Circumnavigation is the mother of all "proof of concept" projects in nautics and aeronautics. We've just published about Planet Solar, the solar powered boat designed to circumnavigate the globe using only solar power, and there is already talk of another project only this time it's going to be an aircraft, powered by solar energy.

The solar aircraft is called Solar Impulse, and it's currently in testing phase, before the big finale of flying around the world using only solar energy as the source of power for all systems onboard the aircraft, including propulsion. Basically, the airplane's top wing surface is covered with solar cells, that generate electricity, stored in batteries, for flying during the night. It has an 80 meter wingspan and a 12 hp electric motors, and severe weight restrictions, which is really putting the strain on developers in pretty much all areas of the project. One of the main challenges is energy management. Reduction of energy consumption is crucial, but so are efficiency improvements in generating, storing and converting of solar energy. Restrictions are present in all aspects of the project. Another significant factor is the pilot, whose weight, but also the need for a pressurized cabin, pose a formidable challenge as well. There is also a need for additional instrumentation, although certain trade offs are going to be made.

The airplane may not be the prettiest of them out there, but in this case form is subject to function. (Image credit: Solar Impulse)

The individual behind the project, Bertrand Piccard, believes this to be a challenge in many ways. He's not trying to break any records, but rather trying to break preconceptions. This project would not be achievable without pushing the boundaries of modern technology.

The spirit of exploration is strong with this bunch. A group a scientists, engineers and yachtsmen has banded together to create a marine vessel powered entirely by renewable energy (mainly solar). Planer Solar is a catamaran (double keel), whose top surface will be completely covered by solar cells. These cells are expected to provide power for the boat, both for propulsion and other on-board power consumption. The US$ 13 million project should be completed sometime next year.

Construction is under way. The 98 feet (30 meters) long vessel will feature about 5100 square feet (490 meters squared) of photovoltaic cells. The project, funded by Rivendell Holding AG from Switzerland, is basically a proof of concept, to be used for the sipping industry, in order to reduce its dependence on fossil fuel. The crew aims to circumnavigate the globe in 120 days, travelling at an average speed of 10 knots. The last big solar powered boat to make a milestone maritime trip was the Sun, which crossed the Atlantic in 29 days.

Here's a rendering of what the boat should look like once finished. If future spacecraft looked like this, it would be great!

Image credit: PlanetSolar.org

See more info and pics on PlanetSolar.