By John Oncea, Editor
The history of photonics began in 1960 with the invention of the laser. Two years later the first laser echoes reflected off the moon. Thus began the field of space photonics, enhancing on-board data handling, high-resolution measurement systems, processing units, and more.
Space photonics is a technology that uses the generation, detection, and manipulation of photons to enable high-speed, low-power communications, remote sensing, imaging, navigation, and health monitoring in space applications. Some examples of photonic devices used to accomplish this include laser diodes, light-emitting diodes, solar and photovoltaic cells, displays, and optical amplifiers.
NASA uses photonics to solve challenges in spaceflight, such as better data communications from space to Earth. One priority is to use lasers to make space communications more efficient for both near-Earth and deep-space missions. NASA is also developing photonic integrated circuits (PICs) to reduce the size, weight, power, and cost of spacecraft microprocessors, communication buses, and other components.
The European Space Agency expects photonics “to make an impact in future Spacecraft engineering by replacing or enhancing conventional electrical approaches in the fields of digital and RF telecom payloads, sensors, micro lidars, and spectrometers by reducing the size, weight, power, or performance of the systems they replace.”
Space Photonics In Action
So, it’s pretty clear that photonics is a valuable tool in space exploration, and following are several examples that prove that value:
- Communication: Photonics-based systems are used to transmit and receive data between satellites, spacecraft, and ground stations using laser beams. Optical communication can offer higher data rates compared to traditional radio frequency communication.
- Lidar and Remote Sensing: Systems use lasers to measure distances and create detailed 3D maps of planetary surfaces or other objects in space. Lidar is also used for atmospheric studies and climate research.
- Spectroscopy: Photonics instruments are employed for analyzing the composition of distant celestial bodies by studying the spectrum of light they emit or reflect. This helps scientists understand the chemical composition and physical properties of celestial objects.
- Imaging: Advanced photonics-based imaging systems, such as hyperspectral imaging and adaptive optics, enable the capture of high-resolution images of planets, stars, galaxies, and other celestial objects.
- Quantum Communication and Sensing: Quantum photonics technologies can enable secure communication and highly sensitive sensing applications in space. Quantum communication uses the principles of quantum mechanics to ensure the security of information transmission.
- Optical Clocks: Ultra-precise optical clocks based on photonics technology can be used in space for highly accurate timekeeping, which is important for navigation, satellite syncronization, and scientific research.
- Energy Generation and Harvesting: Photonics-based solar cells and energy harvesting systems can efficiently convert sunlight into electricity for powering spacecraft and satellites.
- Astrophysics and Cosmology: Photonics instruments play a vital role in studying cosmic phenomena such as black holes, supernovae, and cosmic microwave background radiation. These instruments help astronomers gather data to develop theories about the origins and evolution of the universe.
More From ESA, NASA
ESA considers photonics largely as guided wave technologies either in optical fibers or waveguides. They are developing microwave photonics to offer new functionality and performance to RF payloads. “At the core of these payloads are photonics to generate stable local oscillators, perform optical down conversion, and manipulate the optical microwave signals by routing, beamforming, or filtering them in the optical domain.
“The main components of such a photonic system include lasers, optical amplifiers, WDM components, optical modulators, optical switches, and photonic integrated circuits for optical beam forming, switching and filtering.”
ESA is also developing optical transceiver hardware to allow high-speed (25 Gbps) optical digital links to interconnect future digital processors and photonic integrated circuits, the chip scale integration of multiple optical elements or components which enable complex functions analogous to the electrical integrated chips.
Finally, ESA is employing optopyrotechnics, “A new approach to the detonation of pyrotechnics using short pulses of a laser output to ignite the pyro material. This technology has been baselined for the next European launcher, the Ariane 6. The optoelectronics section together with European industry has been leading the development of key components of this system, from the laser to the safety features such as the optical safety barrier. Other photonic technologies have been studied for use in future launchers include, laser ignition, fiber optic sensing, optical communications, and optical wireless.”
For its part, NASA’s Artemis program, which aims to return humans to the moon by 2024, is set to leverage space photonics in a big way, according to Fagen Wasanni Technologies. “The Lunar Laser Communication Demonstration (LLCD), a pioneering project under the Artemis program, is designed to test the feasibility of using laser communications for future lunar missions. If successful, this technology could provide astronauts with high-speed internet on the moon, enabling real-time communication with Earth and facilitating the transmission of high-definition video and other data.”
In addition to communication, space photonics is vital for navigation and scientific research. The Mars 2020 mission by NASA, which landed the Perseverance rover on Mars, utilized LIDAR technology to map the planet's terrain. “In addition to lunar and planetary exploration, space photonics also holds promise for the study of distant celestial bodies,” writes Fagen Wasanni Technologies. “The upcoming James Webb Space Telescope, for example, will use infrared light to peer into the farthest reaches of the universe, providing unprecedented insights into the formation of galaxies, stars, and planets.”
Space photonics is a multidisciplinary field that involves optics, electronics, materials science, and engineering. Developing photonics technologies for space applications presents unique challenges due to the harsh space environment, including vacuum conditions, extreme temperatures, and radiation exposure. However, the benefits of photonics, such as high data rates, precision measurement capabilities, and efficient energy conversion, make it a valuable tool for advancing our understanding of space and improving space-based technologies.