A "Launch Window" refers to a specific period during which a spacecraft can be launched to achieve its intended mission. This timeframe is determined by various factors, including the alignment of celestial bodies, the spacecraft's trajectory, and the desired destination, such as Mars or the Moon. Launching outside this window may result in increased fuel consumption or failure to reach the target. These windows are crucial for missions like those involving satellites or crewed flights, as they ensure optimal conditions for travel. For example, the International Space Station has regular launch windows to facilitate resupply missions and crew rotations, maximizing efficiency and safety.