The Japan Aerospace Exploration Agency (JAXA) successfully carried out an optical communication experiment using laser beams between its Optical Inter-orbit Communication Engineering Test Satellite "Kirari" (OICETS), at an altitude of about 600 km, and the optical ground station "OGS-OP" (Optical Ground Station Oberpfaffenhofen) of the German Aerospace Center (Deutsche Forschungsanstalt fur Luft- und Raumfahrt, DLR, in Wessling, Bayern) at 10:13 a.m. on June 7, 2006 (Japan Standard Time, JST). JAXA and DLR confirmed that optical communication (downlink from the "Kirari") was successfully performed for 3 minutes.
The "Kirari" has already performed a bi-directional optical communication experiment successfully with the optical ground station of the National Institute of Information and Communication Technology (NICT) last March. However, the DLR optical ground station is unique as it is a mobile station. Therefore, the success this time indicates the possibility of establishing a flexible optical communication network with a satellite and a mobile optical ground station.
The "Kirari" is scheduled to continue experiments including an optical communication test with an optical ground station and an inter-orbit optical communication test with the Advanced Relay and Technology Mission (ARTEMIS) of the European Space Agency (ESA) to acquire statistical
(Follow-up Report) At 12:13 on November 24 (Japan Standard Time, JST), JAXA found that one of the four reaction wheels was disconnected from the onboard attitude control system of the Kirari, Optical Inter-orbit Communications Engineering Test Satellite (OICETS) when JAXA's Okinawa Tracking and Communication Station received telemetry from the satellite.
The Kirari is currently flying normally as it is designed with a redundant system that enables the satellite to control its attitude if one of the four reaction wheels is disconnected.
The optical inter-orbit communications experiment with the Advanced Relay and Technology Mission "ARTEMIS" of the European Space Agency (ESA) was Successfully carried out in early December 2005.
JAXA has been studying the cause of the disconnection. As a result, it is currently estimated that the safety function of the attitude control system disconnected the reaction wheel because its error monitor for the number of revolution indicated an abnormal value.
Based on this investigation result, JAXA started to send a command to reactivate the disconnected reaction wheel from the Masuda Tracking and Communication Station at 1:44 a.m. on April 20 (Thu) (JST), and confirmed that no problem arose in the wheel drive unit as well as the wheel itself. At 2:13 a.m. on April 21 (Fri) (JST), the disconnected reaction wheel was reintegrated into the attitude control system by a command from the Perth ground station. The satellite is now shifted to the attitude control mode with four attitude control reaction wheels. The "Kirari" is now in a stable condition.
On December 9, 2005 (Japan Standard Time, JST), the Japan Aerospace Exploration Agency (JAXA) and the European Space Agency (ESA) succeeded in a bidirectional optical inter-orbit communication experiment using a laser beam between the Optical Inter-orbit Communications Engineering Test Satellite "Kirari" (OICETS) and the Advanced Relay and Technology Mission (ARTEMIS) of the ESA.
This is the first bidirectional optical inter-orbit communication in the world.
The success of this experiment has made it possible for JAXA to acquire enabling technology mainly for on-orbit laser beam acquisition and tracking technology. Also it enables us to collect data for improving transmission speed and volume, and for making onboard communication equipment smaller and lighter, which are essential for a future data relay satellite. In addition, they were able to obtain technology for future international mutual operations through international cooperation with ESA.
Optical inter-orbit communication is a method for satellites that are moving several kilometres per second in respective orbits to transmit and receive laser beams. The distance between them can be as far as about 40,000 kilometres. This inter-orbit communication using laser beams is a highly advanced technology that can be described like "hitting the eye of a needle placed on top of the Mt. Fuji from Tokyo Station." This communication method has a lot of advantages. For example, communication can be more stable because, unlike radio waves, laser beams do not cause interference. Also, onboard equipment can be smaller and lighter, but transmission speed is higher, and large volume data can be smoothly exchanged.
Kirari's optical inter-orbit communication technology is expected to be an essential technology for supporting various future space activities including global data acquisition by an earth observation satellite as a communication method between a low earth orbit satellite and a data relay satellite in geostationary orbit. JAXA will continue to verify enabling technologies and to carry out functional verification in the space environment.
The Status of the Kirari, Optical Inter-orbit Communications Engineering Test Satellite (OICETS):
At 12:13 (Japan Standard Time, JST) on November 24 , JAXA found that one of the four reaction wheels was disconnected from the onboard attitude control system of the Kirari Test Satellite, when JAXA's Okinawa Tracking and Communication Station received telemetry from the satellite.
The Kirari was launched by a Dnepr Launch Vehicle from the Baikonur Cosmodrome in the Republic of Kazakhstan on August 25, 2005, and is now under initial function verification. The Kirari is currently flying normally as it is designed with a redundant system that enables the satellite to control its attitude if one of the four reaction wheels is disconnected.
The optical inter-orbit communications experiment with the Advanced Relay and Technology Mission "ARTEMIS" of the European Space Agency (ESA) is scheduled in early December.
JAXA has released the holding mechanism of the Laser Utilizing Communications Equipment, LUCE, on the Kirari, and confirmed that the release operations were successfully carried out by analyzing telemetry data from the satellite.
JAXA also confirmed that the Kirari satellite was injected into its intended orbit and is functioning normally. After the release of the LUCE holding mechanism was over, Kirari completed its scheduled critical phase, and moved to the initial functional verification phase. Onboard equipment functions will be verified for about three months until November.
Reimei entered the Initial Functional Verification Phase and performed the sun acquisition automatic sequence. JAXA confirmed that the sequence was successfully carried out by analyzing telemetry data from the satellite.
The Reimei satellite completed its scheduled critical phase as it finished the sequence, and move to the initial functional verification phase.
The Japan Aerospace Exploration Agency (JAXA) confirmed the detailed orbit data of the Optical Inter-orbit Communications Engineering Test Satellite (OICETS) "Kirari" and the Innovative Technology Demonstration Experiment Satellite (INDEX).
The nickname of the OICETS is the "Kirari". Apogee altitude 611.4 km Perigee altitude 609.6 km Inclination 97.8 degrees Period 96.9 minutes
The nickname of the INDEX will be announced "Reimei" after its status is confirmed. Apogee altitude 654.1 km Perigee altitude 610.0 km Inclination 97.8 degrees Period 97.3 minutes
The RS-20 rocket was originally designed to intercept other intercontinental ballistic missiles, has been in use in the Russian Strategic Missile Forces for over 25 years.
The RS-20 Voyevoda heavy intercontinental ballistic missile (NATO name Satan) is a two-stage missile that can be equipped with a multiple warhead (6,835 mi) or a light warhead (9,320 mi). It is 34 meters in length, three meters in diameter, and has a maximum launch weight of 211 metric tons.
OICETS will enable optical inter-orbit communications tests between satellites that are tens of thousands of kilometres apart. An optical inter-orbit communications system will bring various advantages: more stable communications with less interference; lighter, more compact communications equipment; and higher data transmission rates. These tests are expected to lead to new technologies that will support the development and utilization of space, including global data reception from Earth Observation satellites and continuous communication links with a manned space station. OICETS was launched into a low Earth orbit, in order to conduct demonstrations with ARTEMIS, the latest geostationary satellite belonging to the European Space Agency (ESA).
The distance between ARTEMIS, a stationary satellite, and OICETS, positioned in a low Earth orbit, is around 45,000 km at its maximum point. As a result, optical inter-orbit communications tests require elements such as high-gain optical antennas, a high-power semiconductor laser, and highly sensitive signal detectors. Using these devices, researchers will be able to test such operations as beam acquisition, to take in an incoming laser beam; beam tracking, to detect and control the angle of the incoming laser; and beam pointing, to transmit a laser beam accurately in the right direction, taking into consideration the relative motion between the two satellites.