Accelerations experienced during low-G flight of Black Brant VC (NAS 21.015) on 4 October 1974

This investigation was to determine whether a Black Brant VC (BBVC) sounding rocket equipped with the Goddard Space Flight Center (GSFC) rate control system (RCS) would produce g-levels which are satisfactory for space processing. Accelerations measured by the Marshall Space Flight Center (MSFC) low-g accelerometer system (LGAS) were compared with accelerations calculated from measured payload RCS gyro data during a low-g flight of BBVC NAS 21.015 at White Sands Missile Range, N.M., on October 4, 1974. Accelerations of up to 0.0002 g existed at the LGAS accelerometers from 70 through 420 sec (5.8 min), with the exception of a spike at 101 sec of 0.0004 g which occurred when the RCS was activated the second time. Accelerations of 0.0001 g existed from 140 through 400 sec (4.3 min). Accelerations of 0.0002 g along the roll axis up to 150 sec and of 0.0015 g in the lateral plane at about 135 sec are being investigated by GSFC. They may be associated with leaking thruster valves or a leak in one of the heat pipe experiments. The vehicle rate buildup each time after the RCS nulls out are also being investigated by GSFC. This rate caused most of the 0.0001 g acceleration experienced after 150 sec into the flight. Aerodynamic drag produced no significant accelerations after about 80 sec. The principal conclusion was that the BBVC with the GSFC RCS produces g-levels satisfactory for space processing.