Cyclone Global Navigation Satellite System
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| Names | CYGNSS |
|---|---|
| Mission type | Weather research |
| Operator | NASA |
| COSPAR ID | 2016-078A, 2016-078B, 2016-078C, 2016-078D, 2016-078E, 2016-078F, 2016-078G, 2016-078H |
| SATCAT no. | 41884, 41885, 41886, 41887, 41888, 41889, 41890, 41891 |
| Website | cygnss-michigan |
| Mission duration | Planned: 2 years Elapsed: 4 months, 6 days |
| Spacecraft properties | |
| Manufacturer | |
| Launch mass | 28.9 kg (64 lb) each |
| Dimensions | 163.5 × 52.1 × 22.9 cm (64.4 × 20.5 × 9.0 in) (L x W x D) |
| Power | 34.7 watts |
| Start of mission | |
| Launch date | December 15, 2016, 13:37:21 UTC |
| Rocket | Pegasus XL F43 |
| Launch site | Cape Canaveral (Stargazer) |
| Contractor | Orbital ATK |
| Entered service | March 23, 2017 |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
| Semi-major axis | 6,903 km (4,289 mi) |
| Eccentricity | 0.00162 |
| Perigee | 514 km (319 mi) |
| Apogee | 536 km (333 mi) |
| Inclination | 35 degrees |
| Period | 95.1 minutes |
| Epoch | April 15, 2017, 22:21:25 UTC |
| Instruments | |
| Delayed Doppler Mapping Instrument | |
The Cyclone Global Navigation Satellite System (CYGNSS) is a space-based system developed by the University of Michigan and Southwest Research Institute with the aim of improving hurricane forecasting by better understanding the interactions between the sea and the air near the core of a storm.
In June 2012, NASA sponsored the project for $152 million with the University of Michigan leading its development. Other participants in CYGNSS' development include the Southwest Research Institute, Sierra Nevada Corporation, and Surrey Satellite Technology.
The plan was to build a constellation of eight micro-satellites to be launched simultaneously in a single launch vehicle into low Earth orbit, at 500 km altitude. The program was scheduled to launch December 12, 2016, and then observe two hurricane seasons. Problems with a pump on the launching aircraft prevented this first launch, but a second launch attempt took place successfully on December 15, 2016.
Forecasting the tracks of tropical cyclones since 1990 has improved by approximately 50%; however, in the same time period there has not been a corresponding improvement in forecasting the intensity of these storms. A better understanding of the inner core of tropical storms could lead to better forecasts; however, current sensors are unable to gather a sufficient quality of data on the inner core due to obscuration from rain bands surrounding it and to infrequent sampling. In order to improve the models used in intensity forecasts, better data are required.
CYGNSS will measure the ocean surface wind field using a bi-static scatterometry technique based on GPS signals. Each satellite receives both direct GPS signals and signals reflected from the Earth's surface; the direct signals pinpoint the microsatellite position and provide a timing reference, while the reflected or "scattered" signals provide information about the condition of the sea's surface. Sea surface roughness corresponds to wind speed. Using a network of eight small satellites enables frequent observations: the mean revisit time is predicted to be 7 hours. The eight microsatellites orbit at an inclination of 35°, and are each capable of measuring 4 simultaneous reflections, resulting in 32 wind measurements per second across the globe.
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