CYGNSS mission highlighted by SwRI
SAN ANTONIO — On Thursday, Aug. 11, Southwest Research Institute (SwRI) opened its doors to media, sharing progress on its Cyclone Global Navigation Satellite System (CYGNSS). The independent, nonprofit, applied research and development (R&D) organization has a long history of involvement in the U.S. space program, including building two of the instruments on NASA’s Juno spacecraft now in orbit around Jupiter, but this is the first mission in which the institute has built the primary spacecraft.
CYGNSS is a constellation of eight small satellites with a goal to improve hurricane intensity forecasting. Citing National Hurricane Center forecast verification data, The spacecraft‘s Principal Investigator, Dr. Chris Ruf, notes while hurricane/tropical cyclone tracking improved nearly 50 percent since 1990, there has not been a corresponding improvement in the accuracy of intensity forecasts.
Each 64-pound (29-kilogram) CYGNSS satellite is equipped with four GPS receivers to measure the signals scattered off the ocean’s surface. By measuring the distortion in the received GPS signals, scientists can determine surface wind speeds. The rougher the ocean, the more distorted the received signal, and thus, the higher the surface wind speed.
Since GPS signals penetrate heavy rain, a CYGNSS will be able to take wind speed measurements of areas other satellites cannot, including the eyewall and inner rainbands of hurricanes/tropical cyclones. This constellation of satellites will also provide more frequent data samples of the same area than existing stand-alone satellites.
Long before the assembly of a single satellite began, the team utilized “hundreds of hours of NASA supercomputer time to run countless simulations of CYGNSS fly-throughs,” according to Aaron Ridley, constellation scientist from the University of Michigan.
These simulations helped the team determine not only how many satellites to include in the constellation but also at what orbital inclination and altitude to place the satellites (this determines what “swath” of the Earth they monitor). Aaron wrote a helpful blog post about some of the decision-making process, as well as the deployment and constellation spacing.
CYGNSS is one of NASA’s new Earth Venture-class missions, the agency’s low-cost, rapid-turnaround Earth science missions. In 2012, the University of Michigan’s proposal for the mission was competitively selected from among 19 proposals submitted to NASA.
Each of the eight CYGNSS satellites was designed, built, tested, and validated at SwRI.
SwRI’s involvement in other missions has been notable; for example, they built the JADE and UVS instruments on NASA’s Juno spacecraft. Additionally, NASA’s New Horizons mission Principal Investigator, Alan Stern, is based at the institute.
The CYGNSS satellites’ GPS receivers and other antennas were provided by Surrey Satellite Technology, and the deployment module was provided by Sierra Nevada Corporation.
After environmental testing of the satellites is complete, the CYGNSS constellation will be transported to Vandenberg Air Force Base to be mated with the Orbital ATK Pegasus XL launch vehicle. The Pegasus XL is an air-launched rocket released from an Orbital ATK “Stargazer” L-1011 carrier aircraft at approximately 40,000 feet (12.2 km). After a five-second free fall, the Pegasus XL rocket’s first stage engine ignites, beginning its ascent to orbit.
CYGNSS will fly atop the 43rd Pegasus XL rocket to launch since 1990, joining the ranks of NASA missions such as NuSTAR and IRIS. The flight is scheduled for 8 a.m. to 9:30 a.m. EST (13:00 to 14:30 GMT) Nov. 21, 2016, from the skies above Cape Canaveral Air Force Station in Florida.
Shannon Moore is a graduate of the University of Texas at San Antonio and a web developer, photographer, writer, and social media manager. Her work has been featured on various conservation and aviation publications, as well as her own websites. A lifelong space geek, Shannon attended Space Camp in 1987 and has followed every crewed and uncrewed mission before and since. She is drawn to space exploration and spaceflight for the awe, inspiration, and human stories involved in every mission, and her goal is sharing that with others through her work — either in photographs, writing, or social media posts.