Satellitlasers

Satellitlasers is a broad term for laser systems used in space applications involving satellites. It includes laser communications between spacecraft, inter-satellite optical links, and satellite laser ranging (SLR), which uses ground-based lasers to measure the distance to satellites with millimeter precision. The field also encompasses experimental concepts such as laser propulsion or debris-removal ideas that rely on directed laser beams in space.

Development began in the 1960s with early laser ranging and communications experiments. The SLR program used ground-based lasers to transmit pulses to satellites equipped with retroreflectors, enabling precise orbit determination and geodesy. Optical communications demonstrations followed, and by the 2010s higher data-rate space links were shown in several experiments. In 2016, China's Micius satellite demonstrated space-based quantum communications, exchanging entangled photons and distributing quantum keys via laser links to ground stations.

Today, satellite lasers enable high-bandwidth inter-satellite links and satellite-to-ground downlinks, offering advantages over radio-frequency systems for certain applications. SLR remains essential for geodesy and time transfer. Research includes advances in adaptive optics, high-efficiency detectors, and robust, power-efficient laser payloads. Quantum communication experiments continue to test secure transmission from space to Earth and, in some concepts, between satellites.

Challenges include precise pointing and tracking, atmospheric losses for ground-based terminals, thermal and radiation environments, power requirements, and safety considerations for laser systems. Weather can interrupt optical links, and hardware must survive space conditions. Despite these and other hurdles, satellite lasers hold potential for global optical networks, precise timing, and new mission architectures in space.