ESA selects Skeleton Technologies’ ultracapacitor for space mission

The European Space Agency has chosen a new ultracapacitor energy storage technology that increases safety while reducing weight and costs for a possible mission in 2018.

Originally developed by Estonian start-up Skeleton Technologies for use in the motor industry, the market-leading technology is 60 times lighter and 30 times more efficient than the lithium ion batteries it will replace, considerably reducing the amount of weight and room required for energy storage on a space vehicle. Although batteries can store more energy than ultracapacitors, they are slow to charge and discharge, and lose 30 per cent of their energy through heat alone. They also require frequent replacement.

Such an energy storage system is required by spacecraft and satellites to provide surges of power when required. Energy from the sun is harvested using solar cells and is stored for when the vehicle moves to the dark side of a planetary object, away from the sun, where the power is used for tasks such as adjusting antennae and moving solar arrays.

Skeleton Technologies’ system uses patented nanoporous carbide-derived carbon (CDC), also known as curved graphene. They have also developed a proprietary method for preparing the ultra capacitors.

“We took a technology that was widely used in the motorsport and Tier 1 automotive market and deconstructed and reconstructed this for use in space in, for instance, a high radiation environment,” said Oliver Ahlberg, Skeleton Technologies’ general manager.

“Normally, our products have twice the energy and four times the power of our competitors’ systems, but the performance of this is even better. However, in space, safety is a major concern. We are currently undertaking further testing of the devices in space-like conditions, with high radiation and in a vacuum. The advantage of our ultra capacitor is that no chemical reaction takes place when charging it, unlike with a lithium ion battery, which can combust if it is faulty. With the Skeleton system the ions are changing places in the electrodes, making it a physical, not chemical reaction. This means we have no issues at all with possible explosions.”

As the ultracapacitors store energy in an electric field rather than in a chemical reaction they are highly efficient at delivering sudden surges of energy and can charge and discharge over a million times, delivering significantly more power for weight than batteries. With every pound of payload put into space currently costing around €9,000, adopting this technology is expected to achieve significant efficiency savings.

As well as the motor industry, the technology is also making inroads into use in the development of smart power grids.