US space agency Nasa has revealed how the International Space Station (ISS) deals with its trash - it throws it out over New Zealand.



Happily none of it makes it to the surface of Earth but occasionally the romantic shooting star in the eastern sky may be no more than a plunging rubbish bin.



Nasa's Earth Observatory site has published a photo of a the rubbish, packed into a Russian unmanned supply ship, heading to Earth.



In the caption they say it happened over "the southern Pacific Ocean". The metadata says the photo was taken just north east of the Chatham Islands - suggesting they tossed out the garbage while floating around 300 kilometres above New Zealand.



In their caption, Nasa says several times a year, robotic spacecraft carrying a variety of items-including food, water, fuel, oxygen, medical supplies, replacement parts, and research materials-are launched from Earth to dock with the ISS.



"After the cargo has been transferred to the ISS, the spacecraft is refilled with refuse, and then undocked and de-orbited-essentially using the Earth's atmosphere as an incinerator for both the spent spacecraft and the refuse," Nasa says.



The photo shows the reentry plasma trail of one such spacecraft, the ISS Progress 42P supply vehicle which is based on the Soyuz design, and can fly autonomously or under remote control from the space station.



The trash was thrown out on October 29.