Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_3/V16NO333.TXT

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Date: Thu, 18 Mar 93 05:34:51
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #333
To: Space Digest Readers
Precedence: bulk


Space Digest                Thu, 18 Mar 93       Volume 16 : Issue 333

Today's Topics:
                    20Khz Power supplies. (3 msgs)
        Actual 20kHz question! (was Re: 20Khz Power supplies.)
                  Asteroid Laser 'Drill' Speculation
                             Beyond 1000!
             Dennis and new tech (was Re: Without a Plan)
               Just a little tap (was Re: Galileo HGA)
                         Lunar ice transport
         Predicting gravity wave quantization & Cosmic Noise
                  Response to various attacks on SSF
                          Retraining at NASA
                            Space markets
                 SSTO: A Spaceship for the rest of us
Water Simulations (Was Re: Response to various attacks on SSF) (4 msgs)
                   What do we do now with Freedom.

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

Date: 17 Mar 93 09:13:00 GMT
From: Roland Dobbins <[e-mail]>
Subject: 20Khz Power supplies.
Newsgroups: sci.space

Ah, Fred, back to your old tricks again.  Seems like old times on BIX.

Too bad there's no moderator here to get you thrown off . . .



---
 . VbReader V1.41. Ok, now for a quick backu.A.&.#^1s.


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

Date: 17 Mar 93 09:13:00 GMT
From: Roland Dobbins <[e-mail]>
Subject: 20Khz Power supplies.
Newsgroups: sci.space

Ah, Fred, up to your old tricks still.  Reminds of of the old days, on BIX.

Too bad there isn't a moderator to throw you out _here_ . . .



---
 . VbReader V1.41. Ok, now for a quick backu.A.&.#^1s.


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

Date: 17 Mar 93 19:12:10 GMT
From: Pat <[e-mail]>
Subject: 20Khz Power supplies.
Newsgroups: sci.space

 Just say "n" to news :-)

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

Date: 18 Mar 1993 00:00:34 -0500
From: Pat <[e-mail]>
Subject: Actual 20kHz question! (was Re: 20Khz Power supplies.)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>In article <[e-mail]>, [e-mail] (Bill Higgins-- Beam Jockey) writes...
>>In article <[e-mail]>, [e-mail] writes:
>>
>
>By the way, is there anyone out there who knows about power supply isolation
>on spacecraft? We sure could use some INFORMED help in this matter. I am
>debating different approaches right now on this subject.
>

Why not use optical isolators :-)

>So pat I snookered you on this one to prove the point that you don't
>always know what you are talking about. :-)

Dennis, I would have been happy if someone had tossed out some
defenses for 20KHz a LONG time back.  And no matter what you say
about DC-DC power conversion, until I start seeing components in
the Thompsons catalog for High power High Frequency distribution
and start seeing industrial power distribution operating at High frequency
I'll be much more impressed.  What works well for a few hundred watts
of CPU power supply, doesn't work real hot at Sub Megawatt ranges.

I'd also be interested to see Generators running at that kind of frequency.

My dusty old power memories, are that for synchronous motor/generators,
the base frequency is tied to the rotational speed.  a major reason
why they have stayed to low frequencies,  you can do coil stacking, but
then you are limited by contactor capacity....

Granted Electro mechanical energy conversion  was one of the most
miserable classes I ever took,  but I passed, graduated and went on
to other things,  and only in the last few years started to really
understand some of the issues,  now that we are looking at Infra-structure
re-developemnt down here.

Gee dennis, you've got me  interested enough to try to dig up that
dusty old tome.  Now What solid state is doing is a whole new field,
and DC-DC High Power conversion has been done for certain problems,
but the applications have always been pretty limited.  A certain
high tension line out of brazil being one  or power shifting through
non-synchronous nets.

Nevertheless dennis,  In good old utility power generation and industrial
process design,  they are pretty conservative  and still use things
like DC Traction motors,  just because the controller design is
simple reliable and well understood.

AC traction motor sare much more efficient, but the Frequency shifting
motor controllers have been viewed as high risk investments in technology.

Washington METRO system,  one of the newest and most modern in America,
still uses DC traction.  One of their big long haul efforts is to plan
to move to AC power.

pat

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

Date: Wed, 17 Mar 1993 23:50:33 GMT
From: "Robert J. Hall" <[e-mail]>
Subject: Asteroid Laser 'Drill' Speculation
Newsgroups: sci.space

Curiosity question: How far are we, technology-wise, from being capable of
focusing a (sufficiently powerful) laser/maser from Earth or LOE onto a near-
earth asteroid, such that we can 'cook' off the surface layer and drill for
ice? (With the intent to see if any present.) Silly idea? I'm thinking about
something along the lines of an SDI-type laser using adaptive optics, and
possibly some sort of refocusing satellite.
--
 Bob Hall                   |
 Boeing Computer Services   | -- The usually disclaimers apply --
 [e-mail] |

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

Date: 18 Mar 93 02:26:42 GMT
From: "Peter T." <[e-mail]>
Subject: Beyond 1000!
Newsgroups: sci.space

In article <1o15ak$[e-mail]>, [e-mail] (Francis Vaughan) says:
>Hmmm, I guess that if you call Beyond 2000 a science program you
>really must be fed on a poor diet.

I tend to agree with you, I call Beyond 2000 a cutesy gadget show.
Eg: did you see the segment on stuffed electronic pet toys for
Japanese? Total drivel!
I watch Beyond 2000 to HOPEFULLY catch something worth
wile, and then usually sit there and try to figure out how it works
for myself, as thats too deep for them.

>For high quality I havn't seen better then the Brits, Horizon
>and the like are very very good.
>
>                                        Francis Vaughan

I can't say that I remember what horizon is like, but my favorite
science show is Quantum on channel 2.

In fact all the good documentaries are on channel 2, sometimes
it's a bit hard to spot them in the TV guide as the names can be
quite obscure and no mention of it being a documentary.

The ultimate would be Quantum with Beyond 2000's budget.

Peter T.

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

Date: Thu, 18 Mar 1993 03:19:01 GMT
From: "Phil G. Fraering" <[e-mail]>
Subject: Dennis and new tech (was Re: Without a Plan)
Newsgroups: sci.space,talk.politics.space

[e-mail] (Bill Higgins-- Beam Jockey) writes:
...
>Which, it is worth pointing out, is trying out risky new technologies
>in its computer, solar cells, and imaging device.  This is something
>that Nick, Henry, and many others advocate strongly.  If SEDSAT-1 is
>successful, these gadgets will have a track record and people will be
>willing to incorporate them into future satellites. (Though I think
>Dennis's payload goes up on the *second* SEDS launch, not the current
>one.)

I think Nick's been doing a couple papers on comet mining.
And Dennis Wingo has a payload going up soon...

I wouldn't have thought either of them would have the time, they seem
to spend so much time flaming away on sci.space...

>"Do you know the asteroids, Mr.Kemp?...    Bill Higgins
>Hundreds of thousands of them.  All
>wandering around the Sun in strange        Fermilab
>orbits.  Some never named, never
>charted.  The orphans of the Solar         [e-mail]
>System, Mr. Kemp."
>                                           [e-mail]
>"And you want to become a father."
>  --*Moon Zero Two*                        SPAN/Hepnet: 43011::HIGGINS

Hmmph. You know they were once called "Vermin of the Skies?"
--
Phil Fraering         |"...drag them, kicking and screaming,
[e-mail]|into the Century of the Fruitbat." - Terry Pratchett,
                       _Reaper Man_

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

Date: Wed, 17 Mar 1993 22:58:51 GMT
From: Dennis Newkirk <[e-mail]>
Subject: Just a little tap (was Re: Galileo HGA)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Bill Higgins-- Beam Jockey) writes:
>In article <[e-mail]>, [e-mail] (Thomas Clarke) writes:
>>
>> You mean sideswiping an asteroid to try to knock the antenna loose is out :-)
>
>Hmm, they're going past Ida in August, and a zero-distance flyby is well
>within the propellant margins, I'm sure...

How about just a puff? I suppose skimming the Jovian atmosphere on
the way to orbital insertion is out too?

Seriuosly, does anyone know if there's any hope that orbital insertion burn
will jolt the antenna loose? Or, is the mesh weak enough that it might tear
apart?

Dennis Newkirk ([e-mail])
Motorola, Land Mobile Products Sector
Schaumburg, IL

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

Date: Thu, 18 Mar 1993 00:40:00 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Lunar ice transport
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Ross  Borden) writes:
>In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>>In article <[e-mail]> [e-mail] (Ross  Borden) writes:
>>>be buried in the regolith (an excellent insulator).  Does anyone know
>>>what the mean temperature of regolith is at, say, 2 meters ?
>>
>>We only have a few data points, but they're all within a degree or two
>>of 255K.  The variation is from site to site -- the temperature at any
>>particular site is absolutely constant at that depth.
>
>    So, if you were to preheat the pipeline by injecting superheated
>steam, could you pump water at, say, 100C the entire length without reheating?

>    Gary Coffman mentions using steam instead of water, but its not clear
>to me why.  Is it for ease of pumping?  I would think that you would be able
>to deliver more mass using liquid phase.

I was suggesting a system that is *self pumping*. The solar heating of
the pipe during lunar daytime boils the water and the system "percolates"
via a set of one way check valves toward the equatorial base. You'd want
to paint the pipe contrasting shades to aid the process. The alternating
hot and cool zones, in conjunction with the check valves, would insure
net flow in the desired direction. Ideally you'd take advantage of gravity
flow in the cool zones by arranging them to be on downhill slopes. You
might still need some active pumping depending on terrain, but it should
be much less costly to let the sun do most of the work.

Gary
--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244     |                     |

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

Date: Thu, 18 Mar 1993 01:49:57 GMT
From: Cameron Randale Bass <[e-mail]>
Subject: Predicting gravity wave quantization & Cosmic Noise
Newsgroups: sci.space,sci.astro,sci.physics,alt.sci.planetary

In article <[e-mail]> [e-mail] (Mark) writes:
>In article <[e-mail]> [e-mail] (Ron Baalke) writes:
>>     Three interplanetary spacecraft, now headed quietly toward Mars,
>>Jupiter and over the poles of the sun, soon may prove the
>>existence of elusive waves in the universe's gravitational field by
>>bobbing on ripples in space like corks bobbing on ripples in a pond.
>
>I'm betting that the following will be observed:  Cosmic Noise.  A large number
>of components will be detected at around wavelengths of 1 AU and above with
>VERY low intensity, if the configuration is sufficiently tuned.  The
>components will have wavelengths that occur at discrete jumps of about 1
>millimeter at 1 AU.

     On the same note, does anyone have a clue as to how the 'expected'
     signal compares with the other effects (Poynting-Robertson drag,
     solar wind, thermal stresses etc.) for which we have no
     independent quantification? Either magnitude or characteristics
     will do.  After all, one quadrillionth of 100 million kilometers
     is only 1 mm, and they're lots of things that kick spacecraft around
     on various scales.  How do they prevent this from becoming an
     unintentional two-week study on solar wind coincidence phenomena?

     Barking up the same tree, does anyone know how they use the doppler
     shift without the argument becoming quite circular?

                               dale bass

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

Date: 17 Mar 93 19:15:58 GMT
From: Pat <[e-mail]>
Subject: Response to various attacks on SSF
Newsgroups: sci.space

When the were building the shuttle, they went and
built like 5??? structural test articles  just so they could get solid
frame data.  One of these STA-99 went on to become a spaceship.

What I don't understand is why they didn't take Enterprise and
use her as a ground test article,  on a long haul basis.
See how she behaves  after 5 years of salt air has hit her.

737's make bad convertibles,  Shuttles make even worse ones.

pat

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

Date: Thu, 18 Mar 1993 01:57:42 GMT
From: Brian Donnell <[e-mail]>
Subject: Retraining at NASA
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Pat)
wrote:
>
> Yeah, I'll have to agree.  I'd like to see more NASA people
> using sci.space as a forum for honest engineering discussion.
> I just don't want to see any Hatch act violations.
>

Amen - but the most of the Hatch Act should be unconsitutional
imho. Another diatribe entirely - so don't get me started. :-)

> STS  4 Billion/year.
> SSF  1 Billion/year
> DSN  200 Million/year
> TDRSS 500 Million/year
> Facilities O&M 1.5 Billion/year.
>

What is your source for these numbers?  Just to make sure we are one the
same wavelength, are you saying, for example, that it costs 4 billion
annually
just to maintain STS in nominal operations (with no considerations for
payloads development and costs, etc.)  I am particularly curious about what
you consider to be infrastructure costs in SSF, since the program is still
in development.

> Investment in infrastructure often times limits modes of thought.

Agreed - the issue is a difficult one with limited funds.

While I would certainly agree that NASA has not been able to incorporate
new technology as fast as would be desired, there is something to be said
for getting the most mileage out of previous investments. Now when it
can be shown that new methods generate a significant savings - then the
proverbial gears should be switched.  (For example, I agree with many of
your
observations in the post about SSF redesign.)

I think perhaps there are stronger arguments that NASA's scope is too large
for the money Congress chooses to allocate. However, be that as it may,
NASA must use its funds first to maintain (and complete where appropriate)
projects upon which it has already embarked.  In some cases, this might
even
mean sticking with an less than optimal design, because better methods were
not available at the onset (and throwing away the old one is prohibitive)
or
the right method is too resource demanding.

Brian Donnell
NASA/JSC

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

Date: Thu, 18 Mar 1993 01:57:34 GMT
From: INNES MATTHEW <[e-mail]>
Subject: Space markets
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Tom) writes:
>
>I like the idea of selling advertising and movie-making rights on our
>current space operations.  If I remember right, NASA has turned it
>down, for National Prestige reasons, I imagine.  Tell you what;
>I'd have a lot more pride in my Nation if it's agents got with it.
>

Actually, (not very reliable) rumor has it that NASA is selling ad
space on the Shuttle's ET.  Rumor also has it that the first customer
is to be Arnold Schwartzeneggar's new movie.

    But then again, it's probably all lies.


--
                        Matt Innes
                        <[e-mail]>

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

Date: Thu, 18 Mar 1993 01:30:20 GMT
From: Gary Coffman <ke4zv!gary>
Subject: SSTO: A Spaceship for the rest of us
Newsgroups: sci.space

The DC series SSTO is an interesting experimental program and deserves
support as such. It's promise is great, as are the risks. However, the
following quotes contain Sherzerisms that need a bit of clarification.

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>Space is an important and growing segment of the U.S.
>economy.  The U.S.   space market is currently over $5
>billion per year, and growing.  U.S. satellites, and to a
>lesser degree U.S. launch services, are used throughout the
>world and are one of the bright stars in the U.S. balance of
>trade.

Satellites are certainly a US dominated area, but commercial
launch services show little indication of being profitable
activities absent government subsidy. Indeed they may actually
be net contributors to the US trade deficit due to costs absorbed
by the US government. This is a problem of both US and non-US launching
entities. Space launch business isn't a profit making operation for
any launching entity at this time unless sunk costs and operational
subsidies are ignored. At best they are net cash flow generators
for firms employed in the business. SSTO has the potential to turn
this around.

>Even the U.S. Space Shuttle, which was supposed to give the
>U.S. routine low cost access to space, has failed.  A
>Shuttle flight costs about $500 million (roughly $10,000 per
>pound to LEO).  Even going full out, NASA can only launch
>each  Shuttle about twice a year (for a total of eight
>flights).

The US has been doing 8 flights with only 3 Shuttles operational,
but that's a minor quibble.

>Spacecraft are complex, expensive, and built to aerospace
>tolerances but they are not the only products of that nature
>we use.  A typical airliner costs about the same as a
>typical launcher.  It has a similar number of parts and is
>built to similar tolerances.  The amount of fuel a launcher
>burns to reach orbit is about the same as an airliner burns
>to go from North America to Ausralia.  Looked at this way,
>it would seem that the cost of getting into orbit should be
>much closer to the $1500 it takes to get to Australia than
>to the $500 million dollars plus it takes to put an
>astronaut up.

Bad numbers. The $1500 represents one first class ticket to
Australia while the $500 million (an inflated number by many
people's calculation) represents delivery of *7* astronauts
*and* up to 40,000 pounds of cargo to LEO. If we take more
reasonable marginal costs of $110 million for a Shuttle flight,
the cost per pound is $2,750. Advantage is still to the airliner,
but it never tops 600 MPH and lets it's *wings* do most of the
work of supporting it's weight. The situations aren't comparable.
Indeed, if Allen's claim is true that an airliner consumes the
same amount of fuel as DC, and Henry says this is 700,000 pounds,
then at $0.11 a pound for JP4, the airline flight costs $77,000
in fuel alone. However this number is bogus since no existing
airliner can take off with 700,000 pounds of fuel on board.

Henry says that DC-Y will mass 800,000 pounds, and that 700,000
pounds of that will be fuel. He further says that LOX is $5 a
pound and represents the bulk of the weight. So ignoring the
hydrogen's extra handling costs, fuel for a DC-Y flight costs
$3.5 million dollars. With a payload of 20,000 pounds (best case),
that's $175 a pound to LEO. That's the equivalent of a airline seat
to Australia costing $31,500. Not cheap, but better than other launch
systems by an order of magnitude. It should be remembered, however,
that projected Shuttle costs per pound were $300 at a similar stage
of it's development. If history is any guide, DC may wind up costing
$1,750 a pound or more by the time it becomes operational. That's a
$315,000 dollar ticket to Australia.

Gary
--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary
Lawrenceville, GA 30244     |                     |

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

Date: 18 Mar 1993 01:23:13 GMT
From: Dave Akin <[e-mail]>
Subject: Water Simulations (Was Re: Response to various attacks on SSF)
Newsgroups: sci.space

In article <[e-mail]> Allen W. Sherzer, [e-mail]
writes:
>>>More importantly, NASA put a huge amount of faith in those tanks with
>>>almost no real life experience to see just where the shortcomings are.
>
>>Hey Allen I don't know how old you are but do you remember the old days
at
>>NAsa? ALL of the EVA's for Skylab were practiced here at MSFC before
>>implementation....
>
>You miss my point Dennis. I think water tanks and practicing on them is
>a great idea. However, to assume that we can corelate actions in the tank
>to the actions needed to assemble a large space structure (like Freedom)
>in free fall is foolish.
>
>The bottom line remains that we have nowhere near the EVA experience base
>to practice any but the most simple EVA activities with any degree of
>confidence.

(Sorry, I think my posting system screwed up the first time...)

I think you are selling our EVA experience way too short here - if you
think
we've only done "the most simple EVA" (I won't even bother to point out
that "EVA activities" is redundant), check out the procedures used on the
Solar Max repair mission, or the "hot-wiring" of Leasat when the GTO
insertion motor circuit failed. These were interfaces built to be
activated
on the ground in a nice, comfortable clean room, and the crew made it look
easy. There is absolutely nothing planned for the space station that
couldn't
be readily performed in EVA. The problem (as highlighted by the
Fisher-Price
report) was that there was just too much stuff to be done.

I was principal investigator on the EASE (Experimental Assembly of
Structures
in EVA) program, which along with the ACCESS experiment from NASA Langley
demonstrated that EVA crew were fully capable of performing assembly of
the
station truss structure, and led to the initial decision for a fully
erectable structure.
The thing which drove them back to the pre-integrated truss design
(besides the
need to save money in a redesign) was that routing the utilities (power,
instrumentation,
communications, cooling, etc.) took A LOT more time than just assembling
the structure. Also, it's a lot easier to check things out initially if
they're hooked
up prior to launch, so you can do the work in that comfy clean room.

As to my first love (neutral buoyancy), let me repeat my bottom line based
on fifteen years of research in the field: It's easy to design a bad
neutral
buoyancy experiment. You do need to take into account viscosity, virtual
mass, relative masses of the crewman's body and the test hardware, etc.
While
all forms of space simulation have their advantages and disadvantages,
neutral
buoyancy is (by far!) the best way to get a human in the loop and
interacting
with the test hardware in a decently realistic microgravity environment.

And, oh, yeah. Yes, it's true that it's difficult to get realistic space
dynamics
underwater. But let me point out that the crew training for Intelsat
dynamics
was not done underwater, it was done with the crewman in foot restraints
in
1-G at the end of a
Intelsat
model floating on air bearings on a flat floor. The whole set-up is still
in the high
bay in Bldg. 9 at JSC, or at least it was last time I was in there.
  - Dave Akin
    Space Systems Laboratory, University of Maryland

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

Date: 18 Mar 1993 01:40:05 GMT
From: Dave Akin <[e-mail]>
Subject: Water Simulations (Was Re: Response to various attacks on SSF)
Newsgroups: sci.space

In article <1o8iu1$[e-mail]> Dave Akin, [e-mail] writes:
>1-G at the end of a
>Intelsat
>model floating on air bearings on a flat floor. The whole set-up is still
Sorry, my poster is having incredible problems today with
Microsoft Word's smart quotes. That paragraph should read:

And, oh, yeah. Yes, it's true that it's difficult to get realistic space
dynamics underwater. But let me point out that the crew training
for Intelsat dynamics was not done underwater, it was done with
the crewman in foot restraints in 1-G at the end of a "cherry-picker"
type contraption, interacting with an Intelsat model floating on air
bearings on a flat floor. The whole set-up is still in the high
bay in Bldg. 9 at JSC, or at least it was last time I was in there.

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

Date: Thu, 18 Mar 1993 02:06:51 GMT
From: Dave Rickel <[e-mail]>
Subject: Water Simulations (Was Re: Response to various attacks on SSF)
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Henry Spencer) writes:
|> The other is the more obvious issue:  the water has viscosity.

Hmm.  I'm reminded (again) of an article from THE INVENTIONS OF DAEDALUS, where
he remarks that Xenon (? sorry, my copy is at home) can be compressed to the
point where it has the same density as water, yet still be gaseous.
Presumably the viscosity is much less than water.  Hmm.  Cost looks like it
should be a factor--20 years ago (sorry again--old CRC) Xenon was selling for
$20/liter (STP)).  Figure a cube, 20 meters on a side, 200 atmospheres pressure
(a bit on the high side).  That's $32,000,000,000 worth of Xenon.  A bit
pricey.


david rickel
[e-mail]

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

Date: Thu, 18 Mar 1993 03:26:15 GMT
From: "Phil G. Fraering" <[e-mail]>
Subject: Water Simulations (Was Re: Response to various attacks on SSF)
Newsgroups: sci.space

[e-mail] (Henry Spencer) writes:

>In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>>... I think water tanks and practicing on them is
>>a great idea. However, to assume that we can corelate actions in the tank
>>to the actions needed to assemble a large space structure (like Freedom)
>>in free fall is foolish.

>As a minor case in point, something that got mentioned at Making Orbit...

>There are two things really wrong with the water-tank simulation of free
>fall.  One is that you are lying in your suit rather than floating in it.
>The other is the more obvious issue:  the water has viscosity.

>When exiting the shuttle airlock, you reach out and grab a handrail
>above the door, and then push off outward.  Apparently, *everyone* who
>tries this for the first time in free fall after water-tank practice
>bonks his helmet against the outside of the airlock, by pushing off
>too hard and helplessly pivoting too far around the handrail.  Even
>if he's been warned about the problem.

In short, the damping motion of the water makes you push too hard?

Are there _other_ fluid effects? Does water flow in the tanks?
What about eddies and the like, from divers and the moving hardware?
Another problem just occured to me, although the damping effect
on motion of the water is probably the main one:

The water imposes a standard reference frame where there is none.
There is a zero velocity: the velocity of the water.

I think that's where the resistance came from that let the tools work
in the tank when they wouldn't on the comsat...

>--
>All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
>                    - Kipling           |  [e-mail]  utzoo!henry

--
Phil Fraering         |"...drag them, kicking and screaming,
[e-mail]|into the Century of the Fruitbat." - Terry Pratchett,
                       _Reaper Man_

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

Date: Thu, 18 Mar 1993 02:08:59 GMT
From: Brian Donnell <[e-mail]>
Subject: What do we do now with Freedom.
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Pat)
wrote:
>
> 1)  Compress the management structure.  keep reston, but fire all but

Agreed. Integration issues by far are the weakest link in the program.

> 2) COmpress the centers.  Either Johnson or MSFC should take lead

Agreed - but this will be very tough to sell.

> 3) Use Russian Heavy launch gear.  The energiya could sling large
> 4)  GO to 51 degree incline orbits.  Take the hit on shuttle payloads,

Use of Russian resources is being investigated heavily as we speak.

> 5)  Look at ET wet facilities for additional space.  Dennis doesn't
> like it,  but the ET's provide lots of volume cheap.  some mods and
> they could be easily clipped onto the truss.
>

What truss? ;-)

> 6)  Building ground spares,  both for methodology developement and

Always a good idea.  Cost may prevent it though.

> 7)  More standardization.  Sure  the SSF lab Modules are Spacehab

Absolutely - this gets us back to point #1 again.

> 8)  engineering developement flights, to improve knowledge base.

Would be nice - but unrealistic.  Our only hope for this kind of thing
now is to draw on Orbiter, Skylab and Russian experience (the latter being
the most useful for this domain).  The redesigned SSF will likely have a
10-year lifespan instead of 30 - so perhaps it will be the building blocks
for the real manned presence to follow.  I know that's where we were
supposed to be now - but let's not cry about it and go on.

Brian Donnell
NASA/JSC

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End of Space Digest Volume 16 : Issue 333
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