The ionic liquid FEEP (IL-FEEP) is new, simplified version of the field emission thruster where the alkali metal propellant is replaced by an ionic liquid. Development of the IL-FEEP thruster is based on the heritage of the cesium FEEP and is currently funded by ESA and EU programmes. This paper presents the results of a recent experimental campaign aimed at assessing the performance of a novel linear slit FEEP emitter fed with a ionic liquid propellant. Tests were done on a newly designed, 8-mm slit FEEP emitter made of glass, fed with EMI-BF4. The test setup allowed for continuous monitoring of the thruster electrical parameters, as well as for direct scanning of the exhaust beam profiles using electrostatic wire probes. The test results essentially validate the possibility to operate the linear slit FEEP emitter with ionic liquid propellant in pure ionic mode and confirm that the glass emitter is suited for operation with the selected propellant. Experimental results show very regular and repeatable performance in positive mode, while operation in negative polarity showed some irregularities in beam profiles. Thruster performance in a later test in alternate polarity mode was remarkably stable over a very long period, in spite of the predominance of positive mode firing that could have affected the propellant composition in the reservoir due to electrochemical degradation. Alternate polarity is therefore regarded as a promising operating mode for the simplified FEEP thruster.
Ionic Liquid FEEP: Recent Experimental Results
MARCUCCIO, SALVO;
2012-01-01
Abstract
The ionic liquid FEEP (IL-FEEP) is new, simplified version of the field emission thruster where the alkali metal propellant is replaced by an ionic liquid. Development of the IL-FEEP thruster is based on the heritage of the cesium FEEP and is currently funded by ESA and EU programmes. This paper presents the results of a recent experimental campaign aimed at assessing the performance of a novel linear slit FEEP emitter fed with a ionic liquid propellant. Tests were done on a newly designed, 8-mm slit FEEP emitter made of glass, fed with EMI-BF4. The test setup allowed for continuous monitoring of the thruster electrical parameters, as well as for direct scanning of the exhaust beam profiles using electrostatic wire probes. The test results essentially validate the possibility to operate the linear slit FEEP emitter with ionic liquid propellant in pure ionic mode and confirm that the glass emitter is suited for operation with the selected propellant. Experimental results show very regular and repeatable performance in positive mode, while operation in negative polarity showed some irregularities in beam profiles. Thruster performance in a later test in alternate polarity mode was remarkably stable over a very long period, in spite of the predominance of positive mode firing that could have affected the propellant composition in the reservoir due to electrochemical degradation. Alternate polarity is therefore regarded as a promising operating mode for the simplified FEEP thruster.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
