Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V16_3/V16NO344.ZIP/V16NO344

Internet Message Format | 1993-07-13 | 36KB

Date: Sat, 20 Mar 93 05:29:17
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #344
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat, 20 Mar 93       Volume 16 : Issue 344

Today's Topics:
                         CD for Pluto Mission
       Clueless Szaboisms (Was Re: plans, and absence thereof)
             Flight time comparison: Voyager vs. Gallileo
   LPI, UAz, and ET resources (was Re: plans, and absence thereof)
   Lunar Arctic, pressure, antifreeze (was Re: Lunar ice transport)
                            NASA SELECT TV
                Predicting gravity wave quantization &
         Predicting gravity wave quantization & Cosmic Noise
Water Simulations (Was Re: Response to various attacks on SSF) (2 msgs)
             Why use AC at 20kHz for SSF Power? (2 msgs)

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

Date: Fri, 19 Mar 93 18:26:19 GMT
From: Dave Jones <[e-mail]>
Subject: CD for Pluto Mission
Newsgroups: sci.space

FRANK NEY ([e-mail]) wrote:
>
> Unless I had a news.hallucination, someone on the group mentioned that
> there was a 300g allocation for some sort of commemorative device.
> This would fall within the range of a CD-ROM.
> --

OK, now think of a CD-ROM with a data retention time measurable in millenia
and we'll be all set.  Nobody right now will give you much past a decade or
two before the errors on the disk become uncorrectable.  You could probably
design a high-redundancy data layout that might give you, oh, 10 % of the
original capacity or around 60 megabytes.  That's enough for some lo-res
imagery and lo-fi sound.

You really need to worry about the effects of heat and vacuum on the CD
though.  It makes you realize why Sagan and Co. opted for a metal grooved
disk on Voyager.  Even then you need to realize that metal doesn't sit
around on the kind of timescales you're talking about, at the size scale of the
structures involved in a data or sound recording.  Remember the high school
physics example of iron and gold blocks interpenetrating over a few months.
Given that kind of mobility in a metal's structure, what's the smallest
structure that can survive intact in a metal over a couple of millenia?


--
||------------------------------------------------------------------------
||Dave Jones ([e-mail])|Eastman Kodak Co. Rochester, NY  |

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

Date: 20 Mar 93 00:24:53 GMT
From: "Phil G. Fraering" <[e-mail]>
Subject: Clueless Szaboisms (Was Re: plans, and absence thereof)
Newsgroups: sci.space,talk.politics.space

Sender: Anonymous NNTP Posting <[e-mail]>
Organization: Univ. of Southwestern Louisiana
Lines: 84
Source-Info:  Sender is really [e-mail]
Source-Info:  Sender is really [e-mail]

[e-mail] writes:

>My paycheck comes in this proportion

>40% Taiwanese National Cheng Kung University Contract
>30% SpaceHab (Where the contract that we won came in at less than 1/3 the
>cost of our competitors due to MY design)
>30% Office of commercial whatever at NASA hq for accelerometer work.

>This will change in the next 30 days to 100% paid for by money that I have
>raised through my own efforts in the private sector to enable me to work on
>SEDSAT 1 through may of next year.

Just a couple comments/questions:

1. SpaceHab corp, as an add-on for the Shuttle, is the last subsidized
provider of microgravity time, a market the Shuttle helped kill for
a while thanks to the three years of downtime/immense backlog of
missions during the 80's.

>Work that I an my collegues are doing here at UAH is helping to bring down
>the cost of materials processing in space by doing the all important
>background engineering that will allow the true testing of the
>microgravity materials science concepts either on Shuttle, COMET, CONSORT
>or any other platform for that matter.

2. COMET seems to be another bad idea: NASA saying, "We've driven up
the cost of manned microgravity research with the Shuttle/Station, so
let's get started on driving up the cost for unmanned users by putting
out a contract for a tiny microgravity sat and overpaying for it and
saying it's cheap."

>So actually I am doing two things. I am bringin money into this country
>from foreign sources, thereby helping to reduce our balance of payments
>while building things that work and lower the cost of doing spaceflight
>experimentation.

I'm glad you're doing what you're doing, and that you intend to
try to do what you are below, _but_ skip down a half a screen...

>As for my other activities, I don't even have to defend them. I will bet
>you one thing Mr. Know it all, when in several years there is a spacecraft
>returning to the moon, you can bet your last nickel that I will have had
>something to do with it and you will still be ranting on sci.space.

>Have a Nice Day
>Dennis, UNiversity of Alabama in Huntsville

>PS Oh by the way the next time you go to Kmart or anywhere else that has
>a NCR cash register that has a modem hooked to it you will be at the
>mercy of hardware that I designed. I worked for 10 years in the commercial
>computer industry BEFORE I ever worked on space experiments. I walked
>away from a secure job to take one at 1/5 the pay because this is where our
>future is and I have bet the farm on it. So next time you talk about
>me and where my paycheck comes from you need to reference this post.

LET ME ASK YOU THIS: IF THE WAY THE GOVERNMENT DOES THINGS AND IS RUNNING
THE SPACE PROGRAM SO DAMN GOOD, THEN WHY WOULD SOMEONE AS TALENTED AS YOU
HAVE TO TAKE AN 80 % CUT IN PAY TO WORK THERE, EVEN AFTER RAISING HALF YOUR
SALARY FROM PRIVATE SOURCES?

(I don't know which stupid gov't rule it is, although personally I
suspect it's the one where Federal Managers get political clout directly
in proportion to the number of people they employ, which means they'll
employ as many low-pay workers as possible; I imagine this makes whoever
has federal management priority on your project very happy that you've
found private funding).

Also, what happens if we go ahead with Fred and it _eats_ money for
future moon exploration or comet exploration for the next fifty years,
leaving us 30 years for now with a couple astronauts in orbit and you
and Nick's flame wars having finally brought about the Imminent Death
of the Net...

_THAT_ is what I don't understand: I can understand getting mad at
Nick, I've done it myself at times. He's remarkably pigheaded. _But_:
why the rabid defense of Freedom to the point where the rest of
us wonder where you get the time for SEDSAT?


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

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

Date: 20 Mar 1993 02:28 UT
From: Ron Baalke <[e-mail]>
Subject: Flight time comparison: Voyager vs. Gallileo
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Henry Spencer) writes...
>In article <[e-mail]> [e-mail] (Ron Baalke) writes:
>>>No, the fundamental problem is that Galileo really could have used a
>>>trip to the fat farm. ...
>>>weight growth during development was nothing short of spectacular.
>>
>>Not true.  Galileo is a heavier spacecraft than Voyager, by design.
>>Galileo is an orbiter, whereas a flyby spacecraft can be built much smaller.
>>Also, Galileo had to be redesigned so many times because of
>>problems with the Shuttle and the Centaur/IUS, and its mass was even
>>reduced at one point.
>
>Certainly Galileo is flying a more ambitious mission, and has had numerous
>problems with its launcher changing underfoot.  However, I stand by my
>original comment:  it's very overweight compared to the original concept,
>and this is a major reason why it strained launcher capability so badly.
>Just because it was meant to go up on Shuttle/Centaur didn't mean they
>*had* to design it to the very limits of what that combination could
>launch.

Galileo was originally designed to go up with the Shuttle/IUS not
the Shuttle/Centaur.  I think
your implication was that Galileo exceeded its mass margins and exceeded
the capability of the Shuttle/IUS, but this did not happen.  Instead,
the IUS turned out not to meet its performance specs, and the Centaur was
brought it instead.  When NASA got timid with the Centaur on the Shuttle,
the IUS was resurrected, but required Galileo to go the VEEGA route.

>The other two S./C. payloads, Ulysses and Magellan, made the
>transition back to IUS easily because they didn't push the limits.

Magellan in its original form (VOIR) was designed to be much bigger, but
was significently scaled back.  It ended up being massively under budget at
50% of the original VOIR budget.

The Shuttle/IUS was not sufficient for Ulysses.  An additional booster, the
PAM-S, was also needed to send Ulysses off to Jupiter at the required
velocity.

>There's nothing about the Jupiter Orbiter/Probe mission that required
>such an elephant of a spacecraft.

True, but the goal is the get as much science return as possible.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Don't ever take a fence
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | down until you know the
|_____|/  |_|/       |_____|/                     | reason it was put up.

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

Date: 20 Mar 1993 02:08 UT
From: Ron Baalke <[e-mail]>
Subject: LPI, UAz, and ET resources (was Re: plans, and absence thereof)
Newsgroups: sci.space,alt.sci.planetary

In article <[e-mail]>, [e-mail] (Pat) writes...
>
>I'd think a place like LPI would be a good place to be
>cranking out prospecting missions.  Lunar Observer should be their
>program.
>They should have been leading the lunar rover programs like ROcky
>and pushing for continued applications for the LEM, etc.

There is nothing to stop LPI from proposing their own missions.  One of
their missions was recently selected for further consideration as a Discovery
mission (Mercury flyby).

Rocky IV, by the way, is a Mars rover.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Don't ever take a fence
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | down until you know the
|_____|/  |_|/       |_____|/                     | reason it was put up.

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

Date: 20 Mar 93 01:16:50 GMT
From: Josh Hopkins <[e-mail]>
Subject: Lunar Arctic, pressure, antifreeze (was Re: Lunar ice transport)
Newsgroups: sci.space

(Bill Higgins-- Beam Jockey) writes:

>(Josh Hopkins) writes:

>> (Bill Higgins-- Beam Jockey) writes:

[On the subject of steam pressurization of a lunar water pipeline..]
>>
>BH>>Cute idea, Gary, but if it could be made to work, it would work
>BH>>only six months a year at best.
>>
>JH> First I want to clear up one thing that might be confusing.  The problem is
>JH> with standard night/day cycles (in which the days add up to six months)
>JH>rather
>JH>than a single six month night as you would expect at a terrestrial pole. I'm
>JH> sure Bill knows this but other readers might be confused.

>The Moon's "Arctic Circle" is very small since its inclination to the
>ecliptic is only 1.5 degrees.  Nevertheless there *is* a small region
>where it'll be night  six months at a time.  And this happens to be
>where the ice is coming from.  And it happens to be the place in
>Gary's system where he needs the most pressure and energy.

True enough.  However, my calculations show that 88.5 degrees latitude is only
about 45 miles from the pole.  Given that the plant almost certainly won't be
exactly on the pole it seems rather likely that this problem could be avoided
or at least worked around.

>This is not insurmountable but it screws up the elegance of Gary's
>idea.

That's reality for you.  Mother Nature just won't do what the engineers want.

>> Secondly, I don't think it should be too hard to isolate the pipeline from
>>the
>> surface to drastically cut down on the heat loss at night.  The pipeline is
>> then essentially radiating to vacuum.

>Good point, but there is a flip side to your argument-- we gotta wait
>until some time *after* dawn for the pipes to warm up again!  Thus
>there is a corresponding time at the beginning of the day when you
>can't operate.

Put parabolic reflectors under the pipeline and you can get a large amount of
energy reasonably quickly.

>Remember Henry's assertion that the temperature is a constant 255 K
>underground?  That nice steady thermal environment is mighty
>attractive.

If you like -20 C.

>>If I had more spare time I'd pull out my steam tables and
>> plug a few numbers.

>I looked at my office copy of the CRC (36th edition, 1954-55.  Hey, it
>was cheap!).  The melting point of ice is depressed to 253 K by a
>"pressure" of "2042 kg/cm^2."
>2110 atmospheres.  Wow. This is a gauge pressure, too, so
>better throw in an extra 1 atm for the Moon.  (-:

Yes.  There are some problems with this technique.

>Lowering the melting point with an antifreeze solution is a better
>idea.  What would be a suitable antifreeze we could derive from lunar
>materials?  You're allowed to use CO2, CH4, and other stuff in comets,
>since we are assuming we've found a lunar water-ice deposit and these
>chemicals would be mixed in.

The big trouble with using antifreeze is that you need lots of it to fill a
thousand kilometers of pipe and that to do things efficiently you need to be
able to recycle it.  Unless you want to run two pipes or produce large amounts
of it on site this would be very expensive.

--
Josh Hopkins                                          [e-mail]
          "Tout ce qu'un homme est capable d'imaginer, d'autres hommes
                     seront capable de la realiser"
             -Jules Verne

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

Date: Sat, 20 Mar 1993 01:48:03 GMT
From: "Jonathan C. Lapin" <[e-mail]>
Subject: NASA SELECT TV
Newsgroups: sci.space

It took about a year of letters and phone calls, but our local (developer-
owned) cable company finally bought a dish and receiver and added the channel
capability they needed to carry NASA SELECT all the time.  As it happened,
they did not have the spare channels or an existing dish and receiver, so we
had to wait.  They also had some trouble decoding the audio, although I never
found out why.

The "big guys" in the area, Storer Cable, carry it on a "Community access"
channel.  They only carry it sporadically at best.  We've got a large
audience of Johnson Space Center employees but they still don't seem to
understand that.

If your cable operator needs more info, NASA SELECT is carried on SATCOM F2R,
Transponder 13.  The look angle is 72 degrees west.  You can contact the
newsrooms of any one of the NASA Centers for more info - the JSC newsroom is
[phone].  Don't bother saying I sent you to them, they won't know me
from a wormhole in the universe.

Jonathan Lapin

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

Date: 20 Mar 1993 02:46:35 GMT
From: Tim Thompson <[e-mail]>
Subject: Predicting gravity wave quantization &
Newsgroups: sci.space

In article [e-mail], [e-mail] (Mark) writes:
>
> I believe that the universe is closed.  That means that all functions are
> decomposeable into a series of harmonics with respect to the closed dimensions.
> I believe that the metric has components at low frequencies that are residual
> from the Big Bang.  They will occur as standing waves, so the idea of wave
> speed is utterly inappropriate.
>
   Now I know why there is an "is science a religion" thread floating around.

---
ALL OPINIONS ARE MINE, ALL MINE, AND CONSTITUTE ULTIMATE UNIVERSAL TRUTH.
THEY ARE ALSO WORTH WHAT YOU PAID ME FOR THEM.
------------------------------------------------------------
Timothy J. Thompson, Earth and Space Sciences Division, JPL.
Assistant Administrator, Division Science Computing Network.
Secretary, Los Angeles Astronomical Society.
Member, BOD, Mount Wilson Observatory Association.

INTERnet/BITnet:    [e-mail]
NSI/DECnet:         jplsc8::tim
SCREAMnet:          YO!! TIM!!
GPSnet:             118:10:22.85 W by 34:11:58.27 N

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

Date: 20 Mar 1993 02:38:40 GMT
From: Mark <[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] (Cameron Randale Bass) writes:
>     Not really wishing to start another discussion on what the 'speed'
>     of gravity means, if the waves travelled instantaneously, how
>     does one define or detect a 'wave'?

I believe that the universe is closed.  That means that all functions are
decomposeable into a series of harmonics with respect to the closed dimensions.
I believe that the metric has components at low frequencies that are residual
from the Big Bang.  They will occur as standing waves, so the idea of wave
speed is utterly inappropriate.

Since there's closure in the spatial dimensions, these components will only
exist at discrete values of wavelength and frequency, which (doing a back of
the envelope calculation) comes out to something on the order of a millimeter
separation for wavelengths of 1 AU (wavelength^2 / universe radius).

If the spacecraft are separated far enough (like by more than 1 AU) you could
detect these components because it's like you'll have a huge antenna detecting
them.  Having more than one spacecraft is crucial in order to triangulate.

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

Date: Sat, 20 Mar 1993 00:19:58 GMT
From: Dave Michelson <[e-mail]>
Subject: Water Simulations (Was Re: Response to various attacks on SSF)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>
>>What about all of the Gemeni EVA's (well a couple of them) They were done
>>in the tank first.
>
>And I don't think any went as expected in flight. That was to be expected
>in those early days.

Just to clarify, most of the Gemini EVA practices were conducted during
the short periods of weightlessness obtainable in training aircraft.
According to Aldrin, the relative ease with which White conducted himself
during Gemini IV misled planners quite badly.  (White was a fitness fanatic
and was apparently in superb physical shape.)

After a string of near disasters, NASA planners began to realize that an
alternative training facility was required and began to investigate
neutral buoyanacy facilities.  Aldrin trained for his EVA's aboard Gemini
XII in a water tank that had once been used for explosive forming.  In
comparison to Cernan, Collins, and Gordon's experience, Aldrin's EVA's
were completely successful and, in the minds of many, the use of neutral
buoyancy facilities for training purposes looked very promising.

The current Neutral Buoyancy Facility wasn't completed until 1968.  According
to Compton and Benson in "Living and Working in Space",

  Underwater simulation of zero g was not perfect, but astronauts found that
  anything they could do in the tank could generally be done in orbit.  Better
  still, underwater simulations were conservative; they required more effort
  than the same task required in space and therefore dis not lead to under
  estimating the difficulty of a task.

They cite several references from 1967-1969 in support of their summary.

As with *any* simulation, use of neutral buoyancy facilities to simulate
zero g must be validated by real experience as the parameters of the
experiment or activity change.  As has been pointed out, it appears that
limits to the usefulness of neutral buoyancy training have been identified
in recent years.

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

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

Date: 20 Mar 1993 02:01 UT
From: Ron Baalke <[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...
>Nobody is saying that the water tanks are valueless.  The astronauts
>themselves say that the tanks are the best ground-based simulation of
>free fall.

Agreed.  The water tanks are the best we can do on the ground to simulate
zero G, but there is a limit on what can be done.  The alternative is to
do more EVA's in space.

>The Intelsat problem was a
>nasty surprise.  There are probably more such surprises lurking.  We can
>either mount a systematic experimental program to discover them before
>they cause trouble, or find out about them the hard way on some crucial
>mission with limited slack in its timeline.

What made Intelsat particularly difficult is that it was not designed to
be serviced in orbit.  The only real hard part was grappling the satellite,
after that, everything else went real smooth.

In December, when Hubble is serviced by the Space Shuttle, you'll see what
a difference this can make.  There is 225 feet of handrails encirlcing
Hubble, and portable handholds and foot restraints can be installed if
necessary.  Hubble was designed so that it can be easily grappled by the
Shuttle's arm.  The instruments are in easily replaced units.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Don't ever take a fence
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | down until you know the
|_____|/  |_|/       |_____|/                     | reason it was put up.

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

Date: 19 Mar 1993 20:45:13 -0500
From: Pat <[e-mail]>
Subject: Why use AC at 20kHz for SSF Power?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Steinn Sigurdsson) writes:
>In article <[e-mail]> [e-mail] (Richard A. Schumacher) writes:
>
>
>   Oh, nuts. So a 20kHz power system saves 2,000 pounds, huh?
>   Assume it costs $3,000 per pound to launch. Spend $6M on
>   the extra weight of a 400 Hz system, and 20 minutes later
>
>If it were to become standard and used on other systems

If the idea were so hot,  then it would be used on other areas.
The only thing I see Utility power generation moving towards is
Higher Voltage.  208/480 three phase is now getting pushed back
by 5-7KV systems for campus distribution.

>it would save a lot more weight in the long run.
There were never plans to ever expand SSF beyonf the
EMCC Eight Man Crew COnfig,  and  that was based upon
very speculative budgeting.

>When you're about to put up the first major piece
>of infrastructure in space, one that might in principle be
>expanded, it becomes sensible to consider the possibility of
>whether a new standard for such things as power systems makes
>sense in the long run.

You mean, the way most things are built upon previous knowledge base?
Gee stein, you seem real positive over this technology,
why don't you go and build some lab equipment that pulls this
as prime power.

>One of the most frequent complaints here against NASA is that
>they don't consider new technologies that might lower costs
>in the long run and don't experiment with different concepts.

Yet,  by the figures presented in the paper, which put
only the most positive glow on 20KHz power, we seee only a
6 Million weight savings and a claimed 150MIllion dollar lifecycle
savings.  if we take the money saved on designing this idea, and put
it in the bank, i bet we'd be looking at lifecycle savings of
more then that.


>Yet, when they do and it doesn't work out they are chastised
>(often by the same people) for wasting money when they could
>have been using old and tried technology, and using the
>magic of 20-20 hindsight it becomes "obvious" that the
>new concept tried wouldn't work.

If they had a solid disciplined engineering developement program
to prove and test all this gear,Id believe it, to be worth
exploring, but to go out on a tremendous technological limb
on an untried technology on the most expensive NASA program this
Decade, maybe even century,  is just plain rank foolishness.

>
>   As for the difficulty of shielding scientific instruments
>   from 400 Hz noise: some EE better go tell those poor
>   fool astronomers who have been flying their instruments
>   in U-2s for 20 years that they're doing it all wrong...
>   (Oh no! Now they're doing the same thing in an SR-71!
>   Stop them before it's too late!)
>
>Those instruments are handbuilt at no small expense.

No doubt, smaller then that for 20KHz.   Aren't most scientific
devices hand built?  if it was production gear,  you'd get it at toys R us
and lots of stuff is production built for 400KHz.  Radars,  computers,
Motors, generators,  Power conditioners, Lights,  Fans,  Air conditioners,
circuit breakers....

None of that stuff is available for 20KHz.

>
>   20kHz power is a Boondoggle. A gold-plated, aerospace-
>   contractor's-wetdream, engineering-porkbarrel boondoggle.
>
>Yeah right, NASA should just stick with old and tried concepts,
>tie swans to balloons, or use large cannon and capsules lit
>with gas lamps. And people wonder why NASA has become afraid
>to take risks and run experimental missions...
>

Careful stein,  you are listening to nick and it's rubbing off.

Actually my simple acid test on 20KHz, is why Boeing doesn't use it.

If resonant inversion was such an efficient method,  and the weight
savings were so high on motors, etc,  then 747's would be converted
over to this standard,  or new boeing hardware would use this.

Aircraft are very weight conscious, probably more so then Rockets.
Airlines make money running packed to the gills,  running with 80%
load, is a fast way to lose money.  some airlines need to carry 93%
of cargo, to even break even on a route.  it depends on schedules
and fares.

I once read, that a 1 pound savings on a 747, translates to a 10,000
dollar savings.  now this was when fuel was high, and god, that's
a real dusty memeory,  but  It does seem illustrative.

Commercial aviation is very weight conscious.  Military are even more,
yet none of these guys have ever looked at this, to my knowledge,
and boeing is very cash rich, and the AF spent 10 years with money
as no object.

pat

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

Date: 19 Mar 93 18:28:21
From: Steinn Sigurdsson <[e-mail]>
Subject: Why use AC at 20kHz for SSF Power?
Newsgroups: sci.space

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


   In article <[e-mail]> [e-mail] (Steinn Sigurdsson) writes:
   >In article <[e-mail]> [e-mail] (Richard A. Schumacher) writes:

   >   Oh, nuts. So a 20kHz power system saves 2,000 pounds, huh?
   >   Assume it costs $3,000 per pound to launch. Spend $6M on
   >   the extra weight of a 400 Hz system, and 20 minutes later

   >If it were to become standard and used on other systems

   If the idea were so hot,  then it would be used on other areas.

And by induction to all other areas we see that nothing new need
be developed...

   The only thing I see Utility power generation moving towards is
   Higher Voltage.  208/480 three phase is now getting pushed back
   by 5-7KV systems for campus distribution.

   >it would save a lot more weight in the long run.
   There were never plans to ever expand SSF beyonf the
   EMCC Eight Man Crew COnfig,  and  that was based upon
   very speculative budgeting.

Look, NASA and others will hopefully over the next few decades
put a lot of power consuming items into orbit and chances are
we'll want to transmit most of the energy by electric currents.
Now, maybe the current systems are optimal for this, maybe it
would be better ab initio but with current power electronics to
have higher frequency AC - _but_ if you think in the long run
a new technology will be an improvement then the time to adapt it
is when you start putting big power hungry semi-permanent structures
into place. For space, that is now.

   >When you're about to put up the first major piece
   >of infrastructure in space, one that might in principle be
   >expanded, it becomes sensible to consider the possibility of
   >whether a new standard for such things as power systems makes
   >sense in the long run.

   You mean, the way most things are built upon previous knowledge base?
   Gee stein, you seem real positive over this technology,
   why don't you go and build some lab equipment that pulls this
   as prime power.

The point is not the 20kHz in particular, the point is that
_now_ is a good time to look into whether to make these kind of
changes - I don't know if the 20kHz is worth it, and I suspect that
the contemptuous dismissal of its potentials by you and other is
posturing bullshit fuelled by hindsight.

   >One of the most frequent complaints here against NASA is that
   >they don't consider new technologies that might lower costs
   >in the long run and don't experiment with different concepts.

   Yet,  by the figures presented in the paper, which put
   only the most positive glow on 20KHz power, we seee only a
   6 Million weight savings and a claimed 150MIllion dollar lifecycle
   savings.  if we take the money saved on designing this idea, and put
   it in the bank, i bet we'd be looking at lifecycle savings of
   more then that.

This is the whole problem your way of "accounting" produces.
What if over the next 150 years using 20kHz power were to save
2 trillion dollars? But, we'll never know, because at any one time
it was cheaper for that one project to stick with the old stuff.
You just don't get it, it's NASAs purpose to look into these
alternatives without having to worry about whether the immediate
benefit to that particular project provides a good return in the
next N quarters. I'm really glad people like you weren't in charge
of the Royal Society of London 150 years ago.

   >Yet, when they do and it doesn't work out they are chastised
   >(often by the same people) for wasting money when they could
   >have been using old and tried technology, and using the
   >magic of 20-20 hindsight it becomes "obvious" that the
   >new concept tried wouldn't work.

   If they had a solid disciplined engineering developement program
   to prove and test all this gear,Id believe it, to be worth
   exploring, but to go out on a tremendous technological limb
   on an untried technology on the most expensive NASA program this
   Decade, maybe even century,  is just plain rank foolishness.

No, it isn't. NASAs _purpose_ is to try out new technology,
Maybe somebody could tell NASA just exactly how much they're allowed
to innovate at any one time? Or are they only supposed to be
innovative on projects that will definitely work out?


   >   As for the difficulty of shielding scientific instruments
   >   from 400 Hz noise: some EE better go tell those poor
   >   fool astronomers who have been flying their instruments
   >   in U-2s for 20 years that they're doing it all wrong...
   >   (Oh no! Now they're doing the same thing in an SR-71!
   >   Stop them before it's too late!)

   >Those instruments are handbuilt at no small expense.

   No doubt, smaller then that for 20KHz.   Aren't most scientific
   devices hand built?  if it was production gear,  you'd get it at toys R us

well, if NASA had gone to 20kHz in 1963 and established a market
then it would probably be cheaper to use that now, maybe.
And, yes, most scientific devices are handbuilt at some
level, especially in astronomy.

   and lots of stuff is production built for 400KHz.  Radars,  computers,
   Motors, generators,  Power conditioners, Lights,  Fans,  Air conditioners,
   circuit breakers....

   None of that stuff is available for 20KHz.

   >   20kHz power is a Boondoggle. A gold-plated, aerospace-
   >   contractor's-wetdream, engineering-porkbarrel boondoggle.

   >Yeah right, NASA should just stick with old and tried concepts,
   >tie swans to balloons, or use large cannon and capsules lit
   >with gas lamps. And people wonder why NASA has become afraid
   >to take risks and run experimental missions...
   >

   Careful stein,  you are listening to nick and it's rubbing off.

   Actually my simple acid test on 20KHz, is why Boeing doesn't use it.

They're probably waiting for NASA to switch to it and to provide a
market large enough that parts manufacturers will mass produce the
components cheaply - and have the database on in-flight safety.
After all, that's how they get a lot of their innovation.

   If resonant inversion was such an efficient method,  and the weight
   savings were so high on motors, etc,  then 747's would be converted
   over to this standard,  or new boeing hardware would use this.

Why, if the cost of change over in the short run is too high, then
they'll never change over because by your accounting rules they're
not allowed to. Maybe somebody will do us a favour and bomb the
factories, then they can be rebuilt to produce whatever the best
current technology is rather than what was frozen in 50 years ago.

   Aircraft are very weight conscious, probably more so then Rockets.
   Airlines make money running packed to the gills,  running with 80%
   load, is a fast way to lose money.  some airlines need to carry 93%
   of cargo, to even break even on a route.  it depends on schedules
   and fares.

   I once read, that a 1 pound savings on a 747, translates to a 10,000
   dollar savings.  now this was when fuel was high, and god, that's
   a real dusty memeory,  but  It does seem illustrative.

   Commercial aviation is very weight conscious.  Military are even more,
   yet none of these guys have ever looked at this, to my knowledge,
   and boeing is very cash rich, and the AF spent 10 years with money
   as no object.

They have the same resistance to change, the changeover is expensive
and you lose compatibility until it is complete - it is the classic
instance of going with low front-end costs and higher long term costs.

Now, it may be that 20kHz AC even then doesn't work out,
but looking at it as an option just wasn't that stupid an idea,
this is why NASA is risk shy, they spend money on something a little
more speculative, one particular path doesn't work out and people
like you are roasting them - give the people a fucking break.

|  Steinn Sigurdsson    |I saw two shooting stars last night        |
|  Lick Observatory    |I wished on them but they were only satellites    |
| [e-mail] |Is it wrong to wish on space hardware?        |
| "standard disclaimer"    |I wish, I wish, I wish you'd care - B.B. 1983    |

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End of Space Digest Volume 16 : Issue 344
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