NASA hears 'heartbeat' from Voyager 2 after inadvertent blackout

NASA's distant Voyager 2 probe has sent a "heartbeat" signal to Earth after mission control mistakenly cut contact, the U.S. space agency said Tuesday. A series of planned commands sent to Voyager 2 on July 21 "inadvertently caused the antenna to point two degrees away from Earth," NASA's Jet Propulsion Laboratory said in a recent update. Voyager 2's twin Voyager 1 was mankind's first spacecraft to enter the interstellar medium, in 2012, and is currently almost 15 billion miles from Earth. Both Voyager spacecraft carry "Golden Records" - 12-inch, gold-plated copper disks intended to convey the story of our world to extra-terrestrials.