Mars-Bound NASA Craft Tweaks Course, Passes Halfway Point
NASA's Mars Reconnaissance Orbiter successfully fired six engines
for about 20 seconds today to adjust its flight path in advance of
its March 10, 2006, arrival at the red planet.
Image right: Artist's concept of Mars Reconnaissance Orbiter en route to Mars. Image credit: NASA/JPL + Browse version of image
Since its Aug. 12 launch, the multipurpose spacecraft has covered about
60 percent of the distance for its trip from Earth to Mars. It will fly
about 40-million kilometers (25-million miles) farther before it enters
orbit around Mars. It will spend half a year gradually adjusting the shape
of its orbit, then begin its science phase. During that phase, it will
return more data about Mars than all previous missions combined. The spacecraft
has already set a record transmission rate for an interplanetary mission,
successfully returning data at 6 megabits per second, fast enough to fill
a CD-ROM every 16 minutes.
"Today's maneuver mainly increases the speed to bring us to the target point
at just the right moment," said Tung-hanYou, chief of the Mars Reconnaissance
Orbiter navigation team at NASA's Jet Propulsion Laboratory, Pasadena, Calif.
The intended nudge in velocity is 75 centimeters per second (less than 2 miles
per hour). The spacecraft's speed relative to the sun is about 27 kilometers
per second (61,000 miles per hour).
Four opportunities for course adjustments were planned into the schedule before
launch. Today's, the second, used only the trajectory-correction engines. Each
engine produces about 18 newtons (4 pounds) of thrust. The first course adjustment,
on Aug. 27, doubled as a test of the six main engines, which produce nearly eight
times as much thrust. Those main engines will have the big job of slowing the spacecraft
enough to be captured into orbit when it reaches Mars. The next scheduled trajectory adjustment, on Feb. 1, 2006, and another one 10 days before arrival will be used, if?necessary, for fine tuning,
said JPL's Allen Halsell, the mission's deputy navigation chief.
The Mars Reconnaissance Orbiter mission will examine Mars in unprecedented detail from low
orbit. Its instrument payload will study water distribution -- including ice, vapor or
liquid -- as well as geologic features and minerals. The orbiter will also support future
missions to Mars by examining potential landing sites and by providing a high-data-rate
relay for communications back to Earth.
The mission is managed by JPL, a division of the California Institute of Technology,
Pasadena, for the NASA Science Mission Directorate. Lockheed Martin Space Systems, Denver,
is the prime contractor for the project and built the spacecraft.
For information about the Mars Reconnaissance Orbiter on the Web, visit http://www.nasa.gov/mro
For information about NASA and agency programs on the Web, visit http://www.nasa.gov/home/index.html
Guy Webster (818) 354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
Dwayne Brown (202) 358-1726
NASA Headquarters, Washington??