[meteorite-list] NASA's Mars Orbiter Makes Successful Course Correction

[Ron Baalke]

Dolores Beasley
Headquarters, Washington                         August 30, 2005
(Phone: 202/358-1753)

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

RELEASE: 05-236

NASA'S MARS ORBITER MAKES SUCCESSFUL COURSE CORRECTION

NASA's Mars Reconnaissance Orbiter (MRO) successfully tested its 
main engines by making a successful trajectory adjustment for 
reaching the red planet on March 10, 2006.

The spacecraft fired all six main thrusters for 15 seconds on 
Saturday. The engine burn followed a 30-second burn of six smaller 
thrusters, which settled propellant in the craft's fuel tank for 
smoother flow. The spacecraft's orientation was adjusted prior to 
the burns to point the engines in the proper direction for the 
maneuver. The MRO returned to the regular cruise-phase attitude 
after the trajectory adjustment. 

"This maneuver accomplished two goals at once," said Mars 
Reconnaissance Orbiter Deputy Mission Manager Dan Johnston of 
NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif. "It 
adjusted our trajectory toward our Mars target point, and it gave 
us a valuable checkout of the orbit-insertion engines." The 
target point is 395 kilometers (245 miles) above the surface of 
Mars. 

Initial analysis of navigational data indicates this first flight 
path correction successfully changed the spacecraft's velocity by 
the intended 7.8 meters per second (17.4 mph). MRO's velocity 
relative to the sun is 32,856 meters per second (73,497 mph). 

The six main engines won't be used again until the craft arrives 
at Mars. The next burn will last about 25 minutes. It will slow 
the MRO enough for the planet's gravity to capture the spacecraft 
into orbit. Each main engine produces approximately 38 pounds of 
thrust. The three remaining opportunities scheduled for 
fine-tuning the trajectory before March will use smaller engines. 
Each smaller engine produces approximately five pounds of thrust. 

"We intentionally designed the initial trajectory after launch 
with a bias in it, so this first correction maneuver would be 
large enough to let us use the main engines," Johnston said.

The next milestone for the MRO mission is today. MRO will turn on 
its instruments to check their condition. The spacecraft was 
launched Aug. 12, and it is in excellent health. MRO has traveled 
approximately 6 million kilometers (3.7 million miles) since launch. 
It has 95.9 million kilometers (59.6 million miles) still to fly 
before reaching Mars.

The MRO mission will examine Mars in unprecedented detail from low 
orbit. Mission science objectives include studying water 
distribution, including ice, vapor or liquid; geologic features 
and minerals. It will also support future missions to Mars by 
examining potential landing sites and by providing a 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 MRO 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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