[meteorite-list] Mars Reconnaissance Orbiter Tweaks Course, Passes Halfway Point

[Ron Baalke]

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109.  TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov

Guy Webster (818) 354-6278
Jet Propulsion Laboratory, Pasadena, Calif. 

Dwayne Brown (202) 358-1726
NASA Headquarters, Washington  					

News Release: 2005-164	  		November 18, 2005

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. 

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-Han You, 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 .

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