What Is a Satellite Launch Window?
A launch window is a particular period of time in which it will be easier to place the satellite in the orbit necessary to perform its intended function.
With the space shuttle, an extremely important factor in choosing the launch window was the need to bring down the astronauts safely if something went wrong. The astronauts had to be able to reach a safe landing area with rescue personnel standing by. For other types of flights, including interplanetary exploration, the launch window must permit the flight to take the most efficient course to its very distant destination. If weather is bad or a malfunction occurs during a launch window, the flight must be postponed until the next launch window appropriate for the flight. If a satellite were launched at the wrong time of the day in perfect weather, the satellite could end up in an orbit that would not pass over any of its intended users. Timing is everything!