Feb. 24, 2006

Dwayne Brown/Erica Hupp 
Headquarters, Washington 
(202) 358-1726/1237 

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

RELEASE: 06-082

NASA'S ORBITER NEARS RED PLANET RENDEZVOUS

NASA's Mars Reconnaissance Orbiter is nearing a crucial milestone. The 
spacecraft is preparing to slow itself to allow the red planet's 
gravity to grab it into orbit on March 10. 

"Once the spacecraft has successfully been placed in position, this 
mission will greatly expand our scientific understanding of Mars, 
pave the way for future robotic missions later in this decade, and 
help us prepare for sending humans to Mars," said NASA's Director of 
the Mars Exploration Program Doug McCuistion.

Designed to examine the planet in unprecedented detail, the orbiter 
will return more data than all previous Mars missions combined. 
Before the orbiter can begin its mission, it will spend approximately 
six months adjusting its orbit with an adventurous process called 
aerobraking.

The initial capture by Martian gravity will put the orbiter into an 
elongated, 35-hour orbit. The planned orbit for science observations 
is a low-altitude, nearly circular, two-hour loop. Aerobraking will 
use hundreds of carefully calculated dips into the upper atmosphere, 
deep enough to slow the spacecraft by atmospheric drag, but not deep 
enough to overheat the orbiter, to gain the desired orbit.

"Aerobraking is like a high-wire act in open air," said Jim Graf, 
orbiter project manager at NASA's Jet Propulsion Laboratory, 
Pasadena, Calif. "Mars' atmosphere can swell rapidly, so we need to 
monitor it closely to keep the orbiter at an altitude that is 
effective and safe." 

As the orbiter nears Mars March 10, ground controllers expect a signal 
shortly after 4:24 p.m. EST indicating the critical engine burn to 
place it into low orbit started. The burn will end during a 
suspenseful 30 minutes, with the orbiter behind Mars and out of radio 
contact. 

The orbiter carries six instruments that will produce data for 
studying Mars from underground layers to the top of the atmosphere. 
They include the most powerful telescopic camera ever sent to another 
planet; it will reveal rocks the size of a small desk. An advanced 
mineral-mapper will be able to identify water-related deposits in 
areas as small as a baseball infield. Radar will probe for buried ice 
and water. A weather camera will monitor the entire planet daily. An 
infrared sounder will monitor atmospheric temperatures and the 
movement of water vapor.

"We're especially interested in water, whether it's ice, liquid or 
vapor," said Richard Zurek, Jet Propulsion Laboratory orbiter project 
scientist. "Learning more about where the water is today and where it 
was in the past will also guide future studies about whether Mars 
ever supported life."

The orbiter can transmit data to Earth at approximately 10 times the 
rate of any previous Mars mission. It will use a 10-foot diameter 
dish antenna and a transmitter powered by 102 square feet of solar 
cells. Scientists will analyze the information to gain a better 
understanding of changes in Martian atmosphere and the processes that 
formed and modified the planet's surface. 

In addition to its own investigation of Mars, the orbiter will relay 
information from future missions working on the surface of the 
planet. During its planned five-year prime mission, it will support 
the Phoenix Mars Scout being built to land on icy soils near the 
northern polar ice cap in 2008, and the Mars Science Laboratory, an 
advanced rover under development for launch in 2009. 

For information about NASA and agency programs on the Web, visit: 

http://www.nasa.gov/home 

For Information about the Mars Reconnaissance Orbiter on the Web, 
visit: 

http://www.nasa.gov/mro 

The mission is managed by the Jet Propulsion Laboratory, a division of 
the California Institute of Technology, Pasadena, for NASA's Science 
Mission Directorate. Lockheed Martin Space Systems, Denver, built the 
spacecraft and is the prime contractor.

	
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