Voyager-1, Earth’s interstellar traveller, calls home on a dying signal

Travelling billions of kilometres away from Earth in interstellar space, the Voyager-1 spacecraft has once again established communication with Earth, although on a very faint signal.
Nasa successfully re-established communication with the Voyager-1 spacecraft on October 24 after a brief pause due to a fault protection system activation.
This incident was triggered when a command to turn on a heater on October 16 caused Voyager 1 to shut down its primary X-band radio transmitter, switching instead to a backup S-band transmitter, which had not been used since 1981.
“The transmitter shut-off seems to have been prompted by the spacecraft’s fault protection system, which autonomously responds to onboard issues,” Nasa said.
The fault protection system is designed to conserve power by disabling non-essential systems when power supply issues arise.
The team at NASA’s Jet Propulsion Laboratory (JPL) faced challenges in detecting the weaker S-band signal, as it travels over 25 billion kilometres from Earth.
Communication typically takes about 46 hours for signals to travel to and from the spacecraft.
The spacecraft typically communicates with Earth using what’s called an X-band radio transmitter, named for the specific frequency it uses. The flight team correctly hypothesised that the fault protection system had lowered the rate at which the transmitter was sending back data.
After confirming the S-band transmitter was operational on October 22, engineers began investigating the root cause of the fault protection activation.
They anticipate that identifying the underlying issue may take days or weeks.
Voyager 1, launched in 1977, continues to provide invaluable data from interstellar space, despite its ageing technology and increasing operational challenges.
Voyager 1 uses liquid hydrazine as fuel, which is converted to gas in short bursts to adjust the spacecraft’s orientation. Each day, it requires about 40 of these pulses to remain aligned with Earth.
The spacecraft officially crossed the boundary known as the heliopause in August 2012, making it the first human-made object to do so. Currently, it is over 25 billion kilometres away from Earth, travelling through the space between stars in the Milky Way galaxy.