Difference between revisions of "Spaceplane"

Revision as of 23:20, 26 December 2013

A spaceplane, the Aeris 4A, in orbit

A spaceplane is a hybrid of a plane and a rocket, capable of both flying in an atmosphere using wings, and moving outside of it using reaction engines.

Construction

Spaceplanes are usually built in the Space Plane Hangar and launched from the runway, although some are launched from the launchpad, often using a rocket to get it into space.

Various pre-built stock spaceplanes are available, although only the Aeris 4A has the means to reach space.

Propulsion methods

Commonly jet engines are used for fuel efficient propulsion in the atmospheres of Kerbin and Laythe. In space or oxygen-free atmospheres, some kind of reaction engine has to be used. Sometimes jet engines are completely replaced by reaction engines to simplify construction, while still being able to propel the craft anywhere. However, a plane with only jet engines cannot reach a stable orbit, because the engines will cease to work when leaving the atmosphere. It is still possible to achieve a high apoapsis though, as long as the acceleration takes place while still in the atmosphere.

Maneuvering methods

Maneuvering inside any atmosphere is usually done using winglets, control surfaces and/or reaction wheels, but RCS is also sometimes used in extreme situations. In space, maneuvering has to be done solely with RCS and reaction wheels. SAS is commonly used to keep a constant attitude while in atmosphere, as the spaceplane will otherwise keep tilting if the center of mass isn't exactly in the same position as the center of lift.

Landing methods

Landing is often done using only the landing gear, which was also used during takeoff. It is possible to use parachutes or rocket engines (such as the Sepratron I) to slow down, in addition to the gear's built-in brakes. However, in case of an emergency or lack of a good landing spot, the command module (if manned) can be separated, slowed down and landed safely using only parachutes. This requires a somewhat dense atmosphere though.

Landing

On a runway

On Kerbin, two runways exist on which spaceplanes can be landed. The first one is located at KSC, where most spaceplanes are also launched. It is quite long and wide, and even if an approach fails, landing is still possible on the flat surrounding area. The second runway, located at the Insular Airfield, is a grass landing strip, much shorter and narrower than the KSC runway, making it a more difficult target.

Elsewhere

Landing somewhere else than on a runway is possible if the terrain is flat enough. Most celestial bodies have rather flat areas, although one has to be careful not to head for occasional mountain ranges, cliffs or craters. The terrain on smaller bodies, especially on the Mun, is usually rougher than on larger ones, making landings there more difficult.

Without an atmosphere

Landing a spaceplane without an atmosphere is difficult compared to landing a conventional lander. The plane's wings increase inertia due to the added mass and they can break. Normal landing gears are difficult to land on due to their facing 90 degrees off of retrograde making hovering impossible. Landing on the normal gears can be done on Minmus for example, but is difficult for bodies with moderate gravity or higher. In most cases, either adding some small down-facing rockets, or some landing legs facing backward is necessary. It is also possible to design a plane with the cockpit built as a lander, and land it "Apollo-style" then return to orbit and dock with the winged half of the ship.

Purposes

• Refueling space stations in orbit around Kerbin
• Landing on Kerbin with the possibility to reuse the craft
• Landing on and taking off from other bodies with an atmosphere, such as Laythe, Duna or Eve

See also

• Spaceplane on Wikipedia