Zur deutschen Seite

The 400 N Propulsion System

Fabrication Responsibility:
Average Power Dissipation:


The bipropellant propulsion system is a repackaged and updated version of those used successfully in the OSCAR 10 and 13 projects. It incorporates the 400 N motor, being provided by a German aerospace company, that utilizes monomethylhydrozine (MMH) for fuel and nitrogen tetroxide (N2O4) for oxidizer. The higher mass of the Phase 3D spacecraft, has required going to multiple propellent tanks to carry the larger amounts required for the mission - over 60 kilograms of MMH and 130 kilograms of N2O4. The plumbing required to transfer the propellants from the tanks to the motor has been designed for simplicity, but with sufficient redundancy to assure safety. Helium gas from a high pressure storage tank is regulated to a lower pressure the lower pressure required to operate the system by pulsing an electrically operated gas valve referenced to a pressure transducer. This gas is used both to pressurize the propellant tanks, through redundant check valves, feed the propellants to the motor and operate the motor valves. The pressure regulation system, includes a second electrically operated valve in series with the first, to take over regulating function should the first fail. A relief valve provides additional safety.
Last updated: Sep 27, 1996
by Ralf Zimmermann, DL1FDT