PART 1: Join us on Mars in July
PART 2: Mars Pathfinder Weekly Status
PART 3: Mars Global Surveyor Flight Status
PART 4: Subscribing & Unsubscribing: How to
JOIN US ON MARS IN JULY!
This summer provides a once-in-a-lifetime opportunity to connect students
and families to NASA's Mars Pathfinder Mission to the Red Planet. On July
4 there'll be fireworks on Mars. Early that morning, retro-rockets will
slow the Mars Pathfinder spacecraft, and sometime during the evening of
Independence Day, you should see the first new Martian surface images in
over 20 years radioed back from an alien explorer newly arrived on the Red
And, thanks to modern telecommunications and an unprecedented
collaboration of NASA, the National Science Foundation, museums, space
interest groups, and media producers, you and your students can
participate in planetary exploration more directly than ever before.
Passport to Knowledge (PTK) and the American Museum of Natural History in
New York will present two, two-hour Live From Mars specials: live,
interactive TV programs to be offered via satellite on Sunday July 6 and
Wednesday July 9, from 14:00-16:00 Eastern (11:00-13:00 hours Pacific).
The free, unencrypted programs will be carried on GE-2, transponder 21,
C-band, 85 degrees West, 4120 MHz, vertical polarity, audio on 6.2 and
6.8. (This is the same satellite where NASA-TV may be found, and will
likely be easily accessible to many schools, museums and science centers.)
The Live From Mars Web site provides extensive background on the mission
and links to other valuable Mars sites. The Live From Mars Teacher's Guide
provides suggestions for hands-on activities you can undertake before
school ends to prepare students so they will appreciate the events of this
summer. The 64-page guide includes the following easy-to-integrate
activities plus 13 more:
Mars Mission Logbook
Mission Planning: Earth/Mars Comparisons
Rocket Science 101
Mapping Topography of Unknown Surfaces
Light Bulb Egg-Drop Challenge
for more details.
Sunday July 6 will not only feature the events of the first two days on
Mars, the best color enhancements of the first pictures returned, and a
chance to hear NASA scientists' first reactions, but also The Planetary
Societys "Planetfest" -- a combination Star Trek convention and
celebration of space exploration and scientific discovery, promising a
good time for all! To be held in Pasadena, California, just a few miles
from the Jet Propulsion Laboratory (JPL) from July 4-6, we plan to link
"Planetfest" in via video to JPL, New York, and many other live locations
around the nation. It's hoped that CU-SeeMe, Real Audio and other Internet
technologies will also share "Planetfest" and the events of "Landing Week"
with those unable to access satellite TV.
Though primarily designed for participation by youngsters, families and
camp groups in science museums and planetariums (since school is "out" in
most places), anyone with access to a movable satellite dish can access
the programming. Many science centers are already planning events around
Pathfinder's landing. We expect many will integrate Live From Mars into
this, but we can't promise or predict. Please check locally and if your
local museum doesn't yet know about what's going on, please share what YOU
know with them, and direct them to our Web site, which will have
increasingly detailed information.
Live From Mars fall programming includes two, hour-long telecasts as we
continue to track the Mars Pathfinder and Mars Global Surveyor missions to
Mars. Broadcasts are carried on NASA-TV, PBS's main satellite, Telstar
402R and many PBS stations around the country. Live From Mars# 4: "With
Pathfinder to Mars ," will be aired October 14, 1997 at 13:00-14:00 EST.
Follow the Pathfinder's travels from launch through landing in the new
school year (97-98) and prepare your kids for Live From Mars #5: "Today on
Mars," scheduled to be broadcast November 18, 1997 at 13:00-14:00 EST.
Live From Mars Web Site: http://quest.arc.nasa.gov/mars
Call 1-908-273-4108 for more information.
Stay tuned and use Live From Mars to link directly to the very latest from
the Red Planet!
Mars Pathfinder Weekly Status Report
[Editor's note: This status report was prepared by the Flight Operations
Manager, Mars Pathfinder Project, NASA Jet Propulsion Laboratory.]
May, 16 1997
The spacecraft remains in good health and is currently about 115 million
kilometers from Earth (26 million km from Mars). The only major spacecraft
activity performed this week was a battery heating and solar array
characterization test. The total flight time since launch is now 163 days,
and we have 49 days until Mars arrival.
Successfully completed the Entry, Descent, and Landing (EDL) and Surface
Operations Readiness Review. The review board, led by Mike Sander, asked
many useful questions and generated several advisories, but agreed that
the project will be ready for pre-entry and surface operations by July 4.
Completed the second of three EDL Operations Readiness Tests (ORT). This
test used the testbed to simulate all pre-EDL operations, including
TCM-5a. In addition, we conducted a simultaneous EDL communications ORT
using the actual spacecraft to simulate the telecom behavior during EDL.
Several members of the EDL data acquisition team traveled to Madrid to
support this test. Although a number of lessons were learned during the
ORT, both the data acquisition and pre-EDL operations teams completed the
Completed a set of surface operations mini-ORTs which tested our strategy
for petal movements after landing, end-to-end image processing and rover
target designation, and the ramp deployment decision process. These three
issues were among the most significant concerns in ORT #5, and appear to
be resolved at this point.
For further information, please visit our website at http://mpfwww.jpl.nasa.gov
Mars Global Surveyor Flight Status Report
[Editor's note: This status report was prepared by the Office of the
Flight Operations Manager, Mars Surveyor Operations Project, NASA Jet
May 16, 1997
This week, flight team members concentrated their efforts on determining
what event caused the Mars Global Surveyor spacecraft to enter safe mode
early in the morning on May 8. Since then, Surveyor has been operating in
a configuration that ensures that the spacecraft has adequate power,
thermal and communications margins. Flight software on the spacecraft
automatically commands entry into this safe mode if it detects an
unexpected event in one or more of Surveyor's subsystems.
One of the major diagnostic activities involved commanding the spacecraft
to transmit portions of its computer memory back to Earth for analysis. An
examination of a region of memory called the Audit Queue revealed that
entry into safe mode occurred when a flight software task timed out and
failed to report back to Surveyor's central processor.
Each software task executed by Surveyor's computer is allocated a certain
amount of time to complete. Time-outs occur when a task fails to complete
in the allocated time. Members of the flight team at the Lockheed Martin
facility in Denver traced the source of this time-out to an infinite loop
that occurred in flight software. A time-out resulted because infinite
loops are impossible to complete.
The infinite loop resulted from the corruption of an area of computer
memory called the Active Script Table. This table contains a list of
programs executed by Surveyor's central processor, and corresponding links
to the locations in computer memory where those programs are stored. A
software task that was executing prior to safe-mode entry caused the
infinite loop when it incorrectly updated one of the entries in the table
by linking that entry back to itself.
Over the last few days, engineers on the flight team reproduced the
safe-mode entry conditions in the spacecraft simulator. Subsequent
analysis indicates that the action that created the infinite loop is
uncommon, but predictable. Consequently, the Flight Operations Manager has
decided to allow the flight team to begin procedures that will return the
spacecraft back to its normal operating state. Once recovery is complete,
the flight team will transmit modifications to Surveyor's flight software
that will prevent this infinite loop condition from occurring again.
Recovery operations may begin as early as Wednesday, May 21.
In other news not related to safe-mode operations, the flight computer
powered down gyroscope #2 on Tuesday, May 13. This power down occurred
automatically when the electrical current used by the gyroscope exceeded a
preset limit. Gyro #2's functions were automatically assumed by Gyro #1
and #3, the transition was smooth, and there is no performance degradation
with respect to Surveyor's ability to point at targets in space. The
powered-down gyroscope will be reactivated after normal operations
After a mission elapsed time of 190 days from launch, Surveyor is 110.33
million kilometers from the Earth, 31.07 million kilometers from Mars, and
is moving in an orbit around the Sun with a velocity of 23.29 kilometers
per second. This orbit will intercept Mars 118 days from now, slightly
after 6:00 p.m. PDT on September 11 (01:00 UTC, September 12). Although
the spacecraft is currently operating in safe mode, all systems are
functioning properly, and no spacecraft hardware problems exist that pose
a threat to the mission.
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