The SUV-sized pallet of old batteries is the most massive object the station has ever jettisoned.

The International Space Station got a little lighter last week.

The orbiting lab discarded a 2.9-ton (2.6 metric tons) pallet of used batteries on Thursday morning (March 11) — the most massive object it has ever jettisoned, NASA spokesperson Leah Cheshier told Gizmodo.

The space junk is expected to fall back to Earth in two to four years, agency officials wrote in an update last week. That update also stated that the pallet will burn up "harmlessly in the atmosphere," but not everyone is convinced that's the case.