When a projectile flies at supersonic speed in a ram-accelerator tube, which is filled with pre-mixed gas of fuel and oxidizer, the gas mixture is compressed and ignited by the shock waves which are formed around the projectile to yield the thrust. This concept has a good scalability and is capable of accelerating payloads of various mass. Utilizing the advantages of the ram accelerator, two direct launch systems are conceptually designed. One of these is a launch system to a low earth orbit and the other is a middle altitude meteorological observation launch system. The LEO launch system is aiming to accelerate a projectile of 2000 kg to the velocity of 6 km/s. To attain this velocity the launch tube of nearly 900 m is needed. The launcher will be located on the western side of the mountain near the equator aimed at 20 degrees from horizontal and towards the east. In the meteorological observation launch system the projectile mass considered is 12 kg and the launch velocity is 1.8 km/s. Required length of the tube in this case is about 35 m. Because of the launch angle of 80 degrees taken from horizontal, it is probably suitable to built the launcher under the ground. To realize the LEO launch system, there are quite a few technical challenges, such as the experimental demonstration of the velocity of 6 km/s, the development of an on-board propulsion system for orbiting the projectile, and solutions of the structural problems of constructing a huge ram accelerator system. On the other hand, the meteorological observation launch system is simpler and smaller than the LEO launch one and it seems that there is no critical problem preventing it from being realized.

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A feasibility study is presented on an application of superconducting linear synchronous motor (LSM) to a large - scale rocket launcher, whose acceleration guide tube of LSM armature windings is constructed as far as the depth of 1,500 meters under the ground. The rocket is released from the linear launcher just after it gets to a peak speed of about 900 kilometers per hour, and flies out the guide tube to obtain the speed of 700 kilometers per hour at the height of 100 meters above the ground. The linear launcher is brought to a stop at the ground surface for a very short time of 5 seconds by a quick control of deceleration. Very large current variations in the single - layer windings of LSM armature which is produced at the higher speed region of 600 to 900 kilometers per hour are controlled successfully by adopting the double - layer windings. The proposed control method makes the rocket launcher ascend stably in the superconducting LSM system, controlling the Corioli’s force.

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This paper summarizes the result of a preliminary study on the use of on-ground take off assists to realize a space plane propelled by rocket engine(s) with off-the-shelf technology. Preliminary study result shows that high speed take-off assist is beneficial for the space plane with rocket engine and ground effect machine seems promising for take-off assist mainly because of its higher velocity compared to other means. Further investigations will be made to get optimum flight trajectory and vehicle configuration.

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N-clusters have unique caged structures like C60 and are expected to be new energetic materials because they have only energetic N-N single bonds. Heats of formation of N-clusters calculated by the semi-empirical molecular orbital calculation were much higher than any other energetic materials. The heat of formation of N60 was 10.48MJ/mol. They all were vibrationaly stable, and N-N bond energies were larger than that of hydrazine, so N-clusters may exist stably. Specific impulse of the propellant added 40% of N60 was 306s compared to 273s of the ammonium perchlorate based propellant. N-clusters are possible to be a new energetic propellant ingredients.

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