ISS (Ionospheric Sounding Satellite)
ISS (Ionospheric Sounding Satellite) 1 and 2 were a pair of Japanese satellites, launched by NASDA (National Space Development Agency) and also known by their national name Ume ("plum"), that collected data on the ionosphere to aid in short-wave radio communication. Their instruments included an ionospheric sounder, a radio noise receiver, plasma measuring equipment, and an ion mass spectrometer. Both measured 3.9 by 0.8 m and were launched by N-1 rockets from Tanegashima.
|spacecraft||launch date||orbit||mass (kg)|
|ISS 1||Feb 26, 1976||988 × 1,003 km × 69.7°||139|
|ISS 2||Feb 16, 1978||973 × 1,216 km × 69.4°||140|