Observed Magnitude and Luminous Efficiency of Reentry Capsule of HAYABUSA Spacecraft

The brightness variation of the sample capsule of the HAYABUSA spacecraft was observed during reentry into Earth's atmosphere on 2010 June 13 UT. The capsule was observed from 13^h52^m01^s through 13^h52^m38^s UT, with three peaks of brightness between 13^h52^m19^s and 21^s UT. The absolute magnitude of the highest peak was -5.7(±0.9) at 13^h52^m18^s.6 UT. The luminous efficiency reached to the largest value of 0.89% (+1.14%, -0.50%) at a time corresponding to an altitude of 58.1 km above sea level.