[meteorite-list] NASA Mars Reconnaissance Orbiter Reaches Planned Flight Path

[Ron Baalke]

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

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

Erica Hupp/Dwayne Brown 202-358-1237/1726
NASA Headquarters, Washington, D.C.

News Release: 2006-106		      	  	     	September 12, 2006

NASA Mars Reconnaissance Orbiter Reaches Planned Flight Path 
 
NASA's newest spacecraft at Mars has completed the challenging half-year task of 
shaping its orbit to the nearly circular, low-altitude pattern from which it will 
scrutinize the planet. 
 
The Mars Reconnaissance Orbiter fired its six intermediate-size thrusters for 12.5 
minutes Monday afternoon, Sept. 11, shifting the low point of its orbit to stay near 
the Martian south pole and the high point to stay near the north pole.  The altitude 
of the orbit ranges from 250 kilometers (155 miles) to 316 kilometers (196 miles) 
above the surface.

"This maneuver puts us into our science orbit," said Dan Johnston, deputy mission 
manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Getting to this 
point is a great achievement." Challenging activities remain ahead this month, 
such as deploying an antenna 10 meters (33 feet) long and removing a lens cap 
from a crucial instrument. The main science investigations will begin in 
November. During its two-year science phase, the mission will return more data 
about Mars than all previous Mars missions combined. 
 
The flight team for the Mars Reconnaissance Orbiter sent the bus-sized spacecraft 
through the upper fringe of Mars' atmosphere 426 times between early April and 
Aug. 30.  This "aerobraking" technique used friction with the Martian atmosphere 
to gradually decrease the highest-altitude point of the elliptical orbit from 45,000 
kilometers (28,000 miles) to 486 kilometers (302 miles). The lowest-altitude point 
during aerobraking ranged from 98 to 105 kilometers (61 to 65 miles). It was 
carefully managed with input from researchers at JPL; Lockheed Martin Space 
Systems, Denver; NASA Langley Research Center, Hampton, Va., and elsewhere, 
based on spacecraft data and atmospheric fluctuations. 
 
During the first three weeks after it arrived at Mars on March 10, the spacecraft 
took more than 35 hours to fly each very elongated orbit. During the final weeks of 
aerobraking, it was flying more than 10 orbits each day. "The pace of work got 
extremely demanding as we got down to two-hour orbits," Johnston said. "We had 
shifts working around the clock." 

Monday's maneuver was the mission's biggest burn since the 27-minute firing to 
slow the spacecraft enough for Mars' gravity to snare it into orbit on March 10. 
The benefit of aerobraking is to avoid hauling unnecessary fuel to Mars for 
thrusters. Compared with relying solely on thruster firings to shrink and shape the 
orbit, aerobraking cut the mission's fuel needs by about 600 kilograms (about 
1,300 pounds.) At least one small adjustment maneuver is still ahead. 

One key remaining preparation for the mission's science payload is deployment of 
the antenna for the Shallow Subsurface Radar, an instrument provided by the 
Italian Space Agency. The antenna, developed by Northrop Grumman Space 
Technology Astro Aerospace, Carpinteria, Calif., remained safely stowed during 
aerobraking. Later this month, it will be released to unfold itself and extend 5 
meters (16.4 feet) on either side of the spacecraft. After this ground-penetrating 
radar has been checked and calibrated, it "has the potential to detect buried 
channels, buried craters and ice layers," said Dr. Roberto Seu of the University of 
Rome La Sapienza, leader of the instrument's science team. 

During aerobraking, a lens cap protected the mission's mineral-mapping Compact 
Reconnaissance Imaging Spectrometer for Mars. Removal of the cap this month 
will allow researchers to start checking and calibrating the spectrometer's 
performance. "Our most important goal is to find where past environments on 
Mars were wet long enough to leave a mineral signature on the surface," said Dr. 
Scott Murchie of Johns Hopkins University Applied Physics Laboratory, Laurel, 
Md., principal investigator for the spectrometer.

A series of trial observations by all the instruments will complete the spacecraft 
checkouts at the end of the month, including tests of all observing modes. In 
addition to data acquisition by the radar and spectrometer, images will be taken by 
the High Resolution Imaging Science Experiment and the Context Imager. The 
Mars Color Imager and Mars Climate Sounder will also begin monitoring Mars' 
atmosphere. During the next four years, these instruments on Mars 
Reconnaissance Orbiter will examine Mars to learn about processes that have 
affected it and to inspect potential landing sites for future missions. The spacecraft 
will also serve as a communications relay for Mars surface missions. 

Information about the Mars Reconnaissance Orbiter is online at 
http://www.nasa.gov/mro . The mission is managed by JPL, a division of the 
California Institute of Technology, Pasadena, for the NASA Science Mission 
Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime 
contractor and built the spacecraft. 

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