After months of extensive upgrades to its Deep Space Network dish in Australia, Nasa has made contact once more with the Voyager 2 probe, which had been flying solo since March.
The 43-year-old spacecraft was sent a series of commands by Nasa on October 29, after which the probe returned a signal confirming it had received the “call” and executed the commands without issue. Its power source is expected to expire by 2025 at the latest.
Nasa’s Deep Space Network (DSN) is a collection of radio antennas around the world used primarily to communicate with spacecraft operating beyond the Moon.
Since the dish went offline, mission operators have been able to receive health updates and science data from Voyager 2, but they haven’t been able to send commands to the far-flung probe, which has travelled billions of miles from Earth since its 1977 launch. The probe is now so far from the Earth that signals take around 17 hours each way to travel between it and the Earth.
Among the upgrades to DSS43 (as the dish is technically known) are two new radio transmitters, one of which hasn’t been replaced in over 47 years. Engineers have also upgraded heating and cooling equipment, power supply equipment and other electronics needed to run the new transmitters.
The successful call to Voyager 2 is just one indication that the dish will be back online in February 2021.
“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,” said Brad Arnold, the DSN project manager.
“This test communication with Voyager 2 definitely tells us that things are on track with the work we’re doing.”
The Deep Space Network consist of radio antenna facilities spaced equally around the globe in Canberra (Australia), Goldstone (California, US) and Madrid (Spain). The positioning of the three facilities ensures that almost any spacecraft with a line of sight to Earth can communicate with at least one of the facilities at any time.
Voyager 2 is the rare exception. In order to make a close flyby of Neptune’s moon Triton in 1989, the probe flew over the planet’s north pole. That trajectory deflected it southward relative to the plane of the planets and it has been heading in that direction ever since. Now more than 11.6 billion miles (18.8 billion kilometres) from Earth, the spacecraft is so far south that it doesn’t have a line of sight with radio antennas in the Northern Hemisphere.