Voyager sends 'heartbeat' signal from 12 billion miles away after NASA lost contact

NASA's Voyager 2 probe, currently cruising beyond the edge of the solar system more than 12.3 billion miles from Earth, has sent a hopeful signal back to mission control. 

This comes after a series of planned operations on July 21 accidentally angled the probe's antenna about two degrees away from Earth, resulting in a near-total communication cut-off between Voyager and NASA's Deep Space Network.

The signal, referred to as a "heartbeat," confirms that the spacecraft is still broadcasting, which was expected by engineers at NASA's Jet Propulsion Laboratory (JPL). The next step for NASA is to send a command back to Voyager 2, coaxing the probe into angling its antenna back toward Earth. 

This process takes about 18.5 hours for a command to reach Voyager 2, and another 18.5 hours for Earth to receive a transmission back from the probe.

If the forced realignment fails, Voyager 2 is expected to reset its antenna to the Earth-facing position on Oct. 15, in one of a planned series of auto-resets that occur throughout the year. Voyager 2 and its twin Voyager 1 were launched into space in August and September 1977, respectively. 

Both probes ventured past the outer solar system planets before heading toward the edge of the heliosphere, the outermost layer of the sun's atmosphere, which separates our solar system from interstellar space.

Voyager 1 reached interstellar space in August 2012 and is currently cruising about 14.8 billion miles from our planet, making it the single most distant human-made object from Earth. Voyager 2 followed in its twin's thruster-steps several years later, leaving the heliosphere in November 2018. Both probes currently have enough power and fuel to last until at least 2025, according to NASA.