The latest in a series of U.S.-European ocean-monitoring satellites is scheduled for launch into orbit on Sunday.
The Jason-3 satellite will be launched from Vandenberg Air Force Base, California, atop a SpaceX Falcon 9 rocket that will then attempt to land its first stage on an unmanned floating barge in the ocean.
The satellite was intended for launch last August, but was put on hold after a Falcon 9 rocket failed in June.
The satellite has a radar altimeter to bounce microwave energy off the ocean and measure sea level heights, which in turn indicate the warming or cooling of surface waters.
The data has practical use in detecting El Nino and its opposite, La Nina, as well as forecasting tropical cyclones and in forecasting.