DLR Laser Terminal in Space Makes Contact with Japanese Ground Station

The flying laptop satellite of the University of Stuttgart. (Credit: University of Stuttgart)
  • For the first time, a signal from the DLR terminal OSIRISv1 was received on a NICT ground station in Japan.
  • OSIRISv1 was developed by the DLR Institute for Communication and Navigation and launched in 2017 on the “Flying Laptop” satellite in cooperation with the Institute for Space Systems (IRS) at the University of Stuttgart.
  • Optical communication systems that use laser beams for data transmission make it possible to significantly increase the data rates between satellites and ground stations.

COLOGNE, Germany (DLR PR) — The resolution of cameras and other sensors on earth observation satellites is increasing steadily. This leads to ever-increasing amounts of data that are still transmitted to earth using radio systems today. The data connection between the satellite and the earth limits the capabilities of the systems.  With optical communication systems that use laser beams for data transmission, a significant increase in data rates is possible. Numerous images can be transmitted with high resolution. 

As part of an international cooperation, researchers from the German Aerospace Center (DLR), the Japanese National Institute of Information and Communications Technology (NICT) and supported by the University of Stuttgart started with channel measurements for laser data transmission in Japan. A first link for this purpose was recently received from space by the optical terminal “OSIRISv1” on an optical ground station in Tokyo.

“Satellite-based laser communication heralds a new era in satellite communication,” says Christian Fuchs from DLR Institute for Communication and Navigation. He is in charge of the work in the field of optical communication at the institute. Next-generation systems already enable data rates of up to ten gigabits per second. They are also smaller, lighter and require less electrical power than comparable radio systems. 

Since laser beams do not penetrate clouds, global networks of optical ground stations are required to achieve the desired availability. OSIRISv1 (Optical Space Infrared Downlink System) was developed by DLR and launched in 2017 on the “Flying Laptop” satellite in cooperation with the Institute for Space Systems (IRS) at the University of Stuttgart.

Joint experiment with researchers in Japan

During the joint experiment, the first measurement data, such as the optical reception power, were recorded. This allows the behavior of the atmospheric transmission channel to be assessed. This is used on the one hand to optimize the design of future systems and on the other hand to plan networks. With the wavelength of 1550 nanometers used, which is provided for in the standards, there is very little measurement data to date.

Also worth mentioning is the precise beam alignment, which is made possible by the attitude control of the Flying Laptop satellite. OSIRISv1 itself does not have any mechanical elements for beam control. Therefore, the attitude control of the satellite must perform this alignment. The University of Stuttgart has successfully optimized the attitude control in joint experiments with the DLR at the DLR ground station in Oberpfaffenhofen.

The measurement data obtained will now be evaluated by the teams and will form the basis for further tests in the near future, both for the NICT ground station and for other partner institutions worldwide. The current measurements in Japan are part of a long history of joint experiments that have so far taken place in Oberpfaffenhofen using Japanese satellites.  Experiments with the Japanese space agency’s OICETS satellite took place in 2006 and 2009 and the tests with the payload Small Optical TrAnsponder (SOTA) of the NICT in 2013.

Further international experiments with DLR payloads will be carried out in the near future: on January 24, 2021, the smallest laser terminal in the world, OSIRIS-CubeL, which the DLR has developed in cooperation with Tesat Spacecom, launched on board the PIXL-1 satellite. OSIRISv3 is to be installed on the Bartolomeo platform of Airbus Defense & Space on board the International Space Station (ISS) as early as next year .

NICT

The National Institute of Information and Communications Technology (NICT) in Tokyo conducts research and development of optical communication in space for the further development of satellite communication of the future. With the SOTA (Small Optical Transponder) satellite, which was tested in orbit from 2014 to 2016, not only optical ground stations in Japan but also research institutions such as DLR, Center National D’Etudes Spatiales (CNES), European Space Agency (ESA) and Canada (Canadian Space Agency (CSA) included. NICT has so far signed a joint research agreement with DLR.

University of Stuttgart

The Satellite technology department of the Institute for Space Systems (IRS) at the University of Stuttgart develops, builds, integrates, qualifies and operates small satellite systems in addition to other fields of research. In the field of satellite technology, they also develop new technologies and payload instruments for satellites and test them under space conditions. This also includes the further development and application of new processes in the area of ​​infrastructure for the construction, qualification and operation of satellites. The University of Stuttgart’s first satellite is the Flying Laptop small satellite, which has been operated successfully by the control center at the University of Stuttgart since July 2017. With a mass of 110 kilograms, the Flying Laptop is still the largest and most complex satellite developed by a German university.