The United States and France plan to launch a new satellite Friday to study rising sea levels on Earth. The Jason 2 spacecraft is due to embark on an Ocean Surface Topography Mission to research changes in Earth's oceans and their links to global climate change. The $433 million spacecraft is intended to pursue a joint mission along with the Jason 1 satellite already on orbit. Jason 1 was launched in 2001 and has been monitoring Earth's seas ever since. The two satellites should be able to cover twice the area that was covered by Jason 1. The major objective of the mission is to measure the sea surface height on a global basis. The new spacecraft is designed to use on board instruments to fire small pulses of light down to Earth and measure the time it takes for them to return. This process should indicate the distance between the satellite and the ocean surface to within an inch or two.