NASA is planning to visit Europa in the late 2020s, with a flyby mission informally called the Europa Clipper. But the spacecraft will have a hard time looking for direct evidence of life, in part because the environment around Europa is horrible. “I’ve been jokingly criticized for calling it evil,” says Peter Spidaliere of NASA’s Goddard Space Flight Center. “It’s the worst place in the solar system for radiation.” Blame Jupiter, whose titanic magnetic field traps and speeds up particles. Jovian radiation would zap any spacecraft instruments that aren’t hidden behind special shields—making it harder to taste misty, ephemeral clouds of water vapor. And it may be difficult for a lander or rover to find much on Europa’s surface, because Jupiter’s radiation belts would rip apart the biological molecules. So instead, Spidaliere and his colleagues propose a small companion spacecraft to the main Europa Clipper, which they’re calling the Bee (Biosignature Explorer for Europa).

The Bee, about half the size of an adult human, would fly at the Clipper’s side all the way to Europa, where it would launch from the mother ship. It would fly through a fresh plume, using a suite of instruments to inspect its contents. The spacecraft would then make a quick exit and perform its analysis far from the radiation belts.

“We are trying to capture a sample before it’s had a chance to be destroyed by radiation,” Spidaliere says.

There is one problem: Scientists have only seen plumes on Europa once before, using Hubble. It’s not clear that they really exist, let alone persist all the time. To date, no one has located the plume again, and some scientists have argued that Hubble actually saw plasma from the volcanic moon Io. But Spidaliere and Amato say they have run simulations based on Hubble’s evidence, and they’re confident the plumes are real and will last long enough for a quick taste in a few years.

Enceladus is a different story. That moon definitely has plumes, and they’re spewing water, water everywhere all the time. Shannon MacKenzie wants to go catch it, with a new Enceladus mission called Theo, for Testing the Habitability of Enceladus’s Ocean. Mackenzie and her fellow graduate students have designed Theo to carry five chemistry instruments that could capture large biological molecules in the plumes.

The Cassini Saturn orbiter has flown by Enceladus two dozen times in the past decade, and the plumes are one of the mission’s most prominent discoveries. But Cassini is going too fast to detect large biological molecules and other potential life clues, which would be smashed in Cassini’s collectors like so many insects on a windshield. It’s not clear how dense the plumes are, or just what they contain, MacKenzie says. “There’s still a lot that we don’t know, which is why we need to go back,” she says.