Mars Orbiter to Arrive at Red Planet March 10

For those who have been impressed with what scientists have learned about Mars so far ? scientists from JPL-NASA with the Mars Reconnaissance Orbiter think they haven't seen anything yet.

The Mars Reconnaissance Orbiter is due to arrive on Mars at 1:25 p.m. March 10.

This mission will provide information for a landing site for the Phoenix Mars Scout, a spacecraft that will land in an icy area of Mars near the north polar ice cap. Its primary mission is to study the history of water on the planet. It will provide data on a landing position for the Mars Science Laboratory, planned launch for 2009. The lab will operate for one Martian year, 687 Earth days, and travel a much larger area than the rovers that are on the planet now. It may also provide information for scientists on landing areas for future manned landings.

MRO launched on Aug. 12, 2005 on its 300,000-million-mile trip to Mars. As of last Friday it was only 15 million miles away from its destination. The spacecraft has had a smooth ride thus far without any major problems. In fact the team performed two trajectory change maneuvers instead of the four planned. As MRO approaches the planet the risks become greater.

"We are getting into the dangerous portion of the mission," said Jim Graf, MRO project manager from JPL.

The dangerous part concerns the beginning phases of achieving orbit around Mars. The first part of that phase is firing the thrusters for 30 minutes. This is critical because if it doesn't fire correctly the spacecraft could fly right past the planet. For 21 of those minutes scientists at JPL will be able to monitor the spacecraft and it then goes behind the planet and out of the scientists cosmic reach. Then for another 30 minutes MRO will continue behind the planet and scientists will hold their collective breaths.

This is the part of the mission where scientists have lost two spacecrafts in the last 15 years. They have a 65-percent success rate of landing orbiters, Graf said.

After the thrusters engage and MRO is in a Mars orbit the phase of beginning the seven-month process of slowing the spacecraft down by skimming Mar's atmosphere, called aero braking.

"We have done aero braking on three different missions," said Robert Lock, lead mission planner at JPL.

He explains that Mar's atmosphere is not smooth. The atmosphere changes seasonally. MRO will also have to deal with sand storms and temperature change.