Pioneering Start: PIXL-1 Small Satellite with the World’s Smallest Laser Terminal in Orbit

CubeSat with laser terminal. (Credit: DLR CC-BY 3.0)
  • The PIXL-1 small satellite was successfully launched on January 24, 2021 at 4:00 p.m. CEST, with the OSIRIS4CubeSat / CubeLCT laser terminal on board
  • The aim of the mission is to test optical communication systems for small satellites, to develop them further until they are ready for the market and to provide a reference system for a new communication standard
  • Technology transfer: The development was carried out on behalf of the German industrial partner Tesat-Spacecom (TESAT), who will produce the laser terminal in series

OBERPFAFFENHOFEN, Germany (DLR PR) — The PIXL-1 small satellite was successfully launched into orbit on January 24, 2021 at 4:00 p.m. CEST from the US spaceport Cape Canaveral with a Falcon-9 launcher from the US company SpaceX. The smallest laser transmission terminal in the world is on board the satellite: “OSIRIS4CubeSat” enables data transmission up to a hundred times faster than conventional radio links and was developed by scientists from the German Aerospace Center (DLR) in close cooperation with the German telecommunications company TESAT based in Backnang near Stuttgart. It provides an important platform for investigating scientific questions. The laser terminal is designed for series production and is sold by TESAT under the name “CubeLCT.” In this way, new value chains are being created in Germany as a business location.

The data transmission by laser can be seen as a “wireless fiber optic connection” and thus enables a much more efficient data transport via satellites in the future – it opens up diverse applications in communication. It also opens up new options for satellite navigation and quantum cryptography. In the satellite mission, the project partners now want to demonstrate that optical communication from space to the ground can be achieved even on the smallest satellites. For the operation of the satellite that is German Space Control Center responsible in Oberpfaffenhofen. 

“With OSIRIS4CubeSat we have developed a basis that will offer many missions new possibilities in the data rate in the future and that offers us at DLR an ideal basis for scientific measurements and the next technological steps in scientific projects,” says project manager Christopher Schmidt from DLR Institute for Communication and Navigation.

OSIRIS4CubeSat laser terminal. (Credit: DLR CC-BY 3.0)

Decisive Step Forward

Up to now, laser terminals were too big to be used on small satellite platforms – such as CubeSats – and they also had too high a power requirement. The launch of PIXL-1 thus opens up new horizons in satellite communication and expands the mission possibilities for small satellites.

OSIRIS4CubeSat and the product CubeLCT

With their dimensions of 10 x 10 x 3 centimeters, they fit perfectly on the smallest satellites, but can also be adapted to larger platforms. The systems are optimized for mission periods of five years in low earth orbit. The DLR Institute for Communication and Navigation has contributed its results and experience from around 15 years of research. The technological leap is achieved through a strong miniaturization of the technology – optics, mechanics and electronics have been closely interlinked for this purpose.

 “The functionality and miniaturization that we have achieved with CubeLCT promotes the smallest satellites into a new capability class and allows us to assign more demanding tasks to constellations”, says Prof. Christoph Günther, Director of the DLR Institute for Communication and Navigation.

Flight model of the laser terminal OSIRIS4CubeSat. (Credit: DLR CC-BY 3.0)

In the PIXL-1 mission, numerous scientific goals are to be examined. In addition to a basic demonstration of the technology, the transmission channel is also to be researched in more detail in order to be able to optimize error protection mechanisms. These findings are an important basis for the international standardization of the technology as well as a further increase in data rates up to one gigabit per second in future missions. This is particularly important in earth observation, which has to transmit ever larger amounts of data.

Diverse Fields of Application

In addition to individual small satellites, these can also be used in megaconstellations. There a large number of satellites work together on a mission, for example in the worldwide distribution of a broadband Internet connection. In the next development steps, optical communication is to be further developed so that optical connections between small satellites in space are also possible.

Another special feature of optical communication is that it can be used to distribute quantum keys.  With the help of this technology, any form of digital communication can be made secure. The DLR Institute for Communication and Navigation is a leader in this research area and will use the new technology platform in space to further develop the quantum key distribution between transmitter and receiver.

Receiving Stations: Building a Network

Weather conditions are a major challenge in laser-based communication, as the laser cannot transmit through clouds. To overcome this limitation, a worldwide network of optical ground stations is to be set up, most of which are to be built at locations with little cloud. With the PIXL-1 pioneering mission, DLR is supporting this approach and will be testing locations and further expanding the reception network in the coming months. The first two ground stations of the network are currently being operated by the German Space Control Center (GSOC) and an industrial partner at two European locations.

To control the PIXL-1 small satellite, two different frequency bands are used for communication. At the beginning, the laser communication is in the ultra-short wave range, for which a new antenna of the GSOC was put into operation. During the actual mission, the satellite works in the S-band, so that the control center can then use its usual ground stations and integrate the satellite into the standard processes as smoothly as possible. From Oberpfaffenhofen, the GSOC controls the satellite in regular operation, conditions the laser terminal and ensures that the data reaches the colleagues at the Institute for Communication and Navigation.

Industrial Cooperation with TESAT

DLR and TESAT have had a very close and successful cooperation since 2016. In the OSIRIS (Optical Space Infrared Downlink System) program, the Institute for Communication and Navigation is developing miniaturized laser transmitter terminals with a compact design that are used for direct optical downlinks from the satellite to the earth. As the client, TESAT was involved in the development from the start. The company from Backnang is a world leader in the field of optical satellite communication and plans to expand the market for small satellites in this context. With the launch of PIXL-1, the technology is now being decisively advanced.  After completion of the development phase, the industrial partner will start series production of the compact satellite laser terminal.

“We at TESAT have a clear vision of overcoming boundaries with our products and connecting people. With the start of PIXL-1, we have come a good step closer to this mission. And the CubeLCT is the result of a very successful cooperation between the DLR Institute for Communication and Navigation and TESAT ”, says Dr. Marc Steckling, CEO of Tesat-Spacecom.