(Almost) A Eulogy for Voyager
For nearly 49 years, Voyager 1 has been traveling away from Earth, transmitting data to NASA researchers, circumventing the gravitational pulls of planets and moons, and carrying a payload of consolidated cultural wealth into the cosmos. Carried by a Titan-Centaur rocket, Voyager 1 took off from the coast of Florida on September 5, 1977. I was exactly 3 months old.
But now, Voyager 1 and its twin Voyager 2 are nearing the end of their lives.
More than 25 billion miles away, outside the gravitational embrace of our solar system and near the end of its mission, Voyager 1 lost another of its scientific instruments. Last week, NASA announced that it had been forced to turn off one of the probe’s three remaining scientific instruments in order to save the craft’s power. The fact that Voyager 1 and Voyager 2 both lasted this long, sending unprecedented information to engineers at NASA’s Jet Propulsion Laboratory in Southern California for nearly half a century, is remarkable. They were originally designed to last only five years.
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“There was a big effort to try to continue the mission until the 50th anniversary of their launches,” Johns Hopkins University space scientist Ralph McNutt said in 2027. Nautilus in 2024. “We’ll see. »
NASA launched Voyager 2 before Voyager 1 in 1977, and the probe had a very similar mission and payload to its twin, which preceded it into space. The two craft, equipped with instruments to support 11 scientific experiments, were designed to take advantage of a rare alignment of planets in the outer solar system. Their goal was to provide unprecedented information and insight into the composition of Saturn, Jupiter, Neptune and Uranus and their many moons. The two Voyagers fulfilled this mission, sending back data that constitute humanity’s closest observation of the worlds on the outskirts of our solar system.
Both Voyager probes cleared their planetary targets in 1990, but they continued on their way outward, beyond the reach of the solar winds and the tug of our home star.
Since the probes do not include solar panels, they get their power from small pieces of plutonium-238 which decay, releasing energy. As this energy source dwindles, instruments have been powered down for their entire service life, while others have been turned off because they were doing their jobs, such as capturing the physical properties of particles in the atmospheres of Jupiter and Saturn, both of which are now far in the field of view of the Voyager probes.
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The first scientific instruments to be powered down were Voyager 1’s photopolarimeter subsystem, which included a small telescope and was designed to measure the intensity and linear polarization of scattered sunlight passing through the atmospheres of Jupiter, Saturn, and Saturn’s rings. This made it possible to obtain information on the properties of particles in these regions.
More recently, NASA engineers decided to turn off Voyager 1’s Low-Energy Particle Telescope and Low-Energy Magnetospheric Particle Analyzer. These instruments measured the speed of particles that collided with sensors, elucidating how many and from where these particles are blown into space by solar winds. The same instruments on Voyager 2 were powered down in March last year.
When they go dark, the Voyager twins will leave behind an impressive array of space telescopes and ground-based detectors that, since their groundbreaking mission, have helped us peer ever deeper into the cosmos. The Vera C. Rubin Observatory in Chile began releasing stunning images last year. This instrument has already identified 11,000 new asteroids and photographed nebulae and distant galaxies located thousands of light years from Earth. NASA launched the James Webb Space Telescope in 2021, and together with the Hubble Space Telescope, launched in 1990, it has also captured unprecedented images of our cosmos. More recently, these two space telescopes have provided the most detailed views of Saturn.
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And now NASA plans to launch the Nancy Grace Roman Space Telescope in September 2026. This powerful camera will capture images in visible and near-infrared light, complementing Webb’s infrared observations and Hubble’s visible and ultraviolet images. This could help unravel dark matter and energy, the unknown and undetected substances and forces that hold our universe together.
As these new tools unfold into mysterious corners of the cosmos, the Voyagers limp along on life support. The team of engineers who monitor and manipulate the long-lived probes during their extended mission told NPR that they plan to conduct instrument tests on the Voyagers this year, which could extend their lifespan into the 2030s. Far from being a sentimental exercise, keeping the Voyagers operating makes scientific sense: The probes float further in interstellar space than any other man-made object. The data they send during the 23-hour journey to Earth could encode information we could never imagine coming.
These first and most distant robots in space are pioneers in our ever-growing appreciation of what makes our universe work. Dimmed, but not clouded, I wish these brave robots the best as they continue to navigate the space between mystery and knowledge.
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Main image: Artsiom P / Adobe Stock
