In the next few days the Mars Orbit Insertion (MOI) sequence will commence on the spacecraft. Most commands will be performed autonomously (without the need for commanding from Earth). However, there are two ground command opportunities still available to alter the spacecraft's flight path, if necessary, in order to raise altitude for its first pass at Mars. These altitude raise decisions will be made by the project at about 24 hours and 6 hours prior to MOI, in close coordination with the navigation team and the navigation advisory group. Right now we don't expect to need an additional maneuver because of how well the spacecraft is flying.
On Sunday evening, MAVEN will slew (turn) to point the main engines in the direction of travel and fire for about 33 minutes in order to slow down the spacecraft enough to "capture" into Mars orbit. Although we have direct line of sight of MAVEN during the entire burn sequence, the observed data back on Earth will actually be viewed 12 minutes after the events occur because of the distance between Earth and Mars. For more details, check out the MAVEN MOI video.
As we approach the last few days before arriving at Mars, you might be interested in the following events:
•Pre-MOI Press Conference at NASA Headquarters: Sept. 17 at 1 p.m. EDT
•Live Television Coverage of the MOI Event: Sept. 21 from 9:30 p.m. to 10:45 p.m. EDT
•Post-MOI Press Conference at Lockheed Martin, Denver: Sept. 21, approximately 2 hours after MOI
All of these events can be watched on the "NASA Channel" on your cable or satellite TV system, or by visiting NASA TV.
As of Sept. 15, the spacecraft is 134 million miles (216 million kilometers) from Earth and 1.2 million miles (2 million kilometers) from Mars. From that distance, Mars as seen by MAVEN is the same size as a baseball as seen from 73 feet away. MAVEN's velocity is 50,174 miles per hour (22.43 kilometers per second) as it moves around the sun.
David F. Mitchell, MAVEN Project Manager at NASA's Goddard Space Flight Center, Greenbelt, Maryland