Pulsed thrust measurements using electromagnetic calibration techniques

A thrust stand for accurately measuring impulse bits, which ranged from 10-1000 mu Ns using a noncontact electromagnetic calibration technique is described. In particular, a permanent magnet structure was designed to produce a uniform magnetic field, and a multiturn coil was made to produce a calibration force less than 10 mN. The electromagnetic calibration force for pulsed thrust measurements was linear to the coil current and changed less than 2.5 parts per thousand when the distance between the coil and magnet changed 6 mm. A pulsed plasma thruster was first tested on the thrust stand, and afterward five single impulse bits were measured to give a 310 mu Ns average impulse bit. Uncertainty of the measured impulse bit was analyzed to evaluate the quality of the measurement and was found to be 10 mu Ns with 95 parts per thousand credibility. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3567803]