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Explore the people, places, events, achievements, struggles and stories that shaped our journey.
Movements, leaders, victories and the continuing fight for equality.
Innovation, patents, science, technology and world-changing contributions.
Pioneers, champions, Negro Leagues, records, activism and excellence.
Meet the people whose lives, choices and achievements shaped the journey.
Black towns, communities, institutions and places where history happened.
Moments that changed communities, movements, institutions and the nation.
Katherine Johnson’s mathematical calculations helped guide some of America’s most important early space missions while she confronted the racial and gender barriers faced by Black women in twentieth-century America.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
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| Mission type | Earth observation satellite |
|---|---|
| Operator | ESA |
| COSPAR ID | HydroGNSS 1: 2025-276AG HydroGNSS 2: 2025-276AH |
| Website | hydrognss.org |
| Mission duration | 10 months, 18 days (in progress) |
| Spacecraft properties | |
| Manufacturer | Surrey Satellite Technology |
| Start of mission | |
| Launch date | 28 November 2025, 18:44 UTC |
| Rocket | Falcon 9 Transporter-15 |
| Launch site | SLC-4E |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Sun-synchronous |
| Altitude | 550 km |
 ESA insingia | |
HydroGNSS (Hydrological Global Navigation Satellite System) is an Earth observation satellite mission by the European Space Agency (ESA) consisting of two identical small satellites carrying GNSS reflectometry instruments. The mission is using satellite navigation signals reflected from the Earth surface to monitor various Essential Climate Variables related to the hydrological cycle.[1][2][3][4][5][6][7][8][excessive citations] It was launched in November 2025 on a Falcon 9 rocket.[9]
HydroGNSS is designed to deliver data on four hydrological parameters aligned with Essential Climate Variables:[10]
The mission's secondary objectives are to measure wind speed over the ocean and sea-ice extent.[10]
The project builds upon previous GNSS reflectometry satellite missions—the CYGNSS constellation by NASA and the TechDemoSat-1 demonstrator by ESA and UKSA. Surrey Satellite Technology Ltd., the prime contractor for HydroGNSS, was involved in both these missions.[11]
HydroGNSS is launching as the first mission of ESA's Scout series of missions, within the FutureEO programme, although it bears the designation Scout-2.[2] That is because the Scout-1 mission CubeMAP was cancelled before its launch due to budgetary constraints.[12][13] ESA requires each Scout mission to move to launch within three years after kick-off and with a budget under €35 million.[14]
In March 2021, ESA has decided to implement HydroGNSS as the second of its new Scout series of missions within the FutureEO programme.[15] In October 2021, ESA has signed a contract with Surrey Satellite Technology to build the mission.[16][17] In March 2023, ESA has decided to build two HydroGNSS satellites instead of just one.[18][19]
In August 2025, the two satellites have passed their Flight Acceptance Review.[20] In September 2025, the two satellites have been transported to California for launch on Falcon 9 later that year.[21][11] After testing, propellant loading, battery charging, and launch adapter integration, the two spacecraft were pronounced ready for launch by ESA in November 2025.[14]
The two satellites were launched on 28 November 2025 at 18:44 UTC from Vandenberg Space Force Base on the SpaceX Falcon 9 Transporter-15 rideshare mission[22][23][14][24][10] and separated from the rocket less than 90 minutes after liftoff. At 21:45 UTC, Surrey Satellite Technology confirmed that they had received first signals from the satellites.[9]
On 19 December 2025, SSTL reported that both HydroGNSS satellites were already collecting Delay Doppler Maps of reflected GNSS signals. One example dataset was collected by HydroGNSS 2 over Central Africa on 5 December 2025, 7 days after launch.[25] In March 2026, SSTL reported that the two spacecraft, still in their commissioning phase, were successfully collecting "promising early measurements" and published a video of the mission's Delay Doppler Maps generated over France, the Mediterranean Sea, and north and east Africa.[26] In July 2026, HydroGNSS completed commissioning and begun full scientific operations.[27]
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Future missions in italics
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Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
HydroGNSS (Hydrological Global Navigation Satellite System) is an Earth observation satellite mission by the European Space Agency (ESA) consisting of two identical small satellites carrying GNSS reflectometry instruments. The mission is using satellite navigation signals reflected from the Earth surface to monitor various Essential Climate Variables related to the hydrological cycle. It was launched in November 2025 on a Falcon 9 rocket.
The European Space Agency (ESA) operates a number of space missions, both individually and in collaborations with other space agencies such as U.S. NASA, Japanese JAXA, Chinese CNSA, as well as space agencies of ESA member states (eg. French CNES, Italian ASI, German DLR, Polish POLSA). ESA organizes its missions into various budgetary programmes. This list follows the divisions of the Science Programme, the FutureEO Programme, and the Space Safety Programme. Missions from other programmes, such as Terrae Novae, FLPP, GSTP, or ARTES, are listed in loosely thematic categories. The current iteration of ESA's Science Programme is the Cosmic Vision Programme, a series of space science missions chosen by ESA to launch through competitions, similar to NASA's Discovery and New Frontiers programmes. It follows the Horizon 2000 and Horizon 2000+ programmes which launched notable missions such as Huygens (Titan lander), Rosetta (comet orbiter and lander), and Gaia (astrometry telescope). These missions are divided into two categories: "Sun and Solar System", space probes studying the Solar System (eg. Solar Orbiter studying the Sun and JUICE currently on its way to Jupiter) and "Astrophysics", space telescopes contributing to interstellar astronomy (eg. CHEOPS characterising exoplanets and Euclid focused on dark matter and dark energy). The Cosmic Vision Programme will be followed by Voyage 2050. A similarly operated programme focused on Earth observation, known as FutureEO, has launched various "Earth Explorer" satellites, which serve many aspects of Geoscience, often related to climate change. These include eg. GOCE and Swarm studying Earth's gravitational and magnetic fields, CryoSat-2 studying Earth's polar ice caps, and EarthCARE characterising clouds and aerosols in the atmosphere. The Earth Explorer missions are complemented by a series of smaller "Scout" satellites starting with HydroGNSS launched in late 2025. A number of Solar System, Astrophysics, and Earth observation missions by ESA have operated outside of these programmes, such as Giotto, Ulysses, Mars Express, Hipparcos, or Envisat. ESA also takes part in human spaceflight missions of other space agencies and commercial partners, eg. by providing European astronauts and major hardware components to the Space Shuttle, Mir, ISS, and Artemis programmes and supporting the Gaganyyan programme. ESA works with European space industry on development of launch vehicles and reentry systems like the Ariane and Vega rockets and the Space Rider spaceplane. Together with other European institutions, ESA develops and operates various satellite constellations for Earth observation, meteorology, communication, and navigation, eg. Meteosat, Sentinel, Galileo, or EDRS. ESA's portfolio also includes public-private partnerships with European satellite operators such as Eutelsat and Inmarsat.
The European Space Agency (ESA; pronounced /ˈiːsə/ EE-sə) is a 23-member international organisation devoted to space exploration. It has its headquarters in Paris and a staff of around 3,000 people globally as of 2025. ESA was founded in 1975 in the context of European integration. Its 2026 annual budget was around €8.3 billion. The ESA human spaceflight programme includes participation in the International Space Station (ISS) and collaboration with NASA on the Artemis programme, especially manufacturing of the Orion spacecraft's European Service Module (ESM). ESA launches and operates uncrewed missions to the Moon, Mars, Jupiter, Venus, Mercury, the Sun, and various comets and asteroids. Other activities include space telescopes, Earth observation satellites, asteroid impact avoidance, telecommunication and navigation satellites, designing launch vehicles (e.g. Ariane 6 is operated through Arianespace with ESA sharing in the costs), and maintaining Europe's spaceport (the Guiana Space Centre in Kourou, French Guiana), as well as space safety and commercialisation.
GNSS reflectometry (or GNSS-R) involves making measurements from the reflections from the Earth of navigation signals from Global Navigation Satellite Systems such as GPS. The idea of using reflected GNSS signals for earth observation was first proposed in 1993 by Martin-Neira. It was also investigated by researchers at NASA Langley Research Center and is also known as GPS reflectometry. Research applications of space-based GNSS-R are focused in altimetry, oceanography (wave height and wind speed), cryosphere monitoring, and soil moisture monitoring.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →The Greenwood District.
