Voyager 1 nears one light‑day mark

Voyager 1 is closing in on a one-light-day distance from Earth, with NASA saying the probe should reach that mark later in 2026. (science.nasa.gov) A light-day is the distance light travels in 24 hours: about 16.09 billion miles, or 25.9 billion kilometers. NASA’s mission table recently listed Voyager 1 at 16,079,874,919 miles from Earth, with a one-way radio light time of 23 hours, 58 minutes and 39 seconds. (science.nasa.gov) That means a command sent from Earth takes almost a full day to reach the spacecraft, and a reply takes almost another day to come back. NASA updated its Voyager status page on April 17, 2026, and said the mission table was briefly offline while engineers refined the numbers because Voyager 1 is so close to the milestone. (science.nasa.gov) Voyager 1 is still operating in interstellar space, which NASA describes as the region beyond the heliosphere, the Sun’s bubble of magnetic fields and solar wind. NASA says Voyager 1 crossed that boundary in August 2012, and Voyager 2 followed in 2018. (science.nasa.gov) The spacecraft launched on Sept. 5, 1977, and it remains the most distant human-made object in existence. Before heading outward, it flew past Jupiter and Saturn and returned data on the outer solar system, including discoveries of new moons and active volcanoes. (jpl.nasa.gov) Voyager 1 is moving away from the solar system at about 3.5 astronomical units per year, according to NASA. One astronomical unit is the average Earth-Sun distance, about 93 million miles, so the probe adds hundreds of millions of miles each year. (science.nasa.gov) The spacecraft is still working with a much smaller power budget than it had at launch. NASA says each probe’s radioisotope thermoelectric generator loses about 4 watts of power a year, forcing mission managers to switch off instruments one by one to keep the mission going. (science.nasa.gov) On April 17, 2026, NASA marked Voyager 1’s Low-Energy Charged Particles instrument as off to save power, while the magnetometer and plasma wave subsystem remained on. NASA said both Voyagers were still functioning in April 2026. (science.nasa.gov, science.nasa.gov) Nearly 49 years after launch, Voyager 1 is nearing a distance where even light needs a full day to span the gap. The spacecraft is still sending back measurements from the space between the stars, just more slowly than ever. (science.nasa.gov, science.nasa.gov)