Sophisticated Spacecraft for Highly Accurate Measurements

“Flying 1300 km high, at 6 km per second, while measuring sea surface heights to about 4 cm,
requires a pretty sophisticated set of instruments,” Spacecraft Mission Director Parag Vaze, Jason-3 project manager at the Jet Propulsion Laboratory, said Friday.

Jason-3’s primary instrument is the Poseidon-3B Altimeter, a radar altimeter that measures variations in the sea level across the world’s oceans with an accuracy as high as 1.3 inches (or 3.3 centimeters). Its goal: an accuracy as high as 1 inch (or 2.5 centimeters). For a full rundown on all the instrumentation on board, visit

The Jason-3 satellite weighs about 1,100 pounds and is about the size of a minivan — 3.3 feet by 3.3 feet by 12.1 feet — once its solar panels are deployed.