Voyager 1 approaches humanity’s first one-light-day milestone

NASA’s Voyager 1 is expected to become the first human-made object one light-day from Earth on November 18. At more than 16 billion miles, a radio signal travelling at light speed will take exactly 24 hours to reach Earth.

The spacecraft and its twin continue returning engineering and science data while travelling at roughly 38,000 mph. Voyager 1 entered interstellar space in 2012; NASA’s small control team sends commands about weekly and continues power-saving work as the probe ages.