Twin Spacecraft Launch to Track Earth's Water Movement
GRACE Follow-On has launched, and both satellites are communicating with ground stations.
A joint
U.S./German space mission to track the continuous movement of water and other changes
in Earth's mass on and beneath the planet's surface successfully launched at 12:47
p.m. PDT (3:47 p.m. EDT) Tuesday from the California coast.The twin
spacecraft of the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO),
a joint NASA/German Research Centre for Geosciences (GFZ) mission, lifted off
on a SpaceX Falcon 9 rocket from Space Launch Complex 4E at Vandenberg Air
Force Base in California, sharing their ride into space with five Iridium NEXT communications
satellites.Ground stations
have acquired signals from both GRACE-FO spacecraft. Initial telemetry shows
the satellites are performing as expected. The GRACE-FO satellites are at an
altitude of about 305 miles (490 kilometers), traveling about 16,800 mph (7.5
kilometers per second). They are in a near-polar orbit, circling Earth once
every 90 minutes.3-2-1 liftoff of Falcon 9 with GRACE-FO! NASA's Gravity Recovery and Climate Experiment Follow-on, or GRACE-FO, launched from Vandenberg Air Force Base on California's Central Coast on May 22, 2018. The twin orbiters shared a ride to space with five Iridium NEXT communications satellites. GRACE-FO will continue a study begun by the original GRACE mission, which proved that water movement can be tracked with high precision by its effect on Earth's gravitational field. GRACE-FO will continue the record of regional variations in gravity, telling us about changes in glaciers, ground water, sea levels and the health of our planet as a whole."GRACE-FO will
provide unique insights into how our complex planet operates," said Thomas
Zurbuchen, associate administrator of NASA's Science Mission Directorate at
NASA Headquarters in Washington. "Just as important, because the mission
monitors many key aspects of the Earth's water cycle, GRACE-FO data will be
used throughout the world to improve people's lives -- from better predictions
of drought impacts to higher-quality information on use and management of water
from underground aquifers."Over its
five-year mission, GRACE-FO will monitor the movement of mass around our planet
by measuring where and how the moving mass changes Earth's gravitational pull. The
gravity changes cause the distance between the two satellites to vary slightly.
Although the two satellites orbit 137 miles (220 kilometers) apart, advanced instruments
continuously measure their separation to within the width of a human red blood
cell.GRACE-FO continues
the U.S./German partnership of the originalGRACEmission, which operated from 2002 through 2017. "This
mission continues and advances an amazing achievement of science and technology
pioneered by the United States and Germany," said Zurbuchen.For 15 years,
GRACE's monthly maps of regional gravity variations provided new insights into
how the Earth system functions and responds to change.Among its
innovations, GRACE was the first mission to measure the amount of ice being
lost from the Greenland and Antarctic ice sheets. The mission improved our
understanding of the processes responsible for sea level rise and ocean
circulation, provided insights into where global groundwater resources are shrinking
or growing, showed where dry soils are contributing to drought, and monitored
changes in the solid Earth, such as from earthquakes.Frank Webb, GRACE-FO
project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California,
noted that to understand changes taking place in the climate system, scientists
need data records several decades long."Extending
the data record from GRACE will allow us to better distinguish short-term
variability from longer-term trends," he said.The GRACE-FO
satellites will spend their first few days in space moving to the separation
distance needed to perform their mission. When they reach this distance, the
mission will begin an 85-day, in-orbit checkout phase. Mission managers will evaluate
the instruments and satellite systems and perform calibration and alignment
procedures. Then the satellites will begin gathering and processing science
data. The first science data are expected to be released in about seven months.JPL
manages the GRACE-FO mission for NASA's Science Mission Directorate in
Washington, under the direction of the Earth Systematic Missions Program Office
at NASA's Goddard Space Flight Center in Greenbelt, Maryland. The spacecraft
were built by Airbus Defence and Space in Friedrichshafen, Germany, under
subcontract to JPL. GFZ contracted GRACE-FO launch services from Iridium. GFZ subcontracted
mission operations to the German Aerospace Center (DLR), which operates the
German Space Operations Center in Oberpfaffenhofen, Germany.For more
information about GRACE-FO, visit:https://www.nasa.gov/gracefo