Europa and / or Enceladus testing for life..
Why don't they just send spacecraft to enter orbit around them and to attempt to fly through the geyser plumes multiple times collecting water samples along the way?
If there's any possibility there's life within their subsurface oceans, then there would definitely be some sort of microscopic organisms at the bottom of the food chain that'll invariably be blasted into space via the geysers.
Why haven't they thought to do this