Well that answers the question of why they were following the first stage and why it seemed like it still had its legs (you can see one sticking up in the tweeted photo).<p>Since I have to guess, I'm guessing it stayed closed up most of the way down, avoiding perhaps even grid fin erosion during high re-entry speeds. It is fun to see a company that has rockets it can expend for experiments like this because it is so far ahead of its nearest launch competitor in terms of costs.