Dr. Valerie Thomas in 1979 standing with a stack of early Landsat Computer Compatible Tapes (CCTs). Thomas was responsible for the development of early Landsat digital media formatting.

 NASA on Wikimedia Commons (public domain) 

Meet Valerie Thomas, the inventor and scientist who launched the longest-running satellite program imaging Earth’s surface

During Thomas's three-decade career at NASA, she connected scientists with the data they need to understand our planet

Scientists use GPS satellites to track Greenland ice sheet melting

Scientists could already measure soil moisture, wind velocities, snow depth with GPS satellites. Now they can also monitor melting ice.