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The European Space Agency\u2019s first Scout mission, HydroGNSS, was launched today, 28 November, marking a significant step in advancing global understanding of water availability and the effects of climate change on Earth\u2019s water cycle.<\/p>\n
The two twin HydroGNSS satellites were carried into orbit at 19:44 CET aboard a SpaceX Falcon 9 rocket, as part of the Transporter-15 rideshare flight from the Vandenberg Space Force Base in California.<\/p>\n
Less than 90 minutes after liftoff, the two satellites separated from the rocket. Then, at 22:45 CET, Surrey Satellite Technology Ltd (SSTL) in the UK confirmed that\u00a0they had received signals, indicating that both satellites were safely in orbit around Earth.<\/p>\n
\t\t\tHydroGNSS deploys solar panels
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Both satellites will use an innovative technique called Global Navigation Satellite System (GNSS) reflectometry to quite literally \u2018scout for water\u2019.<\/p>\n
This process involves the HydroGNSS satellites capturing L-band signals from navigation systems such as GPS and Galileo. These navigation satellites transmit L-band microwave signals that change when they are reflected off Earth\u2019s surface.<\/p>\n
The HydroGNSS satellites will compare these reflected signals with the signals the satellites receive directly from the GNSS satellites to reveal valuable information about the properties related to the water cycle, and more.<\/p>\n
\t\t\tHydroGNSS uses GNSS reflectometry to \u2018scout\u2019 for water
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To do this, each HydroGNSS satellite carries a delay doppler mapping receiver. This consists of two antennas: a zenith antenna, which tracks direct GNSS signals and a nadir antenna, which collects reflected signals and processes them into delay Doppler maps.<\/p>\n
Using this technique, these two small satellites, which orbit Earth 180 degrees apart, will measure soil moisture, freeze\u2013thaw state, inundation and above-ground biomass.<\/p>\n
These data will not only be vital for advancing our understanding of Earth\u2019s water cycle, but also for supporting applications such as flood prediction and agricultural planning.<\/p>\n
Also, by observing the extent of inundation and areas of wetland, HydroGNSS will help reveal wetlands \u2013 important ecosystems that can act as significant sources of methane\u00a0\u2013\u00a0often hidden beneath forest canopies.<\/p>\n
Information on freeze\u2013thaw states will provide insight into the surface radiation balance, energy and carbon exchanges with the atmosphere, and the behaviour of subsurface permafrost in high latitudes.<\/p>\n
Meanwhile, data on above-ground biomass will contribute to estimates of forest carbon stocks and their role in the global carbon cycle.<\/p>\n
\t\t\t\t\t\t\tHydroGNSS satellite: Scouting for water<\/a><\/p>\n Drawing inspiration from the spirit of New Space, the Scouts champion agility and innovation \u2013 harnessing small, smart satellites to shrink proven technologies or test bold new ways of observing our planet.<\/p>\n Each mission races from concept to launch in just three years, on a lean budget of \u20ac35 million that covers everything from design and construction to in-orbit operations.<\/p>\n ESA\u2019s Director of Earth Observation Programmes, Simonetta Cheli, said, \u201cAs the first of ESA\u2019s Scout missions to launch, HydroGNSS marks an important milestone for this new family of rapid, low-cost Earth observation missions, and we extend our thanks to the mission\u2019s prime contractor, SSTL.<\/p>\n