Switzerland's solar-powered aircraft is expected to attempt its first international flight as early as next week to Brussels, the team managing the project said on Thursday.

"Solar Impulse, the zero fuel airplane, will attempt to fly to Brussels Airport as the destination for its first international flight," said the team in a statement.

"The airplane will be ready for take-off as from 2 May 2011 and will depart just as soon as the weather permits," it added.

Solar Impulse made history in July 2010 as the first manned plane to fly around the clock on the sun's energy.

But an international flight involving a foreign airport will be a "big technical challenge," acknowledged the team.

Months of preparations have gone into planning and training for the task, and an entire team of experts, including meteorological specialists, route planners, air traffic controllers, engineers and IT specialists have been roped in.

"Flying an aircraft like Solar Impulse through European airspace to land at an international airport is an incredible challenge for all of us, and success depends on the support we receive from all the authorities concerned," said Andre Borschberg, who piloted July's flight.