UPDATE # 14 - December 11, 1996
PART 1: Teachers: Send us Pictures!
PART 2: Mars Pathfinder Launch
PART 3: Pathfinder Mission Status Report
TEACHERS: SEND US PICTURES!
Live From Mars is really about students taking an active role in
studying Mars. We'd like to get pictures of your students at work on
Mars issues and/or samples of their work. For ideas on this, go to
The following information is intended to help you in submitting your
materials for posting to the Live From Mars Web site. If you have any
further questions, contact Linda (email@example.com) directly.
If it is text:
Send it in the body of an email message to: firstname.lastname@example.org
If it has pictures or diagrams:
It is always our hope that material that comes from the classroom
can be graphically represented on the Web. There are several choices:
If it already exists in electronic form, you can try enclosing the
pictures in a MIME-compliant mail message (if you are familiar with
how to do that...using an email package like Eudora or Pine), or
We can FTP it from a location you specify, or
If it is already on a Web page, we can simply point to it.
Please send Linda a note either with the goodies or with
instructions on how to get at the material (FTP site of Web address).
If these fancy digital techniques won't work:
Black and white diagrams can be FAXed to Linda Conrad at (415)
604-1913, or material can also be sent via U.S. postal mail to the
following address: Linda Conrad, NASA Ames Research Center,
Mailstop T28H, Moffett Field, CA 94035.
Any text should be in electronic format. Photos and art will be
returned if you like.
We would very much like to feature the work of your students on our
NASA site. But we can only display your work if you send it....so
[Editor's note: Donna Shirley is the manager of the Mars Exploration
Program. Donna manages three flight projects and studies of future
missions to Mars. Everyday she deals with scientists trying to
understand Mars, and with the technology we need to go to Mars
without costing a lot.]
MARS PATHFINDER LAUNCH
Donna Shirley - http://quest.arc.nasa.gov/mars/team/shirley.html
December 6, 1996
Another perfect launch for the Mars missions! We are now two for
two thanks to the wonderful Delta rocket built by the McDonnell
Douglas Corporation of Huntington Beach, California. The Kennedy
Space Center launch facility crew and the Goddard Space Flight
Center Office of Launch Systems who procure the Delta also were
The launch happened on the third opportunity, December 4, at 1:58
a.m. EST. The launch period actually opened on December 2, but the
weather was so bad that they decided at 8 a.m. to cancel the
attempt for that day. On December 3 many of us went out to the
launch pad to watch the gantry roll back. This was supposed to
happen at 5 p.m. but didn't actually occur until 7:30 p.m. It got colder
and colder, and there was a prelaunch party scheduled. Gradually,
people trickled away to the party. A few diehards, including me,
Howard Eisen of the rover team, Tom Shaw of the Pathfinder team,
and Dave Murrow of the Mars Surveyor 98 team, were all that were
left to see the rocket standing free of the supporting structure. It
was worth waiting for, shining in the spotlights, gleaming
blue and white.
Later that night, out at the launch control center, I was sitting at a
console with Wes Huntress, head of NASA science; Wes's
deputy, Earl Huckins; Ed Stone, the JPL director; and the Director of
the Kennedy Space Center. At the consoles you can hear all the cross
talk of the launch vehicle people, the spacecraft people, the weather
people, and the range managers. They have big-screen t.v. displays in
the front of the room so you can see the vehicle, the weather data,
the spacecraft team, and other views.
Everything was counting down to a 2:03 a.m. launch. But it wasn't our
day. First, the winds aloft looked bad. The range sent up balloon
after balloon to see what the winds were like, and gradually they
began to improve. By the fourth balloon they looked acceptable and
we all began to get excited. But there was another problem. One of
the ground computers that keeps track of the telemetry from the
propulsion system on the launch vehicle kept having problems. After
much discussion the launch vehicle team decided to change to a
backup computer. But about 2 minutes before the launch time, that
computer had trouble also, and the launch was scrubbed.
Everyone sagged. We'd been running on adrenaline, not a bit sleepy,
but once there was no launch everyone who could went home to bed.
The poor launch team had to shut down the vehicle safely and get
ready for tomorrow.
Just after I got to bed at 3 a.m. I got a call from the "Today" show
saying they still wanted to have me live on their show at 7 a.m. the
next day. Then, they called again at 6 a.m. saying, "No, we'd rather
have you on the morning after a successful launch." Grrrrrr. I finally
got back to sleep, only to get a call at 10 a.m. from some people in
Washington D.C. who needed some information. After that, I had
lunch, did some work, then took a nap until about 10 p.m. and went
back out to the launch control room.
This time everything was going smoothly. The wind was light, the
weather was clear, and they had fixed the balky ground computer.
Everything ticked down. This time I watched the displays until about
30 seconds to launch, then ran outside with Wes, Earl and Ed to see
There was a building between us and the launch pad, but suddenly the
sky lit up like sunrise. "There she goes!" yelled someone, and within
a couple of seconds the fireball rose over the building and streaked
through the sky. The roar of the rocket shook us a couple of seconds
later. The rocket formed a giant arc through the sky, heading for a
fat crescent moon hanging above us like the Cheshire cat's grin. Mars
was a red dot above and to the left of the moon. The Delta's six solid
rocket motors dropped off and twirled glowing through the sky like
fireworks. Then the rocket slid past the edge of the moon (from our
perspective) and disappeared.
I went back and watched the events tick off the schedule. MECO (Main
engine cut-off), Second engine start, SECO, acquisition by the
tracking stations. Everything was perfect.
I went over to the SAEF-2 building where the JPL spacecraft launch
team was waiting for contact with the spacecraft, an event
scheduled for an hour and a half after launch. The team was all
wearing identical Pathfinder t-shirts and sitting in front of
consoles with their headsets on. Everything was quiet because there
was nothing the team could do until the spacecraft separated from
the launch vehicle and had its radio signal acquired by the Deep
We waited. We watched the screens. Guy Beutelschies, the
Pathfinder test conductor, was relaying messages from the launch
control site. Acquisition of launch vehicle telemetry by the ARIA
aircraft which relay telemetry when the ground stations can't see
the vehicle. Third Stage firing and cutoff. Shroud deployment. And
finally, spacecraft separation. Pathfinder was on its own.
Silence. Then a single number changed on the list of spacecraft
telemetry parameters on the consoles. "We have a packet," shouted
Guy. That meant that the spacecraft was talking to the Deep Space
Network. Still, everyone waited. Suddenly, a lot of numbers changed!
"We've acquired the spacecraft!" Then there were cheers from the
whole spacecraft team. They had done it!
After celebrating for awhile with the team, I went out to the
Kennedy Space Center press site, where Tony Spear (the Pathfinder
project manager) and I were on a panel talking to the few diehard
reporters still up at 4:30 a.m.
By 5 a.m. I was sitting in the press room giving an interview to a
newspaper reporter. After a great breakfast in the Kennedy
cafeteria, with a lot of sleepy cameramen and public information
people, I did a live interview for the "Today" show on NBC. They
wanted it outside with the huge Vehicle Assembly Building in the
background. (A "signature shot," they said). I shivered through a
interview in the chilly dawn wind. It turned out I was
competing with myself because I was also on a tape run by "Good
Morning America" on ABC!
That evening, there was a long piece on the Pathfinder mission on
the "Jim Lehrer News Hour" on PBS. And Pathfinder got lots of other
press coverage. The best picture was one by Reuters which was a
time-lapse picture of the arc of the rocket streaking from the
launch pad past the moon.
We're on our way. Wish us luck.
P.S. For a really cool series of launch pictures taken from Jetty
Park, about 1 3/4 miles south of the launch pad, go to
PATHFINDER MISSION STATUS REPORT
December 10, 1996
The Mars Pathfinder spacecraft continues to perform nearly
flawlessly on its 203 million kilometer (126 million mile) flight
path to Mars. Currently the spacecraft is 1.8 million kilometers (1.1
million miles) from Earth, traveling at a speed of 3.2 kilometers per
second (7,155 miles per hour). Temperatures and power utilization
of the lander and cruise stage remain at predicted levels for this
early phase of the mission.
The spacecraft's sun sensors are the only issue being watched
closely on an otherwise beautifully performing spacecraft, the
flight team reported. There are five sun sensor heads on board the
spacecraft, two pointed along the craft's spin axis and three that are
equally spaced around the circular cruise stage that look out at
about 105 degrees from the spin axis. Of the five sensor heads, unit
#4 on the spin axis is obscured or contaminated to the point of not
being useful. Sensor #5, which is also on the spin axis, is providing
good sun orientation data, but at a lower voltage than was expected.
The other three sensor heads are working fine.
The flight team at JPL uploaded a software modification to the
spacecraft on Saturday, December 7, which allowed the on-board
attitude control system to use the sun sensor data from sensor #5 in
its normal calculations of the spacecraft's orientation. The software
patch was successful and the team was exuberant to see the
spacecraft's attitude control estimators operating properly.
The team then began to prepare for turning the spacecraft more
toward Earth to improve the telecommunications link. At the time,
Pathfinder was about 58 degrees from the Earth, which is near the
edge of the antenna's performance. Since this was to be the first
time flight controllers used the propulsion module, they planned a
small turn of two degrees to verify that everything was working
properly. Thirty minutes later, they planned to turn the spacecraft
an additional 20 degrees.
"The turn maneuvers were conducted successfully on Monday morning
[December 12]," said Brian Muirhead, Pathfinder flight system
manager. "The propulsion and attitude control systems worked
properly and the spacecraft's spin axis is currently pointed about 44
degrees from the Sun and 37 degrees from Earth. The downlink
performance improved as expected and we continue to communicate
with Pathfinder at 1,185 bits per second."
The flight team is planning its next maneuver to spin the spacecraft
down from 12.3 rpm to 2 rpm. The maneuver will be performed in the
next few days, Muirhead said. Pathfinder's first trajectory
correction maneuver remains on schedule, to take place on January
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