You’ve done it, folks: you’ve reached the middle of the week. Time to take a quick coffee break to reward yourself and catch up on today’s solar energy news…

The single coolest item on the docket today is the successful maiden voyage of a solar-powered plane in Switzerland. The carbon fiber aircraft has 12,000 solar cells built into its wings, will circumnavigate the globe in 2012, took six years to build, is powered by four electric motors and high-performance batteries, and weighs about as much as a mid-sized car. According to German test pilot Markus Scherdel, “Everything went as it should” during the Solar Impulse’s 87 minute flight (via Reuters).

In other solar tech news, IBM and Saudi Arabian researchers are developing a new system for water desalination that relies on “ultra-high concentrator photovoltaic arrays”, according to Green, Inc at the NYT. The key to the technology? The futuristic-sounding “liquid metal thermal interface” to keep solar collectors cool enough to do their job. The Saudi plant will eventually provide clean water for 100,000 people.

California solar news is particularly hot today: CBS reports on the Governator’s tour of a solar cell plant in Sunnyvale. Calisolar plans to expand its capacity from 60 mW to 200 mW, in the process creating 150 jobs for the state.

Down the coast a bit, SunEdison has activated a 945 kW solar power plant on a water treatment facility in San Diego, via PV Tech. San Diego Mayor Jerry Sanders says, “Large-scale municipal projects like this one show our continued commitment to renewable energy and its benefits both for our environment and the taxpayers.”

Last but not least in California news, CNET reports that San Jose-based Chromasun has raised $3 million in first-round investing for its large scale solar air conditioning. While the product can’t provide all of a building’s cooling needs, “the idea is that the chiller will run on solar power during peak times, offsetting the most expensive periods to purchase electricity.”

Not to neglect solar efforts on the Eastern seaboard, here’s a shout-out to insurance company MassMutual: the company issued a press release announcing plans to install over 500 solar panels on its facility in Springfield, Massachusetts. By using a mix of solar PV and solar thermal technology, the company hopes to see energy expenses cut by $100,000 per year. For more in Massachusetts solar happenings, see our update on the state’s rebate program from earlier today.

And that’s it for today! We’ll see you back here tomorrow for more of the good stuff.