Return to Astypalaea

Strike-slip faults had proven to be very important on Europa. They are common, and they provided a surprisingly large amount of information about the structure and processes of the little planet. After Randy Tufts discovered the archetypical example Astypalaea Linea (“The Fault”) by going through old Voyager images, he wanted to go back to the real source and look more closely. Of course, that meant getting new images from Europe itself. And that in turn meant dealing with the imaging team.

Ordinarily I had little interest in the image-planning process—for two reasons. First, my feeling was it did not really matter where we looked, as long as it was on Europa. It would all be interesting, and sooner or later we were likely to get images with a fairly good sampling of the types of features and their broader context. As for my second reason not to participate: as discussed in earlier chapters, I was emphatically not welcome to work on image-planning. Who needed the grief? But then fate, in the form of Randy Tufts, intervented.

Randy loved “The Fault” on Europa nearly as much as “The Cave” in Arizona, so he convinced me to push for high-resolution images during a later orbit. Other team members (and their students and assistants) had their own agendas and targets in mind. For example, Ron Greeley, a volcanologist, was certain that some of the dark patches we had seen at low resolution must be volcanic lava flows. (He called them “cryo-volcanic,” because the material involved would be cold water rather than molten rock.) Although similar dark patches had already proven to be chaotic terrain, Greeley was determined to continue his search by taking more high-resolution images of the things he thought were volcanic. In the end, high-resolution images of Astylpalaea would prove to be some of the most revealing images of Europa, while the search for volcanic flows yielded only more typical chaotic terrain. But before any of this could happen, we needed to persuade the team to include Astypalaea in the high-resolution sequence.