Announcement:

First light image of SeaHawk-1/HawkEye

The University of North Carolina Wilmington (UNCW) together with NASA, AAC Clyde Space, Cloudland Instruments, and the Gordon and Betty Moore Foundation, is pleased to announce the successful acquisition and retrieval of SeaHawk-1 CubeSat’s first ocean color image from space. On March 22nd, it was downlinked via X-band from SeaHawk-1 CubeSat to the ground station at NASA Wallops and immediately transferred to NASA Goddard, where it was processed.   

This first SeaHawk-1 engineering test image (pictured above) was captured by the HawkEye instrument on March 21st, 2019 at 18:47 UT from an altitude of 588 km and superimposed on Google Map data © 2019 Google, INEGI. At the current altitude that SeaHawk is flying, the pixel resolution of the HawkEye instrument is approximately 130 meters (425 feet) giving us an image size of approximately 6000 lines along track (780 km or 485 mi) x 1800 pixels across track (234 km or 145 mi). The true color full resolution closeup of the region from south of Monterey Bay to north of San Francisco (presented below) was produced by combining three of the Hawkeye bands (red band-6 (670nm), green band-5 (555nm) and blue band-2 (443nm).

 

Below, another view of Monterey Bay in which a slightly different combination of three bands (red band 6 (670nm), green band 5 (555nm) and blue band 3 (490nm) were used to bring out some of the features that can be seen in the water. 

 

Mission and Spacecraft

SeaHawk-1 is a 3U CubeSat (size 30x10x10cm and weight 5kg) designed and built by AAC Clyde Space and launched in December 2018 aboard SpaceX Falcon 9. SeaHawk-1 CubeSat was one of the 64 satellites included in the Spaceflight SSO-A Small Sat Express: their first dedicated ride-share mission for small satellites. SeaHawk-1 is also the first 3U CubeSat specifically designed to carry an ocean color instrument payload (HawkEye). The goal of this proof-of-concept mission is to provide free high-spatial resolution images of Earth’s coastal regions. HawkEye, designed by Cloudland Instruments, is an 8-band multispectral instrument similar to SeaWiFS (one of the most successful ocean color missions to date). It differs in that: it was miniaturized (10x10x10cm) to fit inside the CubeSat, band 7 was modified to improve atmospheric correction, all bands were designed not to saturate over land, and the entire sensor was built with low-cost, off-the-shelf materials. But one of the biggest contributions of SeaHawk-1 is its 130-meter spatial resolution. This high resolution (~8 times better than SeaWiFS or standard global ocean color satellites) ocean color imagery will resolve sub-mesoscale features and will advance our understanding of key coastal processes and ecosystems. Some examples of potential areas of application include early detection of harmful algal blooms, glacier dynamics, threatened coral reefs, storm water runoffs, etc., all of which have direct impact in human well-being or livelihood. SeaHawk-1 follows a sun-synchronous orbit an altitude of ~590km, orbiting 15-times a day with a current repeat time of about 18-days. SeaHawk-1 is one of two identical CubeSats, and SeaHawk-2 is expected to be launched within the next year, potentially reducing the time needed to re-image any given location. Once SeaHawk-1 is fully commissioned and begins operations, data will be available at no cost through NASA’s Ocean Biology Processing Group (https://oceancolor.gsfc.nasa.gov) and UNCW (https://uncw.edu/socon/mission.html). In the near future, the scientific community will also be able to submit requests for image acquisition (e.g. for field support) through UNCW (https://uncw.edu/socon/requests.html ). This project is funded by the Gordon and Betty Moore Foundation through Grant GBMF4526 to UNCW at Wilmington, Department of Physics and Physical Oceanography and Space Act Agreement 450-AGMT-0149 between NASA and UNCW.


It Takes a Village:

UNCW's Satellite Oceanography Lab

Faculty members from the Department of Physical Oceanography and the students from UNCW's Student CubeSat Lab participated in the joint telecon on Friday, when the first image was downlinked to the ground station at NASA Wallops. The UNCW CubeSat Lab is a newly formed student association that was born as a result of the genuine interest in the project by some students from UNCW's Master's Degree in Data Science. The students are now involved in several projects under the guidance of advisors from the Department of Physical Oceanography and the Data Science Program and will be presenting a poster at the upcoming NC Space Grant Student Symposium in April.

Faculty members Prof. Till Wagner, Prof. Frederick Bingham and Dr. Sara Rivero Calle celebrating the succesful retrieval of SeaHawk-1's first light image with the students from UNCW's CubeSat Lab.

 

Our Counterparts

The target location for the first light image was discussed with the entire SeaHawk team. The decision was based on certain requisites that included: a latitudinal range between 20-40 degrees, low probability of cloud cover or sun glint, a combination of land and ocean, and the CubeSat path. NASA Goddard, MD then scheduled the image acquisition and was in charge of processing the raw data up to level 1-A with the assistance of Cloudland Instruments and AAC Clyde Space.

  

Left: Gene Carl Feldman, Liang Hong and Alicia Scott scheduling the first image acquisition at NASA Goddard. 

Right: Image processing group at NASA Goddard analyzing the first HawkEye image within minutes of the downlink.

Meanwhile NASA’s Near-Earth Network (NEN) ground station in Wallops, VA was in charge of downlinking the image from the CubeSat via X-Band and sending it to NASA Goddard for processing.

On the left you can see the location of SeaHawk-1 during the overpass and on the right, a picture of the signal received at NASA Wallops. On the bottom right there is a picture of a similar test done during the first overpass of the SeaWiFS mission 22 years earlier!