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In Search of Origins GREAT2, Ground station for deep space Exploration And Telecommunication phase 2

GREAT2, Ground station for deep space Exploration And Telecommunication phase 2

This is a new ground station built in Saku City, Nagano Prefecture for the purpose of enabling telecommunications with deep space exploration probes.
Currently, additional improvements are being made to enhance the reliability and operation of its system, and to enable giving support to foreign
missions. The system is composed of a 54 m diameter parabolic antenna, a 20 kW-class solid state power amplifier (SSPA), and two receivers.
Although the diameter of this parabolic antenna has been reduced by 10 m from the 64 m of Usuda’s older parabolic antenna, it has the same level
of reception capabilities and is able to track deep space probes with high precision. The improved system can also receive frequencies (Ka-band)
that enables reception of a greater data volume than before, thus enabling it to answer to the diversifying needs of space exploration 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

Objective

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.

Special features

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
Diameter 54m
Weight 2100 tons or less
Mounting system Az-El
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)


© 2003 Japan Aerospace Exploration Agency

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