Image from NASA
47 years ago, launched from Cape Canaveral, Florida, Voyager 1 started its journey into interstellar space and beyond. It was designed to study the outer planets, Jupiter and Saturn, and the edges of the solar system. Voyager 1 completed its mission to study Jupiter and Saturn in 1981. Since then, it’s traveled over 25 billion kilometers and will soon reach one light day. But why is such an old piece of technology still active, and what does this journey mean?
A light day, year, or month does not measure time; it measures distance. One light day means if Voyager 1 were to send a signal to Earth, it would take a day to reach us, and vice versa. For example, the distance from Mars to Earth is about 12.7 light minutes, meaning any signals sent from Mars took 12.7 minutes to reach Earth. Although the distance from Mars to Earth changes, it can range from 3–4 light minutes to well over 20. But why is Voyager 1 approaching one light day so significantly? Reaching a full light day pushes Voyager 1 into a realm of distance no other human-made object has ever approached. It marks a scale where ordinary units like kilometers or miles are no longer useful, and only the speed of light is enough to describe its separation from Earth.
After completing the initial mission of photographing Jupiter and Saturn, Voyager 1 used the gravitational pulls of the planets to slingshot itself towards interstellar space. These gravity-assisted slingshot maneuvers put the spacecraft on a path that would carry it out of the solar system entirely, a first in human history. During its flybys, Voyager took groundbreaking images of Jupiter’s atmosphere, Saturn’s rings, and several moons that were unlike any previously studied moons. These discoveries reshaped our understanding of the outer planets and gave scientists a reason to continue outward, eventually crossing the heliopause–the boundary where the Sun’s gravitational influence ends and interstellar space begins. This transition was the beginning of Voyager 1’s role as the first human-made probe to study the environment between the stars.
One of the moons of Saturn by NASA, by Voyager 1
The Great Red Spot by NASA, taken by Voyager 1
The technology that keeps Voyager 1 running had to be meticulously engineered because 1970s hardware had to perform a flyby of the outer planets, maneuver a gravity-assisted acceleration, and not fail. After all, Voyager 1 cost over $800 million to build. The main systems of the spacecraft are split into four levels: the central bus, radioisotope thermoelectric generators (RTGs), hydrazine thrusters, and the propellant tank. The central bus houses all of the main parts of the spacecraft to operate the spacecraft. In there lies the camera, CPU, and other parts used to control the spacecraft. The RTGs power the spacecraft by converting heat from the decaying plutonium-237 into electricity and also provide heat to keep the spacecraft warm. The hydrazine thrusters are small thrusters used for control of the spacecraft and to keep the antenna pointed at Earth. For larger trajectory changes, such as the gravity-assisted maneuver performed, these thrusters are used to adjust Voyager’s path. Lastly, the propellant tank is a small tank containing hydrazine fuel for thrusters, which is also used to keep the components warm. There are many more parts used to keep the spacecraft running for decades to come, but these are the main parts the spacecraft cannot function without.
Voyager 1 may be in its retirement days, but it continues to exemplify the curiosity of humankind. The spacecraft represents humankind’s long-term commitment to exploration. The spacecraft’s approach to one light day not only represents a scientific measurement but a reminder of how far human engineering and curiosity can reach. Powered by computers weaker than modern calculators and decaying plutonium, it continues to show that exploration does not end when the original mission is complete. As Voyager drifts farther into space, it becomes both a scientific instrument and a reminder of how small we are and how far we can go.
Be First to Comment