Made to last only five years, the two Voyager spacecraft are still pushing through the vacuum of space, representing humanity beyond the Sun’s influence. Voyager 1 and Voyager 2 were both launched in 1977 over a span of just 15 days, aimed at detecting the gas giants in our solar system – Jupiter and Saturn. Much to NASA’s surprise, the space probe uncovered new mysteries of Uranus and Neptune and became the first man-made object to reach interstellar space.
Interstellar space is the cold region beyond the heliosphere, the hot plasma bubble at the edge of our solar system. While Voyager 1 made its historic entry into interstellar space in August 2012, its twin Voyager 2 crossed the heliosphere in November 2018.
After being exposed to such harsh conditions for more than four decades, the effects are now being felt, prompting NASA to consider shutting down the spacecraft. Recently, NASA physicist Ralph McNutt told Scientific American that scientists will continue to commission the two probes.
(Position illustration of Voyager 1 and Voyager 2; Image: NASA)
Voyagers What’s Up?
Both Voyagers are equipped with a power source called a radioisotope thermoelectric generator (RTG). This propulsion system uses plutoniums to convert the heat generated by their natural radioactive decay into electricity to power spacecraft instruments, computers, radios and other systems.
Each space probe is equipped with instruments such as television cameras, infrared and ultraviolet sensors, magnetometers, plasma detectors, and cosmic-ray and charge-particle sensors. However, after 44 years, Voyager 1 has only four functional devices while Voyager 2 has only five.
NASA will change instruments one by one
It’s been a few decades since NASA turned off the cameras on the probe to save energy for other essential tasks. Moving forward, engineers would shut down the rest of the instruments, one by one, until the Voyagers lost communication and drifted into the void of space.
Currently 23.3 billion kilometers from Earth, it takes 20 light hours and 33 minutes to make contact with Voyager 1 while it takes a little less than 18 light hours to make contact with Voyager 2, which is about 19.5 billion kilometers away.
A report from Scientific American suggested that scientists estimated that the plutonium powering the probe could be exhausted by 2025 or perhaps in the 2030s. Recently, NASA revealed that Voyager 1’s Attitude Expression and Control System (AACS), which helps the spacecraft maintain its orientation, suffered a mystery glitch.