O-> O-> O-> O-> O-> O-> O-> O-> O-> O-> O-> O-> O-> O-> O-> O->
THE INTERNATIONAL MARSWATCH ELECTRONIC NEWSLETTER
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Volume 2; Issue 4 (file imw.feb97)
February 1997
Circulation: 661
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HAPPY MARS APHELION!
CONTENTS---------------------------------------------------------
- Latest telescopic images of Mars continually arriving -
- Mars Pathfinder Web user statistics -
- 1996-97 HST Mars images available on-line -
- Mars Pathfinder successfully launched and on its way -
- Mars Global Surveyor cruise proceeding -
- Mars '96 Launch ends in tragedy -
- List of MarsWatch-related WWW pages and addresses -
- -
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Latest Mars telescopic images continue to arrive in the MarsWatch archive
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A number of observers from around the world have begun posting
their CCD images and drawings of Mars on the MarsWatch WWW
archive page (WE THANK YOU!!). These images provide the most
up-to-date information available on the state of the Martian
surface and atmosphere (some images are even posted on the day
after the observations were made!). Much of Mars is chilled to
its lowest temperatures because the planet is at aphelion, or
its farthest point from the Sun. Most observers are reporting
extensive equatorial and orographic (mountain-related) cloud
activity, as well as the continuing retreat of the north polar
cap as the northern hemisphere of Mars transitions into summer.
No global dust activity has been reported, although occasional
evidence for local dust storms has been reported by several
observers as well as the Hubble Space Telescope (HST). To view
or download images from the archive, go to URL:
http://mpfwww.jpl.nasa.gov/mpf/marswatch_images.html
Mars Pathfinder Web user statistics
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Total number of accesses = 323335
Total number of visits = 21447 (visit = group of accesses separated by 180s.)
Total number of bytes transferred = 2174134321 (2.17 Gb)
Number of files accessed on this server = ~400
Highest number of hits per day = 1/30: 53124
Lowest number of hits per day = 2/1: 40142
MPF-Status E-mail list: 3407 subscribers
Access per day = 46190
Visits per day = 3063
1996-97 HST Mars images available on-line
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HST has been imaging Mars between September 1996 and January 1997
as part of a long-term monitoring program by Phil James and
colleagues. Color composites of these HST images can now be
found on-line at the URL:
http://marswatch.tn.cornell.edu/hst96-97.html
Because of the upcoming Space Shuttle servicing mission to HST,
no more HST Mars observations are being planned until mid- to
late-March, right around opposition. Thus, there is an important
need for high-quality groundbased observations to fill this gap
in HST time coverage.
Mars Pathfinder successfully launched and on target
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The Mars Pathfinder spacecraft was successfully launched from
Cape Canaveral on a Delta rocket in the early morning hours of
December 4. The launch was spectacular and completely "nominal"
in NASAspeak. The spacecraft successfully performed its first
two trajectory correction maneuvers, and is proceeding on course
for a July 4 landing in the mouth of the Ares/Tiu Valles outflow
channel on Mars. On February 3, Trajectory Correction Maneuver
#2 was successfully completed. The purpose of this maneuver
was to clean up TCM-1 execution errors and had a magnitude of
about 1.6 m/s. The maneuver consisted of two parts, an axial
component of 1.5 m/s and a lateral component of 0.1 m/s. All
spacecraft subsystems performed as expected, and the resulting
maneuver execution error was less than 2%. The spacecraft was
turned back to Earth after the maneuver, and will remain in
this attitude until late March. Congratulations to the
Pathfinder team for a great start to the mission!
Distances and Velocities of MPF as of: 1997-FEB-06 12:00:00 UTC:
DISTANCE TO EARTH DISTANCE TO SUN DISTANCE TO MARS
19389695.116 km 166862135.249 km 112007028.707 km
12048197.972 mi 103683323.919 mi 69597940.967 mi
GEOCENTRIC VELOCITY HELIOCENTRIC VELOCITY AREOCENTRIC VELOCITY
5.323 km/sec 30.064 km/sec 16.698 km/sec
11908.018 mph 67250.962 mph 37351.903 mph
TIME TO MARS: -148d 04:51:11.0
ONE-WAY LIGHT TIME: 00:01:04.7
DISTANCE TRAVELED SINCE INJECTION: 178352044.5156 km (110822822.4963 mi)
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HELIOCENTRIC ORBIT - EARTH MEAN EQUATOR AND EQUINOX OF J2000 FRAME
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Epoch of Osculating Orbital Elements
1997 MAR 01 00:00:00.000 UTC JD 2450508.5000
1997 MAR 01 00:01:02.185 ET JD 2450508.5007
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Semi-major axis 193216491.013 km
120059161.380 mi
1.29157246771 AU
Eccentricity .236386
Inclination 23.455 degrees
Longitude of Ascending Node .258 degrees
Argument of Perihelion 71.347 degrees
Time from Perihelion Passage 7566827.988 sec
Orbital Period 536.138 days
Mean Motion .77716308E-05 degrees/sec
True Anomaly at Epoch 85.152 degrees
Mean Anomaly at Epoch 58.807 degrees
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HELIOCENTRIC ORBIT - EARTH MEAN ORBIT AND EQUINOX OF J2000 FRAME
===========================================================================
Epoch of Osculating Orbital Elements
1997 MAR 01 00:00:00.000 UTC JD 2450508.5000
1997 MAR 01 00:01:02.185 ET JD 2450508.5007
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Semi-major axis 193216491.013 km
120059161.380 mi
1.29157246771 AU
Eccentricity .236386
Inclination .104 degrees
Longitude of Ascending Node 81.222 degrees
Argument of Perihelion -9.639 degrees
Time from Perihelion Passage 7566827.988 sec
Orbital Period 536.138 days
Mean Motion .77716308E-05 degrees/sec
True Anomaly at Epoch 85.152 degrees
Mean Anomaly at Epoch 58.807 degrees
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More details and progress on the mission can be found at:
http://mpfwww.jpl.nasa.gov/
Mars Global Surveyor cruise proceeding
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The Mars Global Surveyor spacecraft continues to perform well on
its cruise to Mars. The latest estimate for orbital insertion
date is September 12, 1997. Flight engineers continue to
experiment with ways to resolve the slight misalignment of one
of the spacecraft's solar panels, even though this misalignment
is not thought to threaten the success of the mission. The
initial checkout of the MGS science instruments went well, with
no anomalies reported. Check out their new webpage for more
details, see:
http://mgs-www.jpl.nasa.gov/mgs-home.html
Mars '96 Launch ends in tragedy
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The Mars exploration program had a major setback in November as
the Russian Mars '96 mission ended in failure hours after
launch, when the spacecraft failed to attain Earth orbit. The
detailed explanation for the launch failure has not yet been
determined. Scientists from Russia, many ESA member states, and
the U.S. were involved in the ambitious project. Given the
financial hardships in Russia and other nations, it is not clear
whether enough funding can be secured to mount a follow-on
recovery mission for many years.
List of MarsWatch-related WWW pages and addresses
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Here is a list of some of the URLs that you can link to in order
to find more information and background on Mars and the
MarsWatch project:
1996-97 MarsWatch Web site:
http://mpfwww.jpl.nasa.gov/mpf/marswatch.html
MarsWatch Goals:
http://astrosun.tn.cornell.edu/marsnet/imw/marswatch96.info
HST Observations and MarsWatch:
http://mpfwww.jpl.nasa.gov/mpf/hst.html
1996-97 HST Mars images:
http://marswatch.tn.cornell.edu/hst96-97.html
Other 1996-97 Mars images:
http://marswatch.tn.cornell.edu/mars.html
1994-95 HST Mars image archive:
http://marswatch.tn.cornell.edu/hst_archive.html
1994-95 MarsWatch Web site:
http://astrosun.tn.cornell.edu/marsnet/mnhome.html
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Jim Bell and Bob Anderson
Editors, IMW Newsletter
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