A group of scientists and engineers charged by NASA to outline a lander concept for the exploration of Jupiter’s moon Europa came out with its “Science Definition Team” report last week, following a six-month study. Because Europa is one of the primary locations in our Solar System where extraterrestrial life might exist, it’s encouraging to see this positive step toward sending a lander with instruments that might be able to detect life.
A lander is the logical follow-up to the Galileo Jupiter orbiter, which explored Europa in the 1990s. More than a decade ago I attended a similar science definition team meeting, where we suggested sending a new orbiter to Europa. We further recommended that the mission should include a basketball-size lander to analyze any possible organic compounds in the Europan ice. We particularly pushed for the lander because in astrobiological research, you have to get up close and personal and analyze samples on the ground. But due to NASA budget cuts, neither the orbiter nor the lander materialized.
So it’s encouraging to see another swipe at the idea. Even better, this modern conception of the lander includes a more sophisticated suite of instruments, which according to current thinking, would be launched following another Europa flyby mission in the early 2020s. That puts any lander well in the future, but whenever it goes, it will be the first Mars life detection mission since Viking in the 1970s.
Before any instruments are built, scientists will have many more discussions to optimize the mission. Personally, I would suggest taking samples from deep under the surface. I doubt that digging just 10 centimeters down, as outlined in the new report, will be sufficient. It will be necessary to drill down at least 30 cm, or about a foot, due to the horrendous radiation environment at Europa’s surface. Such a drill requires more power, but it will be worth the expense to obtain fresh samples that are not altered by radiation.
There is, however, another solution to the sample return problem. I’m still a fan of Bob Pappalardo’s Europan Clipper concept, wherein the moon’s geysers do all the work for us, and spout liquids from the subsurface into space. Of course, it’s still a challenge to predict the eruptions, intersect the plume, and grab a sample.
This new science definition team report is only the beginning of a mission to Europa, but it’s good to see things moving forward.