Live From Mars was active July 1996-December 1997.
ANSWERING THE CHALLENGE!
Last week in CQ #4: GO TELL IT ON THE MOUNTAIN, we asked:
Olympus Mons is the highest feature on Mars. What is its counterpart
on Earth? Be forewarned: it is not Mount Everest!
If you measure Mauna Kea, Hawaii, from ocean floor to peak, you will
find that it is higher than Mt. Everest, Nepal -- about 30,000 feet
compared to Everest's 29,000 feet.
In last week's BONUS QUESTION we asked:
If you think about how astronomers measure the height of features
on Mars, you'll have a clue to help you answer this question. What do
For Mars, astronomers use the "datum level" -- the reference surface at
which atmospheric pressure is 6.1 millibars (the pressure at the triple
point of water) -- to give a baseline for measurement of altitude. On
Earth we use sea level, but as CQ#3 reminded us, that would currently be
impractical to do on Mars -- though some astronomers think there may once
have been an ocean on Mars, or at least lakes of liquid water, now lost to
space or locked in permafrost.
NEW CHALLENGE FOR THE WEEK
CQ #5: BRUSH UP ON YOUR GREEK!
There is a letter of the Greek alphabet that is very important both to
launching NASA's current Mars missions and to getting to Mars. What
is that letter? Also, explain how it is used.
You are invited to send original student answers to:
email@example.com. Please include the words CHALLENGE
QUESTION in the subject line of your email. The kids' names will be
listed online and token prizes will be given to those will the best
Answers are due within seven full days of Challenge Question
posting. (e.g. If a CQ is posted on April 18, answers are due by
midnight PDT on April 24.)
A list of answers from all students who submitted them will be
posted on the Live From Mars Web site soon.
APRIL WEBCHAT SCHEDULE
Wed. April 23, 9 a.m., PDT: Guy Beutelschies, test director for the
Mars Pathfinder spacecraft, Jet Propulsion Laboratory, Pasadena,
Calif. Guy's job involves leading a team that tests the spacecraft to
make sure everything works!
Tues. April 29, 10 a.m., PDT: Bridget Landry, deputy uplink systems
engineer, Mars Pathfinder, Jet Propulsion Laboratory, Pasadena,
Calif. Bridget teaches computers on the ground to speak the same
language as the Mars Pathfinder.
ONLINE CHAT WITH FAMOUS WOMEN
Female leaders from a broad spectrum of professions have been
invited to participate in NASA's second annual Virtual Take Our
Daughters to Work Day on Thurs. April 24 from 6 a.m. - 4 p.m., PDT.
To view the schedule, profiles and registration information go to the
Women of NASA Web site at
LIVE BROADCAST REMINDER!
Mark your calendars for Thurs. April 24 when Passport to Knowledge
will be broadcasting, live, "Cruising Between the Planets."
LOOKING FOR STUDENT QUESTIONS
For the April 24 Live From Mars broadcast, there may be time to
feature student questions that are submitted before the broadcast.
Student questions should relate directly to the themes covered in
this broadcast: Mars Global Surveyor, Mars Pathfinder and Sojourner,
navigation and trajectory maneuvers, and careers.
Questions may be submitted to firstname.lastname@example.org no later than Sun.
April 20! Include student's name, grade, school, town and state. Also,
send a copy of the question to: email@example.com
PATHFINDER MISSION STATUS
[Editor's note: This status report was prepared by the Office of the
Flight Operations Manager, Mars Pathfinder Mission, NASA Jet
11 April 1997
The spacecraft remains in good health and is currently about 71
million kilometers from Earth. The only spacecraft activities
performed this week were a regular ASI/MET health check, a Heat
Rejection System Pump B cycle, and some modification to Attitude
Control Subsystem fault protection parameters. The total flight
time since launch is now 128 days, and we have 85 days until Mars
We successfully completed an operational readiness test of all
activities from Mars entry -2 days through Sol 2. This test was
performed using the Pathfinder Testbed and Mars Sandbox. The Mars
approach phase included periodic updates to the Entry, Descent, and
Landing flight software parameter set and execution of a
contingency Trajectory Correction Maneuver #5. We are
investigating a minor problem which occurred during airbag
retraction, which did not significantly effect the test. The surface
operations test included a planned failure of the High Gain Antenna
and subsequent Low Gain Antenna operations.
GLOBAL SURVEYOR FLIGHT STATUS
[Editor's note: This status report was prepared by the Office of the
Flight Operations Manager, Mars Surveyor Operations Project, NASA
Jet Propulsion Laboratory.]
Friday, 11 April 1997
This week, the Mars Global Surveyor science team received an
unexpected bonus from the Sun due to a solar flare eruption that
took place on Monday. Eruptions of solar flares occur when
disturbances deep within the Sun's interior cause streams of
electrically charged atomic particles to be ejected from the solar
surface. These charged particles move through the solar system at
speeds in excess of 1,000,000 kilometers per hour.
In order to allow the science team to study this event, the flight
team sent commands to Surveyor that enabled the spacecraft to
record solar flare data gathered from the Magnetometer science
instrument. These commands activated the spacecraft's data
recorders late Wednesday afternoon, about half a day before the
stream of charged particles from Monday's eruption reached
Surveyor. Although past occurrences of solar flares have both
disrupted space communications and damaged spacecraft, Monday's
eruption was relatively mild in comparison. The Mars-bound
Surveyor spacecraft sustained no damage from the solar flare. Late
Thursday afternoon, the navigators on the project canceled the
trajectory correction maneuver that was planned for later this
month. This maneuver would have refined the flight path to Mars by
slightly altering the spacecraft's speed and velocity. However,
analysis showed that this month's maneuver involves a velocity
change of only 40 millimeters per second (less than one-tenth of a
mile per hour). The maneuver was canceled because with such a
small velocity change, the errors in executing the maneuver are
comparable to the size of the maneuver.
This canceled maneuver would have been the third of four planned
maneuvers during the journey to Mars. The first two occurred in
November 1996 and March 1997. The fourth trajectory correction
maneuver will take place on August 25, 1997.
Yesterday marked the halfway point in the journey to Mars with
respect to time of flight. As of April 10, Surveyor has completed
154 of the 308 days required to reach the red planet. The halfway
point in terms of distance between the Earth and Mars occurred last
week on Monday, March 31. This difference in halfway dates arises
from the fact that the positions of the two planets constantly
change during the spacecraft's journey to Mars.
After a mission elapsed time of 155 days from launch, Surveyor is
68.43 million kilometers from the Earth, 48.55 million kilometers
from Mars, and is moving in an orbit around the Sun with a velocity
of 24.98 kilometers per second. This orbit will intercept Mars 153
days from now, slightly after 6:00 p.m. PDT on September 11 (01:00
UTC, September 12). The spacecraft is currently executing the C6
command sequence, and all systems continue to be in excellent
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