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Searching for Other Earths

Fall 2015Sara Seager on how — and why — we look for exoplanets

Opening Space with a ‘Transorbital Railroad’

Fall 2010Robert Zubrin

Satellites at Risk

The Next Homeland Security Challenge May Be in Space

Spring 2003

The New Face of War

Summer 2003David Skinner on whether new technologies make war more tolerable and more just

The Future of Satellites

New Problems and New Players in the Satellite Game

Fall 2003

China’s Space Ambitions—And Ours

Spring 2007Jeff Kueter on the Chinese threat to American space assets and what to do about it

China’s Aims in Space; Debating Nanoethics

Summer 2007


Blog Posts

New satellite to study oceans

Joint U.S.-French mission
May 26, 2008

A joint U.S.-French satellite project announced by NASA this week will track trends in sea levels and the climate. The satellite, which will be launched on June 15, 2008, will help scientists look at the world’s ocean circulation and its links to the Earth’s climate over the next decade.

The Ocean Surface Topography Mission (OSTM)/Jason 2 is a partnership of NASA, the National Oceanic and Atmospheric Administration (NOAA), the French Space Agency Centre National d’Etudes Spatiales (CNES), and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT).

Measurements by past satellites have shown that the mean sea level has risen by about 0.12 inches a year since 1993, twice the rate estimated from tide gauges in the past century, according to the NASA press release -- although “15 years of data are not sufficient to determine long-term trends.”

The oceans, which cover more than 70 percent of Earth’s surface, have a huge impact on Earth’s weather and climate. “Earth’s oceans serve as a thermostat for our planet, keeping it from overheating,” NASA says in its description of the satellite (click here for a PDF). “More than 80% of the heat from global warming over the past 50 years has been absorbed by the oceans. The rate of sea level change allows scientists to estimate how much of this heat the ocean is storing. Scientists want to know how much additional heat the oceans can absorb, and how that absorbed heat affects our global atmosphere.”