optyka: Solar sail

Evidence: 43 • authority: 92

Interstellar photovoltaics.. The term 'Solar Cell' is commonly used for Photovoltaics that convert light into electrical energy. However, light can be harvested from various sources not limited to the Sun. This work considers the possibility of harvesting photons from different star types, including our closest neighbor star Proxima Centauri. The theoretical efficiency limits of single junction photovoltaic devices are calculated for different star types at a normalized light intensity corresponding to the AM0 spectrum intensity with AM0 = 1361 W/m 2 . An optimal bandgap of > 12 eV for the hottest O5V star type leads to 47% Shockley-Queisser photoconversion efficiency (SQ PCE), whereas a na…

Evidence: — • authority: 88

Optimal Propellant-less Control of a Solar Sail. : Solar sails use radiation from the sun to generate thrust without any fuel or propellant. Since this is a form of propulsion that has theoretically infinite use, we would like to test its capability on long-term missions by simulating a spacecraft equipped with solar sails to the Sun-Earth L5 Lagrange point. To control the sail angle, which is the main form of control we have over the sail’s performance, we will devise a form of optimal control based on Pontryagin’s Minimum Principle. Simulating the dynamics in MATLAB SIMULINK, we find that such a control method relies on iterating over initial conditions for the co-states to find the neces…

Evidence: — • authority: 72

Field propulsion refers to spacecraft propulsion concepts in which thrust arises from interactions with external fields or ambient media, rather than primarily from onboard chemical propellant. Early ideas grew from studies of radiation pressure and electrically driven motion; later contractor and agency surveys organized advanced concepts under thermal, field, and photon headings. Several related propulsion systems discussed alongside field propulsion in the broader historical literature surveyed here have since been demonstrated in practice, including electrodynamic tethers in orbit, and applications such as EHD thrust devices. In narrower modern literature, related propellant-less propul…

Evidence: — • authority: 72

Human spaceflight (also referred to as crewed spaceflight, and historically as manned spaceflight) is spaceflight with a crew or passengers aboard a spacecraft, often with the spacecraft being operated directly by the onboard crew. Spacecraft can also be remotely operated from ground stations on Earth, or autonomously, without any direct human involvement. People trained for spaceflight are called astronauts (American or other), cosmonauts (Russian), or taikonauts (Chinese); and non-professionals are referred to as spaceflight participants or spacefarers. Humans have had a continuous presence in space since 2 November 2000, on the International Space Station (ISS). The first human in space…

Evidence: — • authority: 72

In Newtonian mechanics, momentum (pl.: momenta or momentums; more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. If m is an object's mass and v is its velocity (also a vector quantity), then the object's momentum p (from Latin pellere "push, drive") is: p = m v . {\displaystyle \mathbf {p} =m\mathbf {v} .} In the International System of Units (SI), the unit of measurement of momentum is the kilogram metre per second (kg⋅m/s), which is dimensionally equivalent to the newton-second. Newton's second law of motion states that the rate of change of a body's momentum is…

Evidence: — • authority: 72

Solar sails (also known as lightsails, light sails, and photon sails) are a method of spacecraft propulsion using radiation pressure exerted by sunlight on large surfaces. A number of spaceflight missions to test solar propulsion and navigation have been proposed since the 1980s. The two spacecraft to successfully use the technology for propulsion were IKAROS, launched in 2010, and LightSail-2, launched in 2019. A further demonstrator, Advanced Composite Solar Sail System (ACS3), was launched in 2024, and deployed successfully but is not being actively controlled due to a fault. A useful analogy to solar sailing may be a sailing boat; the light exerting a force on the large surface is akin…