Earth's gravity from space

GPS signal occultation by the atmosphere, and the resulting useful data is explained.

The force of gravity not only keeps us from floating away, it also lets NASA study Earth’s water and ice from space. Using a pair of twin satellites named "GRACE," we can monitor our planet’s water.

GRACE on orbit

The twin GRACE satellites are seen in a clean room in Germany in 2002.

One of the GRACE satellites undergoes thermal testing at IABG in Germany.

NASA’s Gravity Recovery and Climate Experiment (GRACE) has measured significant groundwater depletion around the world in recent years. These animations show trends in total water storage from Jan....

GRACE satellites are mounted belly to belly at an IABG testing facility in Germany.

The GRACE satellites are seen at an IABG testing facility in Germany.

GRACE being readied for launch - 2

The GRACE satellites during component integration in a German clean room.

One of the twin GRACE spacecraft is seen during construction in Germany.

The original GRACE satellites in a clean room in Germany.

The GRACE Intermediate Field 48 (GIF48 from UT-CSR) field model is an improved mean gravity field that combines GRACE observations with terrestrial and ocean gravity information for the small-scale...

Measuring Earth's Gravity from Space exhibit

Research based on GRACE observations indicates that between 2002 and 2016, Greenland shed approximately 280 gigatons of ice per year.

Twin GRACE spacecraft being deployed from Breeze

The amount of water stored in the Amazon basin varies from month to month, and can be monitored from space by looking at how it alters Earth's gravity field.

This animation illustrates the highs and lows of the Earth's gravity field as water in the basins of the U.S. changes over time.

These images show the changes in gravity anomalies from GRACE over the Amazon Basin for each month of 2004. 

This image shows the mean annual amplitude of total water storage on Earth in 2007 as measured by GRACE.

Between 2002 and 2016, Antarctica shed approximately 125 gigatons of ice per year, causing global sea level to rise by 0.35 millimeters per year.

GRACE logo

This visualization of a gravity model was created with data from NASA's Gravity Recovery and Climate Experiment (GRACE) and shows variations in Earth’s gravity field.

This animation shows the annual water storage changes over the U.S. from GRACE from 2003 - 2013.

One of the twin GRACE satellites, Flight Model 1, is seen on a trolley during construction in Germany.