International Space Agencies – Missions and Discoveries

GRACE-FO Mission


From UPSC perspective, the following things are important :

Prelims level : GRACE FO mission

Mains level : Impact of climate changes on Cryosphere

The GRACE-FO mission has mapped deviation in Earth’s surface mass and spatial variations in the rate of sea-level rise between 1993 and 2018 using altimetric and gravimetric analysis.

Try this MCQ:

Q.NASA’s VIPER mission sometimes seen in news is related to the study of-




d)None of these

GRACE-FO Mission

  • The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission launched in 2018 is a partnership between NASA and the German Research Centre for Geosciences (GFZ).
  • It is a successor to the original GRACE mission, which orbited Earth from 2002-2017.
  • It carries on the extremely successful work of its predecessor while testing a new technology designed to dramatically improve the already remarkable precision of its measurement system.

How did NASA measure this?

(1) Altimetric Study

  • Altimetry missions are used to know the ocean surface topography — the shape and height of the ocean’s peaks and valleys.
  • Radar altimeters continually send out pulses of radio waves (microwaves) that bounce off the surface of the ocean and reflect back toward the satellite.
  • The instrument calculates the time it takes for the signal to return, while also tracking the precise location of the satellite in space. From this, scientists can derive the height of the sea surface directly underneath the satellite.

(2) Gravimetric Study

  • Gravimetry is a process of using ice’s gravitational pull on a pair of satellites. It helps estimate ice loss and its contribution to sea-level rise.
  • The twin satellites in each mission detect subtle shifts in Earth’s gravity field.
  • The strength of gravitational forces is determined by mass, so changes in Earth’s gravity field indicate a change or redistribution in mass.
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