Bigelow Laboratory Prototype Emerges as Commercial Product

For researchers on the cutting-edge of science, invention is a daily activity. They often have to piece together the tools they need before they can use them in the field, and these new tools can sometimes offer their own opportunities to further scientific research.

In October, the result of one such invention made its commercial debut as the Surface Acquisition System (SAS) Solar Tracker, a device used to autonomously aim shipboard radiometers that measure the color of the ocean's surface. Manufactured and sold by Satlantic, a division of Sea-Bird Scientific, the device is based on a prototype developed at Bigelow Laboratory by Dr. Barney Balch, Bruce Bowler, and David Drapeau.

The team recognized the need for the technology while preparing for an Atlantic Meridional Transect cruise in 2004. During the 8,000-mile journey from the United Kingdom to South America, the researchers would be collecting optical measurements of the sea surface that they and NASA use to validate and compliment ocean color measurements from satellites.

"The NASA ocean color satellites provide crucial metrics for assessing phytoplankton abundance on a global scale in a changing ocean," Balch said. "By measuring the wavelengths of light reflected by the ocean's surface, we can determine the distribution and abundance of the phytoplankton that form the foundation of ocean ecosystems."

In order to obtain light measurements that can be compared to NASA's satellite data, all shipboard sensors must be aimed at highly constrained angles for optimal accuracy. On a moving ship, in which both the sun's angles and the ship's course are constantly changing, this is no simple feat. It requires near constant adjustment of sensors to obtain high quality data, and with 8,000 miles of ocean to cover, the team knew they needed to come up with an effective solution that didn't require them spending all day at the bow of the ship tweaking the equipment.

"When radiometers are in a fixed position on a ship, you have to throw away about 95 percent of the data, which was collected while the instruments were pointed in the wrong direction," Balch said. "We needed a solution that enabled us to collect continuous, autonomous, high-quality data while minimizing the data collected at incorrect viewing angles. We also needed a rugged device that could stand up to the rigors of heavy seas at the bow of a ship."

That solution was the Underway Aiming System, the prototype for what is now the SAS Solar Tracker. The Underway Aiming System incorporated software developed by Balch's group that used real-time navigation data to calculate the relative bearing of the sun and the ship's position in order to continuously adjust the sensors to the optimal viewing angle. The prototype was extremely successful and has since logged more than 200,000 miles on the ocean. It quickly became clear that this innovation could benefit other researchers.

Balch began discussing the device with Dr. Marlon Lewis, the founder of Satlantic, a company that develops optical sensors for oceanographic research and water quality monitoring. In August of 2010, Bigelow Laboratory signed a licensing agreement with Satlantic for the Underway Aiming System. After years of planning and development, Satlantic debuted the SAS Solar Tracker this fall at the international Ocean Optics conference in Victoria, British Columbia, to a wide range of interested parties.

"When we built the Underway Aiming System, we never imagined it would result in a commercial product," Balch said. "We had a problem that needed to be solved, and we solved it. Now we hope that other researchers can benefit from our solution."

To view a time-lapse video of the SAS Solar Tracker in action, visit https://youtu.be/tZteG6b0agE. The video was created by Dr. Maycira Costa at the University of Victoria, who recently acquired two SAS Solar Trackers for use on British Columbia ferries.