Farthest human-made object in space loses contact, goes nearly one light-day away from Earth

NASA briefly lost contact with Voyager 1 in mid-October after the nearly 50-year-old spacecraft stopped transmitting a detectable radio signal during two scheduled communications attempts. The signal returned on October 20, but engineers are still investigating what caused the interruption.

The incident comes just weeks before Voyager 1 is expected to become the first human-made object to reach a distance of one light-day from Earth, a point at which radio messages will take a full 24 hours to travel in either direction.

NASA’s Deep Space Network, a global system of large radio antennas used to communicate with distant spacecraft, failed to detect Voyager 1’s signal on October 18 and 19. The probe is now approximately 16 billion miles (24 billion kilometers) from Earth.

Communication resumed on October 20, about 48 hours after the interruption began. NASA says the team has maintained contact with the spacecraft since then.

An automatic safety response may hold the clue

Engineers are still trying to determine what triggered the communications loss. However, NASA has established that one group of Voyager 1’s thrusters went offline during the incident, prompting its backup thrusters to switch on automatically.

The spacecraft is programmed to respond this way when its onboard computers detect a potential problem with the active thrusters. This automated protection system can place the probe in a stable, safe configuration and pause normal operations while engineers investigate.

The spacecraft’s signal returned before the team sent commands to troubleshoot the issue from Earth.

“This is the first time we’ve seen the spacecraft do something like this, but we are also at a point in the mission where we have to expect the unexpected,” said Kareem Badaruddin, Voyager mission manager at NASA’s Jet Propulsion Laboratory. “We’re relieved to be back in contact with Voyager 1 and are eager to understand what happened.”

The incident is another reminder of the challenges of operating spacecraft launched nearly half a century ago, especially as their onboard power supplies continue to weaken.

NASA is trying to squeeze more life out of Voyager 1

Voyager 1 and its twin, Voyager 2, rely on radioisotope thermoelectric generators (RTGs), which convert heat from decaying plutonium into electricity. As the radioactive material decays, the spacecraft lose about four watts of electrical power each year.

To keep the probes operating, engineers have gradually switched off instruments and other systems that are no longer essential to their missions.

In September, the Voyager team completed a major power-saving effort on Voyager 1, nicknamed the “Big Bang.” Engineers simultaneously switched off three devices and activated lower-power alternatives, helping reduce energy consumption while maintaining the spacecraft’s thermal balance.

The procedure was designed to extend the operating life of Voyager 1’s remaining science instruments. Without the changes, NASA estimated that it would have needed to shut down another instrument as early as summer 2027.

Both spacecraft are now traveling through interstellar space, beyond the heliosphere, which is the enormous bubble of particles and magnetic fields generated by the Sun. They remain the only spacecraft to have directly studied this region.

A 24-hour wait for a message from Earth

Voyager 1 is approaching another remarkable milestone. On November 18, 2026, NASA expects the spacecraft to reach a distance of 16.094 billion miles (25.902 billion kilometers) from Earth, equivalent to one light-day.

A light-day is the distance light travels in 24 hours. Since radio signals travel at the speed of light, reaching Voyager 1 will then take an entire day. A response from the spacecraft will require another day to return.

That means a simple exchange with the probe will take roughly 48 hours, even if everything works as expected. Voyager 1 is currently traveling at approximately 38,000 mph (61,155 kph). Launched in September 1977, it has become the most distant human-made object from Earth, having traveled far beyond the planets it was originally sent to explore.

The one-light-day milestone will not change the spacecraft’s surroundings or operations. But it will offer a striking measure of how far humanity’s most distant explorer has traveled and how long its signals must journey to reach home.

Source: https://interestingengineering.com/space/nasas-voyager-1-briefly-went-silent