MISSIONS

Data Relay Test Satellite "KODAMA"(DRTS)

In Operation

Project Topics

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October 7, 2009 Updated

KODAMA completes regular operation phase

The KODAMA, launched in September 2002, completed its six-and-half-year regular operation phase, and entered the post operation phase.
The KODAMA successfully performed inter-satellite communication experiments with the Advanced Land Observing Satellite "DAICHI" at a global-leading speed of 278 Mbps, and contributed to DAICHI's earth observation activities by relaying a huge volume of data acquired and transmitted by the DAICHI. The KODAMA achieved its scheduled goals as it also successfully carried out inter-satellite communication experiments with the Optical Inter-orbit Communications Engineering Test Satellite "KODAMA," the Small Demonstration Satellite-1 "SDS-1," the Japanese Experiment Module "Kibo," and the earth observation satellite "Envisat" of the European Space Agency.
In the post-operation phase, the KODAMA will continue its relay operations mainly with the DAICHI and Kibo.

Photo: Test image taken by Kibo and relayed via KODAMA

Overview

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"KODAMA" Data Relay Test Satellite (DRTS) to dramatically extend contact time and areas

KODAMA (DRTS), a data relay test satellite launched by the H-II A launch vehicle from the Tanegashima Space Center (TNSC), serves as a data relay station.
A data relay test satellite is a kind of communications satellite in a geostationary orbit that relays data among Low Earth Orbit (300-1,000 km altitude) spacecraft (such as satellites) and ground stations. This relay can dramatically extend the area where real-time communication between Low Earth Orbit spacecraft and ground stations are possible.
When a direct communication link is used, contact time between a Low Earth Orbit spacecraft and a ground station is limited to approximately 10 minutes per visible pass. When KODAMA relays data between an LEO spacecraft and a ground station, real-time communications are possible in 60% of the flight path of the spacecraft. This enables Japan, a relatively small country, to greatly extend contact time between its spacecraft and a small number of ground stations.
Furthermore, transmission from KODAMA has reached a data rate exceeding 240 Mbps - a communications speed that would enable the simultaneous transmission of data contained in 11 BS Digital High Vision channels. KODAMA is scheduled to relay data to and from the Advance Land Observing Satellite "Daichi" and the Japanese Experiment Module "KIBO" on the International Space Station (ISS), and will be used to broadcast the activities of astronauts.


Major Characteristics

International Designation Code 2002-042B
Launch Date 17:20, September 10, 2002 (JST)
Launch Vehicle H-IIA Launch Vehicle No.3
Location Tanegashima Space Center
Shape structure : 2.2 m x 2.4 m x 2.2 m
Box shape
Weight Approx. 1500kg (at the beginning of mission life)
Orbiter Geostationary orbit(GEO) (Longitude 90 degree East)
Altitude Approx. 36,000km
Inclination 0 degrees
Period Approx. 24 hours
Attitude Control Three-axis stabilization (Controlled bias momentum)