Scientists at NASA have designed a new power management plan for their oldest exploring spacecrafts – Voyager 1 and Voyager 2 – as they continue to move away from our Sun into the darkness of interstellar space.
Over the last 42 years Voyager 1 and Voyager 2 have been flying away from Earth and warmth of our Sun travelling towards the dark abyss of space. With each passing day the two spacecrafts have been moving away from the Sun and this effectively means they are getting less and less heat from the Sun to keep their instruments warm. While the two spacecrafts have self-heating systems in place, the underlying technology that relies on natural decay of plutonium-238 radioisotopes produces less and less power each passing year. Based on calculations, the radioisotope thermoelectric generators, or RTGs on the two spacecrafts are producing 40% less power than they originally produced in the first year of operation.
This is why NASA engineers had to come up with a new power management plan to ensure that not only Voyager 1 and 2 continue to deliver us precious data, but also ensure that its vital systems continue to function and less critical systems are put to sleep.
Another challenge that engineers have faced is managing the degradation of some of the spacecraft thrusters, which fire in tiny pulses, or puffs, to subtly rotate the spacecraft. This became an issue in 2017, when mission controllers noticed that a set of thrusters on Voyager 1 needed to give off more puffs to keep the spacecraft’s antenna pointed at Earth. To make sure the spacecraft could continue to maintain proper orientation, the team fired up another set of thrusters on Voyager 1 that hadn’t been used in 37 years.
Voyager 2’s current thrusters have started to degrade, too. Mission managers have decided to make the same thruster switch on that probe this month. Voyager 2 last used these thrusters (known as trajectory correction maneuver thrusters) during its encounter with Neptune in 1989.