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http://en.wikipedia.org/wiki/Rocket_launch

Launching of Mercury-Redstone 2.

A rocket launch is the first phase of the flight of a rocket. For orbital spaceflights, or for launches into interplanetary space, which is usually a fixed location on the ground but may also be on a floating platform such as the San Marco platform, or the Sea Launch launch vessel.

Launches of suborbital flights (including missile launches), can also be from:

• a missile silo
• a mobile launcher vehicle
• a submarine
• air launch:
  • from a plane (e.g. Scaled Composites SpaceShipOne, Skybolt Ballistic Missile, X-15)
  • from a balloon (Rockoon, da Vinci Project (under development))
• a surface ship (Aegis Ballistic Missile Defense System)
• an inclined rail (skyramp)

Launches not into space can also be from:

• the shoulder

"Rocket launch technologies" generally refers to the entire set of systems needed to successfully launch a vehicle, not just the vehicle itself, but also the firing control systems, ground control station, launch pad, and tracking stations needed for a successful launch and/or recovery.

Commercial launches

Commercial launch service providers include:

• Boeing Launch Services Inc. (BLS) - Delta rocket
  • Sea Launch - Zenit-3SL (Zenit rocket stages 1 and 2 with Energia Block DM-SL upper stage)
• EADS SPACE Transportation / Arianespace - Ariane rocket
• International Launch Services (ILS) [1] - Proton rocket
• United Launch Alliance (ULA) - Delta IV And Atlas V
• Starsem - Soyuz rocket
• ISRO - PSLV,GSLV

Viewing rocket launches

In the United States, dates for commercial and manned space launches are matters of public record, and are available months ahead of time. The exact dates of military launches remain confidential until only days before, but the months are public as well.

With the exception of the Space Shuttle, the visitor complex of the John F. Kennedy Space Center in Florida is open to the general public (with a nominal admission fee) for viewing rocket launches from the Space Center and from Cape Canaveral Air Force Station. Viewing Space Shuttle launches from the visitor center requires special reservations. The visitor center is generally 10 km (6 miles) from the launch pads. Special reservations for the Space Shuttle are required because it is a much more powerful vehicle than the expendable launch vehicles currently in use, as well as the possibility of a disaster that would result in immediate death for the astronauts, such as the explosion of Challenger at the launch of mission STS-51-L. Outside the center itself, the best launch viewing sites are along the beaches within the vicinity.

Launches from Vandenberg Air Force Base in California can best be seen from the cities of Santa Maria or Lompoc, or the surrounding beaches.

Launches by Russia from the Baikonur Cosmodrome in Kazakhstan can best be viewed from the city of Baikonur.

Launches by the European Space Agency from Guiana Space Centre in French Guiana can best be viewed from Kourou or the surrounding beaches.

Launch vehicles

If a rocket is launched to deliver a payload from a planetary surface into space it is called a launch vehicle.

There are several broad categories that launch vehicles fall under, including:

• Expendable launch system
• Reusable launch system
• Single stage to orbit
• Two stage to orbit

For the launch vehicles currently in use for human spaceflight, see that article.

There were ca. 46 launches into space in 2004.

Orbital launches

Orbital launch vehicles take off vertically, and then begin to progressively lean over, usually following a gravity turn trajectory.

Once above the majority of the atmosphere the vehicle then angles the rocket jet, pointing it largely horizontally but somewhat downwards, this permits the vehicle to gain and then maintain altitude while increasing horizontal speed. As the speed grows the vehicle will become more and more horizontal until at orbital speed, the engine will cut off.

All current vehicles will stage- jettison hardware on the way to orbit.

When launching a spacecraft to orbit, a "dogleg" is a guided, powered turn during ascent phase that causes a rocket's flight path to deviate from a "straight" path. A dogleg is necessary if the desired launch azimuth, to reach a desired orbital inclination, would take the ground track over land (or over a populated area, e.g. Russia usually does launch over land, but over unpopulated areas), or if the rocket is trying to reach an orbital plane that does not reach the latitude of the launch site. Doglegs are undesirable due to extra onboard fuel required, causing heavier load, and a reduction of vehicle performance.

See also

• Launch mechanisms
• Gravity drag
• Non-rocket spacelaunch‎
• List of rockets
• Orbital spaceflight
• Sub-orbital spaceflight
• Takeoff
• Spaceport
• List of rocket launch sites

External links

• Orbital Launches of 2004
• Scheduled and past launches, in principle all from 1999

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Published in July 2009.

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