The International Space Station detached 2.9-ton pallet of 48 nickel-hydrogen batteries and it’s heading to Earth now.
The array of discarded batteries was attached to a robotic arm that released it 265 miles above Earth’s surface and will spend around two to four years in the lower planet orbit before burning up in our atmosphere.
The move follows NASA’s up-gradation of ISS batteries in which the dated 48 nickel-hydrogen batteries were replaced with 24 lithium-ion units in 2016, with final swap occurring in 2020.
The discarded batteries wasn’t to be left into the orbit to disintegrate, originally it was to return to Earth aboard Japanese H-II Transfer Vehicle (HTV), NASA communications specialist Leah Cheshier said. But, it had to be left behind due to a failed 2018 Soyuz launch in 2018 that altered spacewalk schedules.
The choice of lithium-ion batteries was made keeping in mind their success on Earth as they can withstand much intense heat and thermal events. “The greater energy density of lithium-ion technology reduces the number of needed batteries into fewer cargo manifest spots required for the batteries,” read the statement.
The process of swapping batteries initiated in 2016 when NASA began sending the new batteries via the HTV cargo spacecraft, a process which took almost four years to complete and conducted by 13 astronauts and 14 spacewalks to complete.
This set of added 2.9 ton of garbage is in addition to almost 34,000 pieces of space junk along with millions of smaller objects already floating around Earth.