The buzz is building around NASA’s new X3 thruster, and with very good reason.
The X3 thruster performed very well in a recent round of testing and broke three records simultaneously: in terms of thrust, it generated 5.4 Newtons and both previously existing maximum power output and operating current levels were exceeded. All this while operating at a new threshold of power. Project leader Alec Gallimore, who is also dean of engineering at the University of Michigan, expressed his optimism about the impressive results: "We have shown that X3 can operate at over 100 kW of power."
The previous record had been set at 3.3 Newtons: "It operated at a huge range of power from 5 kW to 102 kW, with electrical current of up to 260 amperes. It generated 5.4 Newtons of thrust, which is the highest level of thrust achieved by any plasma thruster to date."
The X3 thruster was developed by researchers at the University of Michigan thanks to a collaboration with NASA and the US Air Force. The jet is a Hall thruster, which means that it uses an ionic engine. Essentially, a stream of ions—electrically charged atoms—are accelerated to propel the spacecraft. Then to generate thrust plasma is expelled.
More Than Meets the Eye
The short of it is that the X3 travels faster than conventional chemical propulsion rockets but far less fuel is required.
Beyond the fuel benefits, the difference in thrust is also an important factor: chemical fuel equates to greater mass, which means more fuel is required for a lift. Significantly less thrust comes with the ionic engine, creating a longer term of operation.
By comparison, with a Hall thruster speeds of up to 40 kilometers can be achieved on average, versus a five-kilometer speed threshold of a conventional chemical propulsion rocket.
The University of Michigan team also understands, however, that more work on sorting out the details about the operating time will need to be done. To this end, the team plans to expand their work on the X3 with a fresh round of testing to understand its capacity to run 100 hours uninterrupted in 2018.
Another concern is the size and bulk issue. Scott Hall, a University of Michigan Ph.D. student who has been involved with the project the past five years shared, "It's heavy — 500 pounds [227 kilograms]. It's almost a meter in diameter," adding, "Most Hall thrusters are the kind of thing that one or two people can pick up and carry around the lab. We need a crane to move X3 around."
In the not too distant future, there are hopes for this technology to support human transport to Mars by 2024, a project that has been enthusiastically backed by Elon Musk. It seems that in the case of some of these projects, the philosophy of ‘If you build it, they will come’ is being employed, but in this case “they” refers to the scientific community. Still, the question remains: how enthusiastically will they come?