On October 29, 2020, NASA exchanged test commands and a reply with Voyager 2, launched in August 1977. The ground station’s command transmitter had been offline since March 2020 for upgrades; Voyager 2 continued sending data that other Canberra antennas could receive. Those fears were unfounded: on 29 October 2020, NASA received a 'call' from the then 43-year-old craft at one of its huge communication antennas.
At the time, Voyager 2 was about 18.8 billion kilometres (12 billion miles) from Earth and is still hurtling further and further away through the abyss of space. It is so distant that the message, sent at light speed, took about 17.5 hours each way, or about 35 hours for a round trip.
Brad Arnold, the DSN project manager at Nasa's Jet Propulsion Lab, said:
"What makes this task unique is that we're doing work at all levels of the antenna, from the pedestal at ground level all the way up to the feedcones at the center of the dish that extend above the rim. This test communication with Voyager 2 definitely tells us that things are on track with the work we're doing."
The transmitters that send and receive messages to the craft were updated for the first time in 47 years, with other infrastructure also replaced, leading to hopes that Voyager will be able to send back information for years to come.
While it may be remarkable that the craft is operational, the lack of atmospheric drag does not remove the constraints of aging hardware, declining electrical power and reliable communications. These factors limit how long the spacecraft can return information.
Philip Baldwin, operations manager for Nasa's Space Communications and Navigation (SCaN) Program, added:
"The DSS43 antenna is a highly specialized system; there are only two other similar antennas in the world, so having the antenna down for one year is not an ideal situation for Voyager or for many other NASA missions. The agency made the decision to conduct these upgrades to ensure that the antenna can continue to be used for current and future missions. For an antenna that is almost 50 years old, it's better to be proactive than reactive with critical maintenance."
At the time of the 2020 report, NASA was working on space probes that will explore the Moon for water deposits after traces were found earlier in 2020. Perseverance was also on its way to Mars to search for signs of ancient microbial life, rather than known alien fossils.
Why NASA had paused commands to Voyager 2
Deep Space Station 43, a 70-metre antenna near Canberra, Australia, had been offline for major upgrades since March 2020. At the time, it was the only antenna equipped and positioned to transmit commands to Voyager 2.
Engineers replaced transmitters and updated supporting systems, including power and cooling equipment. NASA’s November 2020 report describes the successful October test during that work.
The spacecraft had continued sending health and science data, which other antennas in Canberra could receive. The interruption affected the ability to send commands from Earth; it was not seven months in which Voyager 2 disappeared without any signal.
Why the Canberra station mattered
NASA’s Deep Space Network has facilities in Australia, California and Spain. Their separation around the globe helps maintain communication as Earth rotates.
Voyager 2 follows a trajectory south of the plane of the planets, shaped by its 1989 encounter with Neptune. By 2020, it was too far south in the sky to have the required line of sight from the network’s Northern Hemisphere stations.
Canberra supplied the southern view, and DSS43 supplied the necessary transmitting capability. Having another large dish somewhere on Earth would not automatically solve both problems.
A conversation measured in hours
Radio waves travel at the speed of light, but interplanetary distances make even that speed feel slow. At the distance reported by NASA in late 2020—about 18.8 billion kilometres—a signal needed roughly 17.5 hours for one direction of travel.
A command and its returning confirmation therefore involved about 35 hours of light-travel time. That is the round trip, not a 35-hour journey each way.
This changes the meaning of troubleshooting. An operator cannot send an instruction and expect an immediate response. Commands must be prepared with care, and the confirmation arrives after a long interval in which the signal is simply travelling.
How old was Voyager 2?
Voyager 2 launched on August 20, 1977. It was 43 years old during the 2020 antenna test and reached 49 years since launch in August 2026.
Dates matter in a mission this long. A headline written during one phase can become misleading if its age or distance is repeated years later without context.
For changing mission information, NASA’s Voyager location and status page is a better reference than carrying a historical distance forward as though it were current.
What keeps a mission going for decades?
Deep space does not make hardware immune to age. Power, temperature, instrument health and communication all place limits on what a spacecraft can continue doing. Ground systems need maintenance too, as DSS43’s upgrade demonstrated.
The 2020 exchange is memorable because it shows both sides of that work. The distant spacecraft still understood the instructions, and a major engineering project on Earth successfully restored a crucial part of the connection.
New missions must plan for communication delays from the beginning. Dragonfly’s planned exploration of Titan will also depend on a spacecraft carrying out carefully designed activities far beyond immediate human control.
Voyager 2’s reply was brief evidence of an extraordinary chain still functioning: a transmitter near Canberra, a radio signal crossing interstellar distance and a machine launched in 1977 responding as expected.
Update, 2025: saving power by switching off instruments
Keeping Voyager 2 talking now depends on rationing power. Its nuclear power source loses about 4 watts a year, so in March 2025 NASA said it would switch off the spacecraft’s low-energy charged particle instrument on 24 March 2025, leaving three science instruments running, with the cosmic ray subsystem scheduled to be turned off in 2026. Engineers said the shutdowns could keep at least one instrument working into the 2030s, though unforeseen problems could shorten that.
Sources: NASA JPL, 5 March 2025: NASA turns off two Voyager science instruments to extend mission
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