Future --- Space Plane --- NASA's X-Fleet Spaceship

Today, there are several new X-planes being developed, let's discuss three of them:
- The X-37, which will test many space plane technologies, including re-entry capabilities.
- The X-34, a suborbital vehicle that will test technologies to reduce cost, time and personnel for space launches.
- The X-33, a reusable launch vehicle (RLV) that is a prototype for a space shuttle replacement.

X-37
X-37 is the newest and fastest X-planes among the three mentioned above. The X-37 will not be launched under its own power, but others will. It is designed to be launched into space on a secondary vehicle. A unmanned, programmable plane will ride onboard the space shuttle as a secondary payload. When in orbit, the X-37 will be deployed from the shuttle's cargo bay. It will then remain in orbit for 21 days, performing a number of experiments before returning to Earth and landing like an airplane.
The X-37 is the only one of the two space planes that is designed to be an orbital plane, and is able to travel at about 28,000 km/h.
The aim of the X-37 project is to test RLV technologies in harsh space environments, and demonstrate about 40 advanced airframe, propulsion and operations technologies. A main focus of the X-37 project is to improve the thermal protection systems that keep spacecraft from burning up during re-entry. The vehicle will be propelled by then AR-2/3 rocket engine, which can produce more than 7,000 pounds of thrust. The AR-2/3 uses JP-10 jet fuel, which is a type of kerosene, and hydrogen peroxide as propellants.
Here are the facts of a X-37 plane:
Length - 8.38 m (27.5 feet)
Weight - 6 tons
Length of a wingspan - 4.57 m (15 feet)
Size of the experiment bay - 2.13 X 1.21 m (7 X 4 feet)
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X-34
X-34 is testing new technologies to build future spacecraft that will low mission costs.
In 1999, NASA strapped the unmanned X-34 to the underbelly of an L-1011 carrier aircraft for a captive carry flight, in which the X-34 remained attached to the L-1011 for the duration of the flight. During the test flight, scientist were capable to analyzing several functions of the X-34, including the release of rocket propellant into the engine and electrical connections between the X-34 and the L-1011. Later, the X-34 will be dropped from the L-1011 at an altitude of 40,000 feet, and glide unpowered down to a runway landing. The X-34 space plane will be powered a Fastrac rocket engine, which is built mostly from off-the-shelf components, and has fewer parts than other rocket engines. The Fastrac rocket engine operates with a single turbopump, which is composed of only two pumps -- one for kerosene and one for liquid oxygen. The engine's gas generator cycles a small amount of kerosene and oxygen to provide gas to drive the turbine, and then exhausts the spent fuel.
Here are the facts of a X-34 plane:
Length - 17.6 m (58 feet)
Length of a wingspan - 8.53 m (28 feet)
Speed - 9012 kph (5600 mph)
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X-33
X-33 is the most expensive and the most ambitious of NASA's space planes. The X-33 is a prototype for a unique single-stage-to-orbit vehicle. It's wedge-like shape is unlike any spacecraft that has preceded it.
At its base, the width of the X-33 is longer than its length. The purpose of the design is to allow the spacecraft to hold all of the needed propellant onboard the ship, thus eliminating thr need for solid rocket boosters, so the weight is much be reduced. The cost of launching a X-33 is expected to be only a tenth of the cost of lauching the space shuttle.
The X-33 will be propelled by two uniquely designed engines. It is the first space plane to use Linear Aerospike engines. The shape of the engines is a better fit for the wedge-shaped X-33 than the conventional bell nozzle rocket engines. The Aerospike nozzle is V-shaped, which is called a ramp, is different from the nozzle of the Bell rocket engines. The hot gases are shot from the chambers along the outside of the ramp's surface.
The ultimate goal of the X-33 prject is to produce a commercial aircraft called the VentureStar, which will replace the space shuttle. The size of the VentureStar will be about twice that of the X-33 prototype. Also, the VentureStar will use the same type of engines and the same construction materials. No only would the VentureStar be used to put payloads into space, but it could also be used as a space tourism vehicle. The success or failure of the X-33 will determine whether the VentureStar becomes the vehicle that enables public access to space.
Here are the facts of a X-33 plane:
Length - 21 m (69 feet)
Width - 23.5 m (77 feet)
Speed (when using Linear Aerospike engines) - 14,645 kph (9,100 mph)
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NASA's X-Fleet Spaceship