Little CubeSat is a throwback to times past and a glimpse into the future

March 4 – 8, 2022

SeaHawk: the small satellite that could

The SeaHawk satellite is both a throwback to an earlier era and a glimpse into the future.

In the early space age, scientists and engineers built and launched hardware quickly and frequently – a process of trial and error that helped them experiment with new measurements and designs. Almost every mission served as a proof of concept. Although today’s headlines focus on larger, more expensive craft, moments of daring ingenuity can still be found. Launched in December 2018, SeaHawk was an experimental craft that flew into orbit with a lot to prove.

In a future envisioned by some engineers, satellites could be much smaller and cheaper, with constellations of shoebox-sized spacecraft collectively doing the work once done by spacecraft the size of a a refrigerator or a car. Some of them will be built in public-private partnership. The last few years have seen the launch of such CubeSats and SeaHawk is part of this new lineage.

SeaHawk is a very small satellite designed to monitor ocean color and coastal ecosystems. It measures just 10 centimeters by 10 centimeters by 30 centimeters and flies in a polar orbit at an altitude of 585 kilometers (363 miles). The mission was funded by private grants and the hardware was built and maintained by a team from the University of North Carolina at Wilmington, the Skidaway Institute of Oceanography, Cloudland Instruments and AAC-Clyde Space. " data-gt-translate-attributes='[{"attribute":"data-cmtooltip", "format":"html"}]'>Nasa the scientists helped with the development and have since worked to integrate the data with other ocean color datasets.

According to longtime NASA oceanologist Gene Feldman, the team’s primary goal was to demonstrate that scientifically accurate ocean color data could be collected from a cubesat. After accomplishing this over the past year, the SeaHawk team has set new goals. They are currently trying to demonstrate that they can collect observations of the same body of water on several consecutive days.

The natural color images above were acquired March 3-8, 2022 by the HawkEye sensor aboard the SeaHawk cubesat. Although SeaHawk’s orbit around Earth changes by a few degrees of longitude each day, mission operators were able to observe the same stretch of the Australian coast for six consecutive days, tilting the satellite slightly with each new overpass.

SeaHawk CubeSat in orbit

There was a time when scientists thought it was enough, almost revolutionary, to acquire wide ocean images once every few days. They were beginning to see the ocean on a grand scale, sketching the grand patterns and rhythms. But today they want fine detail, Feldman noted. Where once it was enough to say, “the ocean is blooming with phytoplankton this time of year”, scientists now want to see what is happening daily, sometimes hourly, as conditions change rapidly. In the case of toxic algal blooms in coastal waters or inland lakes, this information is important for human and fisheries safety. Daily measurements can also be useful to researchers working from ships when studying a particular area or even a moving feature in the ocean.

Other ocean observing satellite instruments, such as the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), Moderate Resolution Imaging Spectroradiometer (MODIS) or Visible Infrared Imaging Radiometer Suite (VIIRS) can observe a large part of the ocean. every day. But because they look straight at the planet, the reflection of sunlight off the water (solar glare) can make it difficult to distinguish colors and features. By observing from an angle, SeaHawk removed these light effects.

The tiny HawkEye imager on SeaHawk also observes with significantly higher spatial resolution than MODIS and VIIRS, up to ten times more detail. And the imager is calibrated to the unique light properties of the ocean, which tend to be darker than landforms; such differences often cause other imagers to capture coastal land detail while making it difficult to see in water.

HawkEye has collected over 4,000 images since launch and is currently collecting around 100 new images per week. This data is integrated and archived with other NASA ocean color datasets, likely a first for any Cubesat mission. The team accepts imaging requests from members of the scientific community and continues to push the boundaries of repeated multi-day imaging.

“Our goal from the beginning was to integrate this mission into the infrastructure we’ve built over the past 25 years to support ocean color satellites,” Feldman said, “and to demonstrate that a cubesat can be treated like a normal, believable science mission.. we’ve proven it, and we never imagined that this little satellite would still be working after three years, let alone demonstrating new capabilities that we didn’t have never considered during development.And because they are smaller and cheaper, it will be easier to quickly adapt the second and third generation CubeSats in production to take advantage of what we have learned.

NASA Earth Observatory images by Joshua Stevens, using SeaHawk/HawkEye imagery courtesy of Alan Holmes and Gene Feldman, NASA Ocean Color Web. Story by Michael Carlowicz, with reporting by Joseph M. Smith, NASA EOSDIS Science Editor.

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