The smallest satellite ever operated in orbit Breakthrough Prize

Breakthrough Starshot has taken the first step towards their grand plans to one day send spacecraft to Alpha Centauri. On June 23, the $100 million initiative to send light-propelled spacecraft to our nearest star sent the tiniest-ever satellites into orbit.

An Indian rocket carried six of these miniature satellites, called Sprites, into space. Two of them are attached to the sides of other, larger satellites: the Latvian Venta satellite and the Italian Max Valier satellite. Once communications are established, the Max Valier satellite will release the other four Sprites to orbit on their own.

Each Sprite is a four-gram square of circuit board measuring 3.5 centimetres to a side. Despite their small size, the Sprites carry a lot of instruments. Each one has a computer processor, solar panels, a magnetometer, a gyroscope, and a radio for communicating with researchers on Earth.


Calling home

So far, researchers have only gotten a signal from one of the two Sprites hitching a ride on the larger satellites. The rest have not been released yet because the Max Valier satellite has not made contact with its mission controllers, possibly due to problems with its radio antenna. Without a functioning radio antenna, the satellite will be unable to receive any command to release its cargo.

Zac Manchester, the Harvard researcher leading the project, views even that one signal as a triumph. “We were really just trying to get them up there and communicate with them,” he says. “It’s the first time that a spacecraft on this size scale has worked.”

Relatively soon, hundreds or thousands of Sprites could be mass-produced and launched in bulk to create a huge network of tiny sensors to study Earth’s atmosphere and magnetic field as well as its immediate surroundings. Avi Loeb at Harvard University, who chairs Breakthrough Starshot’s advisory committee, says that this will probably be possible within the next decade.

Manchester says that they could also be useful as part of missions to explore other planets. “You can imagine having them tag along on a planetary exploration mission and deploying them once you get there, and you can do things with these tiny satellites that you wouldn’t want to risk with a larger spacecraft,” he says. Since the Sprites are small and only cost about $25 each, it would be less of a risk to send one into a planet’s atmosphere or even to its surface.

Setting sail

Later on in the century, Breakthrough Starshot has even bigger aspirations to send similar spacecraft deeper into the cosmos.

Their plan to reach another star is based on the StarChip, a miniature spacecraft like the Sprite that is attached to a metre-wide light sail. The sail would be powered by pulses of laser light from an array of high-powered lasers on the ground which would eventually accelerated them to speeds up to one fifth the speed of light.

Such a system could reach Alpha Centauri, the closest star system to us, in a little more than 20 years. Once there, the StarChips would take images and other basic measurements of the binary star and its planet, Proxima b.

Many technical obstacles still remain, including building the necessary lasers and making sure the chips aren’t degraded beyond usefulness by the time they get there, but this flight is one of the first demonstrations that the StarChip idea just might work.