Hope X

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Hope X is a former spacecraft project of the former Japanese space agency NASDA ( National Space Development Agency ) in cooperation with the National Aerospace Laboratory of Japan (NAL). In the meantime, both organizations have been merged into the Japan Aerospace Exploration Agency (JAXA), and the project was no longer pursued.

Development and construction

Hope X is based on the plans for the manned space glider project Hope (H2 Orbiting Plane), which had to be discontinued in 1997 due to financial problems, and on also advanced plans for an unmanned transport shuttle . The manned low-budget space glider Hope X was derived from both projects. The Hope X, which is much smaller than the Space Shuttle , was primarily seen as a test vehicle. Later modifications should, for example, allow transport missions to the International Space Station . A larger, manned variant, Hope XA, should also follow.

Hope-X should have a length of 16.50 m, a wingspan of 12.00 m and a total mass of 13000 kg with a payload of 2000 kg. A modified single-stage H-IIA rocket , which was to be launched from the Tanegashima Space Center , was planned as a carrier for Hope X. For the first test flight, a one-time orbit around the earth in an orbit of 120 to 200 km and a subsequent landing was planned.

Test flights


The first test flight was called the Orbital Re-entry Experiment (OREX). The test specimen was a disk-shaped spacecraft with a diameter of 3.40 m, a thickness of 1.46 m and a launch mass of 865 kg. It was coated with heat-resistant material and contained temperature sensors. The purpose of the test flight was to test the controlled re-entry and the acquisition of measurement data on the temperature profile. The test specimen, named Ryusei , was launched into orbit on February 3, 1994 by an H2 rocket . After orbiting the earth at about 450 km altitude, Ryusei re-entered the earth's atmosphere and plunged into the Pacific Ocean as planned.


The next test flight took place in February 1996 and was called the Hypersonic Flight Experiment (HYFLEX). The experimental missile consisted of a space glider model of 4.40 m in length, 1.04 m in height and 1054 in mass. The model was brought to a suborbital trajectory of 110 km with a JI rocket from the Tanegashima Space Center . During this flight, the active attitude control, which ensures the correct entry angle and navigation to the planned landing site, was tested in particular. HYFLEX parachuted only 3 km from the targeted point on the island of Chichi-jima . A rescue after the ditching was planned, but HYFLEX sank in the ocean.


The next series of test flights were carried out with a reduced model (37% of the size) of the planned space glider. The ALFLEX (Automatic Landing Flight Experiment) had a length of 6.10 m, a height of 1.35 m and a mass of 760 kg. A total of thirteen successful test flights were carried out in Woomera , Australia in July and August 1996 . The ALFLEX was lifted and released by a helicopter , after which it then automatically touched down on a horizontal runway.


The last test flights were carried out in two phases under the name High Speed ​​Flight Demonstration (HSFD).

Phase 1

A test device with its own jet drive was manufactured for the test flights and was completed in August 2002. It is 25% of the planned size of Hope-X. The Aeon airfield on the Kiribati island of Kiritimati was chosen as the test site . The Japanese space agency also maintains a telemetry station there for H-II launches .

The take-off command for the test aircraft was given by remote control, after which the device controlled itself completely autonomously, climbed to a pre-programmed altitude and then went into a steep descent followed by a landing on the 1,800 m long runway.

The three test flights took place on October 18, November 5 and November 16, 2002 with increasing demands. On the last flight, the aircraft climbed to an altitude of 5005 m and reached a maximum speed of Mach 0.46. It was in the air for over 18 minutes.

Phase 2

The second phase of the test flights took place in Sweden in cooperation with the French space agency Center National d'Etudes Spatiales (CNES). The test specimen was the same size as in phase 1 (length 3.80 m, height 1.20 m), but this time it was without its own drive and was completed in March 2003. Esrange near Kiruna in Sweden was selected as the test site .

The only test flight took place on July 1, 2003. The glider was brought to an altitude of 21 km by a stratospheric balloon and then released. In free fall the glider reached a speed of Mach 0.8 after 29 s. The glider then regulated its attitude completely autonomously in order to keep the Mach number constant and then decelerated to Mach 0.75. 14 landing sites had been prepared, and the glider chose one of them independently. About four minutes after releasing, the landing system was to be activated at an altitude of 1,300 m so that the glider dropped on parachutes. The impact should be cushioned by airbags. The landing system failed, however, and the glider was damaged on impact.

As a result, the test program was initially only temporarily interrupted, but then never resumed.

Web links

Individual evidence

  1. ^ The fifth mission: HOPE-X. JAXA, archived from the original ; retrieved on January 17, 2011 (English): "Although the HOPE-X flight experiment had been planned for 2004, it was decided to review the R&D scenario of reusable space transportation technologies, and so the implementation of this experiment has been suspended." (English)
  2. Marcus Lindroos: Hope in the Encyclopedia Astronautica , accessed on January 17, 2011 (English).
  3. Ryusei in the NSSDCA Master Catalog , accessed January 17, 2011 (English).