NASA’s futuristic ion thruster is in every way the science-fiction invention that became a reality.
It has the potential to send spacecraft to planets (including Mars) at huge speeds but by using just a fraction of the fuel that conventional rockets require.
Development on the thruster has been slow but now scientists at NASA and the University of Michigan have made a major breakthrough by breaking the current records for thrust, operating current and overall power.
The team’s current X3 prototype shattered the current record for thrust delivering 5.4 newtons compared to the 3.3 newtons that were achieved previously.
They were then able to double the safe operating current to 250 amperes and even slightly increase the power as well.
These new records might be just numbers to us, but what they boil down to is an engine that can fly astronauts to Mars quicker.
Ion thrusters (otherwise known as the Hall Thruster) are able to offer exceptionally high speeds at very low costs, but there is a trade-off: Limited acceleration.
By operating at a higher power and by delivering more thrust the team can greatly increase the acceleration which in turn means shorter journey times to other planets.
“Mars missions are just on the horizon, and we already know that Hall thrusters work well in space,” said Alec Gallimore, University of Michigan professor of aerospace engineering.
“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.”
How does an ion thruster work?
While conventional chemical-powered rockets ignite fuel to create thrust an ion thruster works a little differently.
Instead an ion thruster ionises propellent by adding or removing electrons to produce ions. In the case of the X3 the thruster works by bombarding the propellent with electrons.
The result is that you have a high-energy electron (negatively charged), colliding with the propellent atom (neutrally charged). This then releases electrons from the propellent resulting in a positively charged ion and in turn you have thrust.
The fuel used is xenon which can be easily stored onboard a spacecraft in much smaller volumes than is required for say a conventional rocket.
Every test of the X3 thruster has to be carried out in a pure vacuum environment, something that has proven difficult to achieve over the last five years of development.
However NASA has been working with the University of Michigan to create a test chamber that can finally allow them to test the X3 to its full potential.
It’s not a quick process though, the test chamber takes a staggering 20 hours to remove all the air from the room.
The next step for the team is trying to put the thruster through some endurance tests.
If they can keep it running constantly and safely for 100-hours that goes a long way towards ensuring that the thruster can handle a journey to Mars that will take many months.