Stable and reproducible production of high velocity projectile in ISAS railgun (HYPAC)

The ISAS (Institute of Space and Astronautical Science) railgun HYPAC (power supply: 6 mF, 10 kV, 300 kJ; rail: 13 mm phi *2 m bore) has been developed with a particular emphasis on stable and reproducible production of a high-velocity projectile so that it can actually be used for scientific impact experiments. A maximum velocity of 7.45 km/s has been obtained for a 0.87 g projectile in 4 mF, 288 kJ operation. The stability and reproducibility of HYPAC are so good that a velocity greater than 6 km/s can always be obtained with a prediction within +or-3% before the experiment. HYPAC is now extensively used for impact experiments for laboratory simulation in the field of planetary science.<>