Mars Reconaissance Orbiter Ready To Go To Work

Updated 9/30/06
Photo links repaired, additional links and photo added 11/26/07

Launched August 12, 2005, NASA's Mars Reconnaissance Orbiter has finally been positioned to begin its task. The orbiter, weighing 2,273 pounds plus a propellant payload of 2,533 pounds, fired it’s thrusters for 27 minutes last March 10th to slow it enough to be captured by Mars’ gravity and swing it into orbit.

This original 35 hour elliptical orbit took the craft as far away as 28,000 miles from the surface to distances as close as 61 miles, where it dipped into the Martian atmosphere in a maneuver called aerobraking. The drag on the space-craft during these encounters eroded this orbit during 426 revolutions until the high point was reduced to 302 miles and an orbit time of 2.4 hours.

This aerobraking maneuver allowed a reduction of about 1,300 lbs. Of propellant over what would have been required if the orbit placement was done with thrusters only.

Six intermediate sized thrusters were fired Monday Sept. 11th for 12.5 minutes to place it in its working orbit of 155 miles near the South pole and 196 miles above the North pole.

The craft was placed into orbit atop a 188 foot tall Atlas V-4012 stage launch vehicle. This version does not use solid fuel booster engines.

The Atlas first stage, weighing 627,000 lbs. at launch uses a Russian built engine powered by liquid oxygen and a rocket fuel similar to kerosene..
This stage operates for about four minutes providing 900,000 pounds of thrust accelerating the spacecraft to about 10,000 miles per hour and an altitude of about 71 miles.
After firing, the first stage separates and falls back into the Atlantic Ocean.

Then the second stage, a Centaur engine, takes over and burns for nine and one half minutes to place the craft into a parking orbit of about 115 miles. The craft then coasts for about 33 minutes as the Centaur positions it for its mission and rotates it to keep it from overheating.
Then over the Indian ocean it fires again for ten minutes to send the craft out of Earth orbit and on its way to Mars.

The next step is to unfold the 33 foot antenna for the Shallow Subsurface Radar, an Italian Space Agency built instrument developed by Northrup Grumman, a California space technology company. This is a ground penetrating radar which will be used to search for water and ice below the surface of the planet.

Another instrument, The High Resolution Imaging Science Experiment, is a high resolution telescopic camera working in both the visible and near-infrared spectrums. With a resolution of 1-2 feet it is capable of imaging items as small as 4 feet across from an altitude of 125 miles. The near-infrared camera will help analyze mineral content of the soil.

Other instruments include a Compact Reconnaissance Imaging Spectrometer , used in the analysis of the soil, and the Mars Climate Sounder to research the atmosphere.

The orbiter will be sending data at the rate of 0.5 to 4 megabits per second for 10-11 hours each day during its 700 day mission. The total amount of data will be over 4 terrabytes - the equivalent of 6,500 compact disks, or as much as 20 times more data than all of the previous planetary missions combined.

Update 9/30/06:

The HiRISE camera has sent back this image of a portion of the Valles Marineris canyon.
This canyon would stretch from Los Angeles to New York city if it were on Earth.
Click on image to enlarge.


Here is the full extent of the Valles Marineris canyon.


Much more at NASA's Mars Reconaissance Orbiter


Additional images from the HIRISE Camera can be found HERE.