As I mentioned yesterday, I’m trying to highlight some of the lesser known bits and bobs on this Mars-bound beast.

With the focus on scooping up soil and ice, it’s easy to forget that Phoenix has some above-ground concerns: It will be a polar weather station. When the 1.2-meter tall weather mast flips up, it will be the tallest point above the surface. Dangling at the top is a tiny little telltale, a wee windsock for the thin martian winds.

Scientists at the University of Aarhus in Denmark built the windsock tube out of Kapton film, and it hangs from Kevlar threads. Both materials can retain their strength during the -128 degree Celsius nights. The surface stereo imager can measure windspeeds by aiming at the telltale and taking long-exposure pictures. An inclined mirror, reflecting a cross from which the telltale hangs, will help in determining accurate deflections.