Emcore cells to power hurricane forecasting mission

24 Mar 2014

Latest multi-junction cells solar cells selected for NASA’s “CYGNSS” micro-satellite constellation.

Privately held aerospace firm Sierra Nevada Corporation (SNC) has awarded a contract to provide the solar cells for a new hurricane-forecasting satellite mission to US-based Emcore.

The deal will see the Albuquerque company supply its latest “ZTJ” multi-junction cells for NASA’s Cyclone Global Navigation Satellite System (CYGNSS) project, which is currently scheduled for launch in October 2016.

CYGNSS will comprise eight low-orbiting (LEO) satellites that will be launched by the same vehicle, with NASA explaining that these micro-satellites can pass over the oceans more quickly than a single large satellite. This means that data about ocean surface roughness – and therefore wind speeds – can be collected more often than is currently possible.

“The goal is a fundamental improvement in hurricane forecasting,” says NASA. “The CYGNSS data will enable scientists to probe key air-sea interaction processes that take place near the core of the storms, which are rapidly changing and play a critical role in the genesis and intensification of hurricanes.”

Each of the satellites, which weight less than 20 kilos, will carry a low-power delay Doppler mapping instrument (DDMI). Once in orbit and with their solar panels deployed they will unfurl to the size of a “full-grown swan” adds NASA, bizarrely.

They will each be capable of measuring four simultaneous reflections, and the constellation will produce 32 wind measurements per second.

Predicting hurricanes: University of Michigan video:

Multi-junction performance
Emcore’s ZTJ cells are its top-of-the-range offering, with a quoted minimum average conversion efficiency of 29.5 per cent generated by the combination of InGaP, InGaAs and germanium layers within the cell’s layered semiconductor structure.

SNC will incorporate the devices into finished panels that will then be delivered to Southwest Research Institute (SwRI), which is managing the mission, for integration.

Emcore has previously provided solar panels to SNC for the second “ORBCOMM” satellite mission back in 2010, and its cells are also being used by the “MAVEN” mission to the planet Mars, which launched late last year.

“We are very pleased to receive this award and are appreciative of SNC's continued confidence in our ability to deliver the highest reliability solar panels for their missions," said Brad Clevenger, general manager of the company’s photovoltaics division.

More than 100 satellite missions already launched have used or are still using Emcore's cells, and in summer 2012 the company announced that another 120 such missions were already under contract over the next few years. One of those is another Mars expedition, the "InSight" geophysical lander craft designed to study the planet's deep interior. It should also launch in 2016.

The emergence of a market for small, low-cost micro- and nano-satellites as highlighted by CYGNSS is a key trend favoring the use of the efficient, lightweight cells that the company has developed.