The first ever experimental characterization of a two-emitter 150 μN FEEP thruster assembly is described in this paper. The envisaged arrangement of FEEP thrusters in all of the near-term missions is in “clusters” of two or three ion emitters. Due to constraints on thrust vector orientation and available room, very close packing of emitters is foreseen. While several test results are available on the behaviour and performance of single ion sources and prototype thruster units, the design and testing issues arising from the combined operation of a multi-thruster assembly were never thoroughly addressed, nor was the assessment of potential interaction effects that may impair the thruster performance. A two-emitters test was therefore recently carried out to assess possible interactions between incident ion beams from adjacent thrusters. A pair of identical, 5-mm linear slit FEEP emitters, was integrated in Alta’s IV1 vacuum facility. The two emitters’ slits were mounted parallel to each other at a distance of 10 cm. The ion beam density was evaluated using a set of single-filament Langmuir probes immersed in the thrusters’ plume. It was observed that the beam profile resulting from combined operation is essentially coincident with the sum of the individual profiles, as indicated by a numerical plume simulation of the test configuration run using Alta’s proprietary 3-D code. The experiment shows that there is no significant interaction between the overlapping plumes, thus demonstrating the feasibility of closely-packed clusters of FEEP emitters.
Experimental Investigation of the Simultaneous Firing of Two FEEP Thrusters
MARCUCCIO, SALVO;
2003-01-01
Abstract
The first ever experimental characterization of a two-emitter 150 μN FEEP thruster assembly is described in this paper. The envisaged arrangement of FEEP thrusters in all of the near-term missions is in “clusters” of two or three ion emitters. Due to constraints on thrust vector orientation and available room, very close packing of emitters is foreseen. While several test results are available on the behaviour and performance of single ion sources and prototype thruster units, the design and testing issues arising from the combined operation of a multi-thruster assembly were never thoroughly addressed, nor was the assessment of potential interaction effects that may impair the thruster performance. A two-emitters test was therefore recently carried out to assess possible interactions between incident ion beams from adjacent thrusters. A pair of identical, 5-mm linear slit FEEP emitters, was integrated in Alta’s IV1 vacuum facility. The two emitters’ slits were mounted parallel to each other at a distance of 10 cm. The ion beam density was evaluated using a set of single-filament Langmuir probes immersed in the thrusters’ plume. It was observed that the beam profile resulting from combined operation is essentially coincident with the sum of the individual profiles, as indicated by a numerical plume simulation of the test configuration run using Alta’s proprietary 3-D code. The experiment shows that there is no significant interaction between the overlapping plumes, thus demonstrating the feasibility of closely-packed clusters of FEEP emitters.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
