Frost has formed not just on the ground around the Mars Phoenix Lander, it has also formed on the telltale mirror it uses to measure how the wind is blowing. What's more, they also had the lander send a sequence of images so we can actually see how the mirror sparkles in the sun as water frost accumulates throughout the morning.
The Mars Phoenix Lander has observed water frost on a Martian morning. Water vapor in the atmosphere had frozen during the night, and as the sun rose through the morning the frost evaporated. I'm surprised that there is enough water in the Martian atmosphere for a visible amount of water frost to form.
Seeing a photograph of water frost got me wondering what it would look like when the Phoenix lander starts being encased in carbon dioxide ice when the winter starts. And will we see even more water frost as time goes by? Is the Phoenix mission going to last enough for us to even see carbon dioxide frost, or even the entire surface around the landing site being covered by a white layer of carbon dioxide ice?