NASA
The International Space Station’s bundle of depleted batteries orbited Earth for nearly three years before deorbiting and returning to the atmosphere on Friday. Most of the debris is thought to have burned up during atmospheric re-entry, but some debris may have reached the surface intact.
Larger space junk regularly falls to Earth in unguided orbits, usually derelict satellites or spent rocket stages. This included a pallet of batteries from the space station weighing more than 2.6 tons (5,800 pounds). NASA intentionally put space junk on the path to unguided reentry.
natural self-cleaning action
NASA spokeswoman Sandra Jones said the agency “conducted a thorough analytical evaluation of the pallet debris and determined it will re-enter Earth’s atmosphere harmlessly.” This was the largest object ever thrown overboard from the International Space Station.
According to the U.S. Space Force, the battery re-entered the atmosphere at 2:29 p.m. ET (1929 UTC). At the time, the pallet would have been flying between Mexico and Cuba. “We don’t expect any parts of it to survive reentry,” Jones told Ars.
The European Space Agency (ESA) also monitored the trajectory of the battery pallet. In this week’s statement, ESA said the risk of pallet fragments hitting people was “very low”, but said “some parts may reach the ground”. Astrophysicist Jonathan McDowell, who closely tracks spaceflight activity, estimates that about 500 kilograms (1,100 pounds) of debris will hit the surface.
“A general rule of thumb is that 20 to 40 percent of a large object’s mass reaches the ground, but it depends on the design of the object.” the aerospace industry company says.
On February 21, a deceased ESA satellite re-entered the atmosphere in a similar uncontrolled manner. The satellite had a mass of 2.3 tons, about the same mass as a discarded battery pallet. ESA, which has established itself as a world leader in space sustainability, has launched a website that provides daily updates on the satellite’s deteriorating orbits.
As NASA and ESA officials have stated, the risk of injury or death from spacecraft reentry is very low. No one has ever died from falling space debris. According to the ESA, the risk of a person being hit by space junk is about 65,000 times less than the risk of being struck by lightning.
This situation is unique in the type and origin of space debris, which is why NASA deliberately dumped it into Earth in an uncontrollable trajectory.
The space station’s robotic arm released a battery cargo pallet on March 11, 2021. Since then, the battery has been floating in orbit, circling the planet about every 90 minutes. Over a period of months or years, low-Earth orbit becomes self-cleaning due to the effects of aerodynamic drag. The drag of air molecules diluted in low Earth orbit gradually slowed the pallet until gravity pulled it back into the atmosphere on Friday.
Launched aboard Japan’s HTV cargo ship in 2020, the cargo pallet carried six new lithium-ion batteries to the International Space Station. The station’s two-armed robot, Dexter, replaced its aging nickel-metal hydride battery with an upgraded unit, with assistance from astronauts on a spacewalk. Nine of the old batteries were attached to the HTV’s cargo pallet before being detached from the station’s robotic arm.
