When will Voyager reach another star?
By: Joshua Potts
Tags: Engineering, NASA, Space, Space Exploration, Technology

Almost forty five years on and now fourteen billion miles from Earth, the famous Voyager 1 probe claims the title of the longest living and farthest traveling craft in the history of space travel. Every day, Voyager 1 communicates data through the Deep Space Network, and NASA is in continued contact with an engineering miracle that is decades old. Voyager 1 could be considered humanity’s first attempt to reach out into the cosmos and search for any life that may lie beyond our own solar system. So, when is Voyager 1 set to reach the next star — and what will we find there?

Voyager is a space test that was dispatched by NASA on September 5, 1977. Built to operate for an extremely long duration and explore the very farthest reaches of our Solar System, Voyager has gathered massive volumes of crucial data about our own eight planets, and finally left the Solar System in 2012, entering into the dark abyss of interstellar space. As of September 2020, it has travelled about a hundred and fifty Astronomical Units, and is the most distant man-made object from Earth.

Each Voyager craft is composed of over sixty-five thousand individual crucial parts. Many of these parts are very similar — for example, there are hundreds of tiny semiconductors and computer memory slots on both crafts. Each flight computer on the two Voyager probes includes more than a million comparable electronic parts.

Just like the HAL PC on board the boat Discovery from the celebrated sci-fi movie, “2001: A Space Odyssey”, both Voyager 1 and 2 are outfitted with extensive programming to control their operations. The Voyager frameworks and flight systems are among the most complex ever built for space. Any perceivable failure can be dealt with by one of the craft’s seven detection and mitigation systems so the probe can remain functional. In just a matter of seconds, Voyager 1 and Voyager 2 can put themselves into protected “safety” states — a capacity that is crucial for their endurance when they are billions of miles from Earth.

The two Voyagers were carefully planned and engineered to withstand intense radiation during the Jupiter gravitational swing-by. They were packed with radiation protective materials which shielded sensitive electronic parts. An unprotected human traveler riding onboard Voyager 1 during its Jupiter flyby would have absorbed a radiation portion multiple times the deadly level. Voyager’s onboard equipment measured its trajectory to a tenth of a degree as it performed this manoeuvre.

If Voyager 1 had been launched in the direction of Alpha Centauri, the closest star to Earth at just over four lightyears away, it would cruise by Proxima B, an exoplanet similar in size and composition to Earth, and situated in the so-called “goldilocks” region around its star. Proxima B could host extraterrestrial life, but unfortunately for us, a visit to Alpha Centauri is not on Voyager 1’s itinerary.

In around forty thousand years, Voyager 1 will float past Gliese 445, an M-type star that is about seventeen lightyears from Earth. This star can be observed by the naked eye in the Camelopardalis constellation. To think that tens of thousands of years into the future our very own human-made spacecraft will approach this faraway star that ancient peoples once lay their eyes upon is a notion that is beyond most of us.

Similarly, Voyager 2 will pass within 4.3 lightyears of the Sirius star, the brightest star in the whole night sky. This will not happen in a thousand years, nor ten thousand years, or even a hundred thousand years. Voyager 2 is destined to reach Sirius by the year 289,000.

But the Voyagers aren’t the only spacecraft to journey to the edge of the Solar System. NASA’s New Horizons spacecraft is travelling through space at over thirty six thousand miles per hour and was the first probe to inspect the dwarf planet Pluto and its tiny moons. It was dispatched in mid January of 2006 and arrived at Pluto in July 2015. If we had launched New Horizons towards Alpha Centauri, it would still take seventy eight thousand years to arrive.

Voyagers 1 and 2 are the only man-made crafts to leave the Solar System and venture into interstellar space, but defining exactly where our Solar System ends is a difficult matter. When Voyager 2 left, it used a plasma science experiment to locate the edge of the heliopause. The heliopause is the boundary between the Sun’s defensive plasma bubble and interstellar space. This experiment detected a significant drop in the concentration of charged plasma particles as it crossed this edge — a good estimate for where the Solar System ends.

Since Voyager 1 launched in 1977, it has narrowly avoided the multicolored billows of Jupiter and the frigid rings of Saturn. The spacecraft is currently multiple times farther from the sun than we are on planet Earth. Even though the visible light landing on Voyager is extremely dim, it is still brushed by a breeze of charged particles travelling through the heliosphere.

Some people don’t consider Voyager 1 and Voyager 2 to be in interstellar space yet, though. The Sun’s gravitational limit lies much farther beyond the probes. A trillion icy celestial bodies still circle the Sun past Pluto and the heliospheric edge. This region of space is known as the Oort cloud and is yet to be proven definitely.

Nearly thirty-five years after blasting off, scientists announced on Thursday the 12th of September 2012 that Voyager 1 had entered what they considered interstellar space. As it leaves our Solar System behind, the robotic spacecraft is thundering towards Gliese 455, also known as AC +79 3888, which lies 17.6 light years from Earth. Sadly, lights will go out on the spacecraft long before it reaches this star.