Europa is Jupiter’s fourth-largest moon, discovered by Galileo just over 400 years ago. It’s also the single location in our solar system that has the most promise for extraterrestrial life. Europa doesn’t actually have an atmosphere—the surface is exposed to the deadly vacuum of space. However, the moon is covered in ice, and scientists believe that oceans of liquid water exist below that frigid surface. The volcanic seafloor of Europa is one of the most volcanically active places in the solar system, and may provide enough warmth and nutrients to be conducive to life.
Given that potential, it's not surprising NASA has had an eye on Europa for awhile. The agency is scheduled to send spacecraft to the icy moon in the 2020s, and last week it was revealed that the flyby mission is named “Europa Clipper.” What should you know about this search for extraterrestrial life?
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1. It will take several years for Clipper to reach Europa.
Europa Clipper is currently scheduled to launch in 2022, though that could be delayed—NASA hopes to use its still-under-development massive Space Launch System (SLS) rocket to launch the spacecraft. It’s safe to say that the mission won’t launch before then, though. Once launched, Clipper will take about six years to reach Europa.
2. This will be a an orbital mission, like Jupiter’s Juno mission.
NASA is not planning to land anything on Europa’s surface during this mission. Europa Clipper will be a fly-by mission, with a long orbit around the moon, similar to the ongoing fly-bys of NASA's Juno spacecraft above Jupiter. The environment around Europa is radioactive, due to Jupiter’s large magnetic field. Because of this, a spacecraft can’t just sit in close orbit around the moon—radiation can corrupt data and disrupt electrical charges. At its closest, Clipper will have a two-week elliptical orbit around the moon. In total, engineers are planning on 40-45 flybys for the mission over the course of two to three years.
3. Clipper’s primary goal is to find out whether Europa supports life.
Clipper will have multiple scientific instruments aboard to begin investigations into potential life on the moon, including cameras to take detailed images of Europa. Because scientists are particularly intrigued by Europa’s icy crust, there will be ice-penetrating radar to take a look at what might be under the surface. There will also be instruments to check the depth and composition of the ocean, as well as thermal scanners to check whether the water vapor above Europa’s surface detected by Hubble is a regular occurrence. (Scientists have posited that warm water “plumes” might erupt from Europa’s surface.) This will all help NASA gain a better understanding of Europa.
4. This isn’t the only Europa mission in development
Scientists think Europa is interesting enough for not one, but two flagship missions. A small lander for Europa is also currently in development, scheduled to launch roughly two years after Clipper. Scientists want time to study Clipper’s data to see what the surface conditions are like, and if there might be an ideal location to place a lander. As you can imagine, scientists want to maximize both the possibility of the lander's success and the science we can accomplish with it. It’s unlikely (though possible) that Clipper will find signs of life from orbit; perhaps the lander will be able to accomplish that from the moon’s icy surface.
These missions will be expensive.
We’re prepping not one, but two Europa missions at the same time. These will be costly. Originally, scientists wanted to do one combined mission that had both Clipper and the lander, but it wasn’t feasible. Weight is very important in missions like this (the heavier the spacecraft, the more propulsion is needed to move it), and because Europa is so irradiated, Clipper will have to carry heavy radiation shielding. Adding a lander to that package was simply not feasible. Plus, having time to study Clipper’s results will make the lander more effective. Combined, these missions could cost as much as $8 billion—but NASA thinks it’s worth it.
We don’t know what we’ll find when we get to Europa, but I can say for sure that I'm excited NASA is going there. The possibilities are endless.