HYFLEX (Hypersonic Flight Experiment) was a National Space Development Agency of Japan reentry demonstrator prototype which was launched in 1996 on the only flight of the J-I launcher. It was a successor of OREX and was a precursor for the Japanese space shuttle HOPE-X.

WebsiteAt JAXA.jp
Apogee110 km (68 mi)
Spacecraft properties
ManufacturerMitsubishi Heavy Industries
Launch mass1,054 kg (2,324 lb)
DimensionsLength:4.40 m (14.4 ft)
Span:1.36 m (4 ft 6 in)
Height:1.04 m (3 ft 5 in)
Start of mission
Launch dateFebruary 11, 1996 (1996-02-11)
Launch siteLA-N, Tanegashima Space Center
End of mission
Disposalsplashed down
recovery failed
Landing dateFebruary 11, 1996 (1996-02-11)
Landing sitePacific Ocean near Chichi-jima

HYFLEX tested the carbon-carbon heat shielding tiles that were intended to be used on HOPE, as well as having the same body shaping in order to gather data on hypersonic lifting. HYFLEX flew in space at 110 kilometres (68 mi) altitude and succeeded in re-entry, but sank in the Pacific after splashdown before it could be recovered.


HYFLEX was an uncrewed lifting body space plane for gaining technological prowess in the design, production, and flight of hypersonic crafts, as well as technology validation of atmospheric reentry.[1][2] The experimental vehicle was covered in carbon–carbon, ceramic tiles, and flexible thermal insulation, which were materials that was to be used for HOPE.[1]

Launched in 11 February 1996 (UTC) from Tanegashima Space Center by a J-I rocket, separation from the rocket was conducted at an altitude of 110 km (68 mi), speed of approximately 3.8 km/s.[3] Attitude control was performed by gas thrusters and aerodynamic rudders.[1] During its descent the craft glided in a right turn circling the island of Chichijima in the Ogasawara Archipelago. HYFLEX had various sensors attached to each parts, and succeeded in gaining data on surface aerodynamic heating and pressure.[3] The craft splashed down in the waters northeast of Chichijima with parachutes, however the floats and riser broke off while floating and recovery was abandoned.[3] HYFLEX was succeeded by ALFLEX.

See alsoEdit


  1. ^ a b c "Hypersonic Flight Experiment "HYFLEX"". JAXA. Retrieved 2018-12-10.
  2. ^ "実験概要と目的" (in Japanese). JAXA. Archived from the original on 16 February 2010. Retrieved 2018-12-10.
  3. ^ a b c "極超音速飛行実験「HYFLEX」" (in Japanese). JAXA. Retrieved 2018-12-10.