The team is tackling an issue with one of Voyager 1's onboard computers, the flight data system, which is stopping it from transmitting data.
NASA engineers are undertaking their last rounds of efforts
in a final push to re-establish communication with Voyager 1. As the
second-longest operating spacecraft in history, Voyager 1 has ventured more
than 24 billion kilometers (15 billion miles) from Earth, securing its place as
the farthest-traveled object crafted by humanity.
NASA announced in a statement that since mid-November 2023,
the interstellar Voyager 1 probe has encountered difficulties transmitting data
gathered by its scientific instruments back to Earth.
Launched in 1977, Voyager 1 is not just the first spacecraft
to travel into interstellar space (making it the farthest human-made object
ever), but it has also made some other substantial discoveries. It found new
moons around Jupiter, spotted another ring around Saturn, and took a special
picture of all the planets together in one shot, like a big family photo.
"Sad and frustrated to have the spacecraft still
working but muted. Even though we know the end could come at any time, losing a
spacecraft is never easy. Especially one like Voyager 1," said Bruce
Waggoner, the Voyager mission assurance manager, in a conversation with
Space.com.
Flight data system
NASA engineers are currently addressing an issue concerning
one of the three onboard computers of Voyager 1, known as the flight data
system (FDS). Although the spacecraft is successfully receiving and executing
commands from Earth, the FDS is experiencing communication difficulties with
one of its subsystems, the telemetry modulation unit (TMU). Consequently,
according to NASA, no scientific or engineering data is being transmitted back
to Earth.
The FDS has multiple functions, including collecting data
from scientific instruments and monitoring the spacecraft's health and status.
It then consolidates this information into a single data package for
transmission to Earth via the TMU. This data is encoded in binary form,
comprising combinations of ones and zeros, which form the basis of all computer
language.
In December, the telemetry modulation unit (TMU) started
transmitting a recurring sequence of ones and zeros, indicating a potential
"stuck" condition. After eliminating other potential causes, the
Voyager team identified the flight data system (FDS) as the source of the
problem. Later, attempts were made to reboot the FDS and restore it to its
previous operational state, but unfortunately, the spacecraft continues to fail
to transmit usable data, according to NASA.
Challenging issues
Consulting original documents written decades ago by
engineers who did not foresee present-day issues is often necessary to address
challenges encountered by the probes. According to the space agency, this
process requires considerable time for the team to grasp how a new command
might impact the spacecraft's operations, thus preventing unintended
consequences.
Furthermore, increasing the challenge is that all commands
dispatched from mission controllers on Earth require 22.5 hours to reach
Voyager 1, which is currently exploring the outer reaches of our solar system,
over 15 billion miles (24 billion kilometers) from Earth. Consequently, the
engineering team must patiently wait 45 hours to receive a response from
Voyager 1, enabling them to assess whether a command produced the desired
outcome.
"This week, the team will send more commands to the
spacecraft to gather information about the status of the onboard systems. In
the coming weeks, the team expects to start making more aggressive attempts to
reset various systems that might influence the FDS," said NASA engineers
in a conversation with IFLScience.
Voyager 2, the sibling of Voyager 1, was launched just 16
days after its counterpart and continues to function effectively. Managed and
operated by NASA's Jet Propulsion Laboratory in Southern California, these
probes are unique in their exploration of interstellar space—the expansive
realm traversed by our Sun and its accompanying planets.