SpaceShipOne
Unpowered flight 09G carried SpaceShipOne high over the [[Mojave Desert
SpaceShipOne is an experimental spaceplane, which on June 21 2004 made the first privately-funded human spaceflight. It is an air launched suborbital spacecraft, using a hybrid rocket motor. It has been developed by Scaled Composites, Burt Rutan's aviation company, in their Tier One program, with no government funding.
SpaceShipOne is a leading contender for the Ansari X Prize, a prize to be awarded to the first demonstrated privately-funded reusable spacecraft. It is expected to make prize-winning flights in September 2004.
Features
SpaceShipOne is designed as a suborbital spacecraft, meaning it will achieve sufficient altitude to reach space but not sufficient speed to sustain orbit. It is designed to exceed 100 km altitude, which is the international definition of the boundary to space and the threshold required to win the X Prize. SpaceShipOne shares some features from earlier rocket planes.
It uses a hybrid rocket motor developed by SPACEDEV Inc, using hydroxy-terminated polybutadiene (rubber) solid fuel with liquid nitrous oxide as an oxidiser.
Two primary flight elements, working in concert, achieve a manned suborbital flight, and taken together they constitute a two-stage horizontally-launched space transportation system that takes off from a runway, and lands on one. The first stage is the White Knight carrier jet, which takes the second-stage, a suborbital rocketplane designated SpaceShipOne, to a high altitude, where it is drop-released and air-launched.
For reentry the wings can be swivelled from horizontal to nearly vertical to provide a stable high-drag configuration. This is referred to as "wing feathering", and Scaled Composites describe the result as "care-free reentry".
The cockpit has space for three people, the pilot and two passengers. It maintains a sea-level pressurized breathable atmosphere, so the occupants do not need to wear spacesuits. The cockpit is also identical to White Knight, right down the equipment installed, to allow greater testing of the design.
Like the Space Shuttle Orbiter, SpaceShipOne is incapable of independent takeoff from the ground, and is also incapable of independently achieving the altitude required to execute a successful spaceflight. For takeoff it is carried under White Knight. The combination of SpaceShipOne and White Knight can take off, land, and fly under jet power to high altitude.
When separated from White Knight in the air, and with its rocket engine not operating, SpaceShipOne is a glider. It is registered with the FAA as a glider, reflecting the fact that most of its independent flight occurs in this mode.
SpaceShipOne's sole means of propulsion is its single hybrid rocket engine. This engine produces the enormous thrust necessary to propel the craft out of the atmosphere. Scaled Composites has not published engine performance statistics.
The rocket engine is ignited while the craft is gliding. Under power, it is soon pointed upwards, and climbs essentially vertically. The longest rocket burn performed in flight so far was 76 seconds (flight 15P), but it can hold fuel for a slightly longer burn than that.
By the end of the burn the craft is flying upwards at a speed somewhat greater than that of sound, and it continues to coast upwards unpowered. If the burn was long enough then it will exceed an altitude of 100 km, at which height the atmosphere presents no appreciable resistance, and the craft experiences free fall for a few minutes.
While at apogee the wings are reconfigured into high-drag mode. As the craft reenters the atmosphere it decelerates violently, but nevertheless achieves high speeds comparable to those achieved on the way up. At some altitude between 10 km and 20 km it reconfigures into low-drag glider mode, and glides down to a landing in about 20 minutes.
White Knight takes longer to descend, and typically lands a few minutes after SpaceShipOne.
Some right-wing commentators have drawn comparisons between the relative inexpense of the SpaceShipOne program and the high cost of the Space Shuttle program, though the technological difficulties of the two programs are completely different. SpaceShipOne, because it flies suborbitally, does not need to reach the high speeds of the Space Shuttle (Mach 3 vs. Mach 25), nor the same altitude (100 km suborbital vs. 400 km orbit). SpaceShipOne also does not carry the same crew (3 men vs. 7) or payload (negligible vs. 25 tons), and makes much shorter flights (a few minutes vs. several days). The SpaceShipOne program is a technical achievement more on-par with the Mercury program than the Shuttle.
White Knight
On April 1, 2004, Scaled Composites received the first license for sub-orbital piloted rocket flights to be issued by the US Department of Transportation. This license permits the company to conduct powered test flights for a period of one year.
SpaceShipOne is registered with the FAA as N328KF. 'N' is the prefix for US-registered aircraft; '328KF' stands for 328 thousand (K) feet (approximately 100 kilometers, the officially designated edge of space). The original choice of registry number — N100KM — was already taken.
All the SpaceShipOne flights have been based at the Mojave Airport Civilian Flight Test Center which reclassified itself (part-time) as the Mojave Spaceport on June 17, 2004. Test pilots for the Tier One project are Brian Binnie, Peter Siebold, Mike Melvill, and Doug Shane.
Flight 15P was SpaceShipOne's first spaceflight, and the first privately-funded human spaceflight. Whilst this was a successful test flight, it had several technical problems, now resolved.
In the table below, the "top speed" reported is the Mach number at burn-out (the end of the rocket burn). This is not an absolute speed.
Flight modes
SpaceShipOne flies in three significant modes: mated to White Knight, gliding, and rocket-propelled.Flight profile
SpaceShipOne takes off from the ground, attached to White Knight in a parasite configuration, and under White Knight's power. The combined craft flies to an altitude of around 14 km, which takes about an hour. SpaceShipOne is then released, and briefly glides unpowered. Rocket ignition may take place immediately, or may be delayed. If the rocket is never lit then the craft can glide down to the ground, as took place in the glide tests.Perspective
The costs of development and construction for SpaceShipOne, although not publicly released, are estimated to be in the range of 20 million dollars (US), roughly twice the value of the Ansari X Prize award. Paul Allen, a cofounder of Microsoft, is the sole source of the funding.Flights
| Flight | Date | Top Speed | Altitude | Pilot |
|---|---|---|---|---|
| 11P | December 17, 2003 | Mach 1.2 | 20.7 km | Brian Binnie |
| 13P | April 8, 2004 | Mach 1.6 | 32.0 km | Peter Siebold |
| 14P | May 13, 2004 | Mach 2.5 | 64.3 km | Mike Melvill |
| 15P | June 21, 2004 | Mach 2.9 | 100.1 km | Mike Melvill |
Scaled Composites report that the next flights will be attempting to win the X Prize. They will not take place before September, due to X Prize rules requiring 60 days notice. They are planning to make three flights within two weeks, rather than just the required two, to allow room for error. See the separate article on SpaceShipOne flight 16P.
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