Breakthrough Starshot, the $100 million initiative aiming to send robotic missions to nearby stars by the mid-21st century, has achieved what might prove to be a “Sputnik moment” in successfully lofting its first spacecraft—the smallest ever launched and operated in orbit.
In 1957 the Soviet Union shocked the world by flying the first artificial satellite, Sputnik 1, an 83-kilogram metallic orb about twice the size of a basketball that broadcast a radio message to anyone listening down on Earth. On June 23, Breakthrough Starshot sent not one but six satellites into low-Earth orbit, riding as supplementary payloads on an Indian rocket launching two other educational satellites built by the European space company OHB System AG. These six satellites are comparatively dainty, but punch far above their weight. Called “Sprites,” each is a 4-gram flake of circuit-board just 3.5 centimeters on a side, packing solar panels, computers, sensors and communications equipment into an area equal to a U.S. postage stamp. Representatives of Breakthrough Starshot, which is funded by the Russian billionaire Yuri Milner, brokered the deal that sent the Sprites piggybacking to orbit. They also worked with the U.S. State Department to ensure the project did not violate strict federal regulations limiting exports of spaceflight hardware.
Manufactured in bulk, low-cost Sprites could be deployed and networked by the hundreds or thousands to create space-based sensor arrays of unprecedented breadth, with each craft so lightweight that it could operate without propellant, shifting or maintaining its orbit solely through the radiation pressure of starlight or the forces imparted by a planet’s magnetic field. More wildly, future iterations of Sprites could become Breakthrough’s hoped-for “StarChips”—spacecraft integrated with gossamer-thin, meter-wide “lightsails” that would travel at 20 percent the speed of light to Alpha Centauri or other nearby stars, propelled by high-powered pulses of photons from a gargantuan ground-based laser array. Progress toward this starry-eyed goal is slow but steady, Breakthrough representatives say, and the organization is set to solicit research proposals for the associated “grand challenges” in optics, communications, materials science and other disciplines later this year.
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