Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V11_3/V11_384.TXT

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Subject: SPACE Digest V11 #384

SPACE Digest                                     Volume 11 : Issue 384

Today's Topics:
    Re: Terraforming Venus (was: Manned mission to Venus)
           Hubble Space Telescope Update - 05/09/90
                Re: Apollo 12
               Reminders for Old Farts
              RE: SPACE Digest V11 #377
    Re: Terraforming Venus (was: Manned mission to Venus)
             Re: SPACE Digest V11
    Re: Terraforming Venus (was: Manned mission to Venus)
               LDEF Newsletter
----------------------------------------------------------------------

Date: 9 May 90 17:32:25 GMT
From: mojo![e-mail]  (Doug Mohney)
Subject: Re: Terraforming Venus (was: Manned mission to Venus)

In article <[e-mail]>, [e-mail] (Russ Cage) writes:
>from Mercury's crust, launch the metal towards Venus, and
>let it burn in the atmosphere.  Magnesium burns in CO2,
>forming magnesium oxide and releasing carbon as soot.

What do you do with the magnesium oxide? I can't think of a lot of things
which grow well in metal-tainted soil ;-)

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

Date: 9 May 90 20:50:02 GMT
From: usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Hubble Space Telescope Update - 05/09/90


                     HUBBLE SPACE TELESCOPE UPDATE
                            MAY 9, 1990

Activation and checkout of the Hubble Space Telescope's
science instruments is continuing to progress well.  The
Faint Object Camera is reported to be ready to have its high
voltage switched on.  The High Speed Photometer has had all five
of its detectors activated at low voltage.  The Goddard High
Resolution Spectrograph low voltage checkout is continuing and
monitoring continues of the Faint Object Spectrograph aft shroud
pressures.

 Ron Baalke                       |    [e-mail]
 Jet Propulsion Lab  M/S 301-355  |    [e-mail]
 4800 Oak Grove Dr.               |
 Pasadena, CA 91109               |    Go Lakers!

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

Date: 9 May 90 17:36:05 GMT
From: concertina![e-mail]  (Steve Hix)
Subject: Re: Apollo 12

In article <[e-mail]>, [e-mail] (Gregory N. Bond) writes:
> I have a question about launch windows.
>
> But for moon shots, well, it seems the moon is always in the same
> relative orbit, so a direct earth-moon window would happen once per
> day (as the earth rotated to the correct spot for launch).  So why is
> the window only open a few days per month?

  1.  The moon's orbit is not quite circular (though close).
  2.  Angle of sunlight at the landing area was seen as important.

There are certainly other important factors.

------------
  The only drawback with morning is that it comes
    at such an inconvenient time of day.
------------

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

Date: Wed, 9 May 90 04:00:22 -0700
From: Eugene N. Miya <[e-mail]>
Subject: Reminders for Old Farts

Hints for old users (subtle reminders) You'll know these.

Minimize cross references, [Do you REALLY NEED to?]
Edit "Subject:" lines especially if you are taking a tangent.
Send mail instead, avoid posting follow ups. [1 mail message worth 100 posts.]
Read all available articles before posting a follow-up. [Check all references.]
Cut down attributed articles.  Summarize!
Put a return address in the body (signature) of your message (mail or
article), state institution, etc. don't assume mail works.
Use absolute dates.  Post in a timely way.  Don't post what everyone will
get on TV anyway.
Some editors and window systems do character count line wrapping:
please keep lines under 80 characters for those using ASCII terms (use <CR>).

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

Date: Wed, 9 May 90 10:01 EST
From: Cheol Kim <[e-mail]>
Subject: RE: SPACE Digest V11 #377


        hello, please unsubscribe my member of your.
        thanks.

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

Date: 9 May 90 18:50:03 GMT
From: agate!shelby!neon![e-mail]  (John Kallen)
Subject: Re: Terraforming Venus (was: Manned mission to Venus)

In article <[e-mail]> [e-mail] (Russ Cage) writes:
#The idea of dropping the atmospheric pressure on Venus
#many-fold, combined with filling the upper atmosphere
#with a dense black soot which would absorb and re-radiate
#most incoming sunlight before it got below the greenhouse,
#is appealing.  Water would have to come from elsewhere.

Bombard the surface with ring fragments from Saturn. There's only
the problem of moving those fellows so that when they hit they don't
add too much to the surface temperature...

#              Oversimplification doesn't solve problems, it just
#[phone]          changes them into less tractable problems.
#Russ Cage, Robust Software Inc.            [e-mail]
_______________________________________________________________________________
 | |   |   |    |\ | |   /|\ | John Kallen        Computer: kom-pyu'-ter (n) a
 | |\ \|/ \|  * |/ | |/|  |  | PoBox 11215         device for generating errors
 | |\ /|\  |\ * |\ |   |  |  | Stanford CA 94309   speedily and unpredictably.
_|_|___|___|____|_\|___|__|__|[e-mail]___________________________

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

Date: 10 May 90 02:11:22 GMT
From: cs.utexas.edu!news-server.csri.toronto.edu!qucdn![e-mail]  (Arnold G. Gill)
Subject: Re: SPACE Digest V11

In article <07MAY90.08604257.0023.MUSIC@SDSUMUS>, [e-mail] (Andy
Edeburn) says:
>
>> The West German Space Agency plans to establish a commercial organization
>> to operate and market its payloads on the Columbus space station.
>                                            ^^^^^^^^^^^^^^^^^^^^^^
>        Um, excuse me. What the h*ll this is?
     A comment from someone who doesn't know what is happening outside the
US? :-)  Columbus is part of the ESA commitment to Freedom.
-------
 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
|  Arnold Gill                        |                                     |
|  Queen's University at Kingston     |     If I hadn't wanted it heard,    |
|  BITNET   : gilla@qucdn             |       I wouldn't have said it.      |
|  X-400    : [e-mail]  |                                     |
|  INTERNET : [e-mail]  |                                     |
 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

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

Date: 10 May 90 03:01:10 GMT
From: voder!dtg.nsc.com![e-mail]  (Lord Snooty @ The Giant Poisoned Electric Head )
Subject: Re: Terraforming Venus (was: Manned mission to Venus)

In "A Step Farther Out" by Jerry Pournelle (many years old now) he advocates
using blue-green algae dropped in massive clouds from above. He assumes that
these will gradually cause rain to precipitate rainstorms, which will
slowly descend through the Venusian atmosphere, will eventually hit the
ground and thereby cool it.

Anyone read this and/or could comment?
--
...........................................................................
Andrew Palfreyman        and i am dumb to tell a weather's wind
[e-mail]        how time has ticked a heaven 'round the stars
        free energy and immortality!

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

Date: 10 May 90 02:53:57 GMT
From: usc!cs.utexas.edu!texbell!nuchat![e-mail]  (Steve Nuchia)
Subject: LDEF Newsletter

I have here a copy of Vol 1, No 2 of the "LDEF Spaceflight Environmental
Effects Newsletter", "distributed free of charge to the greater LDEF
community and professionals working in the discipline areas pertinent
to the LDEF mission.  Both researchers and applications professionals
are invited to join our distributution list.  [Send info to] LDEF Newsletter,
P.O. Box 10518, Silver Springs, MD 20914."

One of the articles is about the budget problems facing the investigators;
I suggest that you offer to pay for a subscription.

This will not become a regular feature, but I recall some questions
a while back about what was being learned from the LDEF, so here goes:


Cover Photo: "Evidence of Erosion of Silver Teflon"
    [Micrograph showing a tuft of material protruding
    from a flat surface, vaguely like a breaking sea wave.]

Specimen of silver teflon analysed at KSC, micrograph shows "striking
evidence for erosion" by atomic oxygen.  The protrusion is a "surface
protected feature", the flat area around it has been eroded away.
The angles of the edges of the feature are "in good agreement with
the expected angle of impingement of atomic oxygen."

Spectroscopy indicates Sodium, Potassium, Calcium, and Clorine,
"characteristic of the salt residue from ocean spray deposited
prior to launch".  Estimated 15-20 microns of erosion over
5 3/4 years.  "[this evidence] suggests that the milky appearance
on ram-facing LDEF surfaces is due to microscopic roughening of
the teflon surfaces due to erosion.

LDEF Deintegration Completed on Schedule

Last experiment removed 29 March.  "The event was appropriately
celebrated at the Cape, although by a somewhat sparce crew.
The ranks of participants had been steadily diminishing as
participants have been drawn away to pursue their own
investigations at their own facilities."  [Sounds like
good material for a _Science_ cartoon: guys in lab coats
standing in buffet line as the LDEF is carved up, then
scurrying off to their labs with their slices]


Freedom Gets an Early "Sample" of LDEF's Potential

SAMPLE is the Solar Array Materials Passive LDEF Experiment.

Hmm... This is a confusing article... Looks like a report on
a meeting, or maybe just the doings of insiders.  Upshot of
it is some preliminary results are being presented to various
folks, and there are SIGs (Special Investigation Groups) for
various things.

They are targeting the September for an LDEF "data workshop"
and a major symposium is planned for spring '91.  Workshops
for spacecraft designers will also be arranged through the
project office.


Technology Updates

John Gregory, U of Alabama, reported burn patterns on
his silver oxide attitude sensor indicates steady 10 degree
yaw with no long term oscillation.  The project office
is accumulating all attitude data into the mission history.

Thermal Control Properties Group: Initial inspection indicated
thermal control materials had been significantly affected.
Analysis is considered very important to Hubble and other
missions, and is proceeding with "all deliberate haste".

Silver Teflon: samples from thermal blankets were relatively
unchanged, but adhesively bonded specimens had significantly
altered solar absorptance and infared emittance, "as might
be expected for the observed discoloration and streaks of
contamination" on the material bonded to aluminum.

Fluorescensce: It was discovered that samples of several materials
exhibit fluorescence under UV light while "control specimens ...
[have] no corresponding fluorescence"

Induced Radiation: "Some of the most sensitive counting facilities
in the country are involved" in measuring induced radioactivity
in LDEF samples.  Structural parts, samples put there for the
purpose, and parts loaned by other experimenters are being
examined.  Results are being used to cross-check the radiation
transport modelling software used in spacecraft design.

Integrated Systems Test: Prior to deintegration they powered
the bird up; batteries charged up normally and electronic systems
functioned properly.  Triggering relays for all experiments
were checked and found to be in the proper position, with
the expected contact resistance.

Solar Cells: Some discoloration and erosion (particularly of
potting compound) but all arrays worked when tested under
halogen lamps.

Mechanisms:  The two valves "borrowed" from the Smithsonian's skylab
worked properly and are still functional.

Experiment Exposure Canisters: The Air FOrce opened their canister,
after verifying that it had vacuum in it and taking a sample
of the gasses.  Impact damage visible on some samples confirmed
that the canister had opened properly.  "The most striking observation
was the change in color of a Nd+:glass laser rod from light pink
to purple."

Structures: VELCRO "in numerous locations" is intact and has
high tear strength.  Further evidence of cold welding between
dissimilar metals has appeared. Stainless steel and aluminum
are involved.  When forced considerable galling is observed
on the contact surfaces.

Seals: "Reports coming in continue to point to long term
success with seals."  A tape recorder on a Canadian experiment,
sealed with conventional technology, tested out at about 1 PSI
per year prior to flight.  Postflight it showed a drop of
[Ta-Da!] about 5 PSI.  Good results from Lockheed tape
recorders too.  O-rings appear to have retained their roundness,
to the naked eye.  Apezion grease appears to have retained its
viscosity and texture on both sides of the seal.

Thermal: Aluminum shield and radiator on the HEPP [solar cell]
experiment have some tarnish over 20% of the surface, with a
concentration near the sheild/radiator intersection.  This is
thought to be due to contamination coming through the slit
from inside the experiment or LDEF.


Meteorids and Debris SIG Sets Broad Goals

The SIG wants to make maxumum use of the LDEF to "characterize
the natural meteoroid and man-made debris environment in low-Earth
orbit."  40% of the LDEF surface was dedicated to M&D experments,
but characterizing the largest (and rarest) particles "requires
characterization of the exposure history of the entire LDEF satellite."

So they're getting cooperation from the other experimenters with
impacts on their samples.  "Several thousand large impact features
have been located, and their stereo images recorded."  One 0.5mm
impact feature was located inside the satellite, "the impactor
having apparently passed within between a thin opening in the frame."

J.A.M. McDonnel of the University of Kent had a debris analysis
experiment at each end of the spacecraft, and reports 10-20
times the concentration of impact features on the forward end.
Since orbiting debris is much slower than the typical meteroid,
this indicated that there is an order of magnitude more junk
than dirt in LEO.  Results presented at 21st Lunar and Planetary
Science Conference at JSC in March.


Budget May Constrain LDEF Data Analysis

Writer belives budget requirements for testing, analysing, and recording
LDEF data were underestimated.  About $12 million currently budgeted
over four years.  Writer wants $4-5 million per year "over the next
several years".


Magnetic Data Tapes Successful Despite Early Concerns

All of the recorders examined so far appear to have functioned
properly; the tapes have been copied and partially read.  Data
have not yet been extensively validated.

They were worried about the tape having dried out in its
final position in the dry nitrogen of the tape canisters.
The tapes were removed without rewinding "and allowed to
soak in ambient atmosphere", which "returned pliability
to the tapes."

The tape in the one recorder operated for the entire mission
did not have this "conformal set".  Lockheed says they are
now using 45% relative humidity in their backfill gas for
recorders.

Investigators at the U of Toronto, working with spare tape
that had been stored in dry nitrogen in the lab, observed
that the oxide had lost some of its adhesion, causing
severe difficulties in simulated read-back.  The flight
tapes did not exhibit this phenomenon though - they
were "well behaved".  "At this time there is no explanation
for this discrepancy; however attention is being focused on
the presence of offgassed material from the electronics."


Editorial by "tech. ed."

"One of the opportunities staring us in the eye that we do *not*
want to miss is the opportunity to use the LDEF experience as
an educational too."  Work loads threaten to cause everybody
to neglect this.

"But one of the reasons we are so absorbed is that we suffer
from a cronic shortage of clones.  And right now nobody is
out there making clones for us.  We need to make our own,
and that's really what this education business is all about."

Advocates making the effort to get students involved in
analysing LDEF results, despite the costs in "our time,
efficiency, accuracy and risk to flight specimens."

"No surprise to me, but ironic in the end, if the greater
benefit to us from LDEF is not in what we learn but what we teach."


Cartoon: LDEF as a grey-beard amadillo, caption "so long and
    thanks for all the tomatos!"  -- Emmett Miller



--
Steve Nuchia          South Coast Computing Services      [phone]
"To learn which questions are unanswerable, and _not_to_answer_them;
this skill is most needful in times of stress and darkness."
        Ursula LeGuin, _The_Left_Hand_of_Darkness_

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

End of SPACE Digest V11 #384
*******************