Work is underway to establish the first interplanetary laser communication link. The $300 million NASA experiment, if successful, will connect robotic spacecraft at Mars with scientists back on Earth via a beam of light traveling some 300 million kilometers. For scientists eager to download bandwidth-intensive imagery and other data collected by planetary orbiters, probes and landers, the laser communications would offer a dramatic breakthrough in the amounts of information spacecraft can reliably transmit back to Earth.