The Long Shot: Photographing a Milk Carton 3500 Kilometres Away


Monday, 27 February 2017

Planet, founded by a team of ex-NASA scientists, launched the rocket on February 14 from Satish Dhawan Space Centre in Sriharikota, India. Part of its payload was a swarm of 88 tiny ‘Dove’ satellites, each the size of a one-litre milk container. Those mini satellites joined 61 others, all belonging to Planet.

The network formed by the satellites gives Planet the ability to take a daily image of Earth’s surface. This will offer useful data for numerous purposes, including GPS, the monitoring of flood, fire and other disasters, accurate imagery of urban expansion, deforestation, sea levels, weather and more.

But first they need to form a grid in low Earth orbit, meaning they must glide into specific positions. Some of the earliest satellite positioning photography to check on the success of this mission has been managed by specialists at UNSW Canberra Space, in the School of Engineering and Information Technology (SEIT).

UNSW Canberra Space’s telescopes, have been utilised to locate and photograph the tiny satellites, some just nine hours after launch. This is the ultimate needle-in-a-haystack search – spotting an object the size of a one-litre milk container, hurtling through space at a distance of 3500 kilometres!

“We see them when the Sun shines on them,” says Associate Professor Andrew Lambert from SEIT, who leads the School’s Space Surveillance research. He and his colleagues were able to photograph part of the flock as it flew low on the horizon before entering Earth’s shadow. “That was incredibly difficult as they are not always where they are supposed to be, particularly when being moved to take up their desired position in the global coverage.”

“A main focus of UNSW Canberra Space is around gliding techniques and aerodynamic forces used to properly and accurately position satellites. We look into techniques and systems to manoeuvre satellites around using novel lift and drag. Believe it or not, low Earth orbit satellites do experience some atmosphere.”

UNSW Canberra Space has funding for at least five of its own satellites in the near future, to further bolster its capability as a world-class space research centre.



Associate Professor Andrew Lambert

UNSW Canberra

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