ISS dropped the heaviest piece of space debris in history (VIDEO)

The robotic arm launched a platform weighing 2.9 tons with 48 nickel-hydrogen batteries at an altitude of about 430 kilometers above the Earth's surface, according to the Daily Mail. The debris will spend the next two to four years in low Earth orbit before burning up in the atmosphere without a trace.

Last year, the ISS finally completed the replacement of nickel-hydrogen batteries with lithium-ion units - the latter withstand extreme temperatures well and are lighter in weight, so they are easier to transport. The spent batteries were planned to be sent back to Earth with the Japanese transport ship H-II (HTV), but this flight never took place.

It is the largest object by weight ever dropped from the ISS. The previous record was set during the STS-118 mission in 2007, when the ammonia system was sent into orbit, it was twice as light.

In total, according to scientists, about 34,000 pieces of space debris larger than 10 centimeters and millions of smaller objects are now flying around the Earth.