EMITS is a flight test of the FEEP thruster presently being prepared at Centrospazio under ESA contract.
The objective of EMITS is to validate the FEEP technology in space by checking the in-orbit operation of a complete propulsion system, including the thruster and all its subsystems. EMITS, the first flight test of a FEEP system, will be hosted in a Get Away Special (GAS) canister on the Space Shuttle. The experiment will fly on the Space Shuttle in early 2000 as GAS Payload G-752.
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| Openable GAS canister |
Canisters arrangement in the Shuttle bay |
EMITS Structural Model |
The experiment goals include primary goals and secondary goals. Primary goals are:
- firing the thruster in space for the first time;
- demonstrating the propellant storage and container sealing functionality;
- demonstrating proper operation in microgravity of propellant feeding by capillarity;
- demonstrating ion beam neutralization;
- testing the power conditioning unit in operational environment.
Secondary goals are:
- assessing the plume current distribution;
- evaluating the propellant backflow and deposition on surrounding surfaces;
- checking the evolution of thruster performance with time.
The thruster performance will be evaluated by means of the electric parameters recorded through the test; in particular, the actual thrust delivered and the thruster specific impulse will be indirectly evaluated. Evidence of the ion beam presence will be gained by means of electrical measurements in the thruster's power supply lines and, independently, by means of ion beam electrostatic probes reading.
Thruster tests will include investigation of:
- emitter threshold voltage;
- steady state operations at different emitter voltages;
- switch on/off capability;
- throttleability over the entire characteristic curve.
The EMITS Assembly
The flight experiment includes two thruster assemblies,the thruster power and control electronics (developed by LABEN, Milan, Italy), several probes and diagnostic devices, a battery, and a computerized experiment control/data storage unit (developed by Techno System Developments, Naples, Italy). The total duration of the experiment will be 2 days. During that period, the thrusters will be repeatedly switched on and off and cycled through their operatonal envelope.
EMITS Top Plate - Thruster Assemblies and Diagnostics
The top plate of the EMITS payload is mounted just behind the Get Away Special Motorized Door Assembly (MDA). Once actuated by the Shuttle crew, the MDA will expose to space the following items:
- a 1 mN thruster (70 mm slit length, about 60 W);
- a 30 µN thruster (2 mm slit length, less than 1 W);
- a low power neutralizer, of the thermionic oxide cathode type;
- a set of diagnostic devices, including quartz crystal microbalances (QCMs) as propellant deposition sensors, electrostatic ion beam probes, and a pressure gauge.
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CENTROSPAZIO
Via A. Gherardesca, 5 - 56014 Ospedaletto, Pisa, Italy
Tel: +39 050 985097 / 985072 - Fax: +39
050 974094
E-mail: centrospazio@cpr.it
These pages are maintained by Salvo Marcuccio.
Last modified: November 14, 1998
