Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v15_0/v15no086.txt

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Date: Sat,  8 Aug 92 05:04:58
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #086
To: Space Digest Readers
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Space Digest                Sat,  8 Aug 92       Volume 15 : Issue 086

Today's Topics:
                            Circles on map
                      Galileo Update - 08/07/92
             Giotto - First Results from Comet Encounter
                       Hubble used for spying?
                         mathematical models
         ReEe: aA 12 mile tether that gernerates 5000v?
                      Source of moon/apollo pix
                                 TSS
             Two-Line Orbital Element Set:  Space Shuttle

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

Date: 8 Aug 92 04:59:50 GMT
From: John Roberts <[e-mail]>
Subject: Circles on map
Newsgroups: sci.space

-From: [e-mail] (Henry Spencer)
-Subject: Re: Weird circle-like things on shuttle map
-Date: 7 Aug 92 20:36:47 GMT
-Organization: U of Toronto Zoology

->On the NASA channel, when they display the globe with the
->shuttle moving around, there are all these cirlce-like things
->that have strange grooves.

-Those are the areas where a shuttle at orbital altitude is in line-of-sight
-(for radio transmissions) of a ground station in the center of the circle.
-There are bites out of some of them because of things like mountains that
-block the view in some directions for some stations.

There's also a circle of the same size showing the Earth's horizon as seen
from the orbiter. The size of the circle is a function of the altitude of
the Shuttle. Note that only a tiny fraction of the Earth's surface can be seen
from the orbiter at any given time. In low Earth orbit, nearly half of the
field of view is taken up by the Earth.

John Roberts
[e-mail]

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

Date: 8 Aug 92 07:40:25 GMT
From: Ron Baalke <[e-mail]>
Subject: Galileo Update - 08/07/92
Newsgroups: sci.space,sci.astro

Forwarded from Neal Ausman, Galileo Mission Director

                                 GALILEO
                     MISSION DIRECTOR STATUS REPORT
                               POST-LAUNCH
                       July 30 - August 6, 1992

SPACECRAFT

1.  Commands were sent on July 31 to increase the spacecraft power margin to

warm the RPM (Retro_Propulsion Module) propellant tanks in preparation for
TCM-14 (Trajectory Correction Maneuver #14) on August 4-7.

2.  Cruise Science Memory Readouts (MROs) were performed by the stored
sequence for the MAG (Magnetometer) and DDS (Dust Detector) instruments on
August 2 and for the EUV (Extreme Ultraviolet Spectrometer) instrument on
August 3.  An additional real-time EUV MRO was performed on July 31, to
return recent data for comparison with earlier EUV data taken under similar
solar conditions.

3.  Another RPM 10-Newton thruster maintenance activity was performed on
August 3.  The activity "flushed" all 12 thrusters; spacecraft performance
throughout the activity was normal.

4.  In preparation for the start of the TCM-14 maneuver, the spacecraft
performed a 4-degree SITURN on August 4 to the desired maneuver attitude.

5.  TCM-14 maneuver sequence memory loads were sent to the spacecraft for
maneuver potions A, B, and C on August 4, 5, and 6, respectively.  Each
maneuver portion, using the L-thrusters is designed to impart a delta velocity
of 6.2 m/sec.  The last maneuver portion (D) is scheduled to be sent on
August 6 for execution on August 7 and will use the L-thrusters and the
axial (Z) thrusters to achieve a delta velocity of about 2.3 m/sec.  Total
delta velocity from the TCM is expected to be about 21 m/sec.

6.  The first three portions of TCM-14 consisted entirely of lateral burns
with each portion containing six nearly identical burn segments. The
spacecraft performance throughout the maneuver activity was normal and near
expected levels. In particular, the RPM tank pressures and temperatures were
normal throughout the 18 burn segments.  After the second segment a portion A,
a sequence planned spin correction and pointing correction activity was
performed.  This correction reduced an accumulated 20 mrad pointing error to
about 4 mrad.  Similarly, other sequence planned pointing corrections were
performed after burn segments 4 and 6.  Preliminary radio navigation data for
TCM-14A indicates about a two percent overburn.  TCM-14B and TCM-14C portion
were performed on August 5 and 6, respectively.  These maneuver portions, like
TCM-14A, exhibited somewhat larger than expected accumulated pointing error.
Furthermore, it was observed that the accumulated pointing error gradually
decreased after each burn segment.  The cause for this unexpected pointing
error behavior is unclear but it may suggest that one L-thruster is performing
about one to two percent above predict.  Radio navigation data after TCM-14B
and TCM-14C indicates about a 1.6 and 1.1 percent overburn, respectively.
The integrated 3-portion overburn is about 1.4 percent.  The final portion,
TCM-14D, will be performed on August 7.  This last portion consists of one
small (0.4m/sec) axial burn followed by a three segment lateral burn of
2.3m/sec.

7.  The AC/DC bus imbalance measurements exhibited little change. The AC
measurement toggled 1 DN and reads 3.1 volts. The DC measurement increased
6 DN for a short time and then returned close to its previous value and now
reads 14.7 volts. Intermittently during pre-TCM burn segments, the DC
imbalance changed and then returned to its previous value.  There was no
consistency as to when changes occurred, i.e., during burns or pre/post
burns.  This measurement variation is consistent with the model developed
by the AC/DC special anomaly team.

8.  The Spacecraft status as of August 6, 1992, is as follows:

       a)  System Power Margin -  70 watts
       b)  Spin Configuration - Dual-Spin
       c)  Spin Rate/Sensor - 3.16 rpm/Star Scanner
       d)  Spacecraft Attitude is approximately 3.1 degrees
           off-sun (lagging)
       e)  Downlink telemetry rate/antenna-40 bps (coded)/LGA-1
       f)  General Thermal Control - all temperatures within
           acceptable range
       g)  RPM Tank Pressures - all within acceptable range
       h)  Orbiter Science- UVS, EUV, DDS, MAG, EPD, and HIC are
           powered on
       i)  Probe/RRH - powered off, temperatures within
           acceptable range
       j)  CMD Loss Timer Setting - 264 hours
           Time To Initiation - 264 hours


UPLINK GENERATION/COMMAND REVIEW AND APPROVAL:

1.  The TCM-14 final sequence and command product was approved by the Project
on July 31.  The maneuver is scheduled to be performed from August 4 thru
August 7.


TRAJECTORY

     As of noon Thursday, August 6, 1992, the Galileo Spacecraft trajectory
status was as follows:

        Distance from Earth         106,822,460 miles (1.16 AU)
        Distance from Sun           160,260,630 miles (1.73 AU)
         Heliocentric Speed           48,550 miles per hour
         Distance from Jupiter        664,407,490 miles
         Round Trip Light Time        19 minutes, 16 seconds

SPECIAL TOPIC

1.  As of August 6, 1992, a total of 8108 real-time commands have been
transmitted to Galileo since Launch.  Of these, 3230  were pre-planned in
the sequence design and 4878 were not.  In the past week, 14 real time
commands were transmitted; 8 were pre-planned in the sequence design.
In addition, 5427 mini-sequence commands have been transmitted since
March 1991; 3269 were pre-planned and 2158 were not. In the past week,
44 mini-sequence commands (SITURN) were transmitted.  Major command
activities this week included SITURN, EUV MRO, and power reconfiguration
activities.

2.  The unexpected lock changes observed during the DSS-63 (Madrid 70
meter antenna) pass are believed similar to the many others observed during
the past two years.  The tracking conditions for this recent event appears
similar to some of those observed on previous occurrences.  There was no
evidence that the spacecraft received or issued a command during the
unexpected lock change.  This recent lock change information was passed to
the team working the lock change ISAs.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | You can't hide broccoli in
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | a glass of milk -
|_____|/  |_|/       |_____|/                     | anonymous 7-year old.

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

Date: 8 Aug 92 07:48:30 GMT
From: Ron Baalke <[e-mail]>
Subject: Giotto - First Results from Comet Encounter
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Stan Ryckman) writes...
>In article <[e-mail]> [e-mail] writes:
>>ESA News Release
>
>>     At 15:30:56 the Dust Impact Detectors reported the first impact of
>>a fairly large particle, followed by two smaller ones.
>
>What is the range of "fairly large?"

I've heard the particle was estimated to be about 30 milligrams, and may
be larger than any of the particles encountered at Halley.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | You can't hide broccoli in
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | a glass of milk -
|_____|/  |_|/       |_____|/                     | anonymous 7-year old.

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

Date: 5 Aug 92 00:56:16 GMT
From: "Hoyt A. Stearns jr." <isus!hoyt>
Subject: Hubble used for spying?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>No.  The Earth is too bright, even at night.  Pointing Hubble at Earth
>(or even the moon) would burn out (or seriously endanger) the Faint
>Object Camera.
>

A PBS broadcast on spying a couple of years ago described the KH11 and KH12
spy satellites.  They seemed remarkably similar in size and shape to the
Hubble telescope. Are you sure they're not related? :-)

--
Hoyt A. Stearns jr.|hoyt@          | International Society of Unified Science|
4131 E. Cannon Dr. |isus.tnet.com  | Advancing Dewey B. Larson's Reciprocal  |
Phoenix, AZ. 85028 |ncar!enuucp!   | System- a unified physical theory.      |
voice_602_996_1717 telesys!isus!hoyt The Universe in two postulates!_________|

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

Date: 8 Aug 92 02:54:58 GMT
From: John Roberts <[e-mail]>
Subject: mathematical models
Newsgroups: sci.space

-From: [e-mail] (R. Kym Horsell)
-Subject: Re: Origin of Life article
-Date: 7 Aug 92 22:43:23 GMT
-Organization: State University of New York at Binghamton

-In article <[e-mail]> [e-mail] (John Roberts) writes:
->There are mathematical formulas for the evaluation of the probability of
->a hypothesis being correct given a particular number of observations.
->Putting biogenesis into mathematical terms may be of limited usefulness
->at this point, because we know so little about it.

-This is rather misleading. The area alluded to is called induction.
-To consider the difficulty of comming up with such formulae -- consider
-the following. An event happens ``n'' times in a row. What is the
-prob of it happening the ``next time''. You may say: n/n=1 (i.e.
-it is certain to happen). You may say 1/2 (i.e. 50:50) or you
-may say 1/(n+1). This last formula is meant to be a compromise
-(we have learnt _something_ from the string of n events; but
-there is still some uncertainty).

-All formulae above can be used (so far as I know) interchangabley;
-none leads to a contradiction. (Unless you set up your system of
-math logic to, e.g., specifically preclude it :).

-There are thus no ``mathematical formulas for evaluation of
-the probability of a hypothesis''. Various statisticians will
-give me an argument. But they are wrong. :)

Predicting a future event is different from evaluating the degree of
confidence that a given distribution model is correct. I don't know about
you, but if I had a coin that came up heads a million times in a row, I'd
be pretty dubious about the model that it's a fair coin. :-)

There are tests like chi-squared for conformance of a statistical sample
to an expected distribution. I don't know if this is what's used for
Boolean random variables, or if something else is used. Is there a
mathematician in the house?

Also see "Rosencrantz and Guildenstern are Dead" by Somebodyorother
(sort of a takeoff on Shakespearean plays).

John Roberts
[e-mail]

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

Date: Thu, 6 Aug 1992 20:32:01 +0000
From: Andrew Haveland-Robinson <[e-mail]>
Subject: ReEe: aA 12 mile tether that gernerates 5000v?
Newsgroups: sci.space

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

>In article <[e-mail]>, [e-mail] (Andrew> Haveland-Robinson) writes:
>>
>> In article <[e-mail]>> [e-mail] writes:
>>
>>>The 5000 volts are induced by the Earth's magnetic field as the spacecraft
>>>orbits. The same principle in using magnets to enduce a voltage when you
>>>pass a magnet through a coil of wire.
>>
>> I can see that this will work, though it's practicality may be limited
>> as it would start to slow down the shuttle if any serious power could
>> be drawn.
>>
>On the contrary, if energy is extracted from an orbiting body, its kinetic
>energy *increases* by this exact amount.  All this additional energy is
>provided by the gravitational binding energy.  A very useful use of a tethered
>loop could be not to extract electric energy at the expense of gravitational
>energy, but the  contrary: electric energy, coming from solar cells for
>instance, can then be used in the opposite way to lift up the satellite orbit.
>
>        Daniel Pfenniger

You make some interesting though to my mind, rather curious assertions.
How does it gain kinetic energy if you take energy out of it?

I think I need some clarification of the principles at work here...

As I understand it, if you take energy out of an orbiting body, it moves
into a higher orbit at a slower velocity. If you take more out then it
ceases to orbit and starts falling to earth.  If there is still an angular
moment then it will stabilise in an orbit (if the Earth doesn't get in
the way of the trajectory!).

I have a problem in conceptualising how to get an object to orbit lower
and quicker.  If you speed it up wouldn't also tend to find a higher orbit
and slow down?

I suppose the current will alternate during the orbit too, depending on which
orbit was chosen (I guess a polar one would be most productive).

Confused of Osea

+-------------------------------------------------------------------------+
| Haveland-Robinson Associates     | Email: [e-mail]         |
| Pine Cottage, Osea Island, Essex |        [e-mail] |
| CM9 8UH England.  0621-88756     | Also:  081-800 1708  081-802 4502    |
+-------------------------------------------------------------------------+

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

Date: Sat, 8 Aug 1992 06:21:00 GMT
From: [e-mail]
Subject: Source of moon/apollo pix
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Edmund Hack) writes...
>In article <[e-mail]> [e-mail] (Bill Higgins-- Beam Jockey) writes:
>>I suspect the Moon just is *not* available in digital form.... though
>>Dennis Wingo has talked about digitizing some of the Lunar Orbiter
>>microfiche just for fun.  The USGS people in Flagstaff would know more
>>than anybody about the availability of Moon data.
>
>According to my contacts at JSC and LPI, none of the Lunar Orbiter or
>Apollo CSM photography is in useable digital form.  All that exists for
>Apollo are long rolls of B&W prints (and the negatives) and maps made by
>USGS and DMA from the stereo pairs.  A project I am working on part-time
>may turn some of the photography and cartography data from the landing
>sites into digital terrain maps.
>
>Due to the early date of the lunar spacecraft designs, the maps we have
>of Mars are more comprehensive and accurate than those of the moon.
>
>
>--
>| Edmund Hack - Lockheed Engineering & Sciences Co. - Houston, TX
>| [e-mail]    SpokesPersonp(Me,or(NASA,LESC)) = NIL
>| "No the game never ends when your whole
>|       world depends on the turn of a friendly card"

If anyone wants to come and spend a couple of weeks here in Huntsville and do
the work, we can digitize the Lunar orbiter images. We have some reall spiffy
cameras and scanners to scan the Micrfilm images from LO I-V.  I just do not
have the time to do it now, I apologize. I do have a few spiffy images from
LO IV that I gave to you on floppy Bill Higgins in 1989. You still have them?
They showed some really great lava tubes and we did a little playing around
with them back then but I am building a satellite and numerous shuttle
payloads now and just can't do it. There is some really good stuff here and
I hope that someone will take us up on this.  We can put it on a R/W optical
disk and then Transfer them to CD ROM for distribution.  Is there any interest
in this?  Please mail me at the above address. Thanks to John Roberts we now
can correlate the images that I have with their approximate locations. I was
able to figure that out finally John.

Dennis, University of Alabama in Huntsville.

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

Date: 8 Aug 92 04:50:36 GMT
From: John Roberts <[e-mail]>
Subject: TSS
Newsgroups: sci.space

-From: [e-mail] (Chuck Shotton)
-Subject: Re: More second-hand info on TSS
-Date: 5 Aug 92 18:51:02 GMT

-Running 12 miles of cable off a spool doesn't seem to be a particularly
-difficult task, even in zero G. Why is it that we have another
-over-engineered solution that has apparently failed? Is this really any
-more difficult to engineer that an elaborate fishing reel? I'm sure it's a
-LOT simpler than most other shuttle systems (including the toilet!).

-It's a little discouraging to continually see minor things screwing up
-over-hyped shuttle missions (like non-functional grapple bars, jammed fax
-machines, burned out cooling fans,

Notice a recurring theme? Tried and true on Earth, then problems show up
in space. Maybe it's just that it's harder to do things in space conditions,
and it's hard to simulate space conditions on Earth. Of course, being aware
of this problem, it's a good idea to plan for numerous tests. For instance,
they could run a smaller tether experiment on many missions, as time allows.

untested telescope mirrors, etc.)

That's not quite correct for HST. The primary mirror was extensively tested,
and in fact the tests showed the error. Hughes Danbury decided to ignore
the warning signs, and not to inform NASA.

-I'm not flaming anyone. I seriously want to know how this cable mechanism
-was designed and tested and how such a simple mechanism can be so screwed
-up.

It was tested on Earth, and showed no problems.
I think they should have designed it for constant tension on the reel. Maybe
they will, next time. :-)

John Roberts
[e-mail]

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

Date: 8 Aug 92 04:05:41 GMT
From: TS Kelso <[e-mail]>
Subject: Two-Line Orbital Element Set:  Space Shuttle
Newsgroups: sci.space

The most current orbital elements from the NORAD two-line element sets are
carried on the Celestial BBS, [phone], and are updated daily (when
possible).  Documentation and tracking software are also available on this
system.  As a service to the satellite user community, the most current
elements for the current shuttle mission are provided below.  The Celestial
BBS may be accessed 24 hours/day at 300, 1200, 2400, 4800, or 9600 bps using
8 data bits, 1 stop bit, no parity.

Element sets (also updated daily), shuttle elements, and some documentation
and software are also available via anonymous ftp from archive.afit.af.mil
(129.92.1.66) in the directory pub/space.

STS 46
1 22064U 92 49  A 92219.67708333  .00381304  69070-4  25599-3 0   201
2 22064  28.4752 306.2844 0005231 278.3917 146.5572 16.15583754   969
EURECA
1 22065U 92 49  B 92219.56250000  .00000116  00000-0  99999-7 0   160
2 22065  28.4567 308.9498 0027753 318.6810 283.7589 15.26603958   918
--
Dr TS Kelso                           Assistant Professor of Space Operations
[e-mail]                    Air Force Institute of Technology

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

End of Space Digest Volume 15 : Issue 086
------------------------------