Launch window

Launch window

Launch window is a term used in aerospace to describe a time period in which a particular rocket must be launched. If the rocket does not launch within the "window", it has to wait for the next one before it can be launched.

For trips into largely arbitrary Earth orbits almost any time will do, but if the spacecraft intends to rendezvous with a space station or another vehicle that is already in an orbit the launch must be carefully timed to occur around the times that the target vehicle's orbital planes intersects the launch site.

To go to another planet without using any kind of gravitational slingshot, if eccentricity of orbits is not a factor, launch windows are periodic according to the synodic period; for example, in the case of Mars the period is 2.135 years, i.e. 780 days. In other cases launch windows are irregular. Sometimes rare opportunities are used. When a rare opportunity is missed, sometimes another target has to be selected.

For launches above low Earth orbit (LEO), the actual launch time can be somewhat flexible if a parking orbit is used, because the inclination and time the spacecraft initially spends in the parking orbit can be varied.

Launch windows are often calculated from porkchop plots which show the delta-v needed to achieve the mission, plotted against the launch time.

Related terms

The term 'launch window' was popularized with the worldwide coverage of the early space program. People in business came to use the phrase window of opportunity to be defined by specific range of dates, within which, they must take action or miss the chance to leverage the marketplace to their benefit.

ee also

*Collision avoidance
*Delta-v
*Delta-v budget
*Hohmann transfer orbit
*Interplanetary travel
*Space rendezvous


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Look at other dictionaries:

  • launch window — n. the period of time during which a missile, spacecraft, etc. must be launched so that it can arrive at a desired location at a specific time …   English World dictionary

  • launch window — a precise time period during which a spacecraft can be launched from a particular site in order to achieve a desired mission, as a rendezvous with another spacecraft. Also called window. [1960 65] * * * launch window noun The period of time… …   Useful english dictionary

  • launch window — {n.}, {Space English}, {informal} 1. A period of time when the line up of planets, Sun, and Moon are such as to make favorable conditions for a specific space launch. * /The mission was canceled until the next launch window which will be exactly… …   Dictionary of American idioms

  • launch window — {n.}, {Space English}, {informal} 1. A period of time when the line up of planets, Sun, and Moon are such as to make favorable conditions for a specific space launch. * /The mission was canceled until the next launch window which will be exactly… …   Dictionary of American idioms

  • launch\ window — noun Space English informal 1. A period of time when the line up of planets, Sun, and Moon are such as to make favorable conditions for a specific space launch. The mission was canceled until the next launch window which will be exactly six weeks …   Словарь американских идиом

  • launch window — launch′ win dow n. ars the time period when a spacecraft must be launched if it is to achieve its mission • Etymology: 1960–65 …   From formal English to slang

  • Launch window — Startfenster bezeichnet den Zeitraum, zu dem ein Start eines Raumflugkörpers möglich ist, so dass die Mission erfüllt werden kann. Gelingt es nicht, den Start innerhalb des Startfensters durchzuführen, muss er bis zum nächsten Startfenster… …   Deutsch Wikipedia

  • launch window — The earliest and latest time a rocket may launch …   Military dictionary

  • Launch Window —    A period of time, ranging from minutes to hours, within which a launch must occur for a rocket or Space Shuttle to place its payload in the proper orbit …   The writer's dictionary of science fiction, fantasy, horror and mythology

  • launch window — noun Date: 1962 window 8 …   New Collegiate Dictionary

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