LONDON, July 31 (Xinhua) -- The world's smallest spacecraft are now successfully travelling in low Earth orbit and communicating with systems on Earth, the Guardian cited scientists as saying.

The miniature satellites, named "Sprites," are only 3.5 cm in length and width and weigh just 4 grams each. They carry radios, sensors and computers powered by sunlight.

While Sprites have previously been used at the International Space Station, this is the first time that such a lightweight miniaturized satellite can be launched into space and communicable, the Guardian reported.

The Sprite project is a part of an ambitious, decades-long project dubbed "Breakthrough Starshot" which aims to send space probes to planets beyond our solar system.

Announced in April, 2016 by Stephen Hawking and Russian physicist and venture capitalist Yuri Milner, its goal is to develop chips with a weight of roughly 1 gram and fit them to a lightweight spacecraft and send them through space with a 100-billion watt laser.

"This is a new frontier of tiny, gram-scale spacecraft," the Guardian quoted Professor Avi Loeb of Harvard University as saying. He is chairman of the advisory committee for the Breakthrough Starshot Initiative.

The Sprites are also very cheap. "Each of them is only tens of (U.S.) dollars in cost," Loeb said.