The Orbital Re-entry Experiment (OREX), renamed Ryusei after launch; flight experiment is part of the research for the H-2 Orbiting Plane (HOPE).

Its purposes are to contribute to HOPE development by accumulating experience in designing and producing a re-entry vehicle and acquiring re-entry data which is difficult to acquire in ground experiments. The OREX vehicle was launched and inserted into orbit by H-II rocket in February 1994. It was then re-enter the atmosphere after one revolution. The vehicle was collected experimental data during re-entry, transmitted after re-entry, and splashed down in the Central Pacific Ocean. The OREX project was conducted in cooperation with the National Aerospace Laboratory (NAL).

The OREX flight experiment is part of the research for HOPE to answer some critical technical questions. OREX is especially designed to acquire the following data related to atmospheric re-entry:

- Aerodynamic and aerodynamic heating data during re-entry
- Heat-resistant structural data during re-entry
- Communications blackout data during re-entry
- GPS navigation data during re-entry and in orbit

The OREX vehicle has a blunt-cone shape. The front of the vehicle, which is subjected to aerodynamic heating du-ring re-entry, is constructed of carbon/carbon material and ceramic tiles. These heat-resistant and thermal protective materials are planned to be used in HOPE. Temperature sensors and pressure sensors are installed in the vehicle.

The Vehicle Evaluation Payload (VEP), renamed Myojo after launch, was a Japanese spacecraft that was launched by an H-2 rocket from the Tanegashima Tanegashima launch site.

It provided a ranging function as well as functions to measure the acceleration and deformation, in order to confirm the accuracy of the H-2 rocket orbit injection and understand the environment of the payload equipment. It remained intentionally attached to the second stage of the H-2 launch vehicle. It carried the OREX reentry experiment on top, which was deployed in orbit.