: 25 Apr 91 20:09:00 GMT
From: mentor.cc.purdue.edu!noose.ecn.purdue.edu!en.ecn.purdue.edu![e-mail]  (/dev/null)
Subject: Re: Saturn V blueprints

In article <[e-mail]>, [e-mail] (Allen W. Sherzer) writes:
> No this is on budget as well as schedule. Unlike other fighter
> competitions this time the Air Force required significant buy
> in by the contractors. Both where expected to put up about half
> the development money. In fact, they may have come in a tad under
> budget.

They were 'expected' to do it because the Pentagon shorted the cash.
Not any special contract agreement.

Also, the Northrop time WAS 6 mo. ahead in completing the prototype,
the Lockheed team was 1 year LATE (they asked for an extension and
got it).

>
> Good engineers CAN estimate the cost of building things; even advanced
> products.
>

I agree, but many times they aren't the ones making the schedule
or budget.

--
+-----------------------------------------------------------------------+
| Brent L. Irvine     |            These are MY opinions   |
| Malt Beverage Analyst     |            As if they counted...:) |
+-----------------------------------------------------------------------+

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

Date: 26 Apr 91 02:37:59 GMT
From: agate!lightning.Berkeley.EDU![e-mail]  (Frank Crary)
Subject: Re: Shuttle Reliability (was: Re: Saturn V and the ALS)

In article <[e-mail]> [e-mail] writes:
>This 97.4% figure for the Shuttle success rate is somewhat misleading.  It's
>really just a measure of how many times the Shuttle has launched without
>blowing up.  Just ask the people working on projects like Galileo, Astro,
>HST, etc., etc., etc., how successful they think the Shuttle has been.  If
>we looked at how many items in all the planned manifests of the Shuttle were
>successfully executed, how low would the success rate be then?  Far below
>50% I would imagine.  Can anyone out there venture a guess?

To quote the Office of Technology Assessment's _Round Trip to Orbit_
(OTA-ISC-419)
"In 1988, a NASA contractor predicted post-Challenger Shuttle reliablity
would be between 97 and 98.6% and used 98% as a representative estimate.
A more recient NASA study of success on the Galileo mission would probably
be between 1 in 36 (97.2%) and 1 in 168 (99.4%)."
In an earlied study, OTA used 96% as an estimate, but said that the reliablity
was almost certainly about 87% (e.g. a greater than 87% probability that the
reliability wa above 87%).

                        Frank Crary
                        UC Berkeley

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

Date: 23 Apr 91 18:23:41 GMT
From: ssc-vax!bcsaic!hsvaic![e-mail]  (Dani Eder)
Subject: Re: Gas Guns and Tethers

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>
>Railgun, coilgun, gasgun, whatever, all are technically feasible for
>small payloads that don't mind thousands of Gs. If you try to scale
>them up to worthwhile payload size, or try to stretch them out for
>reasonable G forces, then either the enviornmental problem of ground
>level hypersonic shock waves, or the sheer physical size of the launcher
>make them impractical.
>
>Tethers need to exceed the theoretical strength of materials limits by
>orders of magnitude to work. Again, a fundamental scientific breakthrough,
>not engineering R&D, needs to occur before tethers can become reality, if
>ever.
>

The lower bound on accelerator g's can be found by considering the
west slope of the island of Hawaii.  There is a region of nearly
constant slope approximately 20km long extending from about the
1 km altitude to approximately the 4 km altitiude.  If a launcher
has a muzzle velocity of 5000 m/s, then basic physics shows the
acceleration required is a=v^2/2d=625m/s^2, or 63 g's.  While this
is more than people can stand, it is by no means 'thousands' of g's.

As far as wothwhile payload size, I personally believe that I could
do useful things with 10 kg payloads at a time, given some progress
in the direction of 'brilliant pebbles', or very small spacecraft
that have sensors and maneuvering capability.  However, I have designed
a gas gun that delivers 5 ton payloads at a time.

Yes, the noise generated by a big hypersonic launcher is great.  So
is the noise generated by the space shuttle.  Give me a similar
5 km clearance zone and the noise will be tolerable.

On the subject of tethers, it is well known that the minimum mass
tether is an exponential taper in cross section per 'scale length'.
The scale length is the length under 1 g which can support it's own
weight under 1 g.  For Amoco performance products T-1000 graphite
fiber, which has a tensile strength of 6895 MPa and a density of
1845 kg/m^3, the scale length under 1 g is 381 km.

If we limit ourselves to an area taper ratio of 100, then we can\
dangle ln(100)=4.6 scale lengths of cable.  This is 1752 km.  The
Earth's gravity well is 6375 km deep, thus we are 27% of the way there.
The theoretical strength can be found from the work done in
diamond anvil cells that reach extremely high pressures.  The
cells routinely reach pressures of over a megabar, or 1 million
atmospheres.  This is 15 times the strength of the graphite fibers.
Thus there is plenty of room to reach a sufficient strength to
do a simple tether.

This ignores the fact that you do not have to have a tether all
the way from orbit to the ground.  A shorter tether hanging vertically
in orbit will have it's lower end moving sub-orbitally.  A launch
system then only has to reach the bottom of the tether, rather than
orbit.  Anything that makes a launch vehicles' job easier is
beneficial.  The reminder of the ride to orbit (which is at the
center of mass of the tether) can be via elevator.

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

Date: 25 Apr 91 13:50:56 GMT
From: media-lab.media.mit.edu![e-mail]  (Marvin Minsky)
Subject: Re: Uploading to alpha Centauri

Oh.  Because of being on the NSS board of governors, we get to meet
the Vice-president next week.  Any suggestions about questions to ask
him?  (I can't promise to remember the answers, but I'll try.)
  (I would like to explain to him why Fred should be replaced by a
station that is remotely-manned by telepresence from earth, but I
expect my colleagues will try to kill me before I manage to make the
point.)

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

Date: 25 Apr 91 21:01:56 GMT
From: mojo![e-mail]  (Doug Mohney)
Subject: Re: Saturn V blueprints

In article <[e-mail]>, [e-mail] (Allen W. Sherzer) writes:
>
>>It was indeed done under fixed price contracts, of about $600M
>>as I recall. However, apparently >both< prime contractors spent
>>more like $1B each on the project. I don't know about the schedule,
>>but they blew the budget significantly
>
>No this is on budget as well as schedule. Unlike other fighter
>competitions this time the Air Force required significant buy
>in by the contractors. Both where expected to put up about half
>the development money. In fact, they may have come in a tad under
>budget.

You are incorrect. They put in MUCH more than half the development money. Maybe
close to 75-80%. The losing contractor (as I previously mentioned and which
you chose to ignore) lost lots of money, and the AF will not conduct business
that way in the future, due to the disincentives of a "Winner Take All"
approach. The long-term effects of this contract on our industrial base are
unclear.

>Good engineers CAN estimate the cost of building things; even advanced
>products.

This contract, and military "products" in general, is fundmentally different
from a commercial good. The producers of the ATF have a locked-in monopoly;
there is no 40/60 split of goods, as with certain second-sourcing of missiles.
The winning contractor will recoup the expenses of his investment through
selective bookkeeping and profits over the years, with no incentive to hold
prices down, other than the threat of Congress cancelling/ordering fewer planes
in the future.

Using the military as an "example" of proper procurement and estimation is a
VERY VERY poor example. I suggest you look up the cases of the C-5, B-1, and
B-2. Oops, forget the A-12, but it was cancelled.



     Signature envy: quality of some people to put 24+ lines in their .sigs
  -- >                  [e-mail]                        < --

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End of SPACE Digest V13 #464
*******************