Abstract: An amount of propellant remaining in an orbiting satellite can be estimated in a more accurate manner than is possible with conventional approached. Pressure and temperature telemetry data received from the satellite can be analyzed using a maximum likelihood estimation approach that reconstructs a predicted tank pressure signal using the temperature data and determines a pressurant volume necessary to make the reconstructed pressure signal match the received pressure signal. Drift of the pressure data received from pressure transducers in the satellite can also be addressed using the current subject matter, as can issues including but not limited to inaccessible propellant due to satellite spin, tank expansion under pressure, and the like. Independent determinations of the amounts of propellant remaining can be made using moment of inertia calculations in situations in which an axis of spin of the satellite is known a priori.