Saving Electricity: Voyager I Style
The Voyager missions launched from Florida in 1977. I was just 3 years old, and have no memory of this event, but the encounters these two spacecraft made with world after world as they traveled across our Solar System have punctuated my own pursuit of science, from a child’s love of planets and dinosaurs to a middle schooler’s awe of Uranus’s rings and giggle while talking about Uranus by name, to a high school students love of Neptune being the most distant world at the moment Voyager 2 gave it a visit.
These twin spacecraft took advantage of a chance rare, once in 176 year, alignment of our solar system’s worlds that would make visiting all of the outer worlds not only possible but possible with a side of significant gravity assists.
Their nuclear power plants, however, won’t last forever, and as their plutonium fuel decays into heat-energy, they generate about 4 watts less per year, according to NASA. Something weird, however, happened to Voyager 1 on Feb 27 when it rolled to better align its antenna with Earth. While this was a routine maneuver, it triggered a power drop that endangered the spacecraft. To make sure the mission continues to have the power it needs to stay warm enough and to communicate back to Earth, mission managers on April 17 shut down Voyager 1’s Low-Energy Charged Particles or LCEP experiment, which had been running for 49 years! Two other experiments, which study magnetic fields and plasmas, remain active.
And while the LCEP experiment is mostly turned off, it is not entirely turned off, and that means there is hope that if the power issues can be understood, the experiment can be turned back on.
In the coming weeks, NASA is going to try something radical, they are, according to their release, going to “swap out a group of powered devices all at once … turning some things off and replacing them with lower-power alternatives to keep the spacecraft warm enough to continue gathering science data.” They will trial this activity with the closer and better powered Voyager 2, and if successful will take on Voyager 1.
And that factor of being closer is really starting to matter as the time it takes to send a message stretches out across hours. On November 15, Voyager 1 is calculated to cross the 1 light day mark, and signals will take a full 2 days to relay to the mission and back again.
While we will eventually lose our ability to communicate with these two cooling spacecraft, this will stop their science but not their motion. They are out beyond our Sun’s protective heliosphere and they are just going to keep on flying until acted upon by some outside force that it’s fun to imagine.
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This content was originally written for the EVSN podcast. Watch video episodes and check out additional content at EVSN.tv.
