NASA's Voyager 1 will become the first human-made object to reach one light-day from Earth on November 18. Project manager Suzanne Dodd said, "If you want to say 'hello' to Voyager, you send your message and then you go home and you wait two days before you finally get a response."

NASA's Voyager 1 spacecraft, which was launched in 1977 to study the outer planets, is on its way to becoming the first human-made object to reach a distance of one light-day from Earth. The milestone is expected to be achieved on November 18, 2026. At that time, the spacecraft will be some 25.89 billion kilometers away from Earth, making communication with mission controllers a challenge due to a delay of up to two days in radio signals.

Voyager 1 was launched on September 5, 1977, to study Jupiter and Saturn. It entered interstellar space in August 2012 and has been sending scientific data back to Earth ever since.

A light-day is the distance light travels in a day. This milestone will impact communication with the spacecraft significantly as radio signals from Earth will take around a day to reach it and vice versa.

Suzanne Dodd, Voyager project manager at NASA's Jet Propulsion Laboratory (JPL), explained the communication delay, saying, If you want to say 'hello' to Voyager, you send your message and then you go home and you wait two days before you finally get a response.

The milestone comes weeks after NASA temporarily lost contact with Voyager 1 when its Deep Space Network failed to pick up signals during two scheduled communications on October 18 and 19.

The communication loss was due to one of the spacecraft's thrusters shutting down, triggering its onboard fault protection system to switch to backup thrusters automatically. The exact cause of this incident is still under investigation.

Despite these challenges, Voyager 1 continues to travel at a speed of around 61,155km/h and operate on its aging systems with a dwindling power supply from radioisotope thermoelectric generators that convert heat from decaying plutonium into electricity.

To extend the mission, NASA engineers conducted a power-saving operation in September by shutting down three devices aboard Voyager 1 and replacing them with lower-power alternatives.

The 'Big Bang' operation is expected to keep its remaining science instruments operational for a longer period.

Without these changes, NASA would have had to turn off another instrument as early as summer 2027.