BUSEK CO., INC. — National Aeronautics and Space Administration SBIR Phase I: Z8

Description

<p style="margin-left:0in; margin-right:0in">Busek proposes to develop a new form of passive electrospray thruster control which will enable extremely fast thruster operations and thereby unprecedented minimum impulse bits. Busek&rsquo;s BET-300-P thruster is under active development as a precision reaction control system (RCS) which will provide orders of magnitude improvements over state-of-the-art alternative attitude control systems (ACS) for CubeSats and small spacecraft. The low inertia of CubeSats combined with vibrational disturbances and resolution limitations of state-of-the-art ACS presently limit precision body-pointing and position control. Busek&rsquo;s electrospray thrusters aboard the ESA LISA Pathfinder (NASA ST-7) spacecraft, recently demonstrated control of a proof mass location to within ~2nm per root Hz over a wide band. The BET-300-P, enhanced by exploitation of its high-speed dynamic response in this program, seeks to extend that success to small spacecraft platforms.</p><p style="margin-left:0in; margin-right:0in">Passively fed electrospray thrusters are highly compact, including fully integrated propellant supplies, and are capable of ~100nN thrust precision with 10&rsquo;s of nN noise. Thrust can be accurately throttled over &gt;30x, up to a scalable maximum of 10&rsquo;s to 100&rsquo;s of uN.&nbsp; While typically operated in largely continuous states they are unique in that emission can be electrically stopped/started at ms time scales. Thus, extremely low impulse bits may be achieved over very short durations, permitting throttling from &lt;0.1uNs up to 100&rsquo;s of uNs. Realization of this fundamental capability of the technology is presently limited by control circuitry. The proposed work seeks to study and overcome these limitations with a new control methodology.</p><p>These traits, combined with &gt;800s specific impulse, and thereby low propellant mass could enable these systems to replace traditional reaction wheel ACS and high-propellant mass cold gas systems; enabling milliarcsec control authority for CubeSats versus the present arcsec level SOA.</p>