An anonymous reader quotes a report from Space.com: New technology could use X-rays to transmit data at high rates over vast distances in outer space, as well as enable communications with hypersonic vehicles during re-entry, when radio communications are impossible, NASA scientists say. The technology would combine multiple NASA projects currently in progress to demonstrate the feasibility of X-ray communications from outside the International Space Station. The radio waves used by mobile phones, Wi-Fi and, of course, radios, are one kind of light. Other forms of light can carry data as well; for instance, fiber-optic telecommunications rely on pulses of visible and near-infrared light. The effort to use another type of light, X-rays, for communication started with research on NASA's proposed Black Hole Imager. That mission is designed to analyze the edges of the supermassive black holes that previous research suggested exist at the centers of most, if not all, large galaxies. One potential strategy to enable the Black Hole Imager was to develop a constellation of precisely aligned spacecraft to collect X-rays emitted from the edges of those black holes. Keith Gendreau, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, thought of developing X-ray emitters that these spacecraft could use as navigational beacons to make sure they stayed in position relative to one another. The system would keep them aligned down to a precision of just 1 micron, or about one-hundredth the average width of a human hair. Gendreau then reasoned that by modulating or varying the strength or frequency of these X-ray transmissions on and off many times per second, these navigational beacons could also serve as a communication system. Such X-ray communication, or XCOM, might, in theory, permit gigabit-per-second data rates throughout the solar system, he said. One advantage that XCOM has compared to laser communication in deep space is that X-rays have shorter wavelengths than the visible or infrared light typically used in laser communication. Moreover, X-rays can penetrate obstacles that impede radio communication.