Despite their excellent name, Discoasters do not resemble John Travolta. Instead they look like the second half of their name ("-aster"). They are microscopic algae whose fossilized remains resemble an asterix (*). These tiny fossils can be found in sea floor sediment, as long as you have a microscope and someone patiently explaining how to prepare a slide to view them from.
I learned about Discoasters for the first time only 8 hours ago because I was able to take a tiny dab of sediment from a core sample taken by the JOIDES Resolution and view them, along with radiolarians and foraminifera from the same sediment, under a microscope. As a science educator, it is exciting to have this kind of opportunity. Teaching a student what has been learned by science without being able to explain how it was learned does not exactly aid credibility. This expedition is great because we are being able to experience for ourselves many of the processes the scientists on board follow to learn from the core samples. It has already been an invaluable experience, and it is only the first day.