In Iodine We Thrust

Iodine electric thrusters enable resilient, responsive spacecraft

18 Ratings

Imagine a situation played-out in the movie 'Gravity' where satellite collisions cascade exponentially, polluting large swaths of space with debris. Critical polar-orbiting communications and observation satellites are destroyed or damaged. Ships don't get storm warnings in time, military and humanitarian missions lose critical intelligence. Satellites with responsive, efficient propulsion systems provide resiliency for Defense and Commerce.


A large field of space debris has knocked-out two of three critical satellites, and the remaining satellite must fill-in the gaps while avoiding its own destruction. That surviving satellite needs to maneuver repeatedly to avoid debris collisions while traveling to multiple orbital locations. A traditional propulsion system would burn through fuel supplies in days or weeks, eliminating years or decades of operational life off of a hundred-million dollar satellite. Solar Electric Propulsion Hall thrusters fueled with Iodine enable high-thrust, high-efficiency orbital maneuvers within existing spacecraft power, volume, and mass limitations. With no pressurized fuel tanks, satellites with Iodine fuel also allow for easy storage and rapid, responsive launches. Efficient Hall thrusters coupled with the high density storage of iodine enables new, resilient satellite capabilities for near-earth orbits and beyond.


Spacecraft are power, mass, and volume limited at launch; using efficient electric propulsion with better fuels opens entirely new capabilities and missions for DoD, civil, and commercial satellites. Traditional spacecraft use toxic chemical propellants and pressurized storage vessels which typically account for over 1/3 of a satellite’s launch mass. Not only is this costly and inefficient from a mass perspective, but ground safety and fueling operations add days or weeks to schedules and come with significant cost and safety risks. Electric Hall thruster propulsion with Iodine propellant is a storable, low-cost, rapid-response solution delivering high-thrust, high-efficiency performance on-orbit. Iodine propellant is stored in a dense form at ambient pressure and temperature eliminating the need, cost, and safety concerns with pressurized toxic propellants.


With significant SBIR funding from numerous sources, Busek developed and tested over 40 combinations of Hall thrusters along the path of creating a wholly domestic series of electric satellite thrusters; technology which flies aboard a number of DoD satellites today. The firm has performed extensive testing on numerous propellants and materials and given its experience, iodine was chosen for its beneficial properties for spaceflight.

"The iSAT project demonstrates maneuverability of Small Spacecraft within the tight constraints of volume, mass, power, and risk to primary payloads." — John Dankanich


A typical electric propulsion system includes a) one or more thrusters and neutralizing cathodes, b) a propellant feed system with valving and a propellant storage system, and c) electronics for command and control. The system takes energy from a spacecraft's solar panels and batteries (the sun provides abundant power in space), to warm the propellant which stores as a solid. Once warmed, it feeds into the thruster which accelerates small amounts of propellant electromagnetically or electrostatically. Individual atoms of propellant exit the thruster at thousands of miles per hour, pushing the satellite in the opposite direction, exactly as taught by Newton's 3rd Law of Motion.


Busek's propulsion technologies enable highly maneuverable satellites which can be safely stored and launched on short notice. This translates to increased dependability and resiliency of the communications and remote sensing spacecraft which are critical to National Security and the global economy.

The 'Compact Low Mass Propulsion for Responsive Space' project is the foundation for projects such as NASA's Iodine Satellite (iSAT), as well as other work on high-power, high-thrust electric spacecraft propulsion.

Thanks to the Air Force's funding efforts, iodine-fueled electric propulsion is a body of work being lead by Busek, a US firm. The benefits of this technology have numerous applications in defense, civil, and commercial applications. Continued work in this field is critical to maintaining the US' technology lead.

Busek's work in iodine propulsion has expanded into gridded ion engine technology, which is useful in low thrust, long-duration, near-earth object, interplanetary missions. Busek recently demonstrated the 'BIT-3', the world's first gridded ion engine operating on iodine. This thruster has the ability to fly small CubeSats from GEO synchronous orbit to the Moon and beyond… it is revolutionary.

Responsiveness and resiliency in space are crucial... storable iodine propellant coupled with highly maneuverable electric propulsion is an enabling capability to meet those mission goals. — Jeffry S. Welsh, Ph.D., Development Division Chief at Operationally Responsive Space (ORS) Office

Busek Co. Inc.

Natick, MA

Busek Co. is an Industry leader in developing high performance space propulsion systems including Hall, Electrospray, RF Ion, Pulsed Plasma, and Green Monopropellant thrusters. Busek’s family of U.S.-designed and manufactured thrusters and electronics span the power spectrum from 2W to 20kW.

Bruce Pote Bruce Pote

Bruce Pote

Director, Hall Thrusters

James Szabo James Szabo

James Szabo

Chief Scientist, Hall Thrusters

Vlad Hruby Vlad Hruby

Vlad Hruby

President & Founder


Compact Low Mass Propulsion for Responsive Space





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