Snow on Mars
BBC News: Phoenix detects Red Planet snow.
The Phoenix spacecraft on Mars has detected snow above its landing site. The US robot used its lidar instrument to probe the structure of clouds and saw large water ice-crystals falling through the Martian "air". The instrument, which works by scattering pulses of laser light off particles in the sky, did not follow the snow to the ground. The data suggests the snow vaporised before it reached the surface - but Phoenix is monitoring the situation.
"We're going to be watching very closely over the next month for evidence that the snow is actually landing on the surface," said Jim Whiteway, of York University, Toronto, lead scientist for the Canadian-supplied Meteorological Station on Phoenix. "This is a very important factor in the hydrological cycle on Mars with the exchange of water between the surface and the atmosphere."
The solar-powered Phoenix lander is expected to go dead in late November or early December. It's heading into the Martian Arctic winter and getting less sunlight to recharge, and also having to spend power to keep warm. Martian winter will peak in April with no sun for three months and temperatures down to -120C/-184F.
When we eventually put people on Mars, they'll have a bunch of trash to clean up from dead and crashed landers... My 2006 NaNoWriMo novel was about a manned mission to Mars using the Mars Direct plan from Robert Zubrin's book The Case for Mars. Fascinating plan, not least because it's fast, cheap, has multiple backups, and doesn't need a thunking great spaceship or refuelling platform to work. We have the capability to put people on Mars and start a permanent settlement with what we have right now. All we need is someone to follow the plan. You send a return vehicle, wait until it's generated enough fuel from the Martian atmosphere, then launch your astronauts with a second return vehicle and a habitat module. Every team has a fuelled vehicle immediately ready on landing, plus a back-up vehicle they brought with them for the next team to use. We need to go to Mars, and we don't need to spend a huge amount to do it.