It’s been a busy solar system week. Thoughts from Saturn coming tomorrow, but we’ve also had the arrival of Mars Reconnaissance Orbiter at the red planet, which means that six spacecraft are now active. MRO will take six months or so to drop down into its science orbit (dipping through the Martian atmosphere on each orbit to gradually change the orbit’s shape).

The other spacecraft are :

Mars Global Surveyor, in orbit since 1999, currently looking for changes in the surface and atmosphere and also providing details on potential landing sites for future missions.

Mars Odyssey, which arrived in 2001 and has provided detailed maps of the mineralogy of the Martian surface for the first time.

Mars Express, ESA’s first solo interplanetary spacecraft. Although the release of the images has been slow, the trickle of high-resolution views of the Martian surface is slowly growing. Where else can you watch dust flow over the edge of a crater on another planet?

Last but certainly not least, Spirit and Opportunity still roving on the surface after two Earth years. For an excellent overview of their first nine months or so, Steve Sqyre’s book is excellent, and you can read sporadic updates at his website.

As you might imagine, these six spacecraft are going to have sent back enough data to keep their scientists busy for many, many years even after their missions end. For the rest of us, today sees the launch of Google Mars which has already consumed large chunks of my day!