Voyager 1 Resumes Sending Science Data From Deep Space

After five nerve-wracking months of communication silence, NASA has successfully restored full data transmission from Voyager 1. The most distant human-made object in history, currently drifting through interstellar space, stopped making sense in November 2023. Thanks to an ingenious software fix beamed billions of miles across the cosmos, the 46-year-old probe is once again sending vital information about the environment outside our solar system.

The 2023 Communications Blackout

The trouble began on November 14, 2023. While Voyager 1 continued to receive commands from Earth and operate normally, the data it sent back became unintelligible. Instead of the usual stream of binary code containing science and engineering data, the spacecraft began transmitting a repeating pattern of ones and zeros.

Engineers at NASA’s Jet Propulsion Laboratory (JPL) in Southern California identified the source of the problem as the Flight Data System (FDS). This is one of the probe’s three onboard computers. The FDS is responsible for packaging data from the science instruments and engineering telemetry before sending it to the telecommunications unit (TMU) for transmission to Earth.

For months, the team analyzed the garbled signal. They discovered that a single chip responsible for storing a portion of the FDS memory had failed. This hardware failure corrupted the code necessary for packaging the data, rendering the transmission useless.

The Long-Distance Repair Job

Fixing a computer glitch on Earth is often as simple as rebooting the system or replacing a part. Fixing a computer located over 15 billion miles away presents a unique set of challenges.

The 45-Hour Lag

Communication with Voyager 1 is incredibly slow due to the vast distance. Radio signals travel at the speed of light, yet it takes approximately 22.5 hours for a command to reach the spacecraft. It takes another 22.5 hours for the response to return to Earth. This means the engineering team had to wait nearly two days to see if any command they sent was successful.

The “Move Furniture” Solution

Since the engineers could not physically replace the corrupted memory chip, they had to find a software workaround. The solution involved moving the affected code to a different location in the FDS memory. However, no single location was large enough to hold the entire section of code.

The team devised a complex plan to slice the code into sections and store them in various places within the FDS memory. They also had to update the code to ensure the scattered instructions could still reference each other and function as a cohesive unit.

On April 18, 2024, the team sent the first command to move the code responsible for engineering data. On April 20, they received the confirmation they had been hoping for. Voyager 1 returned readable engineering data for the first time in five months.

Science Instruments Back Online

Restoring the engineering data was the first major victory, as it allowed NASA to check the health and status of the spacecraft. The next hurdle was getting the science instruments back online.

On May 17, 2024, the team successfully sent commands to resume data collection from two of the four operational instruments:

• The Plasma Wave Subsystem
• The Magnetometer

Shortly after, the remaining two instruments were brought back online:

• The Cosmic Ray Subsystem
• The Low-Energy Charged Particle Instrument

As of mid-2024, Voyager 1 is conducting normal science operations. It is once again actively measuring plasma waves, magnetic fields, and particles in interstellar space.

Why Voyager 1 Data is Irreplaceable

The effort to save Voyager 1 was critical because it provides data that no other spacecraft can capture. Launched in 1977, Voyager 1 crossed the “heliopause” in August 2012. This boundary marks the edge of the heliosphere, the protective bubble of particles and magnetic fields created by our Sun.

Voyager 1 is currently traveling through the Interstellar Medium (ISM). This is the space between stars. It is the only probe capable of sampling this environment directly. Its twin, Voyager 2, is also in interstellar space but travels on a different trajectory and moves slower.

The data returned by Voyager 1 helps scientists understand:

1. The Shape of the Heliosphere: By measuring the pressure and magnetic fields outside the solar bubble, scientists can model the shape of our solar system’s interaction with the rest of the galaxy.
2. Cosmic Rays: The probe measures the intensity of high-energy radiation from exploding stars elsewhere in the galaxy. The heliosphere blocks much of this radiation, so measuring it “in the wild” provides a baseline for galactic radiation levels.
3. Solar Wind Interaction: It observes how the solar wind mixes with the interstellar wind.

The Future of the Mission

Despite this triumph, the Voyager team is racing against time and physics. The spacecraft is powered by a radioisotope thermoelectric generator (RTG), which converts heat from decaying plutonium-238 into electricity.

The generator produces about four fewer watts of power each year. To keep the spacecraft running, engineers have had to turn off non-essential systems, including heaters and cameras. The team estimates that by 2025 or shortly thereafter, they may have to start turning off science instruments one by one to conserve power.

However, the successful repair of the FDS has likely extended the mission’s life significantly. As long as the remaining thrusters can keep the antenna pointed at Earth and the power supply holds out, Voyager 1 will continue to be humanity’s most distant outpost.

Frequently Asked Questions

How far away is Voyager 1 right now? Voyager 1 is over 15 billion miles (24 billion kilometers) from Earth. It is so far that the Sun appears merely as a very bright star in the sky.

Why doesn’t Voyager 1 take pictures anymore? NASA turned off the cameras on Voyager 1 in 1990 after it took the famous “Pale Blue Dot” portrait. This was done to save power and computer memory. Additionally, there is very little light in deep space, and there are no objects close enough to photograph.

How long will Voyager 1 last? Engineers expect at least one science instrument to remain operational until around 2025. After the science instruments are shut down, the spacecraft could continue sending weak engineering data until around 2036, when it will likely fall out of range of NASA’s Deep Space Network.

Is Voyager 2 also having problems? Voyager 2 is currently operating normally. It is approximately 12.6 billion miles from Earth. While it is older than Voyager 1 by a few weeks (it launched first), it follows a different path and remains in good health.