Mars missions have moved one step closer with the development of a Hall thruster, an advanced space engine designed at the University of Michigan, which has broken the records for operating current, power and thrust for a device of its kind.
Achieving high speeds with a fraction of the fuel required in a chemical rocket, Hall thrusters offer exceptionally efficient plasma-based spacecraft propulsion by accelerating small amounts of propellant very quickly using electric and magnetic fields.
Alec Gallimore, professor of aerospace engineering at the University of Michigan, who led the research, said, “Mars missions are just on the horizon, and we already know that Hall thrusters work well in space. They can be optimized either for carrying equipment with minimal energy and propellant over the course of a year or so, or for speed – carrying the crew to Mars much more quickly.”
The challenge is to make them larger and more powerful. The X3, a Hall thruster designed by researchers at University of Michigan, NASA and the US Air Force, broke the previous record set by a Hall thruster, coming in at 5.4 Newtons of force compared with 3.3 Newtons.
The improvement in thrust is especially important for crewed mission – it means faster acceleration and shorter travel times. The X3 also more than doubled the operating current record (250A vs 112A) and ran at a slightly higher power (102kW vs 98kW). The X3 is one of three prototype ‘Mars engines’ to be turned into a full propulsion system with NASA funding.
Scott Hall, a doctoral student in aerospace engineering at the University of Michigan, carried out the tests at the NASA Glenn Research Center in Cleveland, along with Hani Kamhawi, a NASA Glenn research scientist who has been heavily involved in the development of the X3. The experiments were the culmination of more than five years of building, testing and improving the thruster.
NASA Glenn, which specializes in solar electric propulsion, is currently home to the only vacuum chamber in the USA that can handle the X3 thruster. The thruster produces so much exhaust that vacuum pumps at other chambers can’t keep up. Then, xenon that has been shot out the back of the engine can drift back into the plasma plume, muddying the results. However, as of January 2018, an upgrade of the vacuum chamber in Gallimore’s lab will enable X3 testing at the university.
Photos: NASA Photos / Lauren Hughes
October 26, 2017