A Five Year Mission

The Active Cavity Radiometer Irradiance Monitor satellite, (AcrimSat) has completed its five-year primary mission successfully. The satellite was launched in December 1999 to study how solar energy affects the weather and climate here on Earth.

The Acrim III instrument on board the spacecraft is the third of a series of solar monitoring tools built by NASA's Jet Propulsion Laboratory in Pasadena, California. The instrument measures solar irradiance and how it impacts Earth's winds, land and oceans.

"The satellite's measurements of total solar irradiance have been the most precise ever collected," said Roger Helizon, AcrimSat project manager/scientist at JPL. "The mission has provided a wealth of data for its relatively small cost of 30-million dollars."

Data from the instrument is used to create global climate models and to study solar physics. When Venus passed between the Earth and Sun in June 2004, AcrimSat measured a drop in the solar energy equivalent to all the energy used by humans in 2003.

FMI: http://acrim.jpl.nasa.gov