NASA's Voyager 1 spacecraft is set to reach a historic milestone on Wednesday, Nov. 18, becoming the first human-made object to reach a distance of one light-day from Earth, nearly five decades after its launch.
The spacecraft will reach a distance of 16.094 billion miles (25.902 billion kilometers) at 1016GMT, according to NASA.
At that distance, radio signals will take 24 hours to travel from Earth to Voyager 1 and another 24 hours to return, creating a minimum round-trip communication delay of 48 hours.
Launched on Sept. 5, 1977, Voyager 1 was originally designed to explore Jupiter and Saturn before continuing its journey toward interstellar space.
It became the most distant human-made object in February 1998 after overtaking NASA's Pioneer 10 spacecraft and crossed into interstellar space in August 2012, becoming the first spacecraft to do so.
Voyager 1 and its twin, Voyager 2, remain the only spacecraft to have operated beyond the heliosphere, the protective bubble of particles and magnetic fields generated by the Sun.
Despite operating for more than 49 years, Voyager 1 continues to collect scientific data as NASA engineers work to conserve its diminishing power supply.
To celebrate the milestone, NASA has invited people worldwide to participate in its Shine Bright for Voyager's Light-Day event on Tuesday, Nov. 17, by flashing lights toward the sky after sunset.
