Researchers are not sure about the thickness of the ice on Europa. Some scientists believe on a thick shell of 20Km (like Pappalardo) others on a much thinner of even 1Km or less.
"We’re not a life search mission. We’re a habitability mission,” says Robert Pappalardo, Clipper’s project scientist at the Jet Propulsion Laboratory (JPL), which manages the mission."
So we are going to wait 7 years, and spend $5B to actually not search for life on Europa? Why? Sometimes it feels like Nasa is doing everything possible for not searching for life outside earth, which would be a game changing discovery for humanity, several orders of magnitude more important than the habitability of Europa.