“NASA’s Psyche Spacecraft: Blazing a Unique Blue Trail Through the Solar System
Last Friday, NASA initiated the Psyche spacecraft’s journey towards an asteroid sharing its name. Psyche marks a pioneering mission to a metal asteroid, and it’s poised to create a striking blue trail as it traverses the cosmos. The source of this luminescent wake is the spacecraft’s extraordinary propulsion system, set to activate within the first 100 days of the mission.
The spacecraft is equipped with a Hall thruster, which will propel Psyche through space. This innovative thruster emits a brilliant blue glow as it ionizes xenon, a noble gas also employed in headlights and plasma televisions, to propel the spacecraft forward. This represents the maiden application of this technology beyond the moon, a technology NASA has only had access to since 2015. But what makes the Hall thruster so unique, and why has Psyche adopted it?
Efficiency is a critical consideration when planning a space mission. Carrying chemical fuel for a massive interplanetary journey would be akin to driving around the world with all the necessary gasoline stored in your vehicle, as there are no refueling stops en route – an impractical endeavor. To reach its destination, Psyche would require thousands upon thousands of pounds of chemical propellant.
In response to this challenge, engineers turned to electric thrusters. These come in various forms, and for space travel, ion thrusters and Hall thrusters are prominent choices. As NASA’s Psyche chief engineer, Dan Goebel, noted, “They can probably be considered the Tesla versions of space propulsion.” Instead of burning fuel, electric thrusters strip electrons from the propellant’s atoms through a process called ionization, expelling these ions at speeds of around 80,000 miles per hour. This results in a higher specific impulse, analogous to miles per gallon in a car, but for spacecraft, enabling a thruster-powered spacecraft to travel farther with less propellant.
Ion thrusters employ high electric voltages to create a plasma and expel ions into space. NASA’s Dawn mission utilized these to reach the dwarf planet Ceres, but they aren’t the swiftest – according to NASA, it would take the spacecraft four days to accelerate from 0 to 60 miles per hour, far from race car material.
On the other hand, Hall thrusters employ a magnetic field to induce electron circulation in a circle, generating a beam of ions. While they may not achieve the same level of efficiency as ion thrusters, they offer more power. The Psyche team selected this system because it allowed for a smaller and consequently more cost-effective spacecraft.
For the thrusters to function, the spacecraft needs power, which it obtains from the sun through solar panels, and a substance to ionize, in Psyche’s case, xenon gas. Dan Goebel explained, “Xenon is the propellant of choice because it’s inert (it doesn’t react with the rest of the spacecraft) and is easy to ionize.” It also imparts the thrusters with their distinctive blue radiance. Psyche carries approximately 150 gallons of xenon and achieves an impressive fuel economy of about 10 million miles per gallon.
Now that the mission has launched, the team will dedicate the next 100 days to scrutinizing all the spacecraft’s systems to ensure their readiness for the journey. At some point during this period, those resplendent blue thrusters will come to life.
If Psyche proves to be successful, Hall thrusters are likely to become a staple in future space missions, offering a balanced combination of cost savings, efficiency, and power. According to Steven Scott, program manager for the Psyche mission at Maxar, the company that manufactured the thrusters, these propulsion systems could play a vital role in supporting upcoming scientific missions to Mars and beyond. Thanks to these cutting-edge thrusters, Psyche is expected to reach the asteroid belt in just 3.5 years, and we eagerly anticipate discovering what lies at the culmination of its electric blue trail.”
Disclaimer: The views, suggestions, and opinions expressed here are the sole responsibility of the experts. No Nook Explorer journalist was involved in the writing and production of this article.