Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_5/V13_547.TXT

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Subject: SPACE Digest V13 #547

SPACE Digest                                     Volume 13 : Issue 547

Today's Topics:
          Please advise on a telescope for children
              Re: SPACE Digest V13 #516
           Re: Advancing Launch Technology
             Re: Why the space station?y
               Re: Launch Costs
            Honking at cyclists...
             Pegasus/SMEX/-Alive and Will
Re: Launch Costs XXIV -- Wright Bros. Flyer to carry tanks to Kuwait!
Systems Analysis Office created in line with Augustine Report (Forwarded)

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
  [e-mail].  Other mail, esp. [un]subscription requests,
  should be sent to [e-mail], or, if urgent, to
             [e-mail]

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

Date: 13 May 91 20:26:17 GMT
From: agate!linus!think.com!zaphod.mps.ohio-state.edu!cis.ohio-state.edu!sunc!heinlein![e-mail]  (Umesh Thakkar)
Subject: Please advise on a telescope for children

hi,

 I am interested in getting a telescope for my friends
(aged: 8-12), and I would like some recommendations.  I
decided to buy one for them after watching the first
episode of _The Astronomers_, a PBS series.  This
telescope will be used overseas, and so it must be very
durable and easy to use. It must, also, be inexpensive
so that I may be able to afford to buy it.

 Please email.  Thank you in advance.

umesh

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

Date: 13 May 91 21:12:49 GMT
From: mintaka!ogicse!sequent!muncher.sequent.com![e-mail]
Subject: Re: SPACE Digest V13 #516

In article <[e-mail]> [e-mail] (Matthew DeLuca) writes:
[somebody writes, lost attributon sorry:]
>>Conclusion; yes, it could significantly alter the timetable for space
>>development / commercialization.
>
>I don't see how your conclusion follows, myself.  We do not have the
>booster capacity, booster reliability, manned spaceflight experience,
>or telerobotic capability to start exploiting asteroids in the next
>few years, and I doubt it will be all ready to go by the end of the
>decade, either.  We really aren't in *that* big of a rush to get the
>information.

Asteroid and comet exploration makes a _big_ difference in the timetable.
To see one of the reasons why, let's take a little side-trip into orbital
mechanics.

About the mid-1960's, the space explorers started realizing
that we could use planets themselves to gain or lose large amounts
of orbital energy by gravity assist around planets and Moons.
The basic principle is, velocity in equals velocity out, but the
_direction_ can change to any direction we want.  This is limited
by the mass and density of the planet itself.  _Very_ roughly, you
can't change the velocity vector by more than the escape velocity of
the planet.  Since that time, several probes, from Voyager to ICE
to Galileo, have used gravity assists of various kinds to push
spacecraft far beyond what could have been accomplished by rocket power
alone.

Another technique called aerobraking can also be used to change orbits
without rocket power.  This was recently demonstrated with gradual
plane change maneuvers by Hiten and Magellan.  We have also combined
aerobraking and reentry, as in the Apollo return trajectory, or the
Galileo Jupiter probe trajectory.

A paper in 1979 by Dunbar et. al. (which I don't have with me at the
moment, exact reference available on request) demonstrated that gravity
assists could be used to capture large asteroids, for a delta-V of as
little as 3 km/s.  More recently, new asteroids and trajectories have been
discovered requiring only 2 km/s or less impulse delta-v.  Trajectories
that use aerobraking have not yet been published, but these could bring an
additional large savings.

Unfortunately, the amount of mining equipment needed to move the
asteroids we know about (10^6+ tons) is too large to be economically
launched at todays costs.  As you point out, both long-RTLT teleoperation
of this complexity and astronaut travel to the asteroid are far too
expensive or complex to be viable at this time.  Furthermore, the number
of asteroids we know can be captured for less delta-v than the Moon is
less than a dozen. However, from lunar crater studies, it is estimated
that c. 100,000 objects of 100m size or greater, and c. 1,000,000 objects
of size 10m or greater, exist with a delta-v to earth orbit closer than
the lunar surface.

If we could detect asteroids down to 10m, this would solve two problems:

* Our sample size would be nearly 100,000 times larger, allowing us to select
  asteroids with the absolutely minimal impulse delta-v requirements:
  perhaps 500 m/s or less.

* The mass required to move would go from 10^6 tons to 10^3 tons or
  less, requiring much less mining and engine equipment to get the
  ball rolling.  Space mining technology could start small and work its way
  up, following the natural progression of technology from low-cost
  experiments to large-scale, well-known projects.

Given these two advances, comet fragments could be captured with _today's_
launch costs and technology. Ice is very easy to work with compared to
rock, and we can use the following of today's technologies: automated
penetrators, solar-thermal engines, and mylar mirrors, have already been
or will soon be demonstrated (CRAF has a large penetrator chuck full of
sophisticated sampling instruments, including a scanning tunneling
microscope for taking pictures of individual comet molecules).  The
teleoperation required is no more complex than that for CRAF itself.
Asteroids are tougher, but a discovery of sufficient importance will
get the ball rolling on the R&D required to produce tough, low-mass,
high-thruput rock and metal mining equipment for the new vacuum and
microgravity environments.  This will also very likely be automated
at first.  Follow-on missions can have astronauts if we can bring the
cost of manned spaceflight down through the use of comet mass for
shielding, fuel, cooling and life-support.

However, except for one c. 20m object that passed the Earth inside the
orbit of the Moon this January, we have not come close to detecting such
small objects.  A dedicated space-based, infrared earth-crossing asteroid
and comet telescope would solve this problem, detecting tens of thousands
of new, smaller objects.  This should be complemented be an expanded
visual search, and expanded efforts to collect and study asteroid samples
of all varieties from Antartica.

Besides the basic problem of orbital mechanics statistics and size,
there are several commercial-related problems, that if solved by
exploration would greatly invigorate commercial interest:

* the earth-crossing asteroid source(s) of ureleite diamonds

* the possibility of easily-processed metallic regolith on the
  nickel-iron asteroids

* the amount small water-containing fragments in the earth-crossing
  meteor showers, which is a function of the rate of evaporation
  vs. the rate of comet fragmentation

Then there is the unexpected, which is the most sought after
by a good explorer (see my .signature).

In conclusion, the discovery of many new, smaller asteroids and
comets, the solution to several outstanding problems related to
commercial interests, and possible serendipitous discoveries could
greatly speed up the timetable for the utilization of asteroid and comet
resources.


>>I'll cross my fingers that [CRAF] gets out of the planning stages.
>
>You and me both.

Instead of crossing our fingers, let's write to our Congressmen to
make _sure_ that CRAF gets out of the planning stages.  Ditto for
SIRTF, planned to be the most powerful infrared telescope ever launched.
SIRTF is critical for find the large numbers of smaller asteroids and
comets we need to get the space industry ball rolling.

A dedicated asteroid/comet IRAS and a meteor-shower-following IRAS would
also be good, inexpensive missions that could solve many of the
outstanding pure-scientific and industry-related unknowns regarding
the asteroids and comets.


--
Nick Szabo                [e-mail]
"If you understand something the first time you see it, you probably
knew it already.  The more bewildered you are, the more successful
the mission was." -- Ed Stone, Voyager space explorer

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

Date: 13 May 91 15:36:21 GMT
From: wuarchive!zaphod.mps.ohio-state.edu!swrinde!emory!wa4mei!ke4zv![e-mail]  (Gary Coffman)
Subject: Re: Advancing Launch Technology

In article <[e-mail]> [e-mail] (Fraering Philip) writes:
>In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>
>>...down from that of a rich man's toy to everyman's car. The T wasn't
>>high tech compared to the 1901 Olds, just big, dumb, reliable, cheap,
>>and made in huge quanities.
>
>It was larger than earlier cars, but the fundamental advance
>the model T made was in being mass produced. This would not have
>happened if Henry Ford had tried to achieve economy of scale by
>building cars large enough to hold several hundred people.

Actually the T was smaller than many of it's predecessors though it
could often carry more. What made it interesting was that the design
was simplified for mass production. This had several interesting side
effects. Such a simple vehicle was easy to maintain. Fewer parts meant
less things to go wrong. Making large quanities of a standard design
lowered the cost. The "any color as long as it's black" philosopy
succeeded not because black was necessarily a cheaper color, but
because the custom, one off, painting of special colors was avoided.

This concept would work just as well for small launchers as large
launchers, but I believe that the small launcher field can successfully
be developed by private firms designing to meet current commercial demand.
Heavy lift is going to need an initial government funded pump prime to
overcome the chicken and egg effect. I'm confident that once routine
relatively inexpensive heavy lift is available, payloads will be designed
to use the capacity. Note that I don't even believe that an HLV has to
be cheaper per pound to orbit than smaller launchers. I believe that
there will be payloads that will require heavy lift because it will
be cheaper to launch them assembled than to do assembly in space.

Gary

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

Date: 13 May 91 23:00:11 GMT
From: aio!vf.jsc.nasa.gov![e-mail]
Subject: Re: Why the space station?y

>
> I was talking about the difficulties of manuvering into close proximity to the
> station (or any large, open structure). While the RMS will do fine for the
> final docking, that arm is only 15 meters long.  Alot of effort may be
> needed to get within 15 meters of the dacking adaptor without hitting the
> trussd, solar pannels or heat radiators. This is a particular problem is
> there is a docking failure. For example, due to a damaged radar beacon
> the Progress M7 resupply craft almost rammed the Mir space station. A
> ground controlled noticed in time, and aborted the docking. As the
> Progress passed the station (after failing to dock) it nearly hit a solar
> pannel. I feel this sort of accident is a much greater risk for Freedom,
> with so many things sticking out in so many directions.
>
>                     Frank Crary
>                     UC Berkeley

Our proximity operations use a combination of onboard radar tracking and
ground based tracking.  Also you have active man in loop (pilot) override if
the closure rate get to high.  The command and pilots are not passengers
during close  proximity operations.  I have heard and seen the active
interactions between the crew, ground and the onboard and ground systems they
use to approach objects in orbit.  Beleive me the rates are VERY low by the
time you get close.  I'm talking single digit feet per second at several
hundred feet out and much less at closer ranges.   Sure there is some risk.
space flight is just a bit risky.  The risks of docking are very well managed,
understood, and planned and designed for.

--

Mike Kent -      Lockheed Engineering and Sciences Company at NASA JSC
        2400 NASA Rd One, Houston, TX 77058 [phone]
        [e-mail]

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

Date: 13 May 91 07:47:27 GMT
From: agate!hailstorm.Berkeley.EDU![e-mail]  (George William Herbert)
Subject: Re: Launch Costs

In article <[e-mail]> [e-mail] (Paul Dietz) writes:
>Also, consider that it the cost/lb of the Pegasus can probably be
>reduced considerably.  Two more or less straightfoward improvements
>are: higher Isp liquid fuel upper stage(s) and the addition of ramjets
>to the first stage (as was done with the X-15 at one point, admittedly
>with near-disasterous results).

Nobody has yet done a cost/benefit tradeoff that I've seen released on
putting a Higher Isp upper stage on Peg.  My instinct is that it might not
be cost effective... it might add $5 million easily to the price.

Ramjets, however, have less moving parts and are somewhat easier to do
than rocket engines... and very conveniently, the Pegasus first stage
quits at Mach 8 and 120?thousand feet, about the limits of Ramjets. 8-)

-george

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

Date: 13 May 91 16:13:36 GMT
From: snorkelwacker.mit.edu!thunder.mcrcim.mcgill.edu!quiche![e-mail]  (Mark SOKOLOWSKI)
Subject: Honking at cyclists...


Given all the flames that my article has, I want to simply add this:

My point is that we'll have to expand our energy consumption and our
vital space NO MATTER WHAT goes on. Of course we can improve
our efficiency to use this or that source of energy and matter, but
sonner or later we'll have to use the minerals of Antarctica, the
deuterium in the Earth's oceans, and go to the moon in order to
build a plateform there for Mars, Marcury and the asteroids.
Our ever increasing population will need more and more, and each individual
will need more and more of everything. And sooner or later even the
entire solar system won't be sufficient, so we'll have the rest of the galaxy...

Mark

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

Date: 13 May 91 17:35:28 GMT
From: dftsrv![e-mail]  (Dick Palace)
Subject: Pegasus/SMEX/-Alive and Will

--
Dick Palace         Goddard Space Flight Center      [phone]

[e-mail]

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

Date: 13 May 91 21:29:06 GMT
From: mintaka!ogicse!sequent!muncher.sequent.com![e-mail]
Subject: Re: Launch Costs XXIV -- Wright Bros. Flyer to carry tanks to Kuwait!

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>
>I'm of the opinion that small cheaper launchers will emerge without
>NASA's help.

What if NASA hires away the engineers, or takes away the payloads
with launches subsidized at taxpayer expense?   Why should NASA
be going against industry and its trends, rather than helping and
enhancing what industry finds the most useful?


>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.

"To boldly go where many men have gone before." :-)


--
Nick Szabo                [e-mail]
"If you understand something the first time you see it, you probably
knew it already.  The more bewildered you are, the more successful
the mission was." -- Ed Stone, Voyager space explorer

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

Date: 13 May 91 21:32:49 GMT
From: [e-mail]  (Peter E. Yee)
Subject: Systems Analysis Office created in line with Augustine Report (Forwarded)

Jeff Vincent
Headquarters, Washington, D.C.                               May 13, 1991
(Phone:  [phone])


RELEASE:  91-74

SYSTEMS ANALYSIS OFFICE CREATED IN LINE WITH AUGUSTINE REPORT

     NASA Administrator Richard H. Truly today announced the establishment
of a new Systems Analysis and Concepts Office at NASA Headquarters and
designated James D. Bain as its Director.  The creation of the office
is another step in NASA's implementation of recommendations made last
December by the Advisory Committee on the Future of the U.S. Space
Program, also known as the "Augustine Committee."

     The committee recommended that a Systems Analysis and Concepts
Office be established to provide independent and non-advocate decision
support to the NASA Administrator and his immediate office.  The group
would focus on policy alternatives, conceptual and formulative stages
of new programs, and systematic review of the requirements and benefits
of new and ongoing programs.  The committee further recommended that
the new office be staffed by a very few experienced analysts and that
it be augmented by a Federally Funded Research and Development Center
(FFRDC).

      Truly has reviewed several existing FFRDCs from the perspective
of their ability to augment the new office.  Following that review, he
decided to let FFRDC support gradually evolve by tasking analysis of
specific issues to one or more appropriate FFRDCs.

     In a separate recommendation, the Augustine Committee proposed the
establishment of an independent cost analysis function to serve the
Administrator and his immediate office.  In response to that
recommendation, Truly has decided to significantly augment the
independent cost capability recently initiated by the NASA
Comptroller.  This group will report administratively to the
Comptroller and provide independent assessments to the Administrator
and his immediate office, to include the new Systems Analysis and
Concepts Office.

     Bain previously served as the Executive Secretary to the Augustine
Committee and is currently staffing the implementation of the
committee's recommendations within NASA.

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

End of SPACE Digest V13 #547
*******************