Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_9/V16NO891.TXT

Text File | 1993-07-20 | 29KB | 760 lines

Space Digest                Mon, 19 Jul 93       Volume 16 : Issue 891

Today's Topics:
                   DC-X thermal protection (6 msgs)
                   GPS Altitudes (was: DC-1 & BDB)
              GPS in space (was Re: DC-1 & BDB) (2 msgs)
        Henry was right (as usual) (was Re: Space Movie/PR..)
                           Mars Direct Info
                         MOON CABLE (2 msgs)
                    Moon Cable/Beanstalk. (2 msgs)
                          Perseid publicity
                      Space Movie/PR.. (2 msgs)
                        Visit in L.A. at Sept
               Von Braun Team Work & DCX (Was (2 msgs)
              Waste Management aboard Skylab and Shuttle
                  What's the market for Solar Cells?

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

Date: Sun, 18 Jul 1993 13:26:58 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: DC-X thermal protection
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Brad Whitehurst) writes:

>wondering what thermal protection system the DC-X followons will use

The orbital prototypes will have a TPS made of carbon composit, Iconel, and
titanium.

>(I assume DC-X doesn't bother with reentry-grade protection).

Correct. It only has a heat shield at the base to protect from (I
assume) engine heat.

>picture on the back shows the maneuvering flaps deployed, and I was
>thinking that they look rather thin and difficult to shield/cool.

It turns out there is no need to cool them. Peak tempratures on a DC
are actually below Shuttle peak tempratures and the materials can
take it. Some figures:

Location       DC      Shuttle   Material Allowable
Nosetip        2900    3000      3200
Windward ray   1830    2300      2300
Flap           2000    3000      3200
Non windward    900    1200      1500

   Allen

--
+---------------------------------------------------------------------------+
| Lady Astor:   "Sir, if you were my husband I would poison your coffee!"   |
| W. Churchill: "Madam, if you were my wife, I would drink it."             |
+----------------------17 DAYS TO FIRST FLIGHT OF DCX-----------------------+

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

Date: 18 Jul 1993 11:43:58 -0400
From: Pat <[e-mail]>
Subject: DC-X thermal protection
Newsgroups: sci.space

I would have thought DC-X  would have at least tougher shuttle

protection,  or better.  I thought stagnation temperature was a function
inversely proportional to  frontal area.  I saw a heat flow analysis
for Hermes  that was almost 1,000 degrees  higher in points then
on the STS.  It was explained it was because Hermes was smaller
and had less  shock wave  carrying off heat.  Of course, the lecturer
was french, and i may have mis-understood him.

Does DC-Y,1  expect to fly a much shallower  landing approach??  or
something?

pat

--

God put me on this Earth to accomplish certain things.  Right now,
I am so far behind, I will never die.

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

Date: Sun, 18 Jul 1993 16:31:00 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: DC-X thermal protection
Newsgroups: sci.space

In article <22br3u$[e-mail]> [e-mail] (Pat) writes:

>I would have thought DC-X  would have at least tougher shuttle
>protection,  or better.

DC doesn't need that much, it weighs to much, and is less reliable. Why
do it?

>I thought stagnation temperature was a function
>inversely proportional to  frontal area.  I saw a heat flow analysis

DC re-enters at a much slower speed and takes longer to slow down so
it generates less heat.

  Allen

--
+---------------------------------------------------------------------------+
| Lady Astor:   "Sir, if you were my husband I would poison your coffee!"   |
| W. Churchill: "Madam, if you were my wife, I would drink it."             |
+----------------------17 DAYS TO FIRST FLIGHT OF DCX-----------------------+

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

Date: 18 Jul 1993 16:23:23 -0400
From: Pat <[e-mail]>
Subject: DC-X thermal protection
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>DC re-enters at a much slower speed and takes longer to slow down so
>it generates less heat.


I realize you are probably not the best person to ask,  but

How is DC-1, able to fly such a nicer approach path then
STS and Hermes.  Is this the remnant of the silly USAF requirement
that the STS be able to  fly  1,800 miles cross range.

pat
--

God put me on this Earth to accomplish certain things.  Right now,
I am so far behind, I will never die.

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

Date: Sun, 18 Jul 1993 22:08:43 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: DC-X thermal protection
Newsgroups: sci.space

In article <22cbfr$[e-mail]> [e-mail] (Pat) writes:

>I realize you are probably not the best person to ask,  but

True.

>How is DC-1, able to fly such a nicer approach path then
>STS and Hermes.

I'll speculate. I suspect it is related to whatever MacDac found
on their MARV studies. This is a propriatary and I'm sure trade secret
technology.

>Is this the remnant of the silly USAF requirement
>that the STS be able to  fly  1,800 miles cross range.

It's not a silly requirement if you want to fly polar missions and can't
land just anywhere. Also, I don't know DC's crossrange but it is in the
same ballpark as Shuttle.

  Allen
--
+---------------------------------------------------------------------------+
| Lady Astor:   "Sir, if you were my husband I would poison your coffee!"   |
| W. Churchill: "Madam, if you were my wife, I would drink it."             |
+----------------------17 DAYS TO FIRST FLIGHT OF DCX-----------------------+

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

Date: 18 Jul 1993 21:58:49 -0400
From: Pat <[e-mail]>
Subject: DC-X thermal protection
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>>Is this the remnant of the silly USAF requirement
>>that the STS be able to  fly  1,800 miles cross range.
>It's not a silly requirement if you want to fly polar missions and can't
>land just anywhere. Also, I don't know DC's crossrange but it is in the
>same ballpark as Shuttle.


IMNSHO, it's a silly requirement, if it ends up  torquing the design
through a 180 degrees,  and the Shuttle  is not capable of flying polar
missions except from  a brand new launch complex.

Considering  most 90% of the planned missions were out of KSC,
it did seem a little odd to me,  that  they were insisting on this requirement
when it would only be useful for a handful of STS missions.

Kind of like  insisting that  whatever car you buy, has to use those
same old studded snow tires  you bought for the  rambler   last winter.

nobody wants to write off a requirement,   but that  shouldn't  be a control
compared to  things  like mission sorty rate,  or system cost,  or
reliability.

pat
--

God put me on this Earth to accomplish certain things.  Right now,
I am so far behind, I will never die.

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

Date: 18 Jul 1993 15:29:18 GMT
From: "David M. Palmer" <[e-mail]>
Subject: GPS Altitudes (was: DC-1 & BDB)
Newsgroups: sci.space

[e-mail] (Greg Price) writes:

>In <[e-mail]> [e-mail] (SNYDER GARY EDWIN JR) writes:

>>Seeing the discussion on what altitude The Navstar/GPS system works, I
>>thought I should give my information gleaned over the last three years.

>>       ... stuff deleted...         The US Govt has "strongly" requested
>>that when a receiver solves a position above 50K ft that it disables its
>>outputs. This was a hassel with our weather balloon project. A max speed
>>is also defined, something like mach 1.

>I bought a Magellan OEM board. Under "Operational Characteristics" it states
>that max velocity is 950mph (1529 kph) and max accel is 2g. Under Evironmental
>Characteristics, Altitiude, Operating it states -1000 to +58000 feet (-0.30km
>to 17.68km). It goes on to say that domestic firmware for 2000000 meters is
>available. This unit costs about US$500 and does not give you pseudoranges,
>etc. If you want pseudoranges and other good stuff it costs US$1500 (just
>a different EPROM I believe) and you have to sign some docs explaining what
>you intend to do with it, etc, etc. It smells like the US govt has probably
>had more than a strong word to them.

According to someone here who is mounting one on a balloon payload (120,000 ft)
you cannot readout when you are simultaneously going faster than some
speed AND above a certain altitude.  If you are high and slow, or low and
and fast, there is no problem.

Unfortunately, before that was clarified, manufacturers were using OR
instead of AND: If you were high, you lost; if you were fast, you lost.

New Rockwell and new Motorola OEM boards have the 'AND' correct, but
there are at least some old Motorola boards still on the shelf
which use 'OR'.  Use caution and contact the manufacturer.

--
        David M. Palmer        [e-mail]
                    [e-mail]
    Clipper: Privacy for people who have nothing to hide.

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

Date: 18 Jul 1993 11:34:43 -0400
From: Pat <[e-mail]>
Subject: GPS in space (was Re: DC-1 & BDB)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <229kmb$[e-mail]> [e-mail] (Pat) writes:
>>Why is it, cheaper for me to drive to work in DC (Home to the best
>>public transit system in AMerica)  then to take metro.
>
>Bad management. :-)  I assume "AMerica" refers to the country, not the
>continent -- Toronto has the best public transit system on the continent,
>and it's certainly the cheapest way for me to get to work, if you exclude
>bicycling.  (Might be different if I needed a car for other things, but
>in Toronto you don't.)

Best is  certainly  a subjective measure, and I will leave it at that.
I always liked chicago, myself for public transit,  but in terms of
comfort,  modernity and security, WMATA is way up there.

actually, the problem is the tax system.  Parking is subsidized,  Roads
are subsidized,  Metro  is metered.   that is slowly changing.

pat

    who will someday tour toronto,  at less then 90KPH.


--

God put me on this Earth to accomplish certain things.  Right now,
I am so far behind, I will never die.

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

Date: 18 Jul 1993 11:37:38 -0400
From: Pat <[e-mail]>
Subject: GPS in space (was Re: DC-1 & BDB)
Newsgroups: sci.space

  Not that we spend  2 trillion on Mideast oil,  but that probably
1/3rd of our economy would be heavily impacted by the  sudden
interrruption in the Mideast Oil stream.   The ripple shock to
Transportation, chemicals,  Agriculture,  Metals production,
textiles  could be quite severe.  I do remember the 70's
quite well.

pat
--

God put me on this Earth to accomplish certain things.  Right now,
I am so far behind, I will never die.

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

Date: Mon, 19 Jul 1993 02:23:18 GMT
From: Dave Michelson <[e-mail]>
Subject: Henry was right (as usual) (was Re: Space Movie/PR..)
Newsgroups: sci.space

In article <22cv4m$[e-mail]> [e-mail]
(George William Herbert) writes:
>
>I've been working on a project to do a scale model Orion for special
>effects purposes with Footfall movie or miniseries in mind.  It's
>really quite doable.  A ten-meter diameter vehicle will easily work,
>and use up quite a bit of conventional explosives per "jolt".

Some time ago, Henry noted that he had seen a display relating to
a scale model demonstration of the Orion concept at NASM.  Someone
(I forget who) posted back that Henry must be mistaken because those
items were not even in the NASM collection...

According to Frank H. Winter (Asst Curator, Space Science and Exploration
Dept,. NASM), writing in "Rockets into Space" (Harvard Univ. Press, 1990),
p. 136,

"The Orion may seem bizarre, but in 1959 and 1960 small flight-test models
 with high explosives were lifted by small solid-fuel boosters to altitudes
 of about 150 feet, where they proved the feasibility of pulse rockets.
 (One model is now in the National Air and Space Museum in Washington, D.C.)"

Just thought I would set the record straight...

--
Dave Michelson  --  [e-mail]  --  University of British Columbia

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

Date: 17 Jul 93 14:40:26 GMT
From: Ralph Buttigieg <[e-mail]>
Subject: Mars Direct Info
Newsgroups: sci.space

G'day All

Some of my BBS users would like to know more about Zubrin's Mars Direct
proposal. Are there any sites out there with articles, drawings etc? Failing
that, can anyone inform me of a contact address for Mr Zubrin? A E-Mail
address would be nice. I could then write to him and ask for permission to
make available some of his articles on the BBS.

ta

Ralph

--- GoldED 2.41+
 * Origin: VULCAN'S WORLD: Astro/Space BBS [phone]  3:713/635
(3:713/635)

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

Date: Sun, 18 Jul 1993 05:45:06 GMT
From: "Steven R. Garman" <[e-mail]>
Subject: MOON CABLE
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (MR DG HUGHES) writes:
>Consider this...
>
>The cost of lifting payloads into space is extreme.
>
>Probably the most significant reason for this is that the amount of matter
>going into space is so small that economies of scale can't be achieved.
stuff deleted
>Could anyone attemp to answer these...
>
>1] What is the current price for lifting cargo into space?
>
>2] What is a rough estimate of developing the system above?
>
>3] Does the moon have minerals we can mine to make cable?
>
>4] Is there a future market for development in space?

1) $10,000 per kilo according to the U.S. GAO (general accounting office)

2) the cost is infinite, this is called a beanstalk and it is impossible to
do, I will explain shortly.

3) The moon has an excellent supply of materials. the moon has copious
quantities of oxygen, aluminum, titanium, iron, silicon, etc.. Not only
that but much of it is already partially processed and just sitting around
waiting to be picked up.  The oxygen can be retrieve by simply baking
moon-rocks in a solar oven, what could be simpler.

4) Its a matter of opinion, but I would say definately.  The wealth of
resources alone should convince most anyone.  How much is *all* the real estate
on mars worth?  What if it cost us 10 trillion dollars to exploit it?


The trouble with building a moon cable is simple.  There is no known
material which could support its ownweight over that distance.  For
example, how much steel cable could you lower from a mystical floating
platform before the weight of the cable broke the cable.  The answer is ...
not nearly enough to dangle a cable from space.  Even the strongest
materials which can be theorized could only support about a fifty mile long
cable.  One mile of steel cable weighs something like 50 tons, which is way
more than enough to break the cable.

Regards, Jon Priluck




--
[e-mail] | 6172876077 univ | 6177313637 home | Standard Disclaimer
Boston MA USA | Physics is the universe's operating system | UWSA Mem. 168404
 "What do I put in this .sig that could possibly be original?  Oh, Despair!"

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

Date: Sun, 18 Jul 1993 10:42:42 GMT
From: Paul Dietz <[e-mail]>
Subject: MOON CABLE
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Steven R. Garman) writes:

 > 3) The moon has an excellent supply of materials. the moon has copious
 > quantities of oxygen, aluminum, titanium, iron, silicon, etc.. Not only
 > that but much of it is already partially processed and just sitting around
 > waiting to be picked up.

It never ceases to amaze me that folks can get so enthusiastic about
common elements in common rocks, just because they happen to be on the
moon.

Look, if you go into ecstasy over anorthosite, move to the Adirondacks.
Cubic miles of the stuff there for you.

The moon actually has a poor supply of materials.  Little in the way of
organics or moisture, few ore forming processes, and (most importantly)
the cost of extracting what is there is, well, astronomical.

  > The oxygen can be retrieve by simply baking
  > moon-rocks in a solar oven, what could be simpler.

The answer to the last question is as easy as inhaling.  BTW, how
do you propose to prevent the oxygen that you have thermochemically
separated from escaping to space, or from recombining with the metals
to which it had been bound?

    Paul F. Dietz
    [e-mail]

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

Date: 18 Jul 1993 16:20:21 -0400
From: Pat <[e-mail]>
Subject: Moon Cable/Beanstalk.
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Phil G. Fraering) writes:
>[e-mail] (Pat) writes:
>>They also  installed a series of puppet governments.
>In Panama, Columbia, or the U.S.?


Yes.

;-)

--

God put me on this Earth to accomplish certain things.  Right now,
I am so far behind, I will never die.

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

Date: Mon, 19 Jul 1993 05:58:08 GMT
From: Michael Sandy <[e-mail]>
Subject: Moon Cable/Beanstalk.
Newsgroups: sci.space

I would hazard a guess that Beanstalks don't become technically or
economicly feasible until you have _Interstellar_, not just
Interplanetary economies.

Using a beanstalk to lift raw materials  from a planet you aren't
native to, and don't have large scale resources which would be at
risk from an accidents on the Beanstalk would take advantage
of a number of features of the Beanstalk

Having a large initial equipment investment enables better exploitation of
resources.  When you don't have the resources to build Cape Kennedy in
every system you go to, having the infrastructure in Orbit makes a bit
more sense.  It all depends on where your initial infrastructure is,
in a new solar system, all your infrastructure is _already_ in space,
just as the Beanstalk's is.


--
Michael Sandy
[e-mail]
"I resolve to make no non-tautological New Year's Resolutions!"

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

Date: Sun, 18 Jul 1993 17:45:04 GMT
From: Leigh Palmer <[e-mail]>
Subject: Perseid publicity
Newsgroups: sci.astro,sci.space

In article <[e-mail]> , [e-mail] writes:
>I thoroughly recommend more enlightened groups consider public
>participation in the Perseids. Got any plans?

For many years the Royal Astronomical Society of Canada Vancouver Section
has held a Perseid party on Mount Kobau, a good dark sky site
in the Okanagan Valley of British Columbia. It has been quite successful.
I prefer to avoid such parties, though there are clearly many who enjoy
them. I do like to watch with other people, but there seems to be little
point to assembling vast numbers, unless by so
doing you can evengelize successfully about light polution. I have
given up on this cause in cities like Vancouver. Too many of my congeners
are Yahoos who will never care. I wish you success, Mr. Ryan. If you
succeed in raising public support for, say, shielded outdoor lighting
I'll be impressed. California's ruined. I've failed miserably here. Maybe
I should emigrate to Ireland next.

Leigh

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

Date: Sun, 18 Jul 1993 07:30:10 GMT
From: stephen voss <[e-mail]>
Subject: Space Movie/PR..
Newsgroups: sci.space

[e-mail] (Bruce Hoult) writes:

> [e-mail] writes:
> > Or maybe a high budget First Contact with Aliens.. not a "V" or soem such,
> > a first contact that is a bit more up to modern tech/current tech, and
> > possibilties
>
> _Footfall_ could make a good movie, I think.  It's got pretty nifty and well-
> out aliens.  For that matter, so has _The Mote in God's Eye_.
>
>
> >Maybe this time the Government and NASA can play the good guys..
>
> Oh.  I didn't realise you were thinking of a fantasy...


Ok remove government

how about this for a plot

5 years from now the american space program is in mothballs. The Russian
progam is almost non-existent . The only manned program is being done
by a billionaire with a visionary spirit,Bill Gates, he decides he wants
a space program having nothing else to do with his 30 billion dollar
fortune, he funds the final work on the DC clipper project. On one of
his launches he decides to send a member of the press along for the ride
with the crew . This beautiful intelligent reporter(fill in megababe)
for a news network (as close to CNN as possible without having to pay
royalties) goes along with the crew captained by a brave and experienced
(fill in favorite intelligent looking megahunk).

and while they are up there they detect signals with an extraterristial
source(too far away of course to make out clearly)....

fill in the plot

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

Date: 19 Jul 1993 01:58:46 GMT
From: George William Herbert <[e-mail]>
Subject: Space Movie/PR..
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Bruce Hoult) writes:
>_Footfall_ could make a good movie, I think.  It's got pretty nifty and well-thought-
>out aliens.  For that matter, so has _The Mote in God's Eye_.

Footfall is sort of long for a good movie, but it's got a good set
of plots to work with and reasonably accurate science (though X/gamma
ray lasers may not work after all...).

I've been working on a project to do a scale model Orion for special
effects purposes with Footfall movie or miniseries in mind.  It's
really quite doable.  A ten-meter diameter vehicle will easily work,
and use up quite a bit of conventional explosives per "jolt".

-george

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

Date: Sun, 18 Jul 1993 22:24:00 +0200
From: Alexandros Gougousoudis <[e-mail]>
Subject: Visit in L.A. at Sept
Newsgroups: sci.space

Hi,

I start visiting L.A. in September and I want to see some interessting
astronomical sites (JPL?).
Can't the residents and participant of this newsgroup send me some hints what
might be of interesst?
Any Ideas? (Please send the adresses too).

I'am a high-grade student of physics.

cu
 Alex

 * Origin: Krypta.UUCP,UseNet-Berlin,FRG. 24h online! (2:242/1210)

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

Date: 19 Jul 1993 02:11:16 GMT
From: George William Herbert <[e-mail]>
Subject: Von Braun Team Work & DCX (Was
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>Having had some experience with engine/vehicle systems integration
>for SSTO's myself, I feel that the SSME does not have sufficient
>performance for "realistic" SSTO operation, and that engines, such as
>the J-2, RL-10 etc. are totally out of the question ("bad jokes" one
>might say.). We shall see, maybe, someday. It won't be this year, and
>I wouldn't count on it being this century.

My calculation shows the RL-10 will have an Isp about 360 at sea level;
given that, a single RL-10 based demonstrator weighing 10,000 lbs at SL
and 1,000 lbs at burnout should easily work.  It has a takeoff T/W of 1.35
and makes orbital velocity with about 300 m/s to spare, including the
low-altitude thrust losses and gravity losses.

I will concede "realistic"; this vehicle will have no payload.
But it will make orbit.

-george william herbert
Retro Aerospace

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

Date: Mon, 19 Jul 1993 04:50:13 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: Von Braun Team Work & DCX (Was
Newsgroups: sci.space

In article <22cvs4$[e-mail]> [e-mail] (George William Herbert) writes:

>My calculation shows the RL-10 will have an Isp about 360 at sea level;

What assumptions are you making on the nozzle? The RL-10-A-5 (a -4 with
a throttle and new nozzle) which DC-X uses for sea level operations
has a Isp of 373.

   Allen
--
+---------------------------------------------------------------------------+
| Lady Astor:   "Sir, if you were my husband I would poison your coffee!"   |
| W. Churchill: "Madam, if you were my wife, I would drink it."             |
+----------------------17 DAYS TO FIRST FLIGHT OF DCX-----------------------+

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

Date: Sun, 18 Jul 93 15:41:33 +1200
From: Kennelmeister <[e-mail]>
Subject: Waste Management aboard Skylab and Shuttle
Newsgroups: sci.space

Toilet arguements......

How long have these been raging? 40 years?

Here's my 2c. Fell free to tell me that it's totally useless, etc etc

Fred is big(ish). There's anough room (figuratively speaking) to swing a
cat inside.

How about a centrifuge based toilet compartment?

It wouldn't have to spin very fast - just enough to provide
"artifical gravity" for the occupant and his/her waste products.
It could be spun up after the occupant enters, rather than trying to
have some complicated entry procedure...

This would enable the use of fairly basic chemical toilets,
until the basic issue of real zero-g toilets has been solved.

This wouldn't be a viable shuttle solution for obvious reasons,
but is there any reason it can't be used for larger installations?

I fully accept that there are storage/disposal problems still to be
solved, but it would at least help deal with the problems of having
to excrete into a plastic bag, etc and deal directly with the stuff
afterwards.
What does the shuttle smell like after a week in orbit?
What did skylab smell like?

Possibilities. Tankage on the centrifuge. self sealing connections.
When the tanks are full, remove and transfer to a stationary
treatment point. (A space going septic tank?)

We aren't going to be collecting stool and urine samples forever.
Eventually we're just going to be facing problems of waste disposal.
How about teflon lining the tanks to make them easier to clean?

--
Alan Brown
[e-mail]

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

Date: Sun, 18 Jul 1993 04:35:57 GMT
From: Henry Spencer <[e-mail]>
Subject: What's the market for Solar Cells?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (AJ Madison) writes:
>> I'm trying to gather information about the market for solar cell
>> applications in space.
>>
>...if the cells get cheap enough, they may have applications here on earth.
>If you consider what one is looking for in space applications (durability,
>lightweight, reliability, redundancy) are equally desirable here on earth,
>the only big problem is cost.

Unfortunately, it's not that simple.  These are two different markets.
(Yes, there is already an Earth-surface market, although at present it
tends to be for specialized applications in remote areas.)  The space
people want the lightest possible weight, the highest possible output
per square meter, and high radiation resistance, and will pay almost
any price for even small improvements.  Earth-surface users don't care
much about weight, want good efficiency but don't care about small
differences, don't care about radiation at all, and do care about price.
--
Altruism is a fine motive, but if you   | Henry Spencer @ U of Toronto Zoology

want results, greed works much better.  |  [e-mail]  utzoo!henry

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

End of Space Digest Volume 16 : Issue 891
------------------------------