# CYGNSS (Cyclone Global Navigation Satellite System)
*missions*

Eight-microsat LEO constellation launched December 2016 by NASA; each carries a DDMI GNSS-R instrument to measure ocean surface wind speed, soil moisture, flood inundation, and sea ice extent via GPS bistatic reflection at 35-degree inclination.

## Specifications
- **operator**: nasa
- **current status**: operational
- **actual launch**: 2016-12-15
- **orbit type**: LEO 520 km, 35 deg inclination (non-SSO)
- **tasking supported**: false
- **swath km**: 1480
- **launch vehicle**: northrop-grumman-pegasus-xl
- **entity type**: mission
- **last verified date**: 2026-06-11
- **verified by**: agency-doc
- **claim status**: unclaimed
- **provider**: nasa
- **attributes**: {"operator":"nasa","current_status":"operational","actual_launch":"2016-12-15","orbit_type":"LEO 520 km, 35 deg inclination (non-SSO)","tasking_supported":false,"summary":"Eight-microsat LEO constellation launched December 2016 by NASA; each carries a DDMI GNSS-R instrument to measure ocean surface wind speed, soil moisture, flood inundation, and sea ice extent via GPS bistatic reflection at 35-degree inclination.","swath_km":1480,"launch_vehicle":"northrop-grumman-pegasus-xl"}
- **relevance**: in-scope

## Editorial
CYGNSS (Cyclone Global Navigation Satellite System) is a NASA eight-microsat constellation launched in December 2016 into a 35-degree-inclination low Earth orbit. Each spacecraft carries a Delay Doppler Mapping Instrument (DDMI) that receives GPS signals reflected off the ocean surface, sea ice, land, and inland water to derive ocean surface wind speed, soil moisture, flood inundation extent, and sea ice properties through GNSS reflectometry.[^eoportal-cygnss][^nasa-cygnss-mission]

The constellation was designed as eight identical microsatellites flying in formation at approximately 520 km altitude (eoPortal gives a nominal range of 510-524 km; WMO OSCAR lists 500 km as nominal).[^eoportal-cygnss][^wmo-oscar-cygnss] Seven of the eight spacecraft remain operational following the loss of Flight Model 6 in December 2022. As of January 2026, NASA was exploring options for an operational transition of the mission.[^swri-cygnss-extension]

The non-sun-synchronous 35-degree orbit provides a 1,480 km measurement swath and enables revisit of oceanic regions at tropical and subtropical latitudes, supporting tropical cyclone wind monitoring and continental hydrology applications.[^eoportal-cygnss]

## Compositional position
- CYGNSS (Cyclone Global Navigation Satellite System) --[related-topic]--> ocean-surface-winds (topics)
- CYGNSS (Cyclone Global Navigation Satellite System) --[related-topic]--> flooding (topics)
- CYGNSS (Cyclone Global Navigation Satellite System) --[related-topic]--> soil-moisture (topics)
- CYGNSS (Cyclone Global Navigation Satellite System) --[related-topic]--> sea-ice (topics)

## Sources
- [eoportal-cygnss] | CYGNSS - eoPortal Directory | https://eoportal.org/web/eoportal/satellite-missions/c-missions/cygnss | tier=community | accessed=2026-06-11
- [wmo-oscar-cygnss] | WMO OSCAR - CYGNSS (8 sats) | https://space.oscar.wmo.int/satellites/view/cygnss_8_sats | tier=community | accessed=2026-06-11
- [nasa-cygnss-mission] | CYGNSS Mission - NASA Science | https://science.nasa.gov/mission/cygnss | tier=operator-marketing | accessed=2026-06-11
- [swri-cygnss-extension] | NASA extends CYGNSS mission - SwRI press release | https://www.swri.org/newsroom/press-releases/nasa-deems-swri-developed-satellites-healthy-extends-cygnss-mission | tier=operator-press | accessed=2026-06-11

---
Source: https://eo-atlas.org/missions/cygnss
Maintainer: SpectraWorks B.V. (CC-BY 4.0)