Launched in 1977 to explore the outer solar system, the spacecraft Voyager 1, along with its twin Voyager 2, depends on a powerful ground-based radio antenna for communication.
Since 2004, Voyager 1 has been using its backup thrusters after the primary system failed.
Even a slight misalignment of the antennas could sever contact between the spacecraft and Earth, explains Voyager program scientist Patrick Koehn.
The Voyager team suspected that the heaters on the primary thrusters had turned themselves off because of an electronics glitch.
Engineers were concerned that after being dormant for two decades in the cold of space, the thrusters might be beyond repair.
A difficult choice that could have ended Voyager 1’s decades-long journey was presented to NASA mission controllers earlier this year.
The spacecraft Voyager 1 and its twin Voyager 2, which were launched in 1977 to explore the outer solar system, rely on a strong ground-based radio antenna for communication. There was a genuine chance that communication with Voyager 1 would be lost forever if this antenna was turned back on after being taken offline for upgrades.
The spacecraft’s roll thrusters, which keep its antenna pointing toward Earth, were the primary source of concern. Voyager 1 has been using its backup thrusters since 2004 in the event that the primary system fails. There were indications, however, that the backup system might also malfunction. They were in danger of ceasing to function due to a residue accumulation in a fuel line.
Kareem Badaruddin, Voyager Mission Manager, says, “Imagine the nozzle becoming smaller and smaller with debris.”. As the thruster deteriorates, less propulsion is possible. “,”.
That propulsion is essential. According to Patrick Koehn, a scientist with the Voyager program, even a small misalignment of the antennas could cut off communication between the spacecraft and Earth. He claims that “the beam can swing away from the Earth with even a very small tip away, you know, a fraction of a degree.”. “The beam misses the Earth by … [the] distance between the Earth and the Sun by about half a degree. “..”.
When controllers saw that heater switches in the primary system had shut off by themselves, indicating a potential issue, they initially switched to the backup thrusters, according to Badaruddin. Engineers looked again at the main roll thrusters to see if they could be revived as alternatives diminished.
“They revisited and examined the old records. Koehn explains, “They determined it was worthwhile to try turning the heaters back on.”.
However, time was running out. On May 4, Deep Space Station 43, a 230-foot dish in Canberra, Australia, which transmits commands to both Voyagers, was supposed to go offline for maintenance. According to NASA, this dish is the only one with sufficient power to communicate with the Voyagers. It wouldn’t be completely functional once more until February of the following year. Engineers would not be able to give either spacecraft any commands, with the exception of brief operating windows in August and December.
The Voyager crew believed that an electronics malfunction had caused the heaters on the main thrusters to shut off on their own. However, Badaruddin notes that there was also a risk that the spacecraft might blow up if they attempted to turn them back on and activate the main thrusters.
According to him, in order to avoid a disastrous explosion, they had to test the thruster without actually setting it on fire. “.”.
The thrusters had lain dormant for twenty years in the frigid cold of space, and engineers feared they might be irreparable.
On March 20, however, the Voyager crew got good news: the primary roll thruster test went well.
Both spacecraft are aging. The problem with Voyager 1 sending gibberish from deep space was fixed last year, although it began in 2023. Voyager 2 experienced a malfunction in 2023 that resulted in a brief deviation of its antenna from Earth.
The two spacecraft should remain in operation long enough for the Voyager team to commemorate their 50th anniversary in 2027.
“Since we now know the thrusters are in good condition, there’s no reason it wouldn’t go past [2027],” Koehn states.
“It’s a unique lifespan in the history of robotic exploration of the planets,” said Matt Shindell, curator of space history at the National Air and Space Museum at the Smithsonian.
“Insights from these missions are still being used by scientists,” he says. For planets outside of our orbit, the probes “gave us the best data.”. Shindell states that “and in the case of Uranus and Neptune, that’s still the best data we have.”.
He remarks, “It is truly amazing that it is still up and running and still sending back information.”.
“The only artificial objects that can tell us what the space between the stars is really like are the Voyagers,” Koehn continues.
The probes continue to provide scientists with new information, especially about the long-range manifestations of solar activity like coronal mass ejections (CMEs).
