Aug 29 2017

40 Years of Voyager

voyager1_highOn August 20th 1977 Voyager 2 was launched. On September 5th Voyager 1 followed. The reason 2 launched before 1 is because V1 was on a faster trajectory and would arrive at Jupiter several months before V2, and NASA felt it would be easier not to have to explain endlessly to the media why V2 was arriving before V1. At present V1 is 12,959,246,289 miles from Earth, and V2 is 10,657,559,202 miles.

Voyager 1 is the farthest human made object from the Earth. If our civilization collapses tomorrow, the Voyager probes would be the longest surviving artifacts of our existence.

If you do not remember the Voyager missions, then think of what it was like for Horizon to fly by Pluto. Pluto went from a fuzzy blob to a detailed alien world. The Voyager missions were the same, except times four. This was our first closeup look at Jupiter, Saturn, Uranus and Neptune. It was our first closeup look at the large moons of Jupiter – Io, Ganymede, Europa and Callisto. We discovered even more smaller moons of Jupiter and Saturn. We discovered volcanic activity on Io, and that Jupiter has rings of its own.

Our knowledge of the outer solar system exploded, and we were rewarded with seemingly endless gorgeous pictures of these giant worlds and their companions.

The Voyager missions partly took advantage of a rare astronomical event – the syzygy. Every 176 years all of the planets of our solar system will happen to be on one side of the sun. The last such occurrence peaked on March 10th 1982. While the media was obsessed with rumors of the end of the world from the massive earthquakes that would allegedly occur from the combined gravitation tug of all the planets (which is absurd, in case you are wondering), NASA scientists saw an opportunity. The outer gas giants were all within 73 degrees of each other. This meant that they could launch probes that could more easily swing past all four gas giants.

Voyagers 1 and 2 took advantage of this window, which happened to occur right at the time when our technology was capable of taking advantage of it. The probes used gravity assist to increase their velocity, but also to change trajectory so that they could fly by Jupiter then Saturn then Uranus and finally Neptune.

The Voyager missions were perhaps the greatest success for NASA space exploration. Not to diminish any other successes, but the Voyager missions were also perhaps the best PR NASA space exploration has ever had. Voyager was to NASA space exploration what the moon landings were for NASA peopled missions. The missions were a stunning success, and talk focussed around how amazing a feat it was. For only eight cents per US citizen at the time, we sent two probes to the outer planets with stunning precision. According to JPL:

The Voyager delivery accuracy at Neptune of 100 km (62 mi), divided by the trip distance or arc length traveled of 7,128,603,456 km (4,429,508,700 mi), is equivalent to the feat of sinking a 3630 km (2260 mi) golf putt, assuming that the golfer can make a few illegal fine adjustments while the ball is rolling across this incredibly long green.

Part of the public attention the Voyager missions garnered was due to the gold records each contained. These were actual records, plated in gold and shielded so that they would last an estimated 3 billion years. They contained two hours of music and other sounds of Earth, and an included stylus and instructions for how to play them. The gold records, a project headed by Carl Sagan, was our “hey there” to the universe, and people got that.

Having lived through these missions as a young science enthusiast I can tell you this was an amazing experience. I was already interested in science and astronomy specifically, but the Voyager missions increased my interest even further. They were like crack to a science nerd. They captured my attention and represented everything that was awesome about science – the discovery of the unknown, the awe-inspiring view of the universe, and the dedication of skilled experts. It filled me with optimism for the future. If we could accomplish this, what else could we do when we put our collective minds and resources to it?

And now the Voyager probes are leaving the edges of our solar system. Incredibly we are still getting signals from the probes – they are still doing science, giving us information about the cosmic rays at the edge of the heliopause (Voyager 1 crossed the heliopause in 2012). NASA scientists estimate we will be able to communicate with Voyager 1 for another 8 years or so, but they are not sure.

If you want to learn more about the Voyager missions, PBS has a two hour special you can watch online. For me it is also a reminder of how the Voyager missions shaped my view of science, exploration, and science communication.

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