GREAT, Ground Station for Deep Space Exploration and Telecommunication
JAXA has launched for deep space exploration the project for development and operation of new antenna and ground station with expanded capacity.
The new station will be the successor of the existing 64m parabolic antenna located in JAXA’s Usuda Deep Space Center, Nagano, which has served as Japan’s only ground station for deep space* investigation for over the last three decades, but has long outlived its lifespan. Furthermore, in light of the recent demand for technologically advanced interplanetary missions, needs have arisen for reception of larger amounts of data. In fact, Hayabusa2, JAXA’s asteroid explorer launched in 2014 will use for its high capacity transmissions the Ka-band frequencies, beyond the X-band range, which the antenna presently in use communicates in. The new ground station with the antenna, accessible to the Ka-band spectrum will relay the present operation to the future and will certainly contribute to yet to be accomplished interplanetary missions.
*Deep space: The Japanese Radio Law defines Deep Space as the universe more than 2 million kilometers away from Earth.
New Large Antenna for Supporting Deep Space Exploration
To secure operational capacity for JAXA to independently achieve innovative results from deep space exploration by newly enabling the receiving of Ka-band while continuing to cope with X-band communication, which has been used for a long time for deep space missions.
While decreasing the antenna diameter from 64m, the new antenna will improve its reception capacity. We will develop a comprehensive system combining a high-precision tracking antenna and transmitter-receiver against the harsh environment including solar radiation and wind pressure.
|Name||GREAT:GRound station for deep space Exploration And Telecommunication|
|Scheduled time of operation start||Japan Fiscal Year 2019|
|Construction site||1905-1 Tateshina, Maeyama, Saku City, Nagano Pref.
East longitude 138 degrees and 21 minutes
North latitude 36 degrees and 8 minutes Altitude 1580 m
Area : 8 hectare (80000 square meters)
|Design life||Over 20 years|
|Antenna method||Cassegrain antenna with shaped reflector|
|Weight||2100 tons or less|
|Power supply method||Focused beam power supply method|
|Frequency||For tracking and controlling explorers
X-band transmission (7145MHｚ～7235MHz)
X-band reception (8400MHz～8500MHz)
Ka-band reception (31800MHz～32300MHz)
For geodetic VLBI
X-band reception (8200MHz～8700MHz)
|Transmission performance||X-band transmission gain : 69.62dBi or more
X-band transmission power : 20 kW or more
(EIRP will be 142.62 dBm or more.)
|Reception performance||X-band G/T : 53.35 dB/K or more at an elevation angle of 15 to 80 degrees
Ka-band G/T : 59.33 dB/K or more at an elevation angle of 15 to 80 degrees
The above G/T is an effective G/T value that includes propagation loss (the sum of losses caused by atmospheric absorption and precipitation)