The ISS abandons a pallet of 2.9-ton batteries, creating its most massive space trash can

Weighing 2.9 tons and traveling 4.8 miles per second, this pile of old batteries is now the heaviest junk to be dumped from the International Space Station.

The pallet is packed with nickel-hydrogen batteries, and it will remain in low earth orbit for the next two to four years “before burning harmlessly in the atmosphere,” according to a NASA. declaration. SpaceFlightNow reports that the pallet is “the most massive object ever dropped from the outpost into orbit.”

NASA spokeswoman Leah Cheshier confirmed that was the case.

“The outer pallet was the largest object – in mass – ever dropped from the International Space Station at 2.9 tons, more than double the mass of the Early Ammonia Servicing System tank dropped by Space Walker Clay Anderson on mission STS-118 in 2007, ”Cheshier wrote in an email.

NASA ballistic officers “indicate no threat” of paddle crashing against other space objects, but “this article, like all, will be followed by US Space Command,” she added.

It was not the original plan to throw the pallet out like this. The launch failure of a Soyuz rocket in 2018, in which NASA astronaut Nick Hague and Roscosmos cosmonaut Alexey Ovchinin were forced to make an emergency landing in the Kazakh steppe, disrupted the schedule of spacewalks , leading to the remaining pallet.

The NASA spacewalk on February 1, 2021, involving astronauts Mike Hopkins and Victor Glover, was notable in that it has entered into a four-year effort to modernize the space station’s batteries. These batteries store the energy collected by solar panels, but in 2011, NASA decided to switch from nickel-hydrogen batteries to lithium-ion batteries. The production of these batteries started in 2014 and the replacement process started in 2016.

This effort required four supply missions to the Japanese cargo spacecraft H-II Transfer Vehicle (HTV), 13 different astronauts and 14 spacewalks, during which 48 nickel-hydrogen batteries were replaced by 24 batteries. lithium-ion.

Normally, old batteries would be placed inside an HTV and dropped from the ISS, and most items would burn on re-entry. But the failure of the Soyuz launch disrupted the spacewalk pattern and schedule so that, at the end of 2018, an HTV freighter left the station without a pallet of batteries, according to SpaceFlightNow. The battery replacement mission continued, and the HTVs continued to leave the station with pallets, but now with an additional one perpetually attached to the station. Once the mission was over and no more HTVs to come (at least none of the old model – they are being replaced by the HTV-X freighter), the mission planners had to drop the pallet on their own.

So that’s what they did on Thursday, March 11, when mission controllers in Houston used the Canadarm2 robotic arm to “release an outer pallet loaded with old nickel-hydrogen batteries into Earth orbit.” according to at NASA. The object was released approximately 427 km above the Earth’s surface.

“Before, it was okay to launch stuff from the ISS because very few satellites were below [at altitudes below 250 miles (400 km)], »Jonathan McDowell, an astrophysicist from the Harvard-Smithsonian Center for Astrophysics, explained in an email. “This is no longer so true with a bunch of cubesats and with the recently launched Starlinks during the climb into orbit. So I have concerns.

To which he added: “I don’t immediately see what they could have done other than steal an additional HTV just mission to get rid of it.

According to the European Space Agency, around 34,000 objects larger than 3.9 inches (10 cm) currently orbit the Earth, in addition to millions of smaller objects, such as tools and pieces of spacecraft. The volume of objects in space, both functional and non-functional, keeps increasing, causing concern potential collisions and even more orbital debris.

This post has been updated to include comments from Jonathan McDowell.