Lysdrev

Lysdrev is a term that appears in some Nordic-language discussions to describe propulsion systems driven by light. The word is formed from lys, meaning light, and drev, meaning drive or propulsion. In practice, lysdrev may be used as a generic label for technologies that convert photons’ momentum or energy into thrust.

Conceptually, lysdrev covers a range of approaches that use light to move a vehicle. The two broad categories are passive optical propulsion, where sunlight or an external laser beam exerts radiation pressure on a reflective surface to produce thrust (as in solar sails or laser sails); and active photonic propulsion, where light interacts with onboard systems to generate or supplement thrust, or where a directed beam provides propulsion from outside the craft. The underlying physics relies on momentum transfer from photons and, in some concepts, the conversion of light energy into kinetic energy within the vehicle.

Materials and engineering challenges are central. Thrust from light is extremely small, so practical lysdrev concepts require large sail areas, highly reflective and lightweight materials, precise attitude control, and powerful light sources. Efficiency depends on sail mass, reflectivity, and beam quality. In the near term, research often focuses on micro- or nanoscale devices or conceptual demonstrations, while scaling to spacecraft remains an open challenge.

Status and outlook: lysdrev remains largely theoretical and experimental at small scales. It overlaps with broader photonic propulsion research, including solar sails and laser-driven propulsion studied in programs such as Breakthrough Starshot. Mainstream aerospace efforts continue to rely primarily on chemical and electric propulsion, with photonic concepts considered for long-term or specialized applications.

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