Oct 17 2024
The Clipper Europa Mission
I wrote earlier this week about the latest successful test of Starship and the capture of the Super Heavy booster by grabbing arms of the landing tower. This was quite a feat, but it should not eclipse what was perhaps even bigger space news this week – the launch of NASAs Clipper probe to Europa. If all goes well the probe will enter orbit around Jupiter in 2030.
Europa is one of the four large moons of Jupiter. It’s an icy world but one with a subsurface ocean – an ocean that likely contains twice as much water as the oceans of Earth combined. Europa is also one of the most likely locations in our solar system for life outside Earth. It is possible that conditions in that ocean are habitable to some form of life. Europa, for example, has a rocky core, which may still be molten, heating Europa from the inside and seeding its ocean with minerals. Chemosynthetic organisms survive around volcanic vents on Earth, so we know that life can exist without photosynthesis and Europa might have the right conditions for this.
But there is still a lot we don’t know about Europa. Previous probes to Jupiter have gathered some information, but Clipper will be the first dedicated Europa probe. It will make 49 close flybys over a 4 year primary mission, during which it will survey its magnetic field, gravity, and chemical composition. Perhaps most exciting is that Clipper is equipped with instruments that can sample any material around Europa. The hope is that Clipper will be able to fly through a plume of material shooting up geyser-like from the surface. It would then be able to detect the chemical composition of Europa material, especially looking for organic compounds.
Clipper is not equipped specifically to detect if there is life on Europa. Rather it is equipped to determine how habitable Europa is. If there are conditions suitable to subsurface ocean life, and certainly if we detect organic compounds, that would justify another mission to Europa specifically to look for life. This may be our best chance and finding life off Earth.
Clipper is the largest probe that NASA has sent out into space so far. It is about the size of an SUV, and will be powered by solar panels that span 100 feet. Light intensity at Jupiter is only 3-4% what it is on Earth, so it will need large panels to generate significant power. It also has batteries so that it can operate while in shadow. NASA reports that soon after launch Clipper’s solar arrays successfully fully unfolded, so the probe will have power throughout the rest of its mission. These are the largest solar arrays for any NASA probe. At Jupiter they will generate 700 watts of power. NASA says they are “more sensitive” than typical commercial solar panels, but I could not find more specific technical information, such as their conversion efficiency. But I did learn that the panels have much more sturdy, in order to survive the frigid temperatures and heavy radiation environment around Jupiter.
Clipper will take a somewhat indirect path, first flying to Mars where it will get a gravity boost and swing back to Earth where it will get a second gravity boost. Only then will it head for Jupiter, where it will arrive in 2030 and then use its engines to enter into orbit around Jupiter. The orbit is designed to bring it close to Europa, where it will get as close at 16 miles from the surface over its 49 flybys. At the end of its mission NASA will crash Clipper into Ganymede, another of Jupiter’s large moons, in order to avoid any potential contamination of Europa itself.
I always get excited at the successful launch of another planetary probe, but then you have to wait years before the probe finally arrives at its destination. The solar system is big and it takes a long time to get anywhere. But it is likely to be worth the wait.
An even longer wait will be for what comes after Clipper. NASA is “discussing” a Europa lander. Such a mission will take years to design, engineer, and build, and then more years to arrive and land on Europa. We won’t get data back until the 2040s at the earliest. So let’s get hopping. The potential for finding life off Earth should be one of NASA’s top priorities.