Cyclone Global Navigation Satellite System

Cyclone Global Navigation Satellite System
Mission type Weather research
Operator NASA
Website cygnss-michigan.org
Mission duration Planned: 2 years
Spacecraft properties
Manufacturer University of Michigan and
Southwest Research Institute
Launch mass 27.5 kg (61 lb) each
Dimensions Deployed: 51 × 159 cm (20 × 63 in)
Power 34.7 watts
Start of mission
Launch date December 12, 2016
Rocket Pegasus XL
Launch site Cape Canaveral Air Force Station
Contractor Orbital ATK
Orbital parameters
Eccentricity circular
Periapsis 500 km
Apoapsis 500 km
Inclination 35 degrees

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.[1][2] Other participants in CYGNSS' development include the Southwest Research Institute, Sierra Nevada Corporation, and Surrey Satellite Technology.[3]

The plan is to build a constellation of eight micro-satellites that are to be launched simultaneously into low Earth orbit,[2] [4] at 500 km altitude.[5] The program plans to launch December 12, 2016, and then observe two hurricane seasons.[6][7] NASA plans to carry the eight satellites in a single launch vehicle.[8]

Overview

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.[9][10]

CYGNSS is the first of NASA's Earth Venture-class spaceborne missions (a part of the NASA Pathfinder program);[3] the previous EV selections were divided among five airborne remote sensing missions. Launch was slated for November 2016,[11] but is now scheduled for December 12, 2016[6] for a two-year run.[12]

CYGNSS will measure the ocean surface wind field using a bi-static scatterometry technique based on GPS signals.[9][10] 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.[5] Using a network of eight small satellites enables frequent observations: the mean revisit time is predicted to be 7 hours.[9][10] 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.[5]

Science goal

The CYGNSS science goal is to understand the coupling between ocean surface properties, moist atmospheric thermodynamics, radiation, and convective dynamics in the inner core of a tropical cyclone.[5] To achieve this goal, the system will measure ocean surface wind speed in all precipitating conditions, including those experienced in the eyewall. The mission will also measure ocean surface wind speed in the storm's inner core with sufficient frequency to resolve genesis and rapid intensification. As secondary goal, the project will support the operational hurricane forecast community by producing and providing ocean surface wind speed data products.[5]

Instruments

Each CYGNSS satellite carries a Delay Doppler Mapping Instrument (DDMI), consisting of:

The instrument receives GPS signals for the purposes of bi-static scatterometry.[5]

See also

References

  1. ↑ "U-M To Lead $152M NASA Satellite Project". Associated Press. June 19, 2012. Retrieved June 22, 2012.
  2. 1 2 Clark, Stephen (June 21, 2012). "NASA funds satellite mission to measure hurricane winds". SpaceflightNow. Retrieved June 22, 2012.
  3. 1 2 "NASA Selects Low Cost, High Science Earth Venture Space System". NASA. June 18, 2012. Retrieved June 24, 2012.
  4. ↑ Aldridge, James (June 21, 2012). "NASA taps SwRI on research effort to map hurricanes". San Antonio Business Journal. Retrieved June 22, 2012.
  5. 1 2 3 4 5 6 "CYGNSS Factsheet October 2014". University of Michigan. Retrieved: September 27, 2015.
  6. 1 2 "CYGNSS Mission". University of Michigan. Retrieved February 11, 2016.
  7. ↑ Kozlowski, Kim (June 22, 2012). "University of Michigan, NASA team up for hurricane satellite project". The Detroit News. Retrieved June 22, 2012.
  8. ↑ "U-M to Lead $150M NASA Hurricane Prediction Project". University of Michigan. June 19, 2012. Retrieved November 14, 2016.
  9. 1 2 3 "CYGNSS." University of Michigan. Retrieved: August 15, 2015
  10. 1 2 3 Ruf, Christopher S.; Atlas, Robert; Chang, Paul S.; Clarizia, Maria Paola; Garrison, James L.; Gleason, Scott; Katzberg, Stephen J.; Jelenak, Zorana; Johnson, Joel T. (June 26, 2015). "New Ocean Winds Satellite Mission to Probe Hurricanes and Tropical Convection". Bulletin of the American Meteorological Society. 97 (3): 385–395. doi:10.1175/BAMS-D-14-00218.1. ISSN 0003-0007.
  11. ↑ "Missions - CYGNSS". NASA. April 30, 2013. Retrieved September 8, 2013.
  12. ↑ Leone, Dan (June 19, 2012). "NASA To Fund Wind-monitoring Smallsat Constellation". Space News. Retrieved June 22, 2012.
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