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The Okina relay subsatellite (RSAT), part of the Kaguya mission, is similar to the Ouna VRAD satellite, an octagonal cylinder 0.99 x 0.99 x 0.65 m in size with a mass of 53 kg. A dipole antenna protrudes from the top center of the subsatellite and four small S-band patch antennas are mounted on the spacecraft, two on the top deck and two on the bottom. The spacecraft is spin-stabilized at 10 rpm and has no propulsion units. Power is provided by a 70 W Si solar cell array covering the sides of the satellite which charges a 13 AH, 26 V NiMH battery. The relay subsatellite contains one X-band and three S-band VLBI radio sources and a transponder and will relay the 4-way Doppler ranging signal between a ground station and the orbiter for the far side gravity field investigation from a 100 x 2400 km orbit. Okina impacted the Moon on 12 February 2009 at 28.213 N, 159.033 W.

Alternate Names

  • 32055
  • RSAT

Facts in Brief

Launch Date: 2007-09-14
Launch Vehicle: H-2A
Launch Site: Tanegashima, Japan

Funding Agency

  • Japan Aerospace Exploration Agency (Japan)


  • Planetary Science

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
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