Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V16_2/V16NO295.ZIP/V16NO295

Internet Message Format | 1993-07-13 | 26KB

Date: Tue,  9 Mar 93 15:41:09
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #295
To: Space Digest Readers
Precedence: bulk


Space Digest                Tue,  9 Mar 93       Volume 16 : Issue 295

Today's Topics:
             20 kHz Power Supplies "blowing up"! (2 msgs)
                            Aurora Update
                        Huygens will float....
                            JPL Fact Sheet
                          Latest on Geminga
                     Space Station News Headlines
                       The courage of anonymity
     unnecceary violence (was: Nobody cares about Fred?) (2 msgs)
                 Water resupply for SSF (?) (2 msgs)

    Welcome to the Space Digest!!  Please send your messages to
    "[e-mail]", and (un)subscription requests of the form
    "Subscribe Space <your name>" to one of these addresses: listserv@uga
    (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle
    (THENET), or [e-mail] (Internet).
----------------------------------------------------------------------

Date: 9 Mar 1993 08:52 EST
From: "David B. Mckissock" <[e-mail]>
Subject: 20 kHz Power Supplies "blowing up"!
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Pat) writes...
>|Balderdash. I was personally involved in the trade studies
>|performed at WP-04 over the power system distribution
>|frequency for SSF, and nobody in the program ever said
>|the power supplies were single fault tolerant and would explode.
>
>Okay.  My friend was over at Reston,  and that was the reaction there.
>I'm glad you never heard about it,  but that doesn't exclude
>the existence of the information.
>
>Unless you were some sort of demi-god there,  don't expect to
>hear every story in the program.
I worked in a System Engineering organization at the time,
and our job was to help pull together the *ENTIRE* story
concerning the SSF power distribution frequency. We
worked closely with the other work packages, the Internationals,
and Level II. It was our job to hear *EVERY* part of the story
relative to the decision. My guess is that your Reston
contact was outside the loop on the 20 kHz decisions, and
heard spurious rumors.
<< Discussion attacking 20 kHz deleted >>

>Sorry, quoting some rag of documentation doesn't impress me.
The 'rag' of documentation I quoted from is the Program
Definition and Requirements Document, referred to as the
PDRD or SSP 30000. For anyone working on SSF, this document
*IS* the Holy Bible.

You obviously don't understand how NASA operates. For the SSF
program, NASA has three Contractors responsible for building
SSF hardware (McDonnell Douglas, Rocketdyne, and Boeing). A
key part of our Contracts with these folks are their
requirements documents. Each NASA center tailors the
requirements in the PDRD for their individual contract, and
this 'tailored' document is part of the legal contract
between NASA and the Contractor. The requirements documents
are under tight configuration control, as changes to the
requirements lead to changes in the Contract.

At each design review, the Contractor must provide evidence
that their design meets each and every requirement. In
any areas where the design doesn't meet the requirement, a
deviation or a waiver must be processed.

This whole area of requirements verification is treated
very seriously.

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

Date: Tue, 9 Mar 1993 15:51:34 GMT
From: fred j mccall 575-3539 <[e-mail]>
Subject: 20 kHz Power Supplies "blowing up"!
Newsgroups: sci.space

In <[e-mail]> [e-mail] (Henry Spencer) writes:

>In article <[e-mail]> [e-mail] writes:
>>>... it has flown in space -- Spacelab's power system is 3-phase 400Hz AC.
>>
>>Hey Henry do you have a source for that? I would hate to find out that my
>>payload that I am flying on USML-2 is being designed for the wrong power bus.
>>From my understanding the power is 28VDC just like on the orbiter, which is
>>where SpaceLab's power comes from...

>My original source was Fortescue&Stark's "Spacecraft Systems Engineering",
>which I haven't found a significant error in yet.

>However, it did seem curious that Spacelab would use a different power
>system than the orbiter, so I went digging, and it turns out that we're
>both right. :-)

>The orbiter's power system is 28VDC *and* 120V-400Hz-3ph.  The AC seems
>to be used mostly for things like motors; for example, the motors that
>open and close the payload-bay doors run on AC.

Note that this would make it a 'standard' aircraft power system (at
least for military aircraft).  This would seem to imply that any
MILSPEC aircraft system could be used, so long as it would pass that
outgassing requirements, since such systems have already been through
what I would think is a more severe 'shake and bake' than you would
need for the Shuttle.

--
"Insisting on perfect safety is for people who don't have the balls to live
 in the real world."   -- Mary Shafer, NASA Ames Dryden
------------------------------------------------------------------------------
[e-mail] - I don't speak for others and they don't speak for me.

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

Date: Tue, 9 Mar 93 13:48:08 GMT
From: Dean Adams <[e-mail]>
Subject: Aurora Update
Newsgroups: sci.space

[e-mail] (Pat) writes:
 >| >I don't think there were ever more then 12 SR-71s
 >| >operational, samething with U-2s.
 >At the same time.   Sure, as you lose birds, you build more,

Well, that is not quite how the procurement operates.
They can't just turn out airframes on demand.

 > but For reconnaisance, you don't need that many birds.
Depends...

 >|I think there were more than that.  After all, 100 U-2/TR-1s were built.
 >The U2-Tr-1, is 40+ years old,   that means you only need 2/year,
 >for fleet replacement,  and losses.

There were 55 U-2s produced from 1955-60, 12 in 67-68, and during the
1980s there were a total of 8 U-2Rs and 27 TR-1s built.  Those last 35
are the ones currently in operation...

 >|I'm sure they would NOT be in "4 bases".  The SR-71 only operated
 >|from two primary foreign bases.  I doubt an "Aurora" would have ANY.
 >4 Max, for global coverage.

What evidence do you have for saying Aurora operates from 4 bases?

 >|From Nevada, a *Mach 6* vehicle could go just about anywhere...
 >From  nevada,  a cessna can go anywhere too.

No, it can't... unless this "Cessna" is capable of in-flight
refueling, and preferably has a speed of around 4,000 mph.

 >Nevada doesn't have much point as a ops base.

Depends on the "ops".  For SECRET ops of a vehicle with Aurora's
specifications, it has all the point in the world...

 >You are 7,000 miles from your primary target.

Big deal.  That is a 2 hour flight at Mach 6.  U-2 and SR-71 missions
have routinely flown for *considerably* longer durations to reach
their targets.  2 hours is nothing.

 >Then you need to have lots of tankers operating for refueling,

The SR-71 had a large fleet of tankers dedicated *specifically*
for supporting their worldwide operations.  Since Aurora is likely
a smaller operation, it would be even easier to support...

 >the article claimed aurora has a 5,000 mile range,
Possible... but those sort of claims are not much more than blind guesses.

 >barely enough to get across  the pacific and do some work.
The SR-71 has a range of around 3200 miles, and the TR-1 is even less.

 >If you need to have a small army of refueling aircraft,
We have a LARGE army of them...

 >then people notice them.  if the refuelers operate from nevada,
 > they need refuelers.   and the crews get wore out.

The remote tankers would NOT be operating from Nevada, and as far as the
crews go, USAF has been operating tankers for a very long time and I think
they are pretty good at it by now...

 >Simpler to quitetly operate from scotland  korea  or japan.

No, not simpler or quieter at all.  Especially when Aurora is supposed
to make a VERY loud noise when taking off.  There is no way they are
going to be regularly operating anything this secret from anything but
the *most* secret of bases.


 >B-2 was a northrop program.
And it still is...

 >I think the B-2 was Have something......
Sounds like you are thinking of the "Have Blue", which was an early
demonstrator for the F-117 program.  The B-2 was developed under
the Advanced Technology Bomber project...

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

Date: Tue, 9 Mar 1993 13:24:54 GMT
From: Joe Cain <[e-mail]>
Subject: Huygens will float....
Newsgroups: sci.space,alt.sci.planetary,sci.astro

In article <[e-mail]> [e-mail] (Jonathan Stone) writes:
>> [...] the probe
>>would float deep enough such that the refractive index sensor would
>>be fully immersed, but high enough so that the Descent Imager/Specral
>>radiometer is above the waterline.
>                         ^^^^^^^^^^
>
>Is there is a generally-accepted planetary-science generic term
>analogous  to ``waterline'', but for liquids that aren't H20.

good question. Is there a nautical news group? Freeboard, liquidline, ...

>   And do we
>already know enough about Titan's atmospheric composition and surface
>temperature to engineer a probe that will float in  all plausible
>Titanian surface liquids?   If not, what *will* Hugyens float in?
>Liquid ammonia??
>
According to Tobias Owen's article in New Solar System (p. 193) the
composition may be 75% ethane, 20% methane, and 5 % nitrogen, perhaps
like a kilometer deep. Let's see, would water or dry icebergs float in
this? His diagram seems to put them on the bottom but he refers to
"fluffy" aerosols that might float.






Joseph Cain        [e-mail]
[e-mail]        scri::cain
[phone]        FAX [phone] or -0098

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

Date: 9 Mar 1993 10:17 CST
From: University Space Society <[e-mail]>
Subject: JPL Fact Sheet
Newsgroups: sci.space,sci.astro

In article <[e-mail]>, [e-mail] (Dave Michelson) writes...
>In article <[e-mail]> [e-mail] (Ron Baalke) writes:
>>-----------------------------------------------------------------
>>FACT SHEET:      THE JET PROPULSION LABORATORY
>>                          March 1993
>>
>>planet when it was launched August 27, 1962, to Venus (Mariner 1
>>was lost because of a launch vehicle error).  Other successful
>>Mariners included Mariner 4, launched  in 1964 to Mars; Mariner
>>5, launched in 1967 to Venus; Mariner 6, launched in 1969 to
>>Mars; Mariner 7, launched in 1969 to Mars; Mariner 8 and 9,
>>launched in 1971 to orbit Mars.
>
>Interesting summary, but I would hardly classify Mariner 8 as a
>"successful Mariner" :-(
>


It should also be brought out that for JPL's first launch they were partners
with another then army installation, the Army Ballistic Missile Agency (ABMA)
headed by general John B. Medaris and the project manager who was none
other than Dr. Wherner Von Braun.  Just as a little note, our faculty advisor
for our SEDS chapter, Dr. Charles Lundquist, worked with Dr. Ernst Sthulinger
of the Von Braun team to do the calculations on the optimum time to fire
the second stage. You may not believe this but for the early Redstone's the
command to fire the second stage came not from an on board source but from
the ground based on hand calculations by folks like Dr. Lundquist and Dr.
Sthulinger derived from real time telemetry in the form of the doppler
shift fromt he downlink from the launch vehicle!

As Mr. Spock would say "Stone Knives and Bear Skins"!

Dennis, University of Alabama in Huntsville

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

Date: Tue, 9 Mar 1993 14:57:15 GMT
From: Dick Edgar <[e-mail]>
Subject: Latest on Geminga
Newsgroups: sci.space,sci.astro

In article <richard.731642207@astro> [e-mail] (Richard M. Mathews) writes:
>[e-mail] writes:
>>Italian astronomers at the
>>Universities of Milan and Cassino have now reanalyzed optical images
>>recorded over the period 1984-92 and have determined that Geminga
>>moves across the sky at a rate of 0.17 arcsec/year and that its
>>distance from Earth is about 300 light years (G.F. Bignami et al.,
>>Nature 25 Feb. 1993.)
>
>What are the error ranges on these proper motion and distance numbers?
>
I don't know about the proper motion, but the distance estimate I can address.
Quoting from the Holt & Halpern paper (Nature, 357, 306; 28 May 1992):

    Assuming that the observed gamma-radiation is powered by the spin-down
    energy loss of the neutron star, we can use the value of E\dot to
    set a limit on the distance to the source.  The observed flux from
    Geminga above 100 MeV is \sim 4 \times 10^{-6} photons/cm^2/s.  The
    spectrum is relatively flat, with a mean energy of 300 MeV.  If all
    the spind-down energy appears in the form of gamma-rays, and the
    beaming factor is taked to be unity, then an absolute upper limit
    to the distance to the source is \sim 380 parsecs [ed. note: 1240
    light-years].  A fraction of 1% of the rotational energy loss appearing
    as gamma-rays (as is seen in the Vela pulsar) would put the distance
    at \sim 38 parsecs [124 light-years].  Geminga, therefore, may be
    one of the closest known neutron stars.

So to paraphrase:  *if* only 1% of the spin-down energy comes out in gamma
rays (and where does the rest go?  The gamma/x-ray luminosity ratio is
over 1000...), and *if* the radiation is isotropic, then the pulsar is
about 38 parsecs away.  Anyone who knows pulsars care to comment?

The large proper motion, if it holds up, also argues for a fairly
nearby object, but the optical identification is problematic.

---------
Richard J. Edgar  ([e-mail])
University of Wisconsin--Madison, Department of Physics
"It all depends, of course, upon whether or not it
depends or not, of course, if you take my meaning"

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

Date: 9 Mar 1993 16:18:26 GMT
From: CLAUDIO OLIVEIRA EGALON <[e-mail]>
Subject: Space Station News Headlines
Newsgroups: sci.space

Just in the light side. I was in the office of the Branch's Head and saw two pieces of
paper. The first one had written in it:

                  WILL BUILD SPACE STATION FOR FOOD

and the second one had the following;

Space Station News Headlines

Wednesday
    Space Station doomed per OMB...

Thursday
    Space Station may face redesign...

Friday
    Space budget to slash Space Station  40%

Saturday
    Hefflin sees big victory for Station...

Sunday
    Rough year ahead for Space Station ...

MOnday
    JSC offers Station redesign using old oil derricks...

Tuesday
    Heflin calls JSC plan stupid...

Wednesday
    Texas threatens to secede...

Thursday
    Congress votes "ok with us"...

Friday
    Govern Hunt covers Satation overrun with campaign funds...

Saturday
    Sadam buys Space Station as hideout for him and Princess Di...


No wonder this week's Space News have a front page article entitled "Space Station
CHAOS Jeopardizes Coalition"

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

Date: Mon, 8 Mar 1993 14:52:25 GMT
From: Wes Morgan <[e-mail]>
Subject: The courage of anonymity
Newsgroups: news.admin.policy,alt.privacy,comp.org.eff.talk,sci.space

[e-mail] wrote:
>
>It's been six weeks now since I posted the original
>"Challenger" article to sci.space and sci.astro as a
>contribution to the on-going thread reminiscing on the
>tragedy.

The tragedy of pseudonymous posting is that, once used, it must
always be used.  This article provided a perfect example.  There
was nothing in this article which offended me, yet it *had* to
be posted pseudonymously.  Why?  Because this person still doesn't
want to be tied to the original postings.  Having made those
pseudonymous postings, this person (an8785) can't talk about them
in the light of the Usenet day.  This is going to be a problem
for pseudonymous posters; we'll start recognizing them by their
grammatical habits or choice of words, and they'll wind up using
pseudonyms all the time, in *everything* they post.

I had thought of pseudonymity as a cloak, to be used at will;
now, it's starting to look like a deadman switch that has to
be used at all times.

People speak of the 'freedom' of pseudonymity; here's an example of
its restrictions.

--Wes

--
MORGAN@UKCC         |       Wes Morgan       |        ...!ukma!ukecc!morgan

[e-mail]   | University of Kentucky |   [e-mail]
[e-mail] | Lexington,Kentucky USA | [e-mail]
  Mailing list for AT&T StarServer S/E  - [e-mail]

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

Date: Tue, 9 Mar 1993 16:45:10 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: unnecceary violence (was: Nobody cares about Fred?)
Newsgroups: sci.space

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

>   My solution would be to have them work in a larger self sustaining
>   space economy.

>This would be ideal, the problem is the transition, a lot people
>can't hang around for 3-5-10 years until the funds diverted have
>bootstrapped a new system,

Well then those people will need to find new jobs. As a displaced
aerospace worker myself, I can tell you that they won't need as much
retraining as the popular wisdom seems to think.

Since the new system will be far larger and provide more and better
jobs it seems a good trade. Do you agree?

>instead they go get an MBA and start pushing paper,

Well I didn't.

>and then you have to train a new group and recover
>all the lost expertise

If true, so what? The funds to pay for that training will come from
the growth of the space sector. It is a strong win.

>    Rather than the buggy-whip analogy, consider the idea of
>disbanding the armed forces including reserves during peacetime,
>after all they're not actually carrying out their mission then,

I bet to differ. I peacetime their job is to preserve the peace
by providing a credible deterence. Many (myself included) think
that *IS* their job.

>and it's certainly not a jobs program, so why not fire them
>and get new recruits if you need them later.

the analogy doesn't hold. The current system is making space more
expensive. It is hindering development for all so that a few can
keep their jobs.

It would be like preventing Ford from building cars because we want
to preserve a few well paying buggy whip makers.

     Allen
--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------98  DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: Tue, 9 Mar 1993 16:58:16 GMT
From: "Allen W. Sherzer" <[e-mail]>
Subject: unnecceary violence (was: Nobody cares about Fred?)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:

>Oh?  Did Mr. Ford talk to you lately?

No Doug, he's dead.

>The United States government is not Henry Ford.

Irrelevant.

>You KNOW this, yet you
>persist in perpertrating the mythos of "Government can be run like private
>industry."

I don't recall ever saying that. What I *DID* say is that NASA can
buy many services is currently provides itself from the private
sector at considerable cost savings. I also said that these savings
would work to make the space market larger promoting greater use and
more cost savings.

I maintain that spending less money for the same services is a good
thing. You seem to disagree but are a little unclear on the exact
reason (prefering to call me a commie or red-neck depending on your
mood).

>Every time I mention that you have less lobbying money to lobby against Shuttle
>than Rockwell and Lockheed have to lobby FOR STS, you refuse to address
>the issue.

Well I have my own lobbiests. At the moment, I'll see your Rockwell lobbiests
and raise you Lockheed, Boeing, Douglas, and Martin Marrietta. They are all
pushing for SSTO which will end the Shuttle program.

>>My solution would be to have them work in a larger self sustaining
>>space economy.

>There ain't no such thing.

So long as people insist on supporting expensive program which rob
payloads from cheaper systems you are correct.

You yourself already admit this. That's is why your bottom line arguement
is that Shuttle must stay because it's a good jobs program.

>About the only "self-sustaining" part of the space economy are comm sats, with
>future growth in remote imaging.

Sure, but what would happen if launch costs dropped by a factor of two
overnight? That's what would happen if NASA got out of the operations
buisness.

  Allen

--
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  [e-mail]     |  nothing undone"                                       |
+----------------------98  DAYS TO FIRST FLIGHT OF DCX----------------------+

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

Date: Tue, 9 Mar 1993 15:17:29 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Water resupply for SSF (?)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Phil G. Fraering) writes:
>[e-mail] (Nick Szabo) writes:
>
>
>>Likewise, there is no necessity to follow your pilot-plant
>>development plan so strictly.  Oil companies every year drill
>>through miles of rock, gravel, mud, permafrost, ice, etc. that
>>they haven't mapped out in detail beforehand.  Similarly
>...
>1. I think they do map the geography well beforehand; you'd be suprised
>what they know.

Indeed. In an established field they know very well what they'll be
drilling through. And it's very rare to drill miles of rock, etc, most
wells in the US are still less than 3,000 feet deep. I know of only
one in the lower 48 that's 15,000 feet deep, and only a very few that
are over 6,000 feet deep. Well logs are studied and restudied to determine
likely new locations to drill, and seismic mapping is part of every field
survey. The petroleum geologists have a very good picture of what they'll
encounter before the rig begins drilling in most cases. And experienced
drillers develop a very good feel for what's happening with their rigs.
A good driller doesn't hang many tools. A few holes are punched experimentally
into unexplored strata each year, but usually the costs and complications are
enormous. A stuck bit can delay a drilling project for months in certain
situations, a gas pocket can wreck a rig, and unless they're very careful
they can backflood a coal seam with brine and ruin a mine. Sometimes it's
cheaper just to abandon the hole and start over a few hundred feet to the
side rather than continue to try to fix a problem hole.

>2. They don't drill in this country much anymore...

More than you think. I'm getting royalty checks from one they drilled
last year and another is going down as I type. It's estimated that
4,000 rigs are idle in the US, but there are still plenty in operation.
My current well project had to wait it's turn for a rig. What's idle
are mostly the inefficient site built drill rigs. The truck mounted ones
are mostly booked well in advance.

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: Tue, 9 Mar 1993 16:17:37 GMT
From: fred j mccall 575-3539 <[e-mail]>
Subject: Water resupply for SSF (?)
Newsgroups: sci.space

In <[e-mail]> [e-mail] (Phil G. Fraering) writes:

>[e-mail] (Nick Szabo) writes:


>>Likewise, there is no necessity to follow your pilot-plant
>>development plan so strictly.  Oil companies every year drill
>>through miles of rock, gravel, mud, permafrost, ice, etc. that
>>they haven't mapped out in detail beforehand.  Similarly
>...
>1. I think they do map the geography well beforehand; you'd be suprised
>what they know.

You are quite correct.  I've known some of the people involved in
doing this sort of thing for Exxon.  You'd be surprised what a market
for big number-crunchers the oil companies are, so that they can
do analysis on the huge quantity of acoustic and geological data that
they use before they decide to start actually drilling for oil.  The
old days of simply picking a likely spot and drilling until you hit
something are long gone.  It costs too much to drill dry holes, so
lots of analysis gets done to cut down on the percentage of dry holes.

>2. They don't drill in this country much anymore...

That's cuz all the good spots are already taken (and also because of
the way our business structure for petroleum works).

--
"Insisting on perfect safety is for people who don't have the balls to live
 in the real world."   -- Mary Shafer, NASA Ames Dryden
------------------------------------------------------------------------------
[e-mail] - I don't speak for others and they don't speak for me.

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

End of Space Digest Volume 16 : Issue 295
------------------------------