As the numbers of satellites in orbit continue to rise there is a greater need for effective communication solutions that can handle increasing data volumes. Optical communications may hold the answer, enabling operators to get more data from space to Earth faster and more efficiently.
The drive for optical communication is also due to the crowding of traditional radio options in frequencies such as the S-band and X-band, which have been used for decades for satellite communication.
Space-space and space-ground communications are the primary use cases for optical laser communications (lasercom) and in this article we take a look at how the technology works and share some of the products available on the market today.
In the article below we provide a gentle primer of optical communications systems for satellites discussing their history and giving the advantages and disadvantages that they bring, as a quick guide to understanding the promise of the technology. If you are familiar with the technology and would prefer to skip down to see the product listings, please click here.
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Early demonstrations of optical communications technologies date back to the mid-90s. The Communications Research Laboratory (CRL) in Japan successfully demonstrated the Laser Communication Experiment (LCE) on the Japanese Engineering Test Satellite-VI (ETS-VI) satellite in 1994 with the first purpose-built lasercom satellite for demonstrating space-to-ground laser communications.
The ARTEMIS program, a European-led mission, demonstrated bi-directional laser communication between a geostationary orbit and the European Space Agency (ESA) Optical Ground Station (OGS). This incorporated narrower beam divergences than the LCE mission, which allowed higher data rates and enabled a better understanding of atmospheric impairments, particularly at low zenith angles.
The geostationary satellite-based missions allowed for the use of a fixed ground terminal to conduct repetitive measurement of link parameters over many days and have enabled the improvement of propagation models and design changes of subsequent lasercom missions.
Laser communications on small satellites
Small satellites predominantly operate in Low Earth Orbit (LEO) and offer a low-cost platform for researchers to test technologies such as satellite laser communications. For example, the National Institute of Information and Communications Technology (NICT) in Japan and the German Aerospace Centre (DLR) have used such platforms to successfully demonstrate laser communications using satellites in LEO over the last few years.
Table 1: Recent significant missions incorporating small satellite laser communication terminals
|Operator||NICT, Japan||DLR, Germany|
|Launch date||May 24, 2014||June 22, 2016|
|Satellite||SOCRATES (48 kg)||BIROS (130 kg)|
|Mass||5.9 kg||5 kg|
|Size||18×11×10 cm||25×20×10 cm|
|Beacon||1 µm unmodulated||1560 nm modulated|
|Downlink||800, 980, 1549 nm||1545, 1550 nm|
|Modulation||On-Off Keying||On-Off Keying|
|Max. bitrate||10 Mbit/s||1 Gbit/s|
Laser communications on CubeSats
As satellites are getting smaller the need to fit in communications systems that will allow the reduced form factor at lower power and with higher data rates has generated significant interest in laser communications for CubeSats.
The first (brave) attempt to demonstrate laser communication on a CubeSat was on-board FITSAT-1, a 1U system developed at the Fukuoka Institute of Technology in Japan. The satellite carried two arrays of high-power light-emitting diodes (LEDs) along with an experimental RF transceiver and was deployed in October 2012 by the robotic arm of the International Space Station (ISS).
FITSAT-1 used a neodymium magnet as a passive attitude control system with a panel containing 50 green 3W LEDs, achieving 200-W pulses and modulated with a 1-kHz Morse-code signal.
A photomultiplier coupled to a 25 cm ground telescope was used to receive the signals on the ground. Interestingly, the flight model of the FITSAT-1 laser communication payload was tested between the beach of the Fukuoka and the rooftop of the eight-story building of the university which were 12 km apart from each other.
In August 2018, The Aerospace Corporation in the US tested a laser communication system during a mission named Optical Communications and Sensor Demonstration (OCSD) with two LEO CubeSats known as AeroCube-7B and Aerocube-7C. The satellites successfully transmitted data at a rate of 100 Mbps.
Today there are various lasercom products available or approaching the marketplace that have built on these early developments, bringing some significant benefits compared to existing solutions.
Advantages of optical communication
Optical communication systems have several advantages over traditional radio equipment including:
- Higher data rates, so more information may be transmitted in less time and using lower power
- Better signal/noise ratio (weather-dependent) due to higher directivity
- Lack of interference
- Smaller antennae
- Lower overall power requirements
- Increased spectrum availability
- Narrow beams are difficult to intercept and jam
- No International Telecommunication Union (ITU) coordination needed
On the other hand, there are some aspects of optical satellite communications products that can cause issues such as:
- Higher pointing accuracy is needed for satellites
- Potential weather-based disruptions
- Increased mission complexity and risk
- The Sun is a noise source for optical detectors
Commercial optical communications providers
As commercial-off-the-shelf (COTS) components have become more prominent and widely used in small satellites/CubeSats, and the Earth Observation (EO) sector particularly has seen an increase in the number of manufacturers adopting small satellites, the need for higher data rates is growing every year.
This presents a great opportunity for the manufacturers of satellite laser communications equipment and below we have listed a number of products available on the global marketplace in various stages of development, testing and maturity.
Please note that this list will be updated when new products are added to the global marketplace for space – so please check back for more or sign up for our mailing list at the link below for updates.
The Tesat ConLCT80 is a laser communication terminal designed for low earth orbit (LEO) broadband satellites. It has a bidirectional channel data rate of 10 Gbps and beaconless pointing acquisition and tracking. Depending on the data rate it consumes power between 60 Watts to 80 Watts. The product weighs 15 kgs and has a service lifetime of five years.
The Tesat CubeLCT is a laser communication transmitter for Low Earth Orbit(LEO) to Ground data transmission with 100 Mbps data rate. The system has acheived flight heritage. It was part of the PIXL-1 mission in January 2021.
The Tesat TOSIRIS is a laser communication terminal for Low Earth Orbit(LEO) to Ground data transmission with 10 Gbps data rate. The system includes a full hemispherical, coarse beam pointing mechanism. It has a lifetime of 5 years in LEO orbit. The system has acheived flight heritage. It was part of the Airbus‘ Bartolomeo platform on the International Space Station(ISS).
The Tesat LCT135 is a laser communication terminal for transmission up to 80,000km; GEO to GEO, GEO to LEO, GEO to Airborne, GEO to Ground.
The Tesat SmartLCT 70 is a data relay access laser terminal designed for low earth orbit (LEO) satellites. It has unidirectional LEO to geostationary earth orbit (GEO) data rate of 1.8Gbps. It has Wizard Link data interface and has a maximum power consumption rate of 150 Watts. The product weighs 30 kgs and has a service lifetime of ten years.
The Mynaric CONDOR Mk2 is an optical communication terminal suitable for inter-satellite space-space, space-air, space ground connectivity. The optical communication does not require ITU or FCC frequency coordination. The system by design offers higher reliability, performance, bandwidth, and built-in redundancy with 7+ years lifetime in LEO.
The Mynaric Condor Mk3 is an optical communication terminal suitable for inter-satellite space-space, space-air, space ground connectivity. The optical communication does not require ITU or FCC frequency coordination. The system by design offers higher reliability, performance, bandwidth, and built-in redundancy with 7+ years lifetime in LEO.
The Xenesis Xen-Hub is an optical space-based communication terminal consisting of an electronics/photonic modem module, optical head module and an optical amplifier (EDFA) module. The Xen-hub by design can be used as both uplink or downlink space terminal or an optical inter-satellite link (OISL) terminal.
The Xenesis Xen-Node is an optical ground terminal with Dall-Kirkham optical telescope built by Planewave supporting full duplex operation even in daylight. With a 0.5m diameter, the system consists of an electronic/photonic modem module same as Xen-Hub, an optical EDFA module, a high precision telescope, optical bench and an interface unit to a 10GbE Ethernet network.
The Xenesis Xen-Link is an optical communication system consisting of space-based terminal, Xen-hub and optical ground terminal, Xen-node. The Xen-Link uses single wavelength for uplink and downlink paths. Xen-Link is a full turn-key free space communication solution. The system consists of flight certified hardware and features fully interoperable space and ground segments.
The Space Micro μLCT 10 Gbps Lasercom Terminal is a laser-based optical communication terminal for small or large satellites with 10 Gbps data rate. The system includes space micro high efficiency modem, point and track electronics, optical head & pointing assembly, temperature compensated fiber collimating optics and optical amplifier.
The Space Micro μLCT 100 Gbps Lasercom Terminal is a laser-based optical communication terminal for small or large satellites with 100Gbps data rate. The system includes space micro high efficiency modem, point and track electronics, optical head & pointing assembly, temperature compensated fiber collimating optics and optical amplifier
The Archangel Lightworks High altitude laser terminal is a laser terminal flown above cloud for connecting space, ground and airborne assets with hybrid architecture.
The Astrogate Labs ASTRO-LINK is a fully integrated laser communication system providing 1Gbps satellite-to-ground communication for cube/nanosats.
The Ball Aerospace Commerical Lasercom is a free-space optical communication system family of terminals for GEO, LEO and airborne applications. Ball Aerospace offers laser communication hardware solutions designed to support applications with higher bandwidth requirements similar to the optical fiber system on ground.
The Odysseus CYCLOPS is a satellite and ground laser terminal suitable for microsatellite constellations in LEO. The CYCLOPS-DT is a laser terminal for connecting satellite in space to ground for data transmission. CYCLOPS-GT is a ground terminal laser-based solution designed for data transmission from satellites equipped with CYCLOPS-DT.
The AAC Clyde CubeCat is a laser communications module that enables a bidirectional space-to-ground communication link between a CubeSat and an optical ground station, with downlink speeds of up to 1 Gbps and uplink data rate of 200 Kbps.
The EXA ICEPS is an all-in-one, configurable spacecraft system core, designed to be the central operational heart for CubeSats. ICEPS compresses the functions of many cards into a single, 25mm-thick system, using modularity for fully customizable hardware that can range from being simply an EPS or including a range of features.
The Stellar Project LaserCube is a 2-way laser communication terminal enabling downlink and intersatellite link through optical channels for small satellites. The optical communication solutions are designed to have higher performance than radiofrequency solutions. The system does not have any regulatory or licensing issues and also has an enhanced security as the links cannot be intercept/jammed.
If you would like our assistance in finding a suitable optical communication product or service for your needs from our extensive network, please fill out a request for information or proposal, and we’ll get back to you as soon as we can.
Please note that the listings above only include those suppliers for whom we have the full information about their products. There are a number of other companies with technology at various stages of development and testing that haven’t been included, but who may be able to help provide you with a solution.
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