Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_4/V16NO434.TXT

Internet Message Format | 1993-07-13 | 32KB

Date: Thu,  8 Apr 93 05:14:35
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #434
To: Space Digest Readers
Precedence: bulk


Space Digest                Thu,  8 Apr 93       Volume 16 : Issue 434

Today's Topics:
                          (Aero?)space query
      Aerospace companies cooperate in reusable vehicle market.
                       Commercial point of view
                      Delta Clipper Archive Site
                 International Space Year Compendium
                            Martian "gold"
                    Mining Deuterium(sp) on Venus?
                                 MIR
                             NASA "Wraps"
                            nuclear waste
                        Plans, absence therof
                  Portable Small Ground Station?dir
                            Protectionism
                          space food sticks
                      SSF Redesign as of 3/31/93
       What Minerals are Cheaper on Mars? than earth? (2 msgs)
                  Why use AC at 20kHz for SSF Power?

    Welcome to the Space Digest!!  Please send your messages to
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----------------------------------------------------------------------

Date: Wed, 7 Apr 93 15:36:23 MDT
From: [e-mail] (PPL project)
Subject: (Aero?)space query

I am doing some research on airport security and I have some questions for
people with knowledge of the technical aspects of the security failures that
resulted in the Lockerbie explosion.  Sorry for the non-space query, but it
seems likely that many of you will have an overlapping interest.  Please
respond to [e-mail].  - Mike

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

Date: Wed, 7 Apr 1993 21:35:35 GMT
From: Henry Spencer <[e-mail]>
Subject: Aerospace companies cooperate in reusable vehicle market.
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>What would all of you out there in net land think of the big 6 (Martin
>Mariatta, Boeing, Mcdonell Douglas, General Dynamics, Lockheed, Rockwell)
>getting together, and forming a consortium to study exactly what the market
>price pints are for building reusable launch vehicles...

That it was another scheme for sucking money out of the taxpayers' pockets
while delaying actual hardware construction unnecessarily.

Why bother with the stupid consortium?  *All* the bidders in the SDIO
SSTO competition agreed that the specs could be met, and they presented
three different designs for it.  There is no *need* to fool around with
more feasibility studies or configuration game-playing or technology
development.

What we need, at this point, is to build an orbital demonstrator.  It
need not be a full-scale transport prototype, and indeed it need not be
manned, but it must go into orbit repeatedly.  This is the final proof
that the approach is workable, and it is a step we will be ready to
take after the DC-X tests (if we aren't already -- a debatable point).
There is no need to waste time and money repeating the preliminaries
yet again.
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: Tue, 6 Apr 1993 00:01:27 GMT
From: Nick Szabo <[e-mail]>
Subject: Commercial point of view
Newsgroups: sci.space,talk.politics.space

[e-mail] (Greg Moore) writes:


>But, I guess I'm asking you to put your money where your mouth is.

I have been, at various times, invested in Comsat, Qualcomm, GM-H
(Hughes), and Orbital Sciences, companies heavily involved in space
or strongly space-related business.  I also have to pay taxes to
fund NASA et. al.  But my main point, again, is that business style
planning should be used even when there is no immediate intention
to start a business; eg to guide NASA's R&D decisions based on long-term
industrial competitiveness.  We space fans should use exploratory business
planning to develop new visions for the self-sustaining development and
settlement of space.  This gives us a keen awareness of how our goals
relate to other people's, and what kind of exploration, technology,
etc. are needed to minimize the cost of meeting our goals.

>>[central planning]

>    Then tell me, why did oyu mention it?  Obviously because
>you believe it dominates today's space program.  However, we weren't
>discussing it.

I certainly was discussing it; my main point in this thread, & the
original post you responded to, is describing how planning for
commerce and industrial competitiveness is different from traditional
central planning, and why we should use the techniques of the former
for long-range planning & creating visions. To my way of thinking, your
challenge of "put your money where your mouth is" is off the topic; I
never mentioned personal investing.   But I understand why you took
it in that direction, triggered by the phrase "business plan",
so it wasn't like introducing rock climbing.

>    Hmm, so having a goal of an active affordable self-supporting
>presence in space is bad.

No, that's fine, as long as we realize (a) many other people don't
share that goal, and (b) figure out how our goal relates, in terms
of technology, sharing resources, etc., to other people's goals.
With self-sustaining space development we meet a large
number of people's wants & needs regardless of whether those are
the same as ours, but with an eye on developing the tech we need to
meet our goals.  My objections is to setting certain specific
goals (eg base on Mars) at the expense of others (eg comet mining),
as has been done in the space community (eg the ratio of funding
for studies of these alternatives is >1,000:1, with no
good financial or technical reason for such a bias).

>...the reasons for using business style
>planning? Why then use it if you don't ultimately start
>a business?

The key here is "ultimately".  Many kinds of businesses will help us
reach the goal of space settlement (or other goals you might have)
but are not quite economical today, for reasons of launch costs,
technology, materials availability, etc.  Similarly, one of NASA's main
tasks these days is to foster U.S. industrial competiveness.  If we are
to make such businesses possible, or NASA is to achieve its goal
of fostering competivness, we need to anticipate what kinds of
businesses will be viable.  We do that through exploratory business
planning along diverse development pathways, rather
than the obsolete single-vision, fixed-timeframe, divorced from
human needs methodology that has dominated NASA and the space movement
until now, leading to massively expensive failures and shattered dreams.
(To see this destructive mindset still at work, cf. the quotes from
the recent PBS TV special about how we "WILL HAVE" bases on the moon
and Mars by certain dates).

I also accept your apologies, and I hope we are closer to a mutual
understanding now.


--
Nick Szabo                     [e-mail]

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

Date: 7 Apr 1993 19:58:29 GMT
From: "Chris W. Johnson" <[e-mail]>
Subject: Delta Clipper Archive Site
Newsgroups: sci.space

In article <[e-mail]> Joyce Tokar,
[e-mail] writes:
> [....] I read [the Analog article] this morning at the breakfast table;
> got so excited and scanned all boards containing 'space' in their names.
> That is how I find this thread.

People new to this thread, or those just looking for pictures and past
articles concerning the Delta Clipper project, may want to take a look
at the totally unofficial Delta Clipper anonymous ftp site maintained
in the pub/delta-clipper directory of bongo.cc.utexas.edu (128.83.186.13).

Most of the more informative articles on the program that have appeared
in sci.space in the last couple of months are there. Pictures (real and
artists conceptions) are also there to be found. In the area of coming
attractions, several people on the net have been kind enough to offer to
provide me with pictures from the Apr. 3 rollout in the not too distant
future. As soon as I see 'em, you'll see 'em.  :-)

If anyone out there has additional materials related to the project that
they'd like to make available, there's a world-writeable (bot NOT
readable) directory named "incoming" to which you can upload them. Just
drop me line to let me know what's arrived.

Cheers.

----Chris

Chris W. Johnson

Internet:   [e-mail]
UUCP:       {husc6|uunet}!cs.utexas.edu!ut-emx!chrisj
CompuServe: >INTERNET:[e-mail]
AppleLink:  [e-mail]@internet#

...wishing the Delta Clipper team success in the upcoming DC-X flight tests.

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

Date: Wed, 7 Apr 1993 18:25:00 GMT
From: David Ward <abdkw@stdvax>
Subject: International Space Year Compendium
Newsgroups: sci.space

From:    MX%"[e-mail]"  7-APR-1993 12:44:29.16

  Hi,

  I don't have post privileges, and found this,
  and assume the sci.space readers would be
  interested.

    bob s.

Article 2671 of sci.edu:
Xref: rapnet alt.education.distance:532 sci.edu:2671
Path: rapnet!butch!netcomsv!decwrl!sun-barr!news2me.EBay.Sun.COM!cronkite.Central.Sun.COM!texsun!exucom.exu.ericsson.se!ericom!sunic!psinntp!psinntp!pbs.org!tflavell
From: [e-mail]
Newsgroups: alt.education.distance,sci.edu,k12.ed.science
Subject: REPOST: Space Resources Compendium
Message-ID: <[e-mail]>
Date: 1 Apr 93 21:08:32 GMT
Organization: PBS:Public Broadcasting Service, Alexandria, VA
Lines: 25

TO:     Education Liasons, School Librarians, ITV Coordinators
FR:     PBS Elementary/Secondary Service
RE:     Space Compendium
DT:     January 15, 1993

INVESTIGATE AND CELEBRATE SPACE EXPLORATION!

The "1992 International Space Year" Compendium has been jointly
produced by PBS E/SS and the Student Space Foundation with
support from the National Science Teachers Association's
Space, Science & Technology Division to assist educators in
grades K-12 in their planning and celebration for the 1992
International Year of Space.  It is also designed to help
educators and students investigate and celebrate space
exploration for many years to come.  This comprehensive
compendium lists hundreds of classroom resources, including
videos, books, research reports, posters, computer software,
space societies, teacher training workshops, music, and more!
Parents may also find this useful in supporting budding
scientists/astronomers.  135 pgs.  To order copies of the
compendium, send a $10.00 check to: PBS E/SS; Space Compendium; Att: Tom;
1320 Braddock Place; Alexandria, VA 22314-1698.  SORRY,
NO PURCHASE ORDERS ACCEPTED.

END

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

Date: 7 Apr 1993 18:14:37 GMT
From: Jeff Bytof - SIO <[e-mail]>
Subject: Martian "gold"
Newsgroups: sci.space

Probably by far the most valuable material to be "mined" on Mars
will be evidence and/or remains of life forms, if any are found.

-Jeff Bytof
member, technical staff
Institute for Remote Exploration (IREX)

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

Date: Wed, 7 Apr 1993 16:35:04 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Mining Deuterium(sp) on Venus?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>Other odd question or thought..
>
>If Venus has alot of Deuterium(sp) (isetope of Hydrogen) is it worth our while
>and energy to go there to "mine" it?? And if we mine is, what can we use it
>for?
>Space Ships to Mars and beyond? or Would Jupiter be better??
>I know I have heard mention that Deuterium(sp) is good for nuclear reactions in
>some ways.. And good to be used in a Star Ship to another solar system..

Deuterium is more abundant *in relation to ordinary hydrogen*, on Venus,
but it is not more abundant than on Earth because *all* forms of hydrogen
are less common on Venus. The gas giants are much better filling stations
than Venus, but their deep gravity wells, and harsh radiation environments,
make getting such materials there difficult as well. Deuterium in any quanity
we are likely to ever want can be easily separated from seawater. There's
no need to go elsewhere for it.

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: 7 Apr 1993 14:31:11 -0400
From: Pat <[e-mail]>
Subject: MIR
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>How does it compare to the current (?) version of SSF? What are the kosmonauts

It's Flying,  SSF is going through another re-design and de-scoping.

pat

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

Date: 7 Apr 1993 13:14 PST
From: SCOTT I CHASE <[e-mail]>
Subject: NASA "Wraps"
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (David B. Mckissock) writes...

>Finally, the money raised by the 'tax' does not all
>go into a 'slush fund.' At Lewis, the director
>does control a small discretionary fund. Each year,
>any individual at Lewis can submit a proposal to
>the director to get money from this fund to look
>at pretty much anything within the Lewis Charter.

I believe that at all the National Labs, there is a Director's Fund,
which is spent at his discretion.  It is usually quite small, and used
to fund a few projects which, though within the mission of the Lab, and
scientifically interesting (at least to the Director and those who
"carry" the proposal, such as some divisional director), for whatever
reason did not get funded by the regular channels.  At LBL, these
projects tend to be some of the more speculative or long-lead-time R&D
projects.

This is a good mechanism for (a) putting a few dollars into the hands
of people on the scene, rather than relying on the Suits at DOE headquarters
to identify all the interesting research proposals, (b) luring
good people to the Directorship of a Lab, by giving them some direct
control over the direction of at least a few research projects, and
(c) building morale at the Lab by giving the Small People a way to
get small amounts of money to work on projects which interest them even
if they can't convince enough folks at DOE that they should fund it.

-Scott
--------------------
Scott I. Chase            "It is not a simple life to be a single cell,
[e-mail]         although I have no right to say so, having
                 been a single cell so long ago myself that I
                 have no memory at all of that stage of my
                 life." - Lewis Thomas

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

Date: 7 Apr 1993 17:25:39 -0400
From: Pat <[e-mail]>
Subject: nuclear waste
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (fred j mccall 575-3539) writes:
|In <1psg95$[e-mail]> [e-mail] (Pat) writes:
|
|[On the issue of 'burning' nuclear wastes using particle beams...]
|
|>How is it ever going to be an Off- the Shelf Technology if someone doesn't
|>do it?  Maybe we should do this as part of the SSF design goals. ;-)
|
|>Gee fred.  After your bitter defense of 20 KHz power as a Basic technology
|>for SSF, Id think you would support a minor research program like
|>this.
|
|I sometimes wonder if your newsfeed gives you different articles than
|everyone else, Pat.  Just a *few* corrections:
|
|1) I never 'defended' 20kHz power, other than as something reasonable
|to GO LOOK AT.
|

There is an awful big difference between LOOKING at a technology
and making it a design spec item.  When i groused about wasting
Engineering dollars on a highly speculative research area,  you
Launched into the cave man defense.

Here, someone proposes a research area,  for a non-critical project
of high social utility, and you start saying " I will believe it,
when I see it".   Not very consistent, by my book.

|2) I have also never opposed a *research project* into feasibility of
|the spalling reactor approach to 'cleaning' nuclear waste -- I simply
|doubt it could be made to work in the Real World (tm), which ought to
|become clear fairly quickly during a research program into feasibility
|(sort of like what happened to 20 kHz power -- it proved to have a
|down-side that was too expensive to overcome).
|

I worry that the DC-X,Y  will not achieve it's goals too,  but somehow
I don't seem to be as negative  when hypothesizing about real world
goals.

pat

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

Date: 7 Apr 1993 17:36:54 -0400
From: Pat <[e-mail]>
Subject: Plans, absence therof
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (fred j mccall 575-3539) writes:
|In <1pg59o$[e-mail]> [e-mail] (Pat) writes:
|
|>In article <[e-mail]> [e-mail] (fred j mccall 575-3539) writes:
|
|>NASA employees, like other federal workers are prohibited under the Hatch
|>act from engaging in Political campaigns on any level.
|
|Speaking of grossly overly-simplifying, I *think* you just did.  I
|assume that this would also apply to military personnel (as government
|employees)?  If the rules are the same, you have misstated the
|situation.  In the military, my only restrictions on egnaging in
|political campaigns were that I couldn't use government property to do
|it, I couldn't represent myself as representing the opinion of the
|service, I couldn't do it on government property, and I couldn't do it
|in uniform.  I suspect that the rules for NASA personnel are similar
|and that there is no absolute prohibition about engaging in political
|campaigns.
|

Here I am going to have to defer to Greater Authority.

What are the standing NASA regs on Hatch?  I know over here, I keep
reading about how GS employees here in DC can't campaign for local
municipal elections.  It causes great distress,  in fact given the
poor caliber of DC government that  the Federal Workforce who are
besieged by DC  municpal failures  cannot band together to throw the
bums out.

I know there are always disputes on people even wearing campaign buttons to work
and i have heard of disputes on  passing out campaign literature even
when off federal property.

I don't know what the military rules are,  but I've noted a strong
tendency for them to avoid getting close in any way to local political
battles.

When i was in,  i got cautioned for  chatting with some strikers, while
in uniform.  Possible perceptions of being seen supporting a local
employee strike.

Maybe Mary or Ron  can comment on what the rules are?


|>They are also
|>prohibited from taking remuneration from outside sources,  although a recent
|>appellate court ruling has confused things.
|
|The prohibition has never been all that absolute, otherwise people
|wouldn't be able to moonlight (which you are allowed to do).
|

The rules keep changing.   Outside jobs have been a bit
questionable at times,  although a lot of groups use the washington post
rule.  "Can the action withstand  being on the cover of the Post".

And until the recent appelatte court ruling,  I think the ruling did
cover moonlighting jobs too.

|>I would say that being
|>paid by an organization that lobbies for Space would be questionable.
|
|Perhaps, but then again, perhaps not.  I would only consider this
|questionable if the organization was lobbying for things that would
|directly affect the NASA employee and over which he or she had some
|sort of cognizance or control.
|

Yeah, but what if the organization was using the employee to give
advanced access to not yet public information?   It creates
teh specter of conflict of Interest.   Let employees  moonlight
for areas further away from their government jobs.  it's simpler.

>
>>Now as for engaging in PRish activities or responding to requests for infor
>>mation is part of their charter to educate the public.  I am sure
>>Mary or one of the other NASA employees, Ron, Peter, can cite the exact
>>agency guidelines on what is and isn't acceptable use of Government time
>>or Equipment.
>
>>I have always welcomed a free-form debate from NASA employees and their
>>contractors,  provided it remains within the constraints elucidated
>>above.
>
>> While Nick may be off-base on his statements about Devine in particular,
>>he does have a general point, which you seem not to recognize fred.
>
>I "seem not to recognize" his "general point" because he was making a

Don't listen too closely to everything nick says.  It helps keep
your blood pressure down :-)


But if one of the NASA employees here can comment on  how hatch applies,
I wouldn't mind hearing it from the horses mouth.

pat

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

Date: 7 Apr 1993 14:24:50 -0400
From: Pat <[e-mail]>
Subject: Portable Small Ground Station?dir
Newsgroups: sci.space

|The DSN stations are different, and aren't used to monitor Shuttle.
|These stations use huge antennas to gather in the very faint signals
|no hope of duplicating them on an amateur budget.


It may be possible to pick up a scrap radio astronomy antenna
from  a government junk yard.  I know of one guy who did get one.

I think it was a 13 Meter diameter dish.

Now i doubt an amatuer would have the money to build the  tracking
pedestal,  that's probably $500,000  assuming you got all the steel
works.   But it might come with the LNA's and spectrum analyzers and
high resolution recorders,  but to do  Satellitte  commanding you'd
need the digital command modems.   That's a real tough one.

It may be possible for an amatuer to get enough gear to compete with
a university radio science station,  but youd have to settle
for limited traverses  and look angles.

ALso,  to send commands, you need transmitters  and LOTS of power.
I can imagine how much power  DSN uses when they talk to voyager.

pat

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

Date: Mon, 5 Apr 1993 22:57:48 GMT
From: Nick Szabo <[e-mail]>
Subject: Protectionism
Newsgroups: sci.space,sci.econ

[e-mail] (Gary Coffman) writes:

>there's a 15% tax break to companies exporting raw logs from the
> Pacific Northwest to Japanese furniture factories.

Wrong.  Another popular myth making the rounds.  There's a
15% tax break on any export, including high-value-add wood
products like furniture, because we want to cut the trade deficit.

The reason Japanese buy raw logs is straightforward: they have
important, exacting standards unique to their culture which U.S.
mills have been unable or unwilling to meet.  These standards range
from the simple (cutting in metric dimensions) to the complex
(Japanese archictectural traditions & standards, including unique
designs for earthquake protection).

Also note Japanese would rather use PNW wood, grown in a climate similar
to theirs, than tropical wood.  They pay a premium for both raw logs &
finished wood products from here in the PNW.

BTW, there is now a strong statist incentive _against_ raw log exports:
such exports of logs from state & federal lands are now illegal,
another stupid measure that protects low-skill, low-wage jobs (eg
raw log lumbering) and discourages high-skill, high-wage jobs (eg
building finished wood products for the Japanese market).

Of course, it's much easier to claim to be patriotic and Japan-bash
than to try to learn something about another culture so that one
can do business with them.  It's much easier to make up and propagate
myths about "subsidizing raw log export" than to admit and correct
our own shortcomings that have caused the problem.

>More serious examples of government policies causing jobs to be exported
>are the minimum wage laws, the tax code, and environmental regulation.

I largely agree with you here.  Followups to sci.econ.


--
Nick Szabo                     [e-mail]

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

Date: Wed, 7 Apr 1993 19:49:04 GMT
From: Dillon Pyron <[e-mail]>
Subject: space food sticks
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Ethan Dicks) writes:
>John Elson ([e-mail]) wrote:
>: Has anyone ever heard of a food product called "Space Food Sticks?" This
>: was apparently created/marketed around the time of the lunar expeditions, along
>: with "Tang" and other dehydrated foods. I have spoken with several people
>: who have eaten these before, and they described them as a dehydrated candy.
>: Any information would be greatly appreciated.
>
>I also remember eating (and loving) these during the early '70s.  I tried to
>track them down a few years ago and was informed that they have probably
>not been manufactured for at least 20 years and that the ones I ate were
>undoubtably several years old at the time.

Has anyone noticed that articles in this thread are normally very close to
articles in the nuclear waste thread?  Just coincidence, I guess :-)
--
Dillon Pyron                      | The opinions expressed are those of the
TI/DSEG Lewisville VAX Support    | sender unless otherwise stated.
[phone] (when I'm here)     |
[phone] (when I'm home)     |God gave us weather so we wouldn't complain
[e-mail]          |about other things.
PADI DM-54909                     |

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

Date: 7 Apr 1993 20:23:48 GMT
From: Andy Cohen <[e-mail]>
Subject: SSF Redesign as of 3/31/93
Newsgroups: sci.space

In article <1phv59$[e-mail]>, [e-mail] (Pat) wrote:
>
>
> Where are the meetings?
>
> pat

Goldin said during the press briefing that they would be in Crystal City by
the beltway in DC

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

Date: Wed, 7 Apr 1993 16:30:04 GMT
From: Gary Coffman <ke4zv!gary>
Subject: What Minerals are Cheaper on Mars? than earth?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>Idea or thought..
>
>What materials would a commerical company need or want to get from Mars?
>
>All I can think of is maybe some high risk, high cost materials that normally
>can not be found in great quantities or have already been mined out (at least
>easily accesible mined out).. What could mars offer to a commercial company to
>exploit the minerals on Mars?? Just things.. Can anybody give me an answer or
>ideas??

Basically there's nothing on Mars we don't have in greater abundance
right here. When you add in the astronomical transport costs, there's
nothing on Mars worth bringing back to Earth. However, Mars' gravity
well is less deep than Earth's. It would be cheaper to launch Martian
material to solar orbit than to launch that material from Earth. So
if production costs on Mars drop to levels not too greatly higher than
those on Earth, it would make sense to use Martian native materials for
systems in solar orbit. There is a much more attractive source of native
materials, however. That's the asteroids and comets. They have no real
gravity wells of their own, being already in solar orbit. Only orbital
transfer costs are required to get them where needed. The catch, if it
is one, is that they have to be processed in space. There's no proof
that it's cheaper to conduct most industrial processes in space than in

a gravity well. It's also true that labor costs are much lower on Earth
than anywhere else in the solar system. Unless a way is found around
that, extraterrestrial materials will likely remain a curiousity.

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: Wed, 7 Apr 1993 20:36:23 GMT
From: Henry Spencer <[e-mail]>
Subject: What Minerals are Cheaper on Mars? than earth?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Bernhardt Saini-eidukat) writes:
>According to R.G. Burns and D.S. Fisher (Journal of Geophysical Research,
>vol. B95, p. 14,169-14,193, 1990) "ultramafic Fe-Ni sulfides and perhaps
>iron-rich sediments (gossans and abiotic banded iron formations) derived
>from chemical weathering of the basaltic crust, as well as cumulate chromites,
>are likely to be the only ore deposits present on Mars."

Almost certainly there should have been an "in quantity" on the end of that.
Ores are almost by definition the result of rare events, circumstances where
some process, or more than one, went to an extreme.  We do not understand
Mars's geology well enough to make such a broad statement without further
qualification.
--
All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
                    - Kipling           |  [e-mail]  utzoo!henry

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

Date: 7 Apr 1993 17:17:00 -0400
From: Pat <[e-mail]>
Subject: Why use AC at 20kHz for SSF Power?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (fred j mccall 575-3539) writes:
|>|
|>|I don't have to misrepresent your position, nor did I.  No one should
|>|ever actually *use* anything until it's a catalog item -- except it
|>|ain't gonna become a catalog item until after it's in widespread use.
|>|
|
|>Actually,  most things become catalog items, after some reasonable
|>engineering developement program.  Something i've never seen
|>SSF engage in.
|
|Well, that turns out not to be the case.  In any case, your lack of
|knowledge ("I've never seen") is more a ringing condemnation of your
|lack of knowledge than of their lack of engineering development.
|

Gee Fred.  I looked in the Thompson Catalog, and couldn't find an entry
for High Frequency Circuit Breakers,  Transformers,  Fans or Motors.
I can find 400 Hz rated equipment to do the above.

Please direct me to a better catalog.

|>>
|>>Nice to be told what I "can't believe".  And here all this time I
|>>thought that *I* would be the one to tell people that.  You don't get
|>>a 'proven trackrecord' until it's in widespread use, Pat.  Except it
|>>can never go into widespread use because it must have a 'proven
|>>trackrecord' before anyone should use it for anything.
|>>
|>I guess the X-15 doesn't count for proving technology?
|
|Well, you just lost me, Pat.  This comment is supposed to be germane
|to something that was said before it?
|

You get a proven track record after a experimental program proves it works.
Without bizarre interactions to the environment.  That was the whole
point of Mercury and Gemini.  They were building  experience for
Manned Space.   That's what teh X-15 was doing,  building experience,
for  Hypersonic winged vehicles.   AS Mary has pointed out,  that program
delivered a number of firsts.   If SSF  has as a program objective,
building an SSX   a simple  prototype to test in-orbit assembly,
truss behavior,  docking modules,  High Frequency Power........

then I'd believe that SSF has an engineering test program.  This
weeks Space News covers more  on the SSF redesign, where people are criticizing
the total lack of a evolutionary approach in the Freedom program.

|>>[Really?  Where'd you get the egg?]
|>My refrigerator.
|But does the light *really* go off when the door is closed?

Not if it's a 20 Khz light.

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End of Space Digest Volume 16 : Issue 434
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