1. For Odyssey, the orbit lifetime was defined as the time between any given apoapsis and the first apoapsis for which the altitude is predicted to be less than 300 km altitude. (This is consistent with the MGS definition2.) Odyssey was required to maintain a mean lifetime of greater than or equal to 24 hours. The Project also required a 99% low lifetime of greater than 8 hours to accommodate a worst-case Deep Space Network outage that prevented spacecraft commanding. LaRC Monte Carlo analysis indicated that the 99% limit was automatically satisfied by the mean requirement since a 24 hour mean lifetime yields approximately a 15-18 hour 99% low lifetime.
2. Four additional propulsive maneuvers were used to further raise periapsis altitude, perform a minor adjustment to inclination (in conjunction with the second periapsis raise maneuver to save fuel), and further reduce apoapsis altitude in order to achieve the desired science orbit. All maneuvers were successfully executed permitting the science mapping phase of the mission to commence as planned on February 19, 2002.
3. "MarsGlobalSurveyor:AerobrakingMissionOverview,"D.Lyons,J.Beerer,P.Esposito,M.Johnston,W.Willcockson,Journal of Spacecraft and Rockets, Vol36, No3, May-June 1999.