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The 400 N Propulsion System
- Fabrication Responsibility:
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- Size:
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- Average Power Dissipation:
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Description
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