Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_5/V13_550.TXT

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Subject: SPACE Digest V13 #550

SPACE Digest                                     Volume 13 : Issue 550

Today's Topics:
           Re: Question about paint color for cars?
             Re: Laser launchers
                 subscription
Re: Launch Costs XXIV -- Wright Bros. Flyer to carry tanks to Kuwait!
               Re: Saturn V and the ALS
       Re: NASA Headline News for 05/08/91 (Forwarded)
              Re: Why the space station?
      Re: 14 Astronauts have died for space exploration?
            SPACE Digest V13 #517
             Re: Laser launchers

Administrivia:

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Date: 13 May 91 21:33:39 GMT
From: dog.ee.lbl.gov!hellgate.utah.edu!cs.utexas.edu!samsung!rex!uflorida!kluge!serss0![e-mail]  (Jim Stafford)
Subject: Re: Question about paint color for cars?

In article <[e-mail]> [e-mail] (Cyrus Shafai) writes:
>What paint color lasts the longest on cars?
>I have heard that red paint doesn't last too long, and that metallic paint doesn't
>do too well in the sun.
>
>Cyrus Shafai
>--
>Cyrus Shafai            <[e-mail]>
>The Scanning Tunneling Microscopy Laboratory
>Electrical and Computer Engineering, U of Manitoba
>Winnipeg Manitoba

Down here in the subtropics, our cars develop skin cancer at an early age.
The only color that lasts is white.  Metallics do indeed fade after a few
years.  I have an '82 Plymouth Champ (an otherwise wonderful car) that used
to be silver.  The sides still look great, but the upper surfaces are cooked,
with what appears to be mildew growing in dark splotches.  (I kind of like
it, it's very unique and nobody would ever sit on it.)  My wife has an '88
Camry (also silver) that still looks fine; supposedly the newer paints last
longer.

So metallics are bad, blue almost as bad as silver.  Red non- metallic doesn't
seem to fade so much as get very dull as the outer layer of paint oxidizes.
You can remove it, but you only have so much paint.

You could park in the shade, but then the tree sap gets you, and ants move
into your car that eat the sap, etc........

jimbo

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Date: 13 May 91 18:07:14 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!emory!wa4mei!ke4zv![e-mail]  (Gary Coffman)
Subject: Re: Laser launchers

In article <[e-mail]> [e-mail] (Fraering Philip) writes:
>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>
>I also notice you pick the laser system _you_ would use and then go on
>to show that it wouldn't work. Basically all you've proven with that
>argument is that if it's going to be attempted, *you* should *NOT* be in
>charge of the project.

I wouldn't take charge of a project that I don't believe can succeed.
I chose *a* laser system for the example. I don't know of *any* laser
system that we have a clue about knowing how to build that would work
much better.

>Granted, research does need to be done. But you seem to be implying
>that NASA shouldn't do it. Then who? The size of a prototype laser launcher
>is about $100 million, beyond the range of any universities. Private

What I'm implying, no, what I'm outright saying is that I don't think
this system will work better than chemical rockets, if it can be made
to work at all, no matter who does the research. Therefore I am certainly
opposed to spending tax money on it. I don't think this is a Luddite
attitude. I think it is based on a sound view of the technical problems
inherent in the system.

>Not for smaller tethers. They could even reboost themselves by coupling
>with the Earth's angular momentum via the Earth's magnetic field, to make
>up for losses when something gets picked up from ye olde suborbital rocket.

The system originally being discussed was a beanstalk rather than a dynamic
tether. Of course dynamic tethers can be built, but we were talking about
getting something from the ground to orbit.  That's not a job for dynamic
tethers. Dynamic tethers are a low energy way of altering an existing
orbit or changing a suborbital trajectory to an orbital trajectory. As
a means of dramatically reducing the cost of ground to orbit transport,
they aren't in the running. The majority of the cost occurs in the first
5 km.

Let's look at a typical strawman tether launch. Let's propose a 1000 km
tether whose center of mass is in a 700 km orbit. To hook on to the
lower end of the tether, you need to be going faster than the orbital
velocity of a 700 km orbit and be at an altitude of 200 km. If you've
already gone that far, you've paid most of the cost to orbit. So the
tether doesn't buy you that much. And you've added considerable Rube
Goldberg complication to the scheduling of your launch. Above an airless
body like the Moon, a tether begins to make a lot of sense. But for
Earth based launches, you've got to keep the end of the tether above
the majority of air resistance or it'll end up in your lap.

It always comes back to fighting that pesky air. That's why I keep
harping on turning that liability into an asset by using wings and
air breathing engines to get above most of it.

Gary

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

Date: Mon, 13 May 91 17:46:27 -0700
From: [e-mail] (Kevin Synott)
Subject: subscription

Please add me to the space subscription list.
Many thanks in anticipation    Kevin Synott...

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

Date: 13 May 91 15:14:47 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!swrinde!emory!wa4mei!ke4zv![e-mail]  (Gary Coffman)
Subject: Re: Launch Costs XXIV -- Wright Bros. Flyer to carry tanks to Kuwait!

In article <[e-mail]> [e-mail] (Fraering Philip) writes:
>
>They say that the best way to get people to believe a falsehood is to
>tell it over and over and over and over and over and over and over
>again.
>
>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>
>>technology can be left as an exercise to private companies, if they can find
>>a market for such expensive heavy lift capability. An ALS demonstration
>>program can form the base for a real privately built heavy lift transportation
>>system that will benefit from thirty years of technological progress.
>
>>Unlike Nick, I believe that chemical rockets aren't some obsolete technology
>>that needs to be left behind. Rather, what needs to be left behind are
>>obsolete 1940s, 1950s, and 1960s designs for chemical rockets.
>
>[more left out about that 'cheap heavy booster' that's going to
>save the world and even make coffee automatically for everyone,
>although only as good as yankee coffee :-( :-)]
>
>But what if it is easier to develop a just as cheap (per pound)
>light launch vehicle than to develop the heavy one?

I'm of the opinion that small cheaper launchers will emerge without
NASA's help. There is already strong commercial interest in Pegasus
which is not particularly cheap in it's present incarnation. It does
point the way however by using wings and air breathing engines for
the initial stage of the journey to orbit.

I think that government funding will be necessary to prime the pump
for a cheap heavy lift vehicle. I know also that presently there is
no market for such a HLV. Again, I believe that when such capability
becomes routinely available, a market will develop. There was no
shortage of proposed payloads when Saturn was available. They may
not have been commercially viable at Saturn launch prices, but we
will never know since the government decided to scrap Saturn. There
certainly was no shortage of proposals for scientific payloads that
would have been funded by the government. As to Soviet HLV capability,
I understand that the full up configuration has only flown twice. I doubt
anyone is going to trust their one of a kind payload to a system with such
a short track record unless the government is footing the bill.

The ALS demonstration program that I was advocating is fairly long
range. I agree with most of the people who are saying that heavy
lift is not a high priority right now. But in 2020 we may wish we
had pushed a development program back in the late 90s for such a
beast.

Gary

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

Date: 13 May 91 19:45:16 GMT
From: aio!icarus.jsc.nasa.gov![e-mail]  (Brad Mears)
Subject: Re: Saturn V and the ALS

In article <[e-mail]>, [e-mail] ("Allen W. Sherzer") writes:
|> Why would they lowball for a fixed price contract? They would lose
|> a lot of money that way.

One _possible_ reason to lowball on a fixed-price contract is to bet on future
contracts for maintenance, training, updating, etc.  The original builder will
have an edge in those efforts.

Additionally, the cynic in me believes that even on a fixed-price contract,
cost-overruns will be passed to the taxpayer.  I know that isn't the way its
*supposed* to happen, but Congress+Lobbyists = Trouble.

BTW, I'm not defending Shuttle or ALS.  My only goal is to see a cheap, reliable
means of getting to orbit.  And if McDonnell and/or Martin want to build such a
thing, let 'em do it.  But I'm not convinced that just because they say "fixed-
price contract", everything will be peaches and cream.

--
Brad Mears
[e-mail]

----------------------------------------------------------------------------
Opinions are expressly forbidden.  | "It is better to die on your feet
I speak for myself and no other.   |  than live on your knees"
                                   |                    - Dolores Ibarruri
----------------------------------------------------------------------------

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

Date: 13 May 91 20:15:25 GMT
From: emperor![e-mail]  (Dave Rickel)
Subject: Re: NASA Headline News for 05/08/91 (Forwarded)

> The Astronauts Memorial, honoring the 14 U.S. astronauts who
> have given their lives in the exploration of space, will be unveiled
> and dedicated tomorrow at the Kennedy Space Center.

This has almost certainly been covered before--please email me the answers.

Anyway, i can think of ten--three from the Apollo fire, and seven from the
Challenger.  Were the other four in training flights?

How much empty room did they leave?  Enough for a hundred names?  A dozen?


david rickel
uunet!emperor!daver

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

Date: 13 May 91 16:29:44 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Why the space station?

In article <[e-mail]> [e-mail] writes:
>The explorers want many more, smaller probes, and none of the exotic
>systems require assembly...

They do not require assembly because one of their basic design assumptions
is "in-space assembly is not available".  This is like NASA saying "none of
the microgravity experimenters need ISF" because all the experiment plans
assume that only the shuttle orbiter is available.

The smaller probes definitely don't need assembly.  The bigger ones really
could use it.  Just look at some of the elaborate schemes people have put
together trying to do a Mars sample return using existing launchers with
no in-space assembly.  Those plans are far riskier and far more exotic than
putting the mission together in orbit.
--
And the bean-counter replied,           | Henry Spencer @ U of Toronto Zoology
"beans are more important".             |  [e-mail]  utzoo!henry

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

Date: 13 May 91 16:37:26 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: 14 Astronauts have died for space exploration?

In article <Added.sc=[e-mail]> [e-mail] (Bob Rehak Ext. 3-9437, AIS Central Services  -  Swen Parson 146) writes:
>>The Astronauts Memorial, honoring the 14 U.S. astronauts who
>>have given their lives in the exploration of space, will be unveiled
>
>14 astronauts?  Last time I counted there were only 10.

What counting rule are you using?  If you count only deaths incurred as
part of an actual mission, there are only 7.  If you count deaths in the
course of mission-related activities on the ground too, there are something
like 14.  If you try to include the Apollo 1 crew (killed in a ground test)
but exclude the several astronauts killed in on-duty flying accidents, the
rule starts to get very arbitrary and artificial.  Bear in mind that part
of the reason why the astronauts do their own flying is for practice.
--
And the bean-counter replied,           | Henry Spencer @ U of Toronto Zoology
"beans are more important".             |  [e-mail]  utzoo!henry

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

ReSent-Message-ID: <Added.Uc=[e-mail]>
Resent-Date:  Mon, 13 May 91 13:26:47 EDT
Resent-From: Tom <[e-mail]>
Resent-To: [e-mail]
Date:         Fri, 10 May 91 02:20:38 EDT
Reply-To: [e-mail]
From: [e-mail]
Subject:      SPACE Digest V13 #517
Comments: To: [e-mail]
To: david polito <[e-mail]>, Tom McWilliams <[e-mail]>

Re Moons of Jupiter as life-home

>>>Terraforming the moons of Jupiter would probably be easier :-).

>>It might be easier, but with so litte energy (sunlight), the issue is whether
>>it would last, or be worth the effort.

>So, use a bigger mirror. What could it take, one more small stony
>asteroid worth of Al to build a mirror of the requisite size?

Requsite size?
Assuming you want the same sun-light levels as on earth, you would need
mirrors roughly 100 times the size of the surface you want to illuminate.

Of course, Jupiter puts out more heat than the sun (from the moons point
of view) so you might get advantages from using Jupiter as a source, too.

But even so, your logistics problems with huge mirrors begs the 'is it
worth it' question, and the 'would it last' question as well.

You could just terraform with low-energy forms of life, like bella palms and
mushrooms, but that begs the 'worth it' question too.

Especially when the industrial capacity to build huge mirrors implies the
capacity to build O'neill-style colonies, which would be much easier than
any kind of terraforming.

Tommy Mac
Acknowledge-To: <18084TM@MSU>

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

Date: 13 May 91 18:50:11 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!emory!wa4mei!ke4zv![e-mail]  (Gary Coffman)
Subject: Re: Laser launchers

In article <[e-mail]> [e-mail] writes:
>
>A review of the whole thesis point by point:
>
>* The cost/learning curve for chemical rocket vehicles is approaching a
>  limit at about $1,000/max lb. LEO, well above what is needed for
>  affordable space emigration (between $1-$10/max lb. to LEO, depending
>  on whether it is affordable only to upper class, or to upper
>  and middle class.  This stranslates to $4-$40/lb. to a Lagrange point
>  space colony, or $5-$50/lb. to a lunar or asteroid colony.)

Like most learning curves, we can suppose that this one is S shaped
with an initial rather flat rate of improvement followed by a very
rapid rise and settling to another rather flat long term period of
incremental improvement. The argument is then, "Where are we on the
curve right now?" Nick says we are at the top with all the major
improvements already done. I believe we are very near the bottom,
with most of the cost efficiencies still to be made. When we get to
the point where we are cranking out thousands or tens of thousands
of standardized launch vehicles a year, then we will be near the
top of the curve.

>* A discovery significantly changing that curve will also change the
>  cost curves of other internal-chemical vehicles, such as cars,
>  airplanes, etc.  And vice versa.  An advance dropping chem rocket
>  launch costs to $1/max lb LEO. will just as likely drop the cost of a new
>  car to $3, or a round-trip ticket NY-Tokyo to $.75.

I can't get three blocks for $1 in a taxi, I don't expect to get to orbit
for a dollar either. I think you are looking for an unrealistic cost to orbit.

>* The search space for this kind of technology is well-trod, making
>  curve-changing advances highly unlikely.

While we have a pretty good handle on the fundamental principles of
rocketry, I don't think we've begun to scratch the surface on manufacturing
and operating efficiencies. Karl Benz knew how to make a car, but it took
Henry Ford to figure out how to make it cheap.

>* The search space for laser launch, tethers, EML is fresh territory,
>  making it much more likely that R&D on these fronts will provide
>  fundamental, curve-changing advances.

I'm dubious that laser launchers, tethers, or EML will be cost effective
ways to orbit from the Earth's surface. Other methods that we haven't
thought of yet may be better than the chemical rocket. From airless
bodies like the Moon, tethers and EML seem more promising. I'm not
convinced that lasers make sense even there.

>* Government lab's primary role is research on technologies
>  with high potential for breakthroughs, which is too long-term
>  for private industry to undertake.  In other words, government
>  should be breaking new ground.

I agree with this. The argument comes with where that new ground lies
and what constitutes a lab and what constitutes a service organization
providing access to space for scientific payloads.

>* Private industry's role is R&D, and operations, on technology
>  demonstrably profitable in the current or near future.

Agreed.

>* _Therefore_, government labs should be doing R&D on the advanced.
>  new-field launch technologies.  Chemical rocket research should
>  be the job of private industry.

The labs should be doing R&D on ways to provide the *service* of
Earth to orbit cheaply. If that way turns out to be a new standard
manufacturing and operating technique for chemical rockets, then so be it.


>In other words, looking for big chemical rocket cost reductions
>is like going out today and looking for a big gold nugget at Sutter's
>Mill.  It is like being the last in line at an Easter-egg hunt.
>Chances are, somebody already found the good stuff.

More apt is the analogy of the hand made 1885 Benz and the 1914
Model T. That represented a cost reduction from $10,000 to $400
for an automobile with the latter being easier and cheaper to operate
and maintain. We haven't begun to apply the known principles
of mass production and design to cost to the space rocket.

Gary

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End of SPACE Digest V13 #550
*******************