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.
"Our [spacecraft] was designed specifically for aero braking," Lock said. MRO is designed to take much hotter temperatures than it will actually face. "We can take a lot of heat."
The science part of the mission will begin around mid-November, said Candice Hansen, deputy principal investigator from JPL.
This is what the spacecraft was really built for with a high-resolution camera that will send back images more detailed than ever before. Many instruments will work together to keep MRO on a close orbit to the planet and send back data to Earth. The optimum achieved orbit will allow the spacecraft to take images of one area every 17 days. In the past, images were sent back however the orbit took longer and sometimes scientists could not review that specific area again for two to three months. The time lapse with MRO is only 17 days.
"We will get stereo images within a month," Hansen said.
Scientists each have specific area of Mars they think should be studied first, Hansen said. Hansen's point of interest is the planet's terrain.
"In the south cap we see little spots that develope. They turn into fans," Hansen explained. Hansen has plans to set up a website where anyone can make suggestions on what scientists should study on Mars. She knows the suggestions will vary from sensible to absurd but the web site will be a way to open the mission up to the world.
The March 10 orbit landing can be observed on NASA TV on the JPL web site at www.jpl.nasa.gov.