In FEEP thrusters, field ionisation of propellant, usually cesium, occurs on the liquid metal surface at the outlet of a micrometric slit. Some concern was raised on the use of FEEP in low Earth orbit, since it was feared that the relatively high atomic oxygen concentration could provoke clogging of the slit due to cesium oxidation. To assess this potential failure mechanism we have investigated the FEEP thruster compatibility with a 200 km altitude atomic oxygen environment. In our experiment, a 50 mm slit, 1 mN FEEP thruster was exposed to direct impingement of atomic oxygen. Ion emission quality was monitored using scanning electrostatic probes. No significant degradation of the thruster performance was observed after as long as 384 hours total exposure to severe atomic oxygen flux and to an intense molecular oxygen background. It is concluded that the FEEP thruster can survive in a very low LEO environment without failures due to interaction with the residual atmosphere.
FEEP Thruster Survivability in the LEO Atomic Oxygen Environment
MARCUCCIO, SALVO;ANDRENUCCI, MARIANO
2001-01-01
Abstract
In FEEP thrusters, field ionisation of propellant, usually cesium, occurs on the liquid metal surface at the outlet of a micrometric slit. Some concern was raised on the use of FEEP in low Earth orbit, since it was feared that the relatively high atomic oxygen concentration could provoke clogging of the slit due to cesium oxidation. To assess this potential failure mechanism we have investigated the FEEP thruster compatibility with a 200 km altitude atomic oxygen environment. In our experiment, a 50 mm slit, 1 mN FEEP thruster was exposed to direct impingement of atomic oxygen. Ion emission quality was monitored using scanning electrostatic probes. No significant degradation of the thruster performance was observed after as long as 384 hours total exposure to severe atomic oxygen flux and to an intense molecular oxygen background. It is concluded that the FEEP thruster can survive in a very low LEO environment without failures due to interaction with the residual atmosphere.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
