Magellan Update - 11/16/90

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Ron Baalke

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Nov 16, 1990, 6:33:53 PM11/16/90
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MAGELLAN STATUS REPORT
November 16, 1990

The Magellan spacecraft is now performing nominally in mapping mode
after experiencing its third loss-of-signal incident yesterday morning. It
has just completed its 344th mapping orbit.

Shortly after 9:00 AM PST yesterday, the spacecraft failed to return to
Earth communications after the mapping pass of orbit #825. The S-band signal
was reacquired about 40 minutes later, and signal level indicated that the high
gain antenna was off Earth point by 1-1/2 to 2 degrees. The X-band signal
required for radar data playback could not be acquired.

Engineering telemetry indicated that the control system had detected a
"heartbeat loss" similar to the incidents in August. The spacecraft had
switched some components, such as the gyros and the Input/Output unit, but was
continuing to execute its command sequence. The next three star calibrations
were rejected because the one to three degree corrections would be greater than
the limit set within the attitude control system.

At 3:19 PM PST, attitude updates were sent to the spacecraft to correct
the antenna pointing and mapping was resumed at 6:46 PM. The quick recovery
from this loss of signal incident demonstrates the contingency plans which were
developed as a result of the earlier incidents. In August, mapping was
delayed for at least 15 days. Today, mapping was resumed after 9.75 hours,
with a loss of only 3 orbits.

Stephen Saunders, Magellan's project scientist, provided images and text
for a special pictorial on Magellan to be published in the January Astronomy
Magazine.
___ _____ ___
/_ /| /____/ \ /_ /|
| | | | __ \ /| | | | Ron Baalke | baa...@mars.jpl.nasa.gov
___| | | | |__) |/ | | |___ Jet Propulsion Lab | baa...@jems.jpl.nasa.gov
/___| | | | ___/ | |/__ /| M/S 301-355 |
|_____|/ |_|/ |_____|/ Pasadena, CA 91109 |

Eric C. Bennett

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Nov 16, 1990, 8:46:10 PM11/16/90
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I guess this may be considered a 'dumb' question, but, what is the mission
objective (other than the obvious, i.e. mapping Venus) of the Magellan
spacecraft. In other words, what does the science community hope to learn
by mapping Venus?

Eric
--
Eric C. Bennett uucp: {elroy|cit-vax}!wciu!abode!eric
El Monte, Ca Internet: er...@abode.wciu.edu

If you can read this you aren't looking through the hubble space telescope!

DAVIS, SW

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Nov 17, 1990, 3:30:58 PM11/17/90
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In article <1...@abode.UUCP>, er...@abode.UUCP (Eric C. Bennett) writes...


The reason that we are mapping Venus is to answer many unanswered questions
about the earth's origins. For instance; How did two planets,nearly identical in
mass and distance from the Sun,evolve so differently? The picture that I managed to
glimpse on ABC news last night were extraordinary. Why did some of these structures
(i.e. Ishtar Terra) form on Venus and not on earth? It was mentioned that some
cliffs that were formed are so steep,that they would collapse under their own
weight on earth. Venus and Earth,while sisters,certainly don't seem to bear any
family resemblence :-)

Fraering Philip

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Nov 19, 1990, 12:01:41 PM11/19/90
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In article <1...@abode.UUCP> er...@abode.UUCP (Eric C. Bennett) writes:

ecb>I guess this may be considered a 'dumb' question, but, what is the mission
ecb>objective (other than the obvious, i.e. mapping Venus) of the Magellan
ecb>spacecraft. In other words, what does the science community hope to learn
ecb>by mapping Venus?

Comparative geology between Earth, Venus and Mars. And, hopefully, possibly
answering questions where climate and geology are interrelated, like the
'goldilocks effect' where Venus is too hot, Mars is too cold, and the
Earth is just right.

This is probrably the most important question in solar system
geology today. I better stop now before I say anymore broad generalizations.

Phil Fraering
dlbr...@pc.usl.edu
"The huns were imposing on horseback, but who isn't?" - Will Cuppy, _The
Decline and Fall of Practically Everybody_.

Henry Spencer

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Nov 19, 1990, 12:19:57 PM11/19/90
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In article <1990Nov17.2...@isc.rit.edu> swd...@ritvax.isc.rit.edu writes:
>>... what does the science community hope to learn
>>by mapping Venus?
>

> The reason that we are mapping Venus is to answer many unanswered questions
>about the earth's origins...

[Enter cynic mode.] Nonsense. We are mapping Venus to learn more about
*Venus's* geology and origins. This will improve our knowledge of planets
in general, and thereby may eventually improve our understanding of Earth
in some small ways. But that is not the primary objective of the mission.
Statements to the contrary are public-relations hype, concocted in a clumsy
and transparent attempt to make the project seem more "relevant".
--
"I don't *want* to be normal!" | Henry Spencer at U of Toronto Zoology
"Not to worry." | he...@zoo.toronto.edu utzoo!henry

Adams Douglas

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Nov 24, 1990, 6:34:01 PM11/24/90
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In <1990Nov19.1...@zoo.toronto.edu> he...@zoo.toronto.edu (Henry Spencer) writes:
>In article <1990Nov17.2...@isc.rit.edu> swd...@ritvax.isc.rit.edu writes:
>>>... what does the science community hope to learn
>>>by mapping Venus?
>> The reason that we are mapping Venus is to answer many unanswered questions
>>about the earth's origins...
>[Enter cynic mode.] Nonsense. We are mapping Venus to learn more about
>*Venus's* geology and origins. This will improve our knowledge of planets
>in general, and thereby may eventually improve our understanding of Earth

Hey, let's be totally honest. Besides the science, we're also mapping Venus
because it's NEAT! Never lose that thought!

--
====================================================================
Adams Douglas
3206 Raintree Circle -sometime I'll think of a good quote for here-
Culver City, CA 90230
crash!adamsd

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