ADRAS-J2
A spacecraft meant to catch a dead three-ton Japanese rocket stage in orbit and drag it down to burn up, which would be the first removal of an existing large piece of debris.
Why it matters
Old rocket stages are among the largest and most dangerous pieces of space junk. Proving one can be captured and removed would open a business in cleaning up orbits that satellites depend on.
How the technology works
ADRAS-J2 is Phase II of JAXA's Commercial Removal of Debris Demonstration. It builds on ADRAS-J, which in 2024 approached within about 15 meters of the same kind of target.
The new craft must grab a tumbling upper stage about 11 meters long that was never designed to be caught, then lower its orbit.