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SPACE SCIENCE


        Small but mighty NASA weather




        instruments prepare for launch







          Working together, two
          instruments could open the door
          for a more efficient, cost-effective
          way to gather key information for
          weather forecasting.




            wo instruments launching to the
            International Space Station in a few
        Tweeks could be weather forecasting
        game changers. The two novel instruments
        are expected to demonstrate that while
        they are much smaller, much lighter and
        much less expensive than weather satellites
        orbiting today, they can collect some of the
        same essential data.
           The main purpose of the Compact Ocean
        Wind Vector Radiometer (COWVR) instrument
        is to measure the direction and speed of
        winds at the ocean surface. The Temporal
        Experiment for Storms and Tropical Systems
        (TEMPEST) looks at atmospheric humidity.  The COWVR instrument (centre, wrapped in gold foil) in JPL’s Environmental Test Laboratory during vibration
           Designed and built at NASA’s Jet   testing. Credits: NASA/JPL-Caltech
        Propulsion Laboratory in Southern California,
        the two instruments are technology   emissions also increase. A microwave radiometer records these changing emissions and
        demonstrations. NASA will archive the data   processing the data can reveal both the speed and the direction of winds at the ocean surface.
        and make it available to all interested users,   Those measurements are critical for monitoring how storms such as hurricanes develop, and they
        but the main purpose of the mission is to   feed into forecasts and warnings to coastal populations and ships at sea.
        prove the instruments can operate in space   WindSat has far exceeded its projected life span and is still operating, but in 2012 the Air
        and supply data for weather forecasts.   Force began work on a replacement radiometer of the same sort, intending to launch the new
        Together, they’re part of a U.S. Space Force   instrument before WindSat went out of service. The expense and difficulty of building this type of
        mission called Space Test Program-Houston   instrument got DoD scientists thinking about what a next-generation ocean wind sensor could be.
        8 (STP-H8), expected to launch to the space   That’s where NASA came in.
        station on 21 December 2021.           Shannon Brown, a JPL engineer, had been working on a microwave radiometer for the
                                             oceanographic mission Jason-3, developed by NASA, the National Oceanic and Atmospheric
        What’s New About COWVR               Administration, and European partners to measure sea surface height. Brown recognised that
        Almost a decade in the making, COWVR grew   the Jason-3 instrument’s design advances could be repurposed to meet the needs of weather
        from the space-based weather-forecasting   forecasters. “We put a concept together that used most of the Jason-3 hardware designs, and we
        and environmental observation programmes   found it could measure wind speed and direction at a much lower cost than what the Air Force
        of the U.S. Department of Defence (DoD).   was building,” he said.
        The military collects data to forecast ocean   The novel aspect of COWVR is its simplified design. The WindSat radiometer rotates about 30
        surface winds with a spaceborne instrument   times a minute as it gathers data. The engineering challenge of developing and powering up parts
        named WindSat, launched in 2003.     that can rotate many millions of times in space has proven to be one of the most expensive and
           A microwave radiometer, WindSat,   demanding aspects of radiometer development.
        measures naturally occurring microwaves   COWVR reduces the number of moving parts, replacing hardware with algorithms newly
        emitted from Earth’s atmosphere and   developed for the instrument by Brown and his colleagues. The algorithms tease the desired
        surface. Over the ocean, when wind   signals of wind speed and direction out of the raw data stream. Parts that still must rotate are now
        increases and waves grow larger, microwave   housed on a turntable so they don’t need to be powered individually. The streamlined instrument



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