KAGUYA (SELENE) Relay Satellite / VLBI Radio Source Instrument
ODE: Moon
Mission: KAGUYA (SELENE)
Search KAGUYA Relay Satellite / VLBI Radio Source data in Lunar ODE: Product Search
The KAGUYA's Relay Satellite / VLBI Radio Source (RSAT/VRAD) instrument measures the distribution of lunar gravity fields.
RSAT plans satellite to satellite Doppler measurement by using relay sub-satellite (Rstar) to the main orbiter behind the Moon. A complete coverage of Doppler tracking from the orbiter at sufficient low altitude will significantly improve lunar gravity model and will contribute for future geophysical study of interior and tectonics on the Moon. RSAT is a communication subsystem on the Rstar for 4-way Doppler tracking among the main orbiter, the Rstar, and Usuda Deep Space Center as well as 2-way range and Doppler measurements between the Rstar and UDSC. Two transponders, RSAT-1 and RSAT-2 are installed in the Rstar and the main orbiter.
VRAD mission measures angular distances between two radio sources (VRAD-1 and VRAD-2) onboard Rstar and Vstar orbiting the Moon, and Quasars by differential VLBI. VRAD improves accuracy of selenodetic parameters particularly spherical harmonics of the lunar gravitational field by one or two orders in cooperation with 4-way Doppler measurements and 2-way Doppler and ranging measurements between the main orbiter and the Rstar. A VLBI ground network with 2000 km baseline can determine a phase delay with the accuracy of 3.3 ps for using carrier wave of X-band (8.4GHz) with 0.17 rad. (10 degrees) sensitivity, which is equivalent to the accuracy in angular distance of 5.3 × 10-10 (1.1 × 10-4arcsec) or about 20 cm on the Moon.
ODE supports the search, exploration, and download of KAGUYA RSAT/VRAD Derived data products.
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Data Set |
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These datasets include gravity field map, power spectrum of spherical harmonic coefficients of lunar gravity model, covariance matrix of lunar gravity model, spherical harmonic coefficients of lunar gravity model, and lunar gravity model information |
SLN-L-RISE-5-GRAV-MAP-V1.0, SLN-L-RISE-5-GRAV-POWER-V1.0, SLN-L-RISE-5-GRAV-COV-V1.0, SLN-L-RISE-5-GRAV-COEF-V1.0, SLN-L-RISE-5-GRAV-INFO-V1. |
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Doubly differenced 1-way range by differential VLBI. Time intervals of same-beam and switching observations are 60 sec and 120 sec, respectively. |
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Trajectory of Main Orbiter using the estimated lunar gravity model 1 - 11 |
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Trajectory of the Relay Satellite (Rstar) using the estimated lunar gravity model 1 - 11 |
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Trajectory of the VRAD Satellite (Vstar) using the estimated lunar gravity model 1 - 11 |
SLN-L-RISE-5-TRAJ-VSTAR-M2-V1.0, SLN-L-RISE-5-TRAJ-VSTAR-M3-V1.0 |