'Big Bang' fix boosts Voyager 2’s mission: Will it work for Voyager 1?

NASA engineers have successfully extended the operational life of the Voyager 2 spacecraft by reconfiguring its thrusters, a maneuver that could potentially be applied to its twin, Voyager 1. This innovative solution addresses the gradual degradation of the probe's power system, ensuring its continued exploration of interstellar space for at least another year.

The Background: Decades in Deep Space

The Voyager program, launched in 1977, sent two identical probes, Voyager 1 and Voyager 2, on an unprecedented journey to explore the outer planets of our solar system. After completing their planetary flybys, both spacecraft continued their missions, eventually crossing the heliopause—the boundary where the Sun's influence wanes and interstellar space begins. Voyager 1 became the first human-made object to enter interstellar space in August 2012, followed by Voyager 2 in November 2018. These probes, now over 45 years old, are the farthest human-made objects from Earth, transmitting invaluable data about the environment beyond our solar system. However, the radioactive decay of their plutonium-238 power sources, known as Radioisotope Thermoelectric Generators (RTGs), has led to a steady decline in electrical power, threatening the continuation of their scientific missions.

The Mechanism: A Risky 'Big Bang'

The challenge for Voyager 2 was that its attitude control thrusters, which are crucial for orienting the spacecraft to communicate with Earth and point its scientific instruments, were degrading. These thrusters are powered by the same dwindling RTGs. To conserve power, NASA engineers devised a plan to use the spacecraft's main propulsion system, the engine used for trajectory correction burns, to perform the functions of the attitude control thrusters. This involved a complex process of reorienting the spacecraft and firing the main engine in a series of short bursts, effectively 're-igniting' the engine for a new purpose. This maneuver, dubbed the 'Big Bang' by some engineers, required precise calculations to avoid damaging the spacecraft. The risk was that a miscalculation or an unexpected reaction from the old engine could have rendered the probe uncontrollable or even destroyed it. By repurposing the main engine, the spacecraft can now use less power to maintain its orientation, freeing up electrical resources and extending the life of the existing, but declining, power supply.

Who is Affected and How, Concretely

The primary beneficiaries of this maneuver are the scientists and the public who rely on the data transmitted by Voyager 2. The extension of its mission means continued collection of information about the heliosphere's boundary and the interstellar medium. This data is vital for understanding the Sun's impact on its surroundings and the nature of the space between stars. For the scientific community, it means more time to study phenomena that are unique to this distant region, potentially leading to new discoveries about cosmic rays, magnetic fields, and plasma. For the public, it represents the ongoing exploration of the unknown by humanity's most distant emissaries. If the 'Big Bang' maneuver proves successful and sustainable for Voyager 2, it raises the distinct possibility of applying a similar technique to Voyager 1, which faces similar power constraints. Voyager 1's communication antenna is more sensitive to orientation changes, making such a maneuver potentially more complex, but the potential reward—further years of data from the edge of the solar system—is immense.

What Happens Next, and What Would Have to Be True

For Voyager 2, the immediate next step is to monitor its performance closely to ensure the 'Big Bang' maneuver has stabilized its power situation and that the repurposed thrusters are functioning reliably. Engineers will continue to optimize power usage and data transmission. The success of this maneuver for Voyager 2 will be a critical factor in deciding whether to attempt a similar, potentially riskier, procedure on Voyager 1. For Voyager 1 to benefit, engineers would need to adapt the 'Big Bang' concept to its specific configuration, which might involve different engine firing sequences or power management strategies. The key factors for success in either case include the continued integrity of the spacecraft's aging hardware, the accuracy of trajectory and firing calculations, and the availability of sufficient power to execute the maneuvers. If these conditions are met, both probes could continue to send data for several more years, pushing the boundaries of human knowledge further into interstellar space.