Beijing Drop Tower Microgravity Adjustment Towards 10–3 ~ 10−5g Level by Cold-Gas Thrusters

Drop tower is an important facility for conducting microgravity experiments on the ground. Since the Beijing drop tower was put into operation in 2003, a large number of scientific experiments have been carried out in the fields of microgravity fluid physics, combustion, materials science and fundamental physics. The drop tower has two operation modes: single capsule falling and double capsule falling, with the microgravity levels reaching 10⁻²g ~ 10⁻³g and 10⁻⁵g respectively. In order to meet the demand of multi-level microgravity levels in ground microgravity experiments, a double capsule microgravity level control system based on the cold-gas micro thruster is developed. The micro thrusters are mounted in the inner capsule of the double capsule system. During the fall of the double capsule, the cold-gas micro thrusters thrust in the opposite direction of the movement of the structure, which increases the resistance of the inner capsule to realize the control of microgravity level. The measurement results of the high-precision accelerometer show that the 10^–3 ~ 10⁻⁵g microgravity level can be controlled by this system.