Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V12_5/V12_546.TXT

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Subject: SPACE Digest V12 #546

SPACE Digest                                     Volume 12 : Issue 546

Today's Topics:
         NASA Headline News for 11/09/90 (Forwarded)
             Re: LLNL Astronaut Delivery
             Fundamental FITS Information
               Re: Synchronous rotation
            Re: Galileo Update - 11/02/90
             Synchronous rotation
  The Ariane V36 failure (was Re: Ariane launches ON TIME! (again))

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Date: 9 Nov 90 19:38:50 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
Subject: NASA Headline News for 11/09/90 (Forwarded)
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               Headline News
Internal Communications Branch (P-2) NASA
Headquarters

  Friday, November 9, 1990    Audio Service: 202 / 755-1788

This is NASA Headline News for Friday, November 9, 1990

At the Kennedy Space Center, preparations for STS-38
continue to go according to schedule.  Atlantis close out
activities are going well, with aft compartment closeout
scheduled to be completed Sunday evening.  Purging operations
on Atlantis' three fuel cells were finished yesterday.   Ordnance
activities are set for early tomorrow morning, during which time
Launch Pad 39-A will be closed to all non-essential personnel.
The countdown process picks up at 10:30 pm EST, Sunday, Nov.
11.

At Launch Pad 39-B, technicians are servicing the Astro-1
Broad Band X-ray Telescope with argon again.  The film in the
Ultraviolet Imaging Telescope has been removed and will be
replaced with fresh film just prior to launch of Columbia.  Work
to close out orbiter activities progresses with activities such as
updating the mission data contained in the onboard mass
memory unit.

SLS astronauts were at the Operations & Checkout
building yesterday for a series of integration activities.  A Space
Life Sciences-1 team photo was also taken.

  * * * * * * * * * * * * * * * * * * * * * * * * * *

The Galileo spacecraft is now less than 15.4 million miles
from Earth, approaching us at a velocity of more than 23,000
miles per hour.  The first of the twin Earth Gravity Assists is
now just one month away on Dec. 8.  Galileo is in excellent
condition, and the general level of spacecraft activity remains
fairly low.  Galileo will undergo a course correction maneuver
next week to allow for additional fine tuning of its Earth flyby
trajectory.

  * * * * * * * * * * * * * * * * * * * * * * * * * *

Magellan remains in good condition.  Earth and Venus are
still in superior conjunction with the Earth-Sun-Venus angle,
still less than 2.5 degrees.  The downlink from the spacecraft, on
both X and S bands, is reasonably good, with few data
transmission errors resulting from solar interference.  However,
the uplink from the Deep Space Network to Magellan is not
nearly as good, and is accompanied by numerous data errors.

Since the resumption of mapping activities requires a new
mapping sequence to be transmitted to Magellan, Jet Propulsion
Laboratory flight controllers have deferred the mapping
activities until tomorrow.  JPL has predicted that the uplink
data integrity will be regained by later today, and will attempt
to uplink the new mapping sequence at that time.


Here's the broadcast schedule for Public Affairs events on NASA
Select TV.  All times are Eastern.  **indicates a live program.

NASA Select TV programming will resume Tuesday, 11 /
13 / 90


All events and times may change without notice.  This report is
filed daily, Monday through Friday, at 12:00 pm, EST.  It is a
service of Internal Communications Branch at NASA
Headquarters.  Contact:  CREDMOND on NASAmail or at
202/453-8425.


NASA Select TV:  Satcom F2R, Transponder 13, C-Band, 72
degrees West Longitude, Audio 6.8, Frequency 3960 MHz.

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Date: 9 Nov 90 04:35:35 GMT
From: sumax!thebes!polari![e-mail]  (Charles Radley)
Organization: Seattle Online Public Unix [phone]
Subject: Re: LLNL Astronaut Delivery
References: <[e-mail]>, <[e-mail]>, <[e-mail]>
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OOps, I guess government centers are not subject to the restrictions of
commercial companies.    The premise there I suppose is that government security centers have "better" security arrangements that commercial companies.
By thesame token, it should be that much easier for LLNL to launch their
staion using Soviet boosters, and to purchase  Soyuz vehicles, cheaper than developing their own.

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Date: 8 Nov 90 19:39:02 GMT
From: dftsrv!nssdca.gsfc.nasa.gov![e-mail]  (Barry Schlesinger)
Organization: NASA - Goddard Space Flight Center
Subject: Fundamental FITS Information
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This information is posted in response to requests for where general
FITS information can be found.

The best references are the following three papers:

Wells, Greisen, and Harten, 1981, "FITS: a flexible image transport
system", Astronomy and Astrophysics Supplements, v. 44, p. 363.

Grosbo\"l et al., 1988, "Generalized extensions and blocking factors
for FITS", Astron. Astrophys. Suppl., 88,359.

Harten et al., 1988, "The FITS tables extension", Astron. Astrophys.
Suppl., 88,365.

The titles of these papers show that FITS is not exclusively for the
transport of digital images but can transport a wider variety of
structures.

An additional paper, immediately following the 1981 paper cited above
discussed "groups" format.  In practice, this format is used only to
transfer and store radio interferometry results.  It is not widely
used or understood elsewhere.

Originally, as discussed in the first FITS paper, the data matrix
could contain only integers.  By international agreement, it now may
contain IEEE-754 single and double precision floating point numbers.
If a data matrix is composed of floating point numbers, then the
BITPIX keyword in the preceding header has a negatrive value (-32 for
single and -64 for double precision).

The FITS Handbook is not yet available; the first sections, covering
the Introduction, FITS history, and FITS fundamentals are expected to
be available later this year.

We have not yet collected contributed software.  Probably, this office
will have information on software that the originators are willing to
make publicly available before the office itself has software to
distribute.

                    Barry Schlesinger
                    NSDSSO FITS Support Office

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Date: 10 Nov 90 00:45:55 GMT
From: ubc-cs!news-server.csri.toronto.edu!helios.physics.utoronto.ca!physics.utoronto.ca![e-mail]  (Christopher Neufeld)
Organization: University of Toronto Physics/Astronomy/CITA
Subject: Re: Synchronous rotation
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In article <[e-mail]> [e-mail] (John Logajan) writes:
>[e-mail] Phil Stooke writes:
>>This produces stresses and movements in the crust
>>which involve some energy dissipation. Therefore energy is slowly being
>>lost from the system, and that manifests itself as a gradual slowing of the
>>rotation period, until syncronous rotation is reached.
>
>Okay -- so where does the angular momentum go?  It has to be conserved.
>
   It goes into orbital angular momentum, boosting the orbit of the moon
(assuming that the moon was originally rotating around an axis parallel,
not anti-parallel to the orbital axis). Our moon is moving away from us
still, as it tries to lock the Earth to face it.
   Velocity in orbit decreases as the square root of the distance from
the centre of rotation, so higher orbits have higher angular momenta,
with an angular momentum proportional to the square root of the
distance.

>- John Logajan @ Network Systems; 7600 Boone Ave; Brooklyn Park, MN 55428
>- [e-mail], 612-424-4888, Fax [phone]


--
 Christopher Neufeld....Just a graduate student  |
 [e-mail]    Ad astra! |  S = k log W
 cneufeld@{pnet91,pro-micol}.cts.com             |    Boltzmann's epitaph
 "Don't edit reality for the sake of simplicity" |

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Date: 7 Nov 90 08:28:02 GMT
From: eru!hagbard!sunic!mcsun!unido!mpirbn![e-mail]  (Daniel Fischer)
Organization: Max-Planck-Institut fuer Radioastronomie, Bonn
Subject: Re: Galileo Update - 11/02/90
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In article <[e-mail]>
[e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Jean-Yves Herve') writes:
>>There is just one little thing that bugs me: how come the Galileo are given
>>with funny units only, while the Ulysses report have both metric and funny
>>units?
>Probably because Ulysses is a European project and hence the European
>audience is being considered. [...]

But then again, Galileo is an American-German bilateral project, and I can
assure you that we here are metric. The strange obsession of American aerospace
activists (officials and journalists alike, esp. Av'Leak's!) with ancient
unit systems definitely does *not* clarify issues, even for the U.S. audience.
Just think of a) the conversion precision problem: how many figures of a 'mile'
number are significant? The 1.609...-factor connecting it with metric units
causes many writers to provide their mile-values with a ridiculous pseudo-
precision (a topic discussed in sci.space many times...). And b) the fact that
km, mile and nautical mile are all of the same order of magnitude, esp. ml. &
nm. which also sound so similar, frequently causes confusion: when a space
expert tells you a satellite is at '400 miles' altitude, you can never be sure
whether he is talking about ordinary miles or nautical miles (and skipping the
'nautical' because it's sooo obvious). [I am aware that the topic must have
been discussed on the net and in journals countless times before - recall the
'no metric units on Fred'-saga? - but obviously it *has* to be repeated :-< ]

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Date: 9 Nov 90 14:48:56 GMT
From: ubc-cs!news-server.csri.toronto.edu!utgpu!watserv1!ria!uwovax![e-mail]
Subject: Synchronous rotation

Regarding synchronous rotation of natural satellites:

     It is indeed common for satellites to be in synchronous rotation. Of
the nearly 60 satellites in the solar system that are known at present,
rotation states are reasonably well known for perhaps 40, and all but
3 or 4 are in synchronous rotation. Exceptions: Saturn's Hyperion and
Phoebe, Jupiter's Himalia (one of the very distant small satellites).
There might be one or two other small outer satellites of Jupiter whose
periods are now known from photometry and are not rotating synchron-
ously but I'm not quite up to date.

     The reason is that orbiting bodies raise tides in each other. For
instance, the Moon raises a tide in Earth's oceans of a couple of metres
and a tide in the solid crust of a few centimetres. If the Moon once
rotated faster, the Earth must have raised a fairly large tide in the lunar
crust - certainly several tens of centimetres, I would guess (somebody
else can do the math!)  This produces stresses and movements in the crust
which involve some energy dissipation. Therefore energy is slowly being
lost from the system, and that manifests itself as a gradual slowing of the
rotation period, until syncronous rotation is reached. At that point the
tidal deformation is still present but it is locked into one place with
respect to the crust and no more energy is lost. For this to work the
tidal effect must be large enough. We do indeed see that all satellites
close to even small planets like Mars and Pluto are tidally locked. Also
large satellites far from a planet, like Iapetus, are locked because the
tidal effect is greater across a large body (what counts is the difference
in strength of a planet's gravity from the near side to the far side of the
satellite, naturally greater across a larger diameter). The exceptions are
very small and very distant moons (Phoebe, Himalia) and the special case
of Hyperion which is in chaotic rotation because of its bizarre shape and
complex interactions with Titan as well as Saturn.


Phil Stooke
Department of Geography,
University of Western Ontario,
London, Ontario, Canada N6A 5C2

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Date: 10 Nov 90 15:11:30 GMT
From: eagle![e-mail]  (Ronald E. Graham)
Organization: NASA Lewis Research Center
Subject: The Ariane V36 failure (was Re: Ariane launches ON TIME! (again))
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I included sci.engr in this follow-up, hoping for some extra technical
insight.  The original posting was sent to sci.space and sci.astro.

In article <[e-mail]>, [e-mail]
     (M. S. Bennett) writes...

[From an article entitled "Ariane Returns to Business" by Neville Kidger...]

>     Arianespace, the company which markets and flies the Ariane launcher,
>has resumed operations following the loss of the V36 launcher in February
>1990.
>     The loss of the rocket - with two Japanese commercial satellites
>aboard - was found to have been due to the presence of a piece of cloth
>in the water supply line to one of the four Viking first stage engines.

I've never been part of a failure investigation (thankfully ;-)) since I
joined NASA, so I don't know much about the procedure.  I hope someone can
offer insight on the following questions:

(1) the failure was due to a piece of cloth.  How could this have been
    isolated after the failure?
(2) what is the mechanism by which a piece of cloth was able to cause the
    failure?  By that I mean
    - was the cloth of sufficient size/porosity to totally restrict water
      flow?  or did it have to be?
    - how is a piece of cloth able to be in the water line anyway?
    - what is the sequence of events leading to the failure, given the
      presence of the cloth?
(3) how can Arianespace ensure no repeat of this mechanism/sequence of
    events?

Please don't give any over-simplified answers like "they screwed up," or
"they need to look harder."  Unless (3) absolutely requires a very simple
answer.  I won't assume you know what you're talking about.  And, if there
are some answers out there, I will gladly summarize.

RG - lvron@earth (or mars, or saturn - your choice) .lerc.nasa.gov

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End of SPACE Digest V12 #546
*******************