NASA testing 'roll-up' solar panels on ISS

NASA will test a new flexible solar panel on the International Space Station, that rolls up to form a compact cylinder and may offer substantial cost savings as well as an increase in power for satellites in the future.
Traditional solar panels used to power satellites can be bulky with heavy panels folded together using mechanical hinges.
Smaller and lighter than traditional solar panels, the Roll-Out Solar Array, or ROSA, consists of a centre wing made of a flexible material containing photovoltaic cells to convert light into electricity.
On either side of the wing is a narrow arm that extends the length of the wing to provide support, called a high strain composite boom.

The booms are like split tubes made of a stiff composite material, flattened and rolled up lengthwise for launch.
The array rolls or snaps open without a motor, using stored energy from the structure of the booms that is released as each boom transitions from a coil shape to a straight support arm.

ROSA can be easily adapted to different sizes, including very large arrays, to provide power for a variety of future spacecraft.
It also has the potential to make solar arrays more compact and lighter weight for satellite radio and television, weather forecasting, GPS and other services used on Earth.

In addition, the technology conceivably could be adapted to provide solar power in remote locations.
The technology of the booms has additional potential applications, such as for communications and radar antennas and other instruments.
The ROSA investigation looks at how well this new type of solar panels deploys in the microgravity and extreme temperatures of space.
The investigation also measures the array's strength and durability and how the structure responds to spacecraft manoeuvres.
"When the array is attached to a satellite, that spacecraft will need to manoeuvre, which creates torque and causes the wing, or blanket, to vibrate," said Jeremy Banik, from the Kirtland Air Force Base in New Mexico.

"We need to know precisely when and how it vibrates so as not to lose control of the spacecraft. The only way to test that is in space," said Banik.
"This structure is very thin, only a few millimetres thick, and heats up very quickly, dozens of degrees in a few seconds," he said.
"That creates loads in the wing that could cause it to shudder. That would create problems, for example, if a satellite was trying to take a picture at the same time," he added.