Voyager 1- 41 Years Later
Voyager 1 launched on September 5th, 1977. This mission, along with Voyager 2 are two of the most important robotic missions in NASA history.
The Voyager missions were possible because of a unique planetary alignment that allowed for a spacecraft to visit the outer planets using a series of gravity assist maneuvers. This fortuitous alignment of the outer planets occurs once every 175 years or so.
A Cal Tech article from 1970 noted that Thomas Jefferson was President the last time the planets were aligned this way; the next time will be in 2148.
The Grand Tour as it was initially called, was the name that NASA gave to the program that would visit the outer planets. But due to its massive cost, it was canceled and replaced with the Mariner Jupiter-Saturn or the Voyager program. A scaled-back but still monumental undertaking.
Voyager 1 had a unique course that allowed it to flyby Titan, at the expense of visiting the outer planets as Voyager 2 accomplished. Both spacecraft were identical, carrying the same science instruments, and imaging systems.
Voyager 1 visited Jupiter in March of 1979 and Saturn in November of 1980. During these flybys it imaged one of Jupiter’s Galilean moons, Io, showing a surface scarred by the intense volcanism of the 400 plus volcanoes on its surface. Voyager 1 also imaged Europa and Ganymede during its Jupiter flyby. The Voyager spacecraft observed that there are indications of a subsurface ocean beneath the icy crust of Europa.
Once past Jupiter, Voyager 1 continued on to Saturn, studying Titan and giving us glimpses of that unique moon. The Titan flyby didn’t provide conclusive information due to the cloud cover on that planet, but it was a critical first step in exploring this mesmerizing moon.
Both Voyager 1 and 2 are operational, though some instruments have had to be shut down. The power limitations of the decaying radioisotope thermoelectric generator, or RTG, is the reason for these shutdowns. Out of the ten instruments on the spacecraft, scientists can operate four on Voyager 1 and five on Voyager 2.
Both of these lonely robotic spacecraft are expected to operate into the 2020's, quite the lifetime for any spacecraft, let alone ones that are over 13.3 billion miles away from Earth. To give you an idea how far out Voyager 1 is, consider this. If you were to travel at the speed of light, it would take you 19 hours and 50 minutes at the time of publishing this article on 9/5/18. Nearly a day at light speed, I don’t even want to calculate how long that would take in a car on a road trip!
Check out more on Voyager 1 at this JPL website.
You can also learn about gravity assists at this NASA website. I plan on doing an article on this technique in the future, but for now, check this out.
Today’s article originally released as a podcast episode that you can listen to in your web browser here.