The spatial temperature and atomic number density of the plume generated by
a 3-kW-class arcjet thruster are determined with a small number of absorpt
ion measurements across the plume based on diode-laser absorption computeri
zed tomography. The maximum temperature and atom number density increase wi
th the massflow rate and discharge current. The increase trend is not alway
s found with the specific input power, although there exists an increasing
trend with it at a fixed massflow rate. The development of the plume is stu
died with the measurements of the plume at different locations. The techniq
ue should also be applicable to arcjet or other hypersonic flow systems wit
hout much modification.