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Subject: SPACE Digest V13 #062

SPACE Digest                                      Volume 13 : Issue 62

Today's Topics:
              Galileo Update - 01/18/91
     CRRES experiments continue after four successes (Forwarded)
             Astronauts in the Van Allens
        Re: Fwd: NASA Plans To Redesign Space Station
      Future of the Shuttle (was: space news from Dec 17 AW&ST)
             Re: Salyut 7 burn-up
         Re: Planetary Society [Part 2 of 2]

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
  [e-mail].  Other mail, esp. [un]subscription requests,
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----------------------------------------------------------------------

Date: 18 Jan 91 18:57:30 GMT
From: sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Galileo Update - 01/18/91


                         GALILEO STATUS REPORT
                           January 18, 1991

     The status of the Galileo spacecraftas of end of day January 17 is as
 follows:

       o System Power Margin - 66 watts
       o Spin Configuration - All-Spin - cruise mode
       o Spin Rate/Sensor - 2.89rpm/star scanner
       o Spacecraft Attitude Sun Point Angle - approximately
         1.7 degrees plus or minus 0.3 degree
       o Downlink telemetry rate/antenna - 40 bps
        (uncoded)/LGA-2 (Low Gain Antenna)
       o General Thermal Control - all temperatures within
         acceptable range
       o RPM (Retro Propulsion Module) Tank Pressures - all
         within acceptable range

     Yesterday on the Galileo spacecraft, the CDS "B" (Command Data Subsystem)
memory copy activity was successfully completed; spot-check memory readouts
indicated no anomalies or parity errors.

     Today, cruise science memory readouts were completed for the EUV
(Extreme Ultraviolet Spectrometer), MAG (Magnetometer) and DDS (Dust Detector)
instruments.  In addition to the science readouts, a planned sun acquisition
was successfully completed.

     A total of 2950 real-time commands have been transmitted to Galileo.  Of
these, 1557 have been pre-planned in the sequence design and 1393 were not.
In the past week, a total of 149 real time commands were sent; 141 were
preplanned and 8 were unplanned.

     Over the coming weekend, spacecraft activity will be limited to a planned
radio science calibration on Saturday and a sun acquisition on Sunday.

      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | [e-mail]
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | [e-mail]
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |

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

Date: 18 Jan 91 18:49:10 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: CRRES experiments continue after four successes (Forwarded)

Brian Dunbar
Headquarters, Washington, D.C.                   January 17, 1991
(Phone:  [phone])

Jerry Berg
Marshall Space Flight Center, Huntsville, Ala.
(Phone:  [phone])


RELEASE:  91-9

CRRES EXPERIMENTS CONTINUE AFTER FOUR SUCCESSES

     The Combined Release and Radiation Effects Satellite (CRRES)
is scheduled to resume experiments early Friday morning following
four successful chemical releases in the last week.  The next
release opportunities will be for either a lithium or large
barium release early Friday morning, with possible times of 12:20
a.m., 12:50 a.m., 1:20 a.m., 1:40 a.m. and 1:55 a.m. EST.
Weather permitting, the release will be visible in the south-
southeastern sky, slightly more than halfway between the horizon
and the zenith.

     The CRRES releases aid scientists studying the way that
charged particles interact with the Earth's magnetic and electric
fields by creating artificial auroras.  Natural auroras occur
when high-energy particles from the sun strike the Earth's upper
atmosphere.  Understanding the Earth's magnetic field is
important because disturbances in the field, such as those that
create natural auroras, can disrupt high-frequency
communications, produce damaging currents in terrestrial power
systems and create magnetic storms that affect sensitive
instruments on Earth and in space.

     Last weekend, one release each of barium and lithium were
performed, and two more barium experiments were completed Monday
night and early Wednesday morning.

     "The chemical release operations went off without a hitch
during these opportunities," said Dr. David Reasoner, CRRES
project scientist at the Marshall Space Flight Center,
Huntsville, Ala.  "The satellite and the U.S. Air Force satellite
control facility have performed flawlessly.  The optical
instruments at the observing sites were pointed precisely at the
release."

     The current CRRES chemical release "campaign" involves seven
planned releases, with four opportunities to make the remaining
three releases through Jan. 24.  Late Saturday night and early
Sunday morning, two releases were completed as scheduled.  Cloudy
weather over much of the United States did not permit the glowing
barium and lithium gas clouds to be seen from the ground, but a
more than sufficient number of observation stations in North
America and the Caribbean were able to provide good observation
support for the experiments.

     The 3.3-lb. barium release at 9:17 p.m. EST Saturday
resulted in a cloud that glowed bright green initially and then
changed to a dimmer purplish-blue as the barium atoms ionized
upon exposure to sunlight.

     At 2:05 a.m. Sunday morning, the 1.6-lb. lithium release
produced a red glow in the night sky, with observers estimating
its size as approximately the diameter of the full moon and
remaining visible for a few seconds.  Its apparent brightness was
relatively dim because of the human eye's low response in the red
region of the spectrum, Reasoner said.  Nevertheless, the cloud
was reported, for its brief duration, to be the brightest object
in the sky, he added.  The lithium release was timed to coincide
with certain positions of CRRES and NASA's Dynamics Explorer-1
satellite as well as the Japanese AKEBONO satellite.  All three
satellites have instruments for detecting the artificially
injected lithium ions.

     The Monday night barium release occurred at 11:11 p.m.
EST.  Afterward, Reasoner hailed the operation, saying, "We
believe we have accomplished a significant experiment.  Excellent
optical data were obtained from many sites, with one particular
site tracking the barium ions for two hours."

     The fourth barium release took place at 1:25 a.m. EST
Wednesday morning.

     Given clear weather, remaining releases should be visible
from the entire continental United States, most of Canada,
Central America, the Caribbean and much of South America.  During
some of the release opportunities, the clouds may be visible low
in the western skies from western Africa and Europe, several
hours before dawn.

     For current information about upcoming release
opportunities, the CRRES Coordination Center "hotline" message
may be heard by calling 205/544-5356.  This is not a toll-free
number.

     CRRES is a joint program of NASA, through its Marshall Space
Flight Center and the Department of Defense's Space Test
Program.  CRRES is operated and controlled from the Air Force's
Consolidated Space Test Center, Sunnyvale, Calif.

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

Date: 16 Jan 91 22:12:19 GMT
From: hpcc05!hpcc01![e-mail]  (Graham Flower)
Subject: Astronauts in the Van Allens




     I recently read that manned space missions about the earth are limited
     to altitudes below 300 km or so due to the Van Allen belts. Could somebody
     explain to me just why this is? Apparently transit through them is ok
     (Apollo missions) so what is going on here?


Graham Flower ms 90-TT               |  Better to have convictions and act on
Hewlett-Packard  350 W Trimble Rd    |  them, even if they are wrong, than to
Microwave Semiconductor Division     |  waffle in indecision endlessly.
San Jose, California, 95131          |

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

Date: 16 Jan 91 20:09:18 GMT
From: usc!samsung!rex!rouge![e-mail]  (Fraering Philip)
Subject: Re: Fwd: NASA Plans To Redesign Space Station

In article <[e-mail]> [e-mail] (Jonathan Leech) writes:

>If adopted, this would help vindicate Oliver Harwood's modular
>tetrahedral station approach. Having the temerity to propose it got him
>kicked out of Rockwell in the mid-80s.
>Jon Leech ([e-mail])    __@/

You mean they're still doing things like kicking people out of organizations
for coming up with different ideas on how to do things?

Doesn't most of the benefits of the Space program come not from the
actual hardware we've built (except for the weather and comm sats) but
because it pushes new technology?

Confused in Lafayette,
Phil
[e-mail]

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

Date: Fri, 18 Jan 91 10:09:14 -0500
From: "Allen W. Sherzer" <[e-mail]>
Subject: Future of the Shuttle (was: space news from Dec 17 AW&ST)
Newsgroups: sci.space
Cc:

In article <[e-mail]> Henry Spencer writes:
|>I think it is clear that the Shuttle will no longer be a significant
|>part of NASA planning. But then, with a man-rated HLV costing far less
|>than the Shuttle and a space station, there is little need ...

|Uh, where is this "man-rated HLV"?  I don't see it in current inventory.

We have three options available to us. All three options could be built
for about the cost of one new orbiter. In the mean time, we have options
to put people up using Delta or Atlas.

|And if it's not, then the Shuttle *does* figure in NASA's plans for this
|decade, at least, and that means replacement orbiters will be needed.

For what? Most of the missions can go up on Titan IV for far less money.
For those missions which must use the Shuttle, we will have four left.

|Maintenance of the shuttle fleet requires an orbiter supply, and said
|maintenance can be abandoned only when the fleet itself is about to be
|abandoned.  That won't happen soon.

All this means is that the transition is beginning now. The HLV will be
available in three to five years.

Is this burning our bridges behind us? To some extent, yes. I think that
is the only way to motivate NASA to make real change. The Shuttle costs
too much and is sucking up all the money which could go to building
cheaper alternatives. Under the current budget situation the choice is
either another orbiter or a HLV, but not both.

    Allen
--
+----------------------------------------------------------------------------+
|Allen W. Sherzer | America does best when it accepts a challenging mission. |
|   [e-mail]   | We invent well under pressure. Conversely, we stagnate   |
|                 | when caution prevails.   -- Buzz Aldrin                  |

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

Date: 13 Jan 91 21:39:20 GMT
From: isis!scicom![e-mail]  (Bruce Watson)
Subject: Re: Salyut 7 burn-up

In article <[e-mail]>, [e-mail] (A.C.Beresford) writes:
> Since it is already in atmosphere the question has no meaning
> It is however an observed fact that re-entring satellites
> have been observed at heights of 109Km in the self-luminous
> phase. You can model the process approximately both
> numerically and analytically ( DG King-Hele Satellite
> orbits in an atmosphere) which gives a figure something
> like 1 day left by time orbit height = 160Km



....and one orbit left at 117 kms.

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

Date: 9 Jan 91 18:26:33 GMT
From: netcom!teda!ditka!mcdchg!tellab5!balr!clrcom![e-mail]  (Bob Martin)
Subject: Re: Planetary Society [Part 2 of 2]

In article <[e-mail]> [e-mail] (John Roberts) writes:
>
>Perhaps some kind person could post the "official position" of the Planetary
>Society on this subject.

I just happen to have a copy of the Planetary Societies "Mars
Declaration" right here.

Mars is the world next door, the nearset planet on which human
explorers could safely land.  Although it is sometimes
as warm as a New England October, Mars is a chilly place, so
cold that some of its thin carbon dioxide atmosphere freezes
out at the winter pole. There are pink skies, fiekdls of boulders,
snad dunes, vast extinct volcanos that dwarf anything on
Earth, a great canyon that would cross most of the United
States, sandstorms that sometimes reach half the speed of
sound, strange bright and dark markings on the surface,
hundreds of ancient river valleys, mountains shaped like
pyramids and many other mysteries.
  Mars is a storehouse of scientific information - important in
its own right but also for the light it may cast on the origins of
life and on the safeguarding the environment of the Earth.  If Mars
once had abundant liquid water, what heppened to it?  How
did a once Earthlike workd become so parched, figid and
comparatively airless?  Is ther something important on Mars
that we need to know about our own fragile world?
  The prospect of human exploratoin of Marse is ecumenical-
remarkable for the diversity of supporting opinion it embreaces.
It is being advocated on many grounds:

-As a potential scientific bonanza-for example, on
climatic change, on the search for present of past life,
on the understanding of enigmantic Martian landforms, and
on the application of new knowledge to understanding
our own planet
- As a means, through robitic precursor and support
missions to Marse, of reviving a stagnant U.S. planetary
program.
- As providing a coherent focus and sense of purpose
to a dispirited NASA for many future research and
development activities on an appropriate timescale and
with affordable costs.
-As giving a crisp and unambiguous purpose to the
U.S. space station - needed for in-orbit assembly of the
interplanetary transfer vehicle or vehicles, and for
study of long-duration life support for space travelers.
- As the next freat human adventure, able to excite and inspire
people of all ages the world over.
- As an apeture to enhanced national prestige and
technological development
- As a realistic and possibly unique opportunity for the
United States and the Soviet Union to work together in
the spotlight of world public opinion, and with other
nations, on behalf of the human species.
- As a model and stimulant for mutually advantageous
U.S. / Soviet cooperation here on Earth.
- As a means for economic reconversion of the aerospace
industry if and when massive reductions in strategic
weapons - long promised by the United States and the
Soviet Union - are implemented.
- As a worthy application of the traditional military
virtues of organization and valor to great expeditions
of discovery.
- As a step towards the long-term objective of establishing
humanity as a multi-planet species.
- Or simply as the obvious response to a deeply felt
perception of the future calling.

Advances in technology now make feasible a systematic
process of exploration and discovery on the planet Mars-
beginning with robot roving vehicles and sample return
missions and culminating in the first footfall of human beings
on another planet.  The cost would be no greateer than that of a
single major strategic weapons system, and if shared among
two or more nations, the cost to each nation would be still
less.  No major additional technological advances seem to be
reuired, and the step from today to the first landing of humans
on Mars appears to be technologically easier than the step
from President John F. Kennedy's announcement of the Apollo
program on May 25, 1961 to the first landing of humans on the
Moon on July 20, 1969.

We represent a wide diversity of backgrounds in the
fields of science, technology, religion, the arts, plitics and
government.  Few of us adhere to every on of the arguments
listed above, but we share a common vision of Mars as a
historic, constructive objective for the technological ambitions
of the human species over the next few decades.


Hope this answers a few questions.

--
+-Robert C. Martin-----+:RRR:::CCC:M:::::M:| Nobody is responsible for |
| [e-mail]    |:R::R:C::::M:M:M:M:| my words but me.  I want  |
| uunet!clrcom!rmartin |:RRR::C::::M::M::M:| all the credit, and all   |
+----------------------+:R::R::CCC:M:::::M:| the blame.  So there.     |

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

End of SPACE Digest V13 #062
*******************