Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V13_3/V13_308.ZIP/V13_308

Internet Message Format | 1991-06-28 | 19KB

Return-path: <[e-mail]>
X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson
Received: from hogtown.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/[e-mail] (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests)
          ID </afs/andrew.cmu.edu/usr1/ota/Mailbox/sbwMnLC00WBwQ6:U5Z>;
          Thu, 28 Mar 91 01:27:35 -0500 (EST)
Message-ID: <[e-mail]>
Precedence: junk
Reply-To: [e-mail]
From: [e-mail]
To: [e-mail]
Date: Thu, 28 Mar 91 01:27:28 -0500 (EST)
Subject: SPACE Digest V13 #308

SPACE Digest                                     Volume 13 : Issue 308

Today's Topics:
       MAJOR SOLAR FLARE ALERT - 21 MARCH - TWO EVENTS
             Re: Galileo asteroid imaging
        Re: Gailileo asteroid photo techniques
           Jonathan's Space Report, Mar 19
          Request for spacecraft positions.
              Galileo Update - 03/22/91
              Info on the future
              Station Atmosphere

Administrivia:

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

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

Date: Fri, 22 Mar 91 02:11:55 MST
From: [e-mail] (CARY OLER)
Subject: MAJOR SOLAR FLARE ALERT - 21 MARCH - TWO EVENTS
X-St-Vmsmail-To: st%"[e-mail]"

                        --  MAJOR SOLAR FLARE ALERT  --

                                MARCH 21, 1991

                              Flare Event Summary
                          Potential Impact Assessment


                                    --------



MAJOR ENERGETIC EVENT SUMMARY

     Two major flares erupted from Region 6555 on 21 March.  The first
began at 20:17 UT, peaked at 20:31 UT and ended at 20:34 UT on 21 March.
It was located at S13E29 and attained a class X1.0/1N rating.  It was
associated with rather weak radio bursts and had a low integrated x-ray
flux.  This event was impulsive.  No sweeps were observed.

     The second major flare began at 23:35 UT, peaked at 23:44 UT on 21
March, and ended at 00:01 UT on 22 March.  This event attained a class
M5.4/2B rating and was associated with a fairly strong Type IV event.
However, this flare was impulsive as well.

     Region 6555 (now located at S24E30) remains impressive and is the
largest and most complex region currently visible.  Spot counts have
increased to 75 in this region, which still maintains a magnetic beta
configuration.


POTENTIAL TERRESTRIAL IMPACT ASSESSMENT

     The first major flare (the X-class event) will not have a terrestrial
impact.  It was a high-amplitude event in x-rays, but has not produced any
significant radio emissions and was quite impulsive.

     The second major flare is still being studied and the potential
impacts will not be fully known until later on 22 March.  It presently
appears as though a small risk exists for a light terrestrial impact
(mostly over the higher latitudes) sometime on 24 March.  However, this
flare was not radio rich.  The only truly noteworthy phenomena associated
with this flare was the moderate to strong intensity Type IV which
accompanied the flare.  The integrated x-ray flux of this flare was low.
So there is a higher probability that no terrestrial impacts will be
observed.  A more accurate assessment will be released on 22 March after
all of the data has been analyzed.

     Isolated major flaring will likely continue from Region 6555 over the
next 24 to 72 hours.  Minor M-class flaring will certainly continue at a
fairly frequent rate.  Associated minor SIDs/SWFs could cause momentary
disruptions in HF radio communications.  A total of seven SID's/SWF's were
observed (some are unconfirmed at the present time) on 21 March, associated
with the fairly frequent M-class flaring from Region 6555.

     A period of minor geomagnetic storming occurred between 12:00 UT and
15:00 UT over middle latitudes.  This period was preceded by a sudden impulse
which occurred near 06:00 UT on 21 March over some middle latitude stations.
Locally, the only significant perturbation occurred at 13:45 UT and was
rated as a minor storm level fluctuation with a fairly rapid rise-time and
slow decay.  High latitudes experienced active to severe storming during
this period.  Some high latitude auroral storming was also noted in
conjunction with this increased geomagnetic activity.  It is difficult to
pinpoint the cause of this activity, as there were several events which may
have been responsible.  However, at the present time, it appears as though
the major class M6.7/2B flare of 19 March is most likely responsible.  Auroral
activity remained confined to the high and northerly middle latitudes.  HF
radio conditions during this period of storm activity was degraded to
generally poor levels over middle latitudes and very poor levels over the
high latitudes.  Conditions improved rapidly after 16:00 UT, as did
geomagnetic activity over the middle latitudes.

     A bulletin stating the potential impacts of the last major M-class
flare will be issued later on 22 March.  The POTENTIAL MAJOR SOLAR FLARE
WARNING and the POTENTIAL SATELLITE PROTON EVENT WARNING remain in effect.
Geomagnetic activity should remain at unsettled to active levels over the
next 24 hours.  Auroral activity will remain at low to moderate levels over
the middle and/or northerly middle latitudes on 22 March, with moderate to
high levels of activity likely over the high latitudes.  Low latitudes will
not witness any auroral activity.


**  End of Alert  **

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

Date: 22 Mar 91 08:15:13 GMT
From: theory.tn.cornell.edu![e-mail]  (Jeff Moersch)
Subject: Re: Galileo asteroid imaging

In article <[e-mail]> [e-mail] writes:
>be well known in time. The strategy will be to take as many redundant frames
>as possible with different image motion compensation rates, in order to get
>at least a few frames with very little smear. At least, that was the plan in
>November. The lightcurve variations suggest a complex shape, and the images

As of the February imaging team meeting at Caltech, the current strategy for
closest approach is not to have totally redundant frames.  The problem is that
the error ellipse for Gapra's location is very large (larger than an image
frame), so if the frames were all pointed exactly alike, they could all
completely miss the asteroid.  To deal with this, there is a mosaic sequence
planned which will cover the entire ellipse (I forget to how many sigma).

Jeff Moersch
[e-mail]

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

Date: 20 Mar 91 11:41:43 GMT
From: theory.tn.cornell.edu![e-mail]  (Jeff Moersch)
Subject: Re: Gailileo asteroid photo techniques

In article <[e-mail]> [e-mail] (Jonathan Leech) writes:
>In article <[e-mail]>, [e-mail] (Magnus Olsson) writes:
>|> How "close" is 1000 miles in this context - i.e. what kind of resolution will
>|> the images have? Will they be comparable ith e.g. Voyager's pictures of
>|> Miranda?
>
>    Which leads me to wonder: is the ``exposure time'' for the Galileo
>CCDs much shorter than the Voyager vidicons?  Either way, will the
>Target Motion Compensation technique developed for Voyager be useful
>when zipping by such a close target?
>--

My Galileo SSI camera specs are 400 miles away right now, but a back-of-the-
envelope using number from memory gave me a resolution of something in the
low tens of meters per pixel.  I don't recall right now what is planned in
terms of image motion compensation - when I get back to my office on Monday
I can post it to the net if anyone is interested.  One thing I definitely
do recall from the last SSI team meeting is that it was decided *not*
to spend the propellant to turn around and look at Gaspra after we pass
by.  That kind of maneuver (called a "SCITURN") would have cost something
like 1/20th of the currently budgeted fuel surplus (we have to save for
Jupiter).  However, the engineers are known to be very conservative with
those surplus estimates, so perhaps if we go to Ida and want to turn around,
we'll then have the chance.

Jeff Moersch
[e-mail]

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

Date: 20 Mar 91 15:56:28 GMT
From: magnus.acs.ohio-state.edu!zaphod.mps.ohio-state.edu!usc!elroy.jpl.nasa.gov!freedom!xanth![e-mail]  (Jonathan McDowell)
Subject: Jonathan's Space Report, Mar 19


Jonathan's Space Report

Mar 19 1991 (no.68)
----------------------------------------------------

Launch of STS-37/Atlantis and the Gamma Ray Observatory
remains due for early April. Atlantis is on pad LC39B.

Viktor Afanas'ev and Musa Manarov continue in orbit aboard the
Mir/Kvant/Kvant-2/Kristall/Soyuz TM-11/Progress M-6 complex.
More spacewalks are planned in the next month. Manarov now
holds the record for cumulative time spent in space.

Kosmos-2136 was launched on Mar 6 by Soyuz from Plesetsk.
It is in a reconaissance satellite type orbit, but seems
to have unusually low drag as its orbit is decaying rather
slowly.

A classified Department of Defense satellite, USA-69 = 1991-17A
was launched by a Titan IV rocket from Space Launch Complex 4-East
at Vandenberg AFB, California on Mar 8. Press reports claim
that the satellite is a Lacrosse radar imaging satellite.
___________________________________
|Current STS status:              |
|Orbiters                         |
|                                 |
|OV-102 Columbia        OPF Bay 1 |
|OV-103 Discovery       OPF Bay 2 |
|OV-104 Atlantis        LC39B     |
|                                 |
|ML/ET/SRB stacks                 |
|                                 |
|ML1/STS-37/ET/OV-104   LC39B     |
|ML2/STS-39/ET          VAB Bay 3 |
|ML3/STS-40             VAB Bay 1?|
-----------------------------------

10 years ago:  19 Mar 1981  The Progress-12 cargo craft undocked from
the Salyut-6 space station and was deorbited over the Pacific.

20 years ago:  21 Mar 1971  The first of the NSA's JUMPSEAT
electronic intelligence satellites was launched by a Titan IIIB/Agena D
rocket from Vandenberg into highly elliptical orbit.

30 years ago: 24 Mar 1961. A Redstone rocket was flown on the
Mercury-Redstone Booster Development (MR-BD) flight, a final test
of the Mercury-Redstone launch vehicle prior to Alan Shepard's piloted
flight.

(c) 1991 Jonathan McDowell. Information in this report is obtained
from public sources and does not reflect the official views of NASA.

 .-----------------------------------------------------------------------------.
 |  Jonathan McDowell                 |  phone : [phone]                 |
 |  Space Science Lab ES65            | uucp:                                  |
 |  NASA Marshall Space Flight Center | bitnet :                               |
 |  Huntsville AL 35812               |  inter : [e-mail]  |
 |  USA                               |   span : ssl::mcdowell                 |
 '-----------------------------------------------------------------------------'

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

Date: 22 Mar 91 17:34:43 GMT
From: bu.edu!transfer!lectroid!STRATUS.COM![e-mail]  (Mark Adam)
Subject: Request for spacecraft positions.

I was wondering if somebody could mail me the coordinates and velocity
vectors for the apacecaft that are currently traveling thoughout the
solar system. I'm interested in all of the current missions. I'd prefer
the information in xyz format. I'll also need a time reference. I'm
going to add this information the information about the position of the
planets that was recently posted.

Thanks in advance.

mark ------------------------

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

Date: 22 Mar 91 18:02:15 GMT
From: usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov![e-mail]  (Ron Baalke)
Subject: Galileo Update - 03/22/91


                           GALILEO STATUS REPORT
                               March 22, 1991

     As of noon (PST) Thursday, March 21, 1991, the Galileo spacecraft is
35,826,900 miles from the Earth and traveling at a heliocentric speed of
68,380 miles per hour; distance to the Sun is 110,452,750 miles (1.2 AU).
Round trip light time is 6 minutes, 24 seconds.

     The spacecraft status as of end of day of March 21 was as follows:

        o System Power Margin - 75 watts
        o Spin Configuration - Dual-Spin - cruise mode
        o Spin Rate/Sensor - 3.15 rpm/star scanner
        o Spacecraft Attitude Sun Point Angle - approximately
          4.5 degrees (leading) plus or minus 0.3 degree
        o Downlink telemetry rate/antenna - 40 bps/LGA-1 (Low Gain Antenna)
        o General Thermal Control - all temperatures within
          acceptable range
        o RPM Tank Pressures - all within acceptable range
        o Orbiter Science- all powered off except HIC, DDS,
          MAG, EUV and UVS
        o Probe - powered off, temperatures nominal
        o CMD Loss Timer Setting - 240 hours
          Time To Initiation - 216 hours

     A NO-OP command was successfully sent on March 18 to reset the Command
Loss Timer to 240 hours, its planned value for this mission phase.

     Cruise Science Memory Readouts (MROs) were successfully performed for the
EUV (Extreme Ultraviolet Spectrometer), MAG (Magnetometer) and DDS (Dust
Detector) instruments on March 15.  The third of seven planned UVS (Ultraviolet
Spectrometer) Lyman Alpha data collection activities was also completed on
March 15.

     A 17-degree SITURN was successfully completed on March 15.  The turn
resulted in the spacecraft leading the sun by about 10 degrees; spacecraft
performance throughout this activity was normal.

     The spacecraft successfully completed its first HGA (High Gain Antenna)
correct activity while in celestial cruise mode; spacecraft performance was
normal and no unexpected events were observed.

     The TCM-9B (Trajectory Correction Maneuver) sequence was sent to the
spacecraft on March 19.  Prior to maneuver execution, the EPD (Energetic
Particle Detector) was powered on and stepped from sector position 4 to 0, the
minimum contamination location.  Subsequent to the maneuver, the EPD was
repositioned back to Sector 4.

     The TCM 9-B was performed on March 20 and consisted of one portion
employing a single positive Z burn segment followed by two lateral burn
segments.  Spacecraft performance throughout the manuever activity was normal.
RPM (Retro Propulsion Module) pressures and temperatures were near predicted
levels; the regulator remained closed and thruster temperature profiles
observed were similar to other burns.  However, after the final lateral burn,
the regulator opened at about 17.1 bar, near the predicted level.  The
spacecraft experienced some small attitude and spin rate change (1.5 mrad and
.033 rpm, respectively) during the positive Z burn.  No sequence commanded
attitude correction was made but a spin correction was made.  At the end of
the lateral burn segment, sequence planned attitude and spin rate corrections
were made.  Preliminary radio navigation data indicates the positive Z burn
was about 1 percent high; the lateral burn was also high but estimated to be
less than 0.5 percent.  Better trajectory data will be available after more
tracking data is collected.

     The AC/DC bus imbalance measurements exhibited some activity.  The AC
imbalance reading fluctuated about 2 DN and now reads 45.2 volts; the DC
measurement dropped from 10 volts to 1.5 volts (82 DN) on March 15 and has
subsequently gradually increased and now reads about 5.5 volts.  The large
drop occurred more than an hour after a spacecraft thruster firing.  Nearly
coincident with bus imbalance change, the -X RTG temperature transducer
measurement also changed.  Other power-related telemetry and subsystem related
telemetry are normal.  Throughout the maneuver activity on March 20, the AC
and DC bus imbalance measurements were fairly stable and fluctuated about
1-2 DN.

     Commands were sent on March 20 to power off the UVS supplemental heater
to provide more power margin for RPM thermal control.  Additionally, Delay
Action Commands (DACs) were sent to power off the UVS heater again on April 10
after it is turned on by stored sequence control.

     The Ground Data System (GDS) Test Plan for Joint JPL and German Space
Operations Center (GSOC) testing was published and formal interface testing has
started.  The JPL Data Management Team (DMT) has received for validation a
sample Experiment Data Record (EDR) produced by GSOC from data received from
the Galileo spacecraft during a post Earth demonstration track with the German
Weilheim Tracking Station.  GSOC will later merged this data with DSN (Deep
Space Network) data supplied by the DMT and a set of test Low Rate Science
(LRS) Fields and Particles (F&P) EDRs and Supplementary EDRs (SEDRs) will be
generated for final validation by the Principal Investigators.  Other interface
products are also being systematically produced, transferred, and validated as
part of the interface testing currently in process.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|      Ron Baalke         | [e-mail]
     | | | |  __ \ /| | | |      Jet Propulsion Lab |
  ___| | | | |__) |/  | | |___   M/S 301-355        | Change is constant.
 /___| | | |  ___/    | |/__ /|  Pasadena, CA 91109 |
 |_____|/  |_|/       |_____|/                      |

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

Date: 22 Mar 91 18:51:29 GMT
From: psuvm![e-mail]
Subject: Info on the future

I plan to do an informative speech on NASA's future projects and missions.  I'm
 asking anyone that is willing to E-mail the latest info on Space Station Freed
om, Lunar Bases, Manned Mars Missions, Civilian Space Travel and any suggestion
s for topics.  I'd also like to find some related magazine articles.  So if any
one has read any good ones E-mail the title and magazine it appeared in.

Thanks in advance,

Jason Koszarsky, JBK4@PSUVM

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

Date: 21 Mar 91 17:35:15 GMT
From: rochester!kodak!acadia![e-mail]  (Vance Cochrane)
Subject: Station Atmosphere

I have a general question.  When the soviets are up in their Mir for many months
at a time, how is the atmosphere provided? Do they cart it up every so often
(sounds doubtful) or do they ( or we for that matter ) use some sort of chemical
regeneration?

thanks in advance.

--------------------------------------------------------------------------------
Vance E. Cochrane CFII               "Say, Can we get some approaches around
Eastman Kodak Company                 here?"
Rochester, New York
--------------------------------------------------------------------------------

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

End of SPACE Digest V13 #308
*******************