Wireless laser communication systems developer Astrolight successfully performed a satellite-to-ground laser communication test using a portable OGS-1 optical ground station.
Astrolight, working with the European Space Agency (ESA), established the laser communication link using the OGS-1 optical ground station, located near ESA’s Izaña-1 (IZN-1) ground station, located at Teide Observatory in Tenerife, Spain, and an experimental laser transmitter system Osiris onboard the ‘Flying Laptop’ satellite, flying in low Earth orbit at around 600 km altitude.
The final objective of this test campaign is to demonstrate a reliable, high-bit-rate ad-hoc low-Earth orbit (LEO)-to-ground laser communication capability between a representative satellite and Astrolight’s OGS-1 portable optical ground station.
The experiment highlighted the unique portability and ease-of-use of Astrolight’s solution. The complete system, including the telescope, receive optical head, tracking computer, detector and modem, was disassembled at Astrolight’s facility in Vilnius, Lithuania, and placed into four pieces of luggage each under 32 kg, which were then transported 480 km by a compact SUV, placed on a plane via regular check-in desk, flown to Tenerife and then transported up the mountain by car. Astrolight’s OGS-1 was then reassembled and ready for operation in two hours, which is also the time it took to prepare the ground station for the trip.
With OGS-1 operating from a car battery, a light signal transmitted from the Flying Laptop satellite, equipped with the OSIRIS optical communication terminal, was successfully coupled into the detector despite the uncharacteristically strong wind conditions at Teide Observatory at the time. Besides LEO-to-ground downlink experiments, special calibration procedures for satellite tracking with the portable mount were tested and various large pieces of space debris and satellites were tracked.
The repeated tracking experiments showcased the OGS-1 tracking software’s ability to compensate for imperfect mounting and actuation of the telescope using commercial-off-the-shelf (COTS) equipment. The week-long test campaign concluded with successful disassembly of the ground station and a journey back to Vilnius, where OGS-1 was also operational immediately after the trip.
“We were able to couple the signal from the satellite laser transmitter into a 105 μm fibre while the satellite was travelling at 7.8 km/s, about 2000 km away from us at 5 degrees of elevation above the horizon,”
says Laurynas Mačiulis, Astrolight co-founder and CEO.
ESA is presently upgrading the Agency’s optical ground station at Tenerife, which until now could only be used for laser ranging, with an optical communication package.
“For this optical communication test, we are tracking and receiving a laser light signal from LEO at ESA’s IZN-1 station using the portable ground station from Astrolight as well as with our existing laser terminal,”
says Clemens Heese, Head of the Optical Technologies Section at the European Space Agency.
“By performing this test with two terminals simultaneously, we can see and study differences in the links, which is very useful for joint assessment and for optimising the respective systems – there was a lot of engineering discussion which was very fruitful for both ESA and Astrolight. This test was important because a portable optical ground station that you can pack in a suitcase and move to a place where you need to send or receive data offers a lot of possibilities for connecting remote locations – like disaster areas – that don’t have data communications.”
The test aimed to verify the portability and ruggedness of Astrolight’s portable optical ground station design. The terminal provided excellent performance despite being subject to rough handling and mechanical stress during the trip to Teide Observatory and being operated in rough windy conditions.
“Our next milestone is to develop and install a larger optical ground station permanently situated in southern Europe. It will re-use design elements from our portable system but with a larger telescope and will be capable of achieving 10 Gbps downlink speeds from LEO satellites. We plan to install the ground station by Q1 of next year,”
says Laurynas Mačiulis.
Strong need for satellite laser communication
The volume of data that needs to be transmitted from Earth to space and vice versa is growing tremendously. The needed data throughput will only increase with the expansion of spaceflight activities in all domains, including weather forecasting, broadcast, data relay, scientific and climate data gathering and navigation services, as well as human missions.
The revolution that fibre internet has brought to terrestrial internet data capabilities is comparable to what laser communication can bring to the ‘space internet’. Laser communication is by its nature much more secure, has a much narrower beam width and is more difficult to intercept or jam. Laser communication will enable next-gen security and the implementation of protocols working with quantum principles, such as quantum key distribution for a secure key exchange.
“We are at the technology development stage where the support of ESA and its infrastructure is crucial, and we are extremely satisfied with our cooperation,”
says Laurynas Mačiulis.
This test is the first cooperation in the field of free space optical communications between the European Space Agency and the Lithuanian-based company Astrolight.
Courtesy of Astrolight