초록 ▼

A method and system for use as a modeling tool accurately estimates propellant remaining aboard a spacecraft at the completion of a transfer orbit by iterating mass flowrate in a linear optimized fashion until the difference between a predicted .DELTA.V and observed .DELTA.V is minimized. Actual fli

A method and system for use as a modeling tool accurately estimates propellant remaining aboard a spacecraft at the completion of a transfer orbit by iterating mass flowrate in a linear optimized fashion until the difference between a predicted .DELTA.V and observed .DELTA.V is minimized. Actual flight pressure telemetry data is used to calculate a corresponding mass flowrate which must have been produced by a liquid apogee motor (LAM) for the spacecraft to reach the desired position. A thruster specific impulse value (ISP) is derived from ground test data to allow computation of the amount of propellant consumed during transfer orbit. When this value is subtracted from the known initial propellant load, the propellant remaining at the beginning of life (BOL) of a satellite can be calculated.

대표청구항 ▼

[ What is claimed is:] [1.] A method for estimating propellant remaining in a spacecraft after the spacecraft has attained a transfer orbit, said spacecraft having a liquid propulsion subsystem, said method comprising:receiving in-flight liquid propulsion subsystem data;determining a measured change

[ What is claimed is:] [1.] A method for estimating propellant remaining in a spacecraft after the spacecraft has attained a transfer orbit, said spacecraft having a liquid propulsion subsystem, said method comprising:receiving in-flight liquid propulsion subsystem data;determining a measured change in velocity based on input ranging data;generating an initial value for mass flowrate;determining a fixed specific impulse value based on input ground acceptance test data;determining a calculated change in velocity based on the fixed specific impulse value and the initial mass flowrate;comparing the calculated change in velocity to the measured change in velocity;adjusting the mass flowrate value and determining a new calculated change in velocity if the prior calculated change in velocity is not within a predetermined range of the measured change in velocity; andestimating the remaining amount of propellant based on the current mass flowrate value if the current calculated change in velocity is within the predetermined range.