Data Relay Test Satellite "KODAMA"(DRTS)

In Operation

Project Topics

September 10, 2012 Updated

KODAMA on-orbit operations mark 10 years

The KODAMA, which was launched on Sept. 10, 2002, has marked its 10-year anniversary. The KODAMA succeeded in a data relay experiment with the world's fastest speed of 278 Mbps using the Advanced Land Observing Satellite "DAICHI," and has been contributing to global land observations and disaster monitoring with the DAICHI by utilizing KODAMA’s broad view area and real-time and large-volume data relay capacity. Some 95% of DAICHI's 6.54 million scenes (or almost one PB of observation data) were received on earth through KODAMA's relays.
Also, in these 10 years, the KODAMA successfully conducted data relay tests with six different spacecraft including the International Space Station (ISS) Japanese Experiment Module “Kibo,” and its operating rate for experiments has reached as high as 99%.
As we expect more data relay satellite utilization plans in the future, we continue to operate the KODAMA while preparing to maintain our country's satellite data relay capability.



"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)