Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V08/V8_243.TXT

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From ota Sat Jun  4 03:03:58 1988
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Date: Sat, 4 Jun 88 03:03:42 PDT
From: Ted Anderson <ota>
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Subject: SPACE Digest V8 #243

SPACE Digest                                      Volume 8 : Issue 243

Today's Topics:
          Re: Radar (was Shooting the Moon)
            Re: When in doubt, nuke it...
               Re: Space Shuttle Names
               Re: Space Shuttle Names
             cooling by radiation
               Re: cooling by radiation
               Re: cooling by radiation
               Re: cooling by radiation
            Bureaucracy vs. space
              Re: Bureaucracy vs. space
               Re: cooling by radiation
----------------------------------------------------------------------

Path: ucbvax!pasteur!agate!ig!uwmcsd1!bbn!husc6!uwvax!rutgers!paul.rutgers.edu!styx.rutgers.edu!masticol
From: [e-mail] (Steve Masticola)
Newsgroups: sci.space
Subject: Re: Radar (was Shooting the Moon)
Date: 8 May 88 14:05:09 GMT

So who said anything about using radar for surface mapping? I meant
collision avoidance on descent, and possible use as an instrument for
some kind of scientific data gathering to prevent it from being a
one-use-only box. (I admit I don't know what kind of data the radar
could be used to acquire; I'm a doctor, not a surgeon!) Those with
legitimate ideas on this are encouraged to follow up. However...

    >>>>>>    READ BEFORE FLAMING. <<<<<<

) Another gross generalization from
) --eugene miya, NASA Ames Research Center, [e-mail]

U-betcha. :-)

-Steve ([e-mail]) - Help stamp out cute .sigs

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

Date: 23 May 88 14:49:32 GMT
From: phri!dasys1![e-mail]  (Tom Neff)
Subject: Re: When in doubt, nuke it...

In article <[e-mail]> [e-mail] (Lee Mellinger) writes:
>... You've probably seen the pictures from these "benign" locations.
>Lander 1 came down about 10m from a boulder that would certainly
>destroyed it had it landed there.

This is sort of a classic fallacy.  If the surface was evenly covered
with 3m boulders at 40m average spacing in a honeycomb pattern, a lander
of 4m average diameter would have about a 0.0275 chance of striking one
of the boulders on landing.  Yet about 60% of all landing sites would
lie within 10m of one of the boulders!

I think you guys should be asking yourselves what you could put on board
Mars Observer to give you 1m resolution or better at selected sites,
rather than fantasizing about nuking a landing pad.

Tom Neff

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

Date: 6 May 88 21:39:18 GMT
From: mnetor!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Space Shuttle Names

> I've heard the story on how the Enterprise was named, but how did they
> come up with a New Age / UFOphilic name like Atlantis ?

Enterprise aside, the orbiters are named after famous oceanographic
vessels.

NASA is to spaceflight as            |  Henry Spencer @ U of Toronto Zoology
the Post Office is to mail.          | {ihnp4,decvax,uunet!mnetor}!utzoo!henry

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

Date: 7 May 88 06:04:00 GMT
From: snail![e-mail]
Subject: Re: Space Shuttle Names

I believe that the Atlantis was a US oceanographic research vessel of
the 19th century. With the exception of Enterprise, all the shuttles are
named for such ships.

They had to have some sort of system, didn't they?

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

Date: Mon, 16 May 88 18:18:04 EDT
From: John Roberts <[e-mail]>
Subject: cooling by radiation

As I recall, the Space Shuttle is supposed to cool itself while in orbit
by opening the cargo bay doors, and pointing the cooling array at the
earth.  Since this is much less efficient than pointing at open space, I
presume there must be some good reason for this choice. Is it because
faster cooling might damage something, because this position keeps the
cooling surfaces out of the sun most of the time, or for some other
reason?

                                                      John Roberts
                                                      [e-mail]

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

Date: 18 May 88 01:04:46 GMT
From: thumper![e-mail]  (Phil R. Karn)
Subject: Re: cooling by radiation

> As I recall, the Space Shuttle is supposed to cool itself while in
> orbit by opening the cargo bay doors, and pointing the cooling array
> at the earth.  Since this is much less efficient than pointing at open
> space, I presume there must be some good reason for this choice. Is it
> because faster cooling might damage something, because this position
> keeps the cooling surfaces out of the sun most of the time, or for
> some other reason?

I believe the reason has to do with thermal control in the payload bay.
Pointing the bay at the earth is much more benign than pointing it
either at the sun or at deep space.

Back when we thought we could launch an amateur PACSAT (packet radio
satellite) from a GAS canister on the shuttle I took a look at the
thermal environment. It can be summed up in one word: horrendous!  If
you design your payload to survive direct sunlight, it will freeze if
the bay is oriented to deep space for any length of time. If you design
it to work in shadow, it will fry in the sun.  And, of course, GAS
customers are peons -- you get no say over the orbiter's attitude, and
they usually can't even tell you what they expect it to be at any given
time during the mission.

You don't get a single microwatt of the kilowatts being generated by the
orbiter's fuel cells. You have to waste half the canister just carrying
batteries -- no lithium batteries are allowed, this is a man-rated
vehicle. You may well end up using most of your battery power just
keeping warm. The best you can do is compromise on the thermal design
and hope that they'll keep it pointed at earth most of the time.

I'll take a free-flying payload (with an unmanned launcher to fly it on)
any day. At least you know what the thermal environment will be so you
can plan for it.  The selling of the shuttle as a platform for easy,
inexpensive, small scale space applications is one of the biggest con
jobs in history.

Phil

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

Date: 20 May 88 23:27:07 GMT
From: thumper![e-mail]  (Phil R. Karn)
Subject: Re: cooling by radiation

> And of course it would all be so much better for a small experimenter
> on a big shared unmanned platform, right?

Partially yes. Have you ever seen the GAS Safety Manual? I have. Just
read it sometime if you want to get depressed. And my copy was published
BEFORE the Challenger disaster.

I really want my platform to be FREE-FLYING, not just unmanned.  But the
GAS program was not originally set up to actually launch payloads. A
couple of very persistent people finally persuaded NASA to allow it;
remember GLOMR and NUSAT? They could launch their payloads from a GAS
can, but only through the use of a NASA-developed deployment mechanism
that took fully HALF the can's already-cramped interior. (I know -- I
visited Goddard during the NUSAT preparation and and inspected the
actual flight mechanism with spacecraft attached).

Even worse, the NASA safety people insisted that the deployments occur
on the LAST day of a week-long mission. Why? Because they were worried
about the possibility of a collision between the spacecraft and the
shuttle orbiter, and doing it on the last day would minimize this. (As
it turned out, they were able to move up the NUSAT/GLOMR deployment
because the dry cells in the can (remember -- no orbiter power) weren't
expected to last the entire mission. And GLOMR didn't make it out at
all, and had to be brought back and relaunched).

AMSAT has had considerable experience flying small secondary payloads on
unmanned launchers, primarily Delta and Ariane. Yes, there certainly are
interface and safety requirements. We fly solid and hypergolic kick
motors on Ariane, and share space with $100M Landsats on Delta. It's
perfectly reasonable for them to require assurance that our payloads
won't kill somebody or ruin a mission. And with 13 satellites launched
we've built an absolutely perfect track record in this regard.  (The
Ariane launch failure that occurred in 1980 was caused by a first stage
engine defect, and had nothing to do with our payload).

Even if you're allowed to deploy something from a GAS can, however,
you're in an entirely different league. The bureaucracy levels and
safety requirements are orders of magnitude higher, and the service
provided by the vehicle itself is much worse. Standard facilities, like
battery charging and telemetry while on the pad, are not provided.  Your
payload may have to survive for months on the ground before launch
without your being able to touch it. Instead of being deployed in a
known, preselected attitude within minutes of reaching orbit, you get
dumped out at an unpredictable time and attitude chosen by NASA, not
you, and they couldn't care less about the thermal beating your payload
might have to take in the meantime.  The orbit is much lower than that
typical of unmanned launchers, but conventional kick motors are
completely out of the question because of the safety rules.  So either
you resign yourself to a <1 year lifetime, or you take a big detour and
go off to build solar-powered thermal thrusters.  And perhaps you'll
even have time left to work on whatever payload you wanted to fly in the
first place.

These drawbacks are inherent from BOTH the man-rated and the shared-bus
nature of the Shuttle, and would work against anyone trying to use it
for low cost, small-scale space research or applications.

Phil

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

Date: 19 May 88 17:03:21 GMT
From: attcan!utzoo![e-mail]  (Henry Spencer)
Subject: Re: cooling by radiation

> Back when we thought we could launch an amateur PACSAT (packet radio
> satellite) from a GAS canister on the shuttle I took a look at the
> thermal environment. It can be summed up in one word: horrendous! ...
> ... The selling of the shuttle as a platform for easy, inexpensive,
> small scale space applications is one of the biggest con jobs in
> history.

And of course it would all be so much better for a small experimenter on
a big shared unmanned platform, right?  Let us give credit, and blame,
where it is due: the problem here is not the launch vehicle, it is the
big-shared-platform concept.  Unfortunately it's hard to get away from
that concept if you use the shuttle, or the space station, or the ISF,
or Mir, or any other scheme for sharing support facilities to reduce
costs and operational overhead.

The fundamental, underlying difficulty here is simply that the shared
facilities are trying to do too many different things.  If shuttle
flights really were dead cheap, once a week, commercially run, as some
people once hoped, there's no obvious reason why "payload bay will face
Earth at all times, barring major emergencies" wouldn't be written into
the contracts for some large fraction of the multi-payload flights.
Customers who wanted warm environments would choose Earth-facing
flights; those who wanted cold would choose sky-facing flights.  (In
fact it is not obvious to me why NASA couldn't make this sort of promise
now, for some flights at least, if they were making a serious effort to
respond to customer needs... which they aren't, of course.)  Things
haven't worked out quite that way, unfortunately, and the salesmen have
forgotten to tone down the hype to match.

> ... no lithium batteries are allowed, this is a man-rated vehicle.

As I've mentioned before, if I can fly lithium batteries on a man-rated
Hercules transport aircraft, there is no fundamental reason why I should
be forbidden to fly them on a man-rated shuttle.  I would agree with the
above if you changed the last part to "this is a NASA man-rated
vehicle".

NASA is to spaceflight as            |  Henry Spencer @ U of Toronto Zoology
the Post Office is to mail.          | {ihnp4,decvax,uunet!mnetor}!utzoo!henry

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

Date: 20 May 88 18:01:06 GMT
From: jumbo![e-mail]  (Jorge Stolfi)
Subject: Bureaucracy vs. space

Henry Spencer writes:

>   As I've mentioned before, if I can fly lithium batteries on a
>   man-rated Hercules transport aircraft, there is no fundamental
>   reason why I should be forbidden to fly them on a man-rated shuttle.

Except that the shuttle is NOT a Hercules transport.

For starters, an airplane is MUCH gentler than the shuttle.  In an
airplane, the flight proper usually the smoothest part of the whole
trip; if a palyoad can survive the truck ride to the airport, it can
surely survive the flight.  An airplane takes off, flies and lands in an
horizontal position; it doesn't turn somersaults at takeoff the way a
shuttle does.  The maximum acceleration of a cargo plane is far less
than that of the shuttle.  The shuttle payload must whithstand going
from 1 atm to vacuum during takeoff, and from frying to freezing many
times over when in orbit.

Furthermore, the design safety factors seem to be much smaller in the
shuttle than in a cargo airplane.  An airplane may be able to fly and
land even with a ten-foot hole in the cargo bay.  I doubt the shuttle
would survive re-entry with a one-foot hole, a few missing tiles, or
even a bent bay door.  Safety factors are smaller also for the payloads
themselves, and for the gadgets that are supposed to keep them in place
during flight.  Add to that that we have had eighty years of experience
with airplanes and airplane cargo, with millions of flights and
vehicles; whereas we had only 25 shuttle flights.

Finally, a shuttle is substantially more expensive than a cargo plane,
and a and a lot more precious --- lose one and you have lost 1/4 of the
fleet.  Yes, if NASA had a few dozen shuttles (and the money to operate
them), things wouldn't be so critical; but they haven't, and wishing
that the impossible were true doesn't help.

NASA's payload regulations for the shuttle may be exaggerated, but
comparing them with those for cargo airplanes is unfair and meaningless.

Jorge Stolfi
[e-mail], ..{..decvax,ucbvax,allegra}!decwrl!stolfi

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

Path: ucbvax!pasteur!ames!lll-tis!lll-winken!uunet!attcan!utzoo!henry
From: utzoo![e-mail] (Henry Spencer)
Newsgroups: sci.space
Subject: Re: Bureaucracy vs. space
Keywords: shuttle, bureaucracy, man-rated, private enterprise, hype
Date: 22 May 88 01:33:56 GMT
Lines: 54
Apparently-To: [e-mail]

> Except that the shuttle is NOT a Hercules transport.

You will note that I said "fundamental reason".  I'm not claiming that
the current shuttle can be treated like a Hercules; I'm claiming that
there is no deep reason why *a* manned shuttle can't be treated like a
Hercules.

> For starters, an airplane is MUCH gentler than the shuttle.

Are you sure you aren't drawing your experience entirely from airliners?
When you get aboard a Hercules, they hand you a pair of ear protectors.
The noise and vibration probably aren't as bad as a shuttle at takeoff,
but they last a whole lot longer.  Remember also that the ride on a jet
airliner at 35000 feet is a whole lot smoother than on a
propellor-driven cargo plane bumping and bouncing along at low altitude.

> ...An airplane takes off, flies and lands in an horizontal position;
> it doesn't turn somersaults at takeoff the way a shuttle does...

I wasn't aware of the shuttle turning any somersaults!  The worst-case
loading in the shuttle is the same as that of an aircraft: the
possibility of a very hard landing.  The shuttle does impose a higher
fore-and-aft loading than that of an aircraft, but 3 G is hardly
bone-breaking.

>... The shuttle payload must whithstand going from 1 atm to vacuum
>during takeoff, and from frying to freezing many times over when in
>orbit.

So must any payload flown on an unmanned launcher, and they have rather
less stringent requirements imposed on them.  (For that matter,
conditions in a Hercules cabin aren't always as friendly as those on an
airliner.)  So change my comment slightly: for "payload" substitute
"space-qualified payload".  There is a *large* difference between being
space-qualified and being shuttle-qualified.

> An airplane may be able to fly and land even with a ten-foot hole in
> the cargo bay.  I doubt the shuttle would survive re-entry with a
> one-foot hole, a few missing tiles, or even a bent bay door...

Please remember that STS-1 landed successfully with a number of missing
tiles.  Not in critical areas, admittedly, but even a Hercules will have
trouble surviving small failures if you pick the locations carefully.

> Finally, a shuttle is substantially more expensive than a cargo plane,
> and a lot more precious...

Here we get to the real problem, and the real reason I said "fundamental
reason".  NASA has no interest in achieving a compromise between safety
and utility -- the sort of compromise that is necessary for almost any
aircraft.  On the contrary, NASA has every reason to shoot for the
highest possible level of safety even if it makes the shuttle nearly
useless.

"To be completely safe, you have to sit on the fence and watch the birds."
                            -- Orville Wright.

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

Date: 23 May 88 02:38:06 GMT
From: portal!cup.portal.com![e-mail]
Subject: Re: cooling by radiation

So, just what are Lithium batteries, and why would they be prohibited on
a space flight, when I am allowed to take one in my watch and mingle
around thousands of people in public places? Are they radioactive?  What
about a leak?

                               [e-mail]

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

End of SPACE Digest V8 #243
*******************