SpaceShipOne

SpaceShipOne merupakan pesawat yang bukan milik kerajaan yang pertama mencecah kawasan hampagas di angkasa pada altitude 100 kilometer. Ini merupakan nilai rambang, telah diiktiraf secara rasmi sebagai pengesahan untuk penerbangan angkasa. SpaceShipOne dilancarkan oleh pesawat induk White Knight. Juruterbang Mike Melville secara rasmi disenaraikan sebagai angkasawan swasta yang pertama. Angkasawan sebelum ini hanya menaiki kapal angkasa yang direka, dibayar, dan beroperasi melalui agensi kerajaan.

SpaceShipOne dibiayai oleh orang kuat Microsoft, Paul Allen dengan modal sebanyak US$20 juta yang bertujuan mendapatkan hadiah X-Prize. Yayadan Ansari X-Prize ditubuhkan bagi menggalakkan penerbangan angkasa oleh sektor swasta dan sehingga kini 26 pasukan telah menyahut cabaran untuk bersaing bagi mendapatkan hadiah sebanyak US$10 juta.

Program Tier One ditubuhkan oleh Rutan secara rasmi pada April 2003 sebagai satu langkah bagi membina perlancungan angkasa melalui kejuruteraan dan design inovasi. Untuk memenangi hadiah X-Prize, SpaceShipOne perlu melakukan dua penerbangan dalam tempoh dua minggu. Walaupun sekiranya SpaceShipOne berjaya, kejayaan ini tidak akan mematahkan semangat 25 pasukan lain, tetapi kejayaan ini akan memberikan galakan kepada pasukan lain untuk memberikan peluang lain bagi orang awam mengalami keseronokan penerbangan angkasa.

Fail:SpaceShipOne-09G.jpg

Penerbangan tanpa kuasa 09G membawa SpaceShipOne merentasi Gurun Mojave untuk ujian aerodinamik.

SpaceShipOne adalah kapal terbang angkasa ujian dibiayai secara persendirian yang dimajukan oleh syarikat Burt Rutan, Scaled Composites, dalam program Tier One mereka, sebagai penyertaan mereka dalam pertandingan Hadiah X Ansari. Pada 21 Jun 2004 ia melakukan it made the first privately-funded human spaceflight.

Ciri-ciri

SpaceShipOne direka sebagai kapal angkasa suborbital, bererti ia akan mencecah ketinggian mencukupi bagi mencapai angkasa tetapi tidak mempunyai kelajuan yang mencukupi bagi mengekalkan orbit. Ia direka bagi melebihi ketinggian 100 km, yang merupakan ketetapan antarabangsa sebagai sempadan angkasa dan merupakan tahap yang diperlukan bagi memenangi Hadian X. SpaceShipOne berkongsi sesetengan ciri dengan kapal terbang roket terdahulu.

Ia menggunakan motor berasaskan enjin hibrid direka oleh SPACEDEV Inc., menggunakan bahan api pepejal 'hydroxy-terminated polybutadiene' (getah) dengan cecair nitrous oxide sebagai pengoksida.

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.

Jenis penerbangan

SpaceShipOne flies in three significant modes: mated to White Knight, gliding, and rocket-propelled.

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.

Profil penerbangan

SpaceShipOne takes off from the ground attached to White Knight, 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.

Enjin roket dihidupkan 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.

Pembangunan

Kos pembangunan dan pembinaan SpaceShipOne, walaupun tidak diumumkan, adalah dianggarkan sebanyak USD 20 juta, sekurang-kurangnya dua kali ganda daripada nilai hadiah Ansari X Prize. Paul Allen, a cofounder of Microsoft, is the sole source of the funding.

Ujian penerbangan

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Semua penerbangan SpaceShipOne bermula dengan White Knight membawa SpaceShipOne ke altitud lebih kurang 14km, as demonstrated in this captive carry test of the two-vehicle system.

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.

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.

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.

Juruterbang yang menguji projek SpaceShipOne ualah Brian Binnie, Peter Siebold, Mike Melvill, dan 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, and SpaceShipOne is now being closely examined for technical defects in order to rectify them prior to making an X Prize attempt.

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.

SpaceShipOne powered test flights
Penerbangan	Tarikh	Kelajuan Tertinggi	Altitud	Juruterbang
11P	17 Disember 2003	Mach 1.2	20.7 km	Brian Binnie
13P	8 April 2004	Mach 1.6	32.0 km	Peter Siebold
14P	13 Mei 2004	Mach 2.5	64.3 km	Mike Melvill
15P	21 Jun 2004	Mach 2.9	100.1 km	Mike Melvill

Pautan luar

• SpaceShipOne di laman web Scaled Composites
• SpaceShipOne video footage di laman web BBC News (memerlukan RealPlayer; this is not the 100km flight, but an earlier, shorter test flight, probably flight 14P)
• Private Craft to Shoot for Space oleh Irene Mona Klotz, Discovery News
• Gambar-gambar pelancaran pada 21 Jun 2004