Astroscale is a 2025 Gizmodo Science Fair winner for developing a satellite designed to rendezvous with space junk, with the goal of capturing it and guiding it toward a fiery grave in Earth’s atmosphere.
The question
Can the space industry develop new technologies that help tackle the growing problem of debris and create a more sustainable orbital environment?
The results
On February 18, 2024, Astroscale launched its ADRAS-J (Active Debris Removal by Astroscale-Japan) mission on board Rocket Lab’s Electron rocket. The goal of the mission was to demonstrate its ability to approach, observe, and characterize a defunct spacecraft.
The mission target was Japan’s H-2A rocket’s upper stage. This chunk of space junk has been in orbit for nearly 15 years, measuring approximately 36 feet long (11 meters) and weighing 6,613 pounds (3 tons). “Early in the program, we had a whole list of candidates,” Hisashi Inoue, chief engineer at Astroscale Japan, told Gizmodo. “We picked the target that wasn’t farthest away, and we also had some ground observations and information on the target and how it’s behaving.”
Around three months after its launch, the ADRAS-J mission came within nearly 50 feet (15 meters) of the defunct rocket stage. With its unprecedented close approach, Astroscale became the first company to approach a large piece of space debris. It was a challenging feat, Inoue explained, as the debris is flying in space at a speed of 4 miles per second (7 kilometers per second), or faster than the speed of a bullet.
As opposed to other rendezvous missions, the company could not communicate with the defunct rocket part. “This is junk, it’s not telling us where it is or how it’s moving,” he said. “So that makes it more complicated than just talking with a cooperative client.”
Since its target is not equipped with GPS, the ADRAS-J spacecraft had to rely on limited ground-based observations to locate and rendezvous with the spent second stage. Despite the challenges, the satellite was successful in creeping up on its target and performing a fly-around to capture images and data of the upper stage.
ADRAS-J served as a demonstration mission, paving the way for a follow-up that will attempt to remove the debris for real. For Astroscale’s second mission, the satellite will attempt to match the tumble rate of the wayward rocket, align itself, and dock with it. Once it’s docked, the satellite will grab the rocket with a robotic arm and lower its orbit using its thrusters before releasing it on a trajectory toward Earth’s atmosphere. The decommissioned vehicle will then burn up in Earth’s atmosphere, putting an end to its stint in orbit.
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