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Space


J-I

A third new launch vehicle concepts emerged during 1991-1992. Called J-I, the new booster would serve the small satellite community with a one-metric-ton payload capacity to LEO in its basic configuration. The J-I is the first rocket in Japan to be developed by combining existing rockets. After some evolution the J-I design solidified around a 3-stage, solid-propellant vehicle using modified H-II strap-on booster for the first stage and the second and third stages of the M-3SII, with a LEO payload capacity of up to 900 kg. Growth options include adding two or more small strap-on boosters or augmenting the first stage with two additional H-II class strap-ons.

The project, approved in 1993, was sponsored by NASDA with cooperation from ISAS. The first orbital mission was scheduled for 1998, but a 2-stage sub-orbital mission HYFLEX (Hypersonics Flight Experiment) was conducted in 1996. HYFLEX test design and modeling principles were critical to the development of a future space plane (References 124 and 135-139).

HYFLEX (Hypersonic Flight Experiment) was performed for the purpose of accumulation of designing, constructing and operating technology of a vehicle flying at hypersonic speed like a plane and acquisition of various data which are difficult to obtain by ground tests. The surface of the vehicle is covered with carbon/carbon, ceramic tiles, and flexible insulator, which are planned to be used on the HOPE. The navigation of the vehicle employs IMU and the attitude control is to be performed by using combination of RCS and elevons. The vehicle is equipped with temperature and pressure sensors, and refectometers.

HYFLEX vehicle was launched by J-I launch vehicle in February 1996. It collected several useful data in flight and splashed down in the ocean. But it was unsuccessfully recovered.

The development of the second J-I launch vehicle has been suspended, according to a reexamination in the Space Development plan of space Activities Commission.

J-I


Background Information
First Launch:
February 1996
Flight Rate:
2 per year
Launch Site:
Osaki Launch Site (Tanegashima, Japan)
Capability:
1,980 lb to LEO

History

  • Conceptual study conducted in 1991
  • Preliminary design conducted in 1983
  • Critical design conducted in 1994
  • First flight in February 1996

Description

  • Three-stage vehicle combining the H-II solid rocket booster for stage 1 and the M-3SII upper stages for stage 2 and 3 and payload fairing
  • Stage 1 burns HTPB composite grain fuel, generating 350,000 lb of thrust
  • Stage 2 burns HTPB composite grain fuel, generating 118,000 lb of thrust
  • Stage 3 burns HTPB composite grain fuel, generating 29,700 lb of thrust

Profile

Length:
108.6 ft
Launch Weight:
196,000 lb
Diameter:
5.9 ft (stage 1)
Liftoff Thrust:
350,700 lb
Payload Fairing:
22.5 ft x 5.4 ft




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