In August of 2022, NASA will send a robotic spacecraft to the Main Asteroid Belt to explore a truly unique object: a metal asteroid. This object is known as 16 Psyche, is one of the largest asteroids in the Belt, and is composed almost entirely of iron and nickel. The most widely-accepted theory is that it used to be the core of a protoplanet in the Belt that experienced a massive collision that sent its rocky crust and mantle into space.
The spacecraft, also named Psyche, was submitted as part of a call for proposals for NASA’s Discovery Program in 2015 and was selected as the 14th Discovery mission by 2017. Most recently, the spacecraft passed a crucial milestone by moving from the planning and designing phase to the manufacturing phase, where all of the hardware that will allow it to make the journey is being assembled.
This comes on the heels of the mission sailing through a key stage in the development process, the critical design review. This phase consists of NASA examining the designs for all of the project systems, the scientific instruments, and the engineering subsystems – communications, propulsion, power, avionics, and the flight computer.
Lindy Elkins-Tanton, the managing director and co-chair of the Interplanetary Initiative at Arizona State University, is also the principal investigator of the Psyche mission. “It’s one of the most intense reviews a mission goes through in its entire life cycle,” she said. “And we passed with flying colors. The challenges are not over, and we’re not at the finish line, but we’re running strong.”
This puts Psyche on track to become the fourth spacecraft to explore the Asteroid Belt in-depth, and the first spacecraft to ever explore a metal asteroid. As such, the scientific returns for this mission are expected to be profound. This is particularly so since it is impossible for scientists to study the core region of Earth up-close, owing to the extreme depth, pressure, and temperatures involved.
But Psyche, measuring 226 km (140 mi) in diameter, is accessible and could tell us things about planetary formation. Once there, the Psyche spacecraft will use a magnetometer to measure its magnetic field and a multispectral imager that will capture images of the surface and gather data on its composition and topography.
Meanwhile, the spacecraft’s two spectrometers will analyze the neutrons and gamma rays coming from the surface, which will help reveal the overall composition of the asteroid itself. To test the spacecraft, the team built prototypes and engineering models of the instruments and many of the spacecraft’s engineering subsystems.
These were then rigorously put through their paces to see if they could endure the kind of stresses involved and perform their crucial tasks while in deep-space – like operating the spacecraft, obtain science data, and communicate it back to Earth. Said Elkins-Tanton:
“This is planning on steroids. And it includes trying to understand down to seven or eight levels of detail exactly how everything on the spacecraft has to work together to ensure we can measure our science, gather our data and send all the data back to Earth. The complexity is mind-boggling.”
With the launch window rapidly approaching, the mission team is wasting no time getting the spacecraft assembled. The Solar Electric Propulsion (SEP) Chassis, which is the main body of the spacecraft, is already being built by the aerospace technology company Maxar Technologies (whom NASA contracting to build the Psyche mission) at their facility in Palo Alto, California.
Meanwhile, engineers at NASA JPL are also working hard to get Psyche mission-ready, which includes engineers building and testing the electronic components. In accordance with COVID-19 safety requirements, the engineers are observing social-distancing, and team members who have been deemed non-essential are working remotely.
JPL is also responsible for providing Psyche’s avionics subsystem, which includes the spacecraft’s flight computer. Once the electronic components are all assembled, connected, and tested, the team will begin testing the subsystem as a whole as well as its software. Said Henry Stone, a member of JPL and the project manager for Psyche:
“One of the things we pride ourselves on in these deep-space missions is the reliability of the hardware. The integrated system is so sophisticated that comprehensive testing is critical. You do robustness tests, stress tests, as much testing as you can – over and above. You want to expose and correct every problem and bug now. Because after launch, you cannot go fix the hardware.”
Once the SEP Chassis is ready, it will be delivered to to NASA’s Jet Propulsion Laboratory (JPL) in Southern California, at which point the assembly and testing of the full spacecraft will begin. This final stage is known as the Assembly, Test, and Launch Operations (ATLO), which is scheduled to begin by February of 2021.
The delivery of the spacecraft’s solar arrays will follow a few months later. By April 2021, every instrument is expected to be delivered to JPL’s main cleanroom to be integrated into the spacecraft. “I get goosebumps – absolutely,” said Stone. “When we get to that point, you’ve made it through a huge phase, because you know you’ve done enough prototyping and testing. You’re going to have a spacecraft that should work.”
Originally, the mission was scheduled to launch by 2023 atop a SpaceX Falcon Heavy rocket. However, upon the selection of the mission by NASA in May of 2017, the launch date was pushed up to August 2022 to target a more efficient trajectory. This flight path will take it past Mars for a gravity assist in May 2023 and will rendezvous with the asteroid in early 2026.
Further Reading: NASA