A pallet of garbage weighing nearly 3 tons was jettisoned from the ISS

NASA sent commands to the ISS this week to have astronauts aboard the space station release a 2.9-ton cargo pallet loaded with old batteries into orbit. NASA says it's the most massive object ever jettisoned from the orbiting space station. The garbage carrier will be in orbit for 2 to 4 years before it reenters the atmosphere and burns up.The pallet was left behind at the space station by the ninth and final Japanese HTV supply ship that delivered the battery carrier to the space station last May. When the pallet first arrived at the space station, it had six new lithium-ion batteries attached. Those six batteries have been connected to the space station power truss over the last year.

Four HTV missions between 2017 and 2020 delivered 24 upgraded lithium-ion power storage units to the ISS. Those batteries replaced 48 aging nickel-hydrogen batteries over the years. As the old batteries were removed from their housings on the exterior of the ISS, they were mounted onto HTV cargo pallets during spacewalks spanning several years.

The pallets were mounted inside the unpressurized cargo bay of the HTV supply ship for the trip to and from the space station, and the robotic arm of the space station was able to remove and reinstall the cargo tray. As the HTVs left the space station, they entered the atmosphere over the South Pacific Ocean, where most of the spacecraft battery hardware burned up with any debris leftover falling into a remote part of the ocean.

After the ninth and final HTV mission, Japan retired the spacecraft and is developing a new cargo freighter known as the HTV-X. With the HTV fleet retired, there was no way to retrieve and dispose of the final cargo pallet. Instead, the pallet with no propulsion system is expected to reenter the Earth's atmosphere in 2 to 4 years, with atmospheric drag gradually lowering its orbit and it will burn up harmlessly in the atmosphere.