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Precision Thrusters
Testbeds
JPL recently dedicated its new Microthrust Propulsion Laboratory
(MPL). MPL is a unique, world-class environment to develop, test
and evaluate microthrust propulsion technologies for future formation
flying, interferometry, and drag-free missions. The facility consists
of a Class-10-capable, 1000 sq ft cleanroom, featuring a 2 m diameter,
2 m long ultra-high vacuum (UHV) test chamber capable of reaching
vacuum pressures into the 10-9 Torr range. This low pressure is a
requirement to adequately assess thruster performance, lifetime,
neutralization and potential spacecraft contamination issues under
realistic space environmental conditions. The chamber also features
a new Nano-Newton Thrust Stand (nNTS) capable of < 0.5 micro-Newton
resolution thrust measurements. The UHV chamber is equipped with
a probe positioning system able to perform plume mapping using Faraday,
emissive, and Langmuir probes to determine beam current, potential
and plume plasma temperature distributions, and may be equipped with
additional, special probes as needed. Mapping is performed in a single
plane per test run, but probe height and distance from thruster may
be adjusted to obtain full 3-D mapping. Quartz crystal microbalances
(QCMs) and witness plates will be used for studies of contamination
potentials.
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JPL Microthrust Propulsion Laboratory |
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MPL UHV Chamber and Thrust Stand Port |
Additional test stands exist in regular laboratory environments,
including a cryo-pumped bell jar facility for initial thruster evaluation
and performance testing, and cathode development, a micro-Newton
thrust stand with a resolution of about 0.5 micro-Newton, and a cathode
test facility. The cathode test facility consists of a 0.3m dia.
by 0.7 m long stainless steel Ultra-High vacuum (UHV) chamber able
to operate at pressures as low as 10-11 Torr. It features a residual
gas analyzer for contaminant gas characterization, and a precision
leak valve allowing cathode testing to be performed in environments
up to 10-4 Torr.
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MiXI Thruster Lab
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Micro Newtron Thrust Stand with 0.5
micro-Newtron Resolution
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In addition, the Advanced Propulsion Technology Group, who is conducting
this work at JPL, maintains a large suite of vacuum test facilities
of varying sizes, dedicated to various electric propulsion developments,
including flight hardware acceptance test and lifetests.
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2.4-m dia. x 5.5-m long Stainless Steel
Tank
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3-m dia. x 8 m long Stainless Steel Tank
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