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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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