NASA is investing $89 million to see if it can achieve limitless flight using solar photovoltaic technology.

The Vulture prototype project aims to create a demonstration aircraft that could spend five years to eternity in the air, being dispatched around the world for unmanned operations at 60,000 feet.

It sounds like the stuff of science fiction. But it’s actually just an improvement on the 2003 Helios project, which launched an unmanned solar airplane into the sky and broke elevation and endurance records before it crashed in the Pacific Ocean.

While $89 million is a sizeable investment, the potential payout is tremendous, said NASA aerospace engineer Craig Nickol.

“The dollar per flight hour is actually very attractive,” Nickol said.

Not only would the plane be available in the sky for extremely long periods, but it would also probably require very little manpower on the ground. If it never has to land for maintenance or to refuel, its on-the-ground footprint becomes very small, Nickol said.
When Helios flew in 2003, it was outfitted with 20-percent efficiency solar cells, which were some of the most advanced at the time.

“Since then, there have been tremendous advances in multi-junction solar cells,” Nickol said. “However, those advances don’t come cheaply.”

The magic behind making the Vulture an operational project will lie in using the highest-efficiency solar cells and energy storage devices possible without weighing the plane down too much.

Nickol said the requirements for the prototype are that it will be able to fly above air traffic at about 60,000 feet, that it will be able to fly fast enough to cut through 99 percent of headwinds and that it will be able to store enough energy to make it through long nights.

Remaining energy-efficient will inevitably slow the plane down. Nickol said he expects its typical speed to be about 90 miles per hour.

It will be able to take the place of satellites in the event of emergencies and will be able to go in for closer military surveillance operations.

Nickol said he expects the Vulture prototype to have a 30-day demonstration flight in 2014.

There are other private companies engineering solar-powered endurance planes as well.

“It’s sort of the wild west out there for airplanes,” Nickol said. “It’s hard to tell what will make it and what won’t. The frontier in aeronautics has really been pushed out.”