Breakthrough Starshot, a multi-million dollar interstellar research project funded by Russian billionaire Yuri Milner, has launched the smallest ever spacecraft into low earth orbit. The development can be seen as a giant leap toward the project's grander goal of developing nano crafts, called StarChips, and sending them to our neighbouring star system, Alpha Centauri (4.37 light-years away) at speeds between 15% and 20% of light .
The project, announced by Milner and cosmologist Stephen Hawking under the Breakthrough Initiative, delivered six prototypes of the smallest crafts, called "Sprites", on 23 June as supplementary payloads on an Indian booster launching two educational satellites. Two sprites are attached to both satellites, while four await deployment.
Scientific American noted that "the six satellites are comparatively dainty, but punch far above their weight". Each Sprite, weighing 4 grams and measuring 3.5cm on each side, costs $25 to make and looks like a US postage stamp carrying solar panels, computers, sensors, and radio equipment on a single circuit board. Once they've been deployed successfully, the sensors – magnetometers and gyroscopes – positioned on each circuit board will be used for tracking their movement while understanding their orbital dynamics.
"This mission is designed to test how well the Sprites' electronics perform in orbit and demonstrates their novel radio communication architecture," a Starshot press release said.
As of now, only one exterior mounted sprite is in communication with ground stations in California and New York. Zac Manchester, who created the concept of Sprites for Breakthrough Startshot, said, "We've gotten signals from at least one Sprite, but we're not sure which because we haven't received two signals simultaneously". The other four sprites are still awaiting deployment as Max Valier, the satellite carrying them may have failed to deploy its own radio communication antenna.
Despite the setback, Manchester is bullish about the success of the mission and believes mission controllers can attempt various fixes as the mother ships are in stable orbit. "This is the first time we've successfully demonstrated Sprites end-to-end by flying them in space, powering them with sunlight and receiving their signals back on Earth," he said.
Manchester noted each Sprite generates 100 milliwatts of electricity in direct sunlight but assured that under ideal circumstances, 100mWs is sufficient to transmit data at a rate similar to that of a fax machine. He also added, "Those 100 milliwatts are enough to operate Sprite's on board microprocessors, which surpass many full-sized satellites from the 1990s in terms of raw computing power".
As reaching for the stars at about 37,000 miles per second is still a long-shot, Manchester believes a swarm of cheap and unmanned sprites could also come handy in exploring promising asteroids, moons, planets or signs of extraterrestrial life. "You wouldn't care if a whole bunch of them were destroyed in the process," he said.