Two basic methods for mass determination are: (1) direct measurement, (2) volume and density determination. Both methods or variations have been used to determine space vehicle propellant mass with varying degrees of success. Stringent propellant loading accuracy requirements of k0.5 percent for the Saturn S-IV Stage have led to the development of a Cryogenic Calibration Weigh System. The method employs accurate electronic force transducers and measuring systems as the standard and experimental weighings have verified achievement of better than the required accuracy.
