Before Argo, the temperature and salinity of the subsurface oceans could only be measured from ships or fixed point moorings.

UNESCO: World Water Assessment Programme (WWAP)

Based on the Phoenix lander, the craft is tasked with giving us a peek beneath the planet's surface, armed with tools that include a geodetic instrument from the Jet Propulsion Laboratory, which will be used to calculate Mars' rotation axis, a seismic wave sensor and a subsurface heat probe, to measure the planet's internal temperature.

ENGADGET: NASA InSight tapped for Mars drilling mission in 2016

Today Argo provides the first-ever global-scale, all-weather subsurface observations of the oceans, an unprecedented dataset for researchers studying the temperature, salinity, and circulation of the global oceans and how these change over periods ranging from days to decades.

UNESCO: Building the Wealth of Nations