Active Cavity Radiometer Irradiance Monitor Satellite

ACRIMSAT is the acronym for Active Cavity Radiometer Irradiance Monitor Satellite. It is a dedicated satellite and instrument that is one of the 21 primary observational components of NASA's Earth Observing System program. Acrimsat was launched on 20 December 1999 from Vandenberg Air Force Base as the secondary payload on a Taurus rocket along with KOMPSAT and placed into a high inclination, 700 km. sun-synchronous orbit where it's ACRIM3 instrument continues the long-term monitoring of the total solar irradiance (TSI).

The ACRIM3 instrument has made state of the art measurements of the TSI since the start of its Science Mission in April of 2000. It extends the TSI measurement database begun by earlier ACRIM instruments on the NASA Solar Maximum Mission (1980-1989) and Upper Atmosphere Research Satellite (1991-2001). ACRIMSAT/ACRIM3 tracked the TSI during a 2004 transit of Venus, and measured the 0.1% reduction in the solar intensity caused by the shadow of the closer planet. [cite journal| author=G. Schneider, J. M. Pasachoff, and Richard C. Willson|title=The Effect of the Transit of Venus on ACRIM's Total Solar Irradiance Measurements: Implications for Transit Studies of Extrasolar Planets|journal=The Astrophysical Journal| volume=641|pages=565–571|year=2006| url=http://www.journals.uchicago.edu/cgi-bin/resolve?doi=10.1086/500427|doi=10.1086/500427|format=dead link|date=June 2008 – ^{[http://scholar.google.co.uk/scholar?hl=en&lr=&q=author%3A+intitle%3AThe+Effect+of+the+Transit+of+Venus+on+ACRIM%27s+Total+Solar+Irradiance+Measurements%3A+Implications+for+Transit+Studies+of+Extrasolar+Planets&as_publication=The+Astrophysical+Journal&as_ylo=2006&as_yhi=2006&btnG=Search Scholar search]} ]

Richard C. Wilson (Columbia University) is the principal investigator for the mission and leads the Science Team. The ACRIMSAT group at the Jet Propulsion Laboratory (JPL), led by the JPL Mission Manager and Instrument Scientist, Roger Helizon, designed and built the ACRIM3 instrument and operates the ACRIMSAT/ACRIM3 mission via the ACRIM tracking station at the JPL Table Mtn. Observatory.

ACRIMSAT (international designator 1999-070B) is a spin-stabilized, single-purpose satellite constructed by Orbital Sciences Corporation. The end-to-end cost of the ACRIMSAT satellite, the ACRIM3 instrument, launch, ground station, operations and the science team activities during its 8 year mission to date has been less than $30 million - a good example of the efficacy of NASA's 'Better, Faster, Cheaper' initiative. .

References

External links

* [http://acrim.jpl.nasa.gov ACRIMSAT Project homepage]
* [http://www.acrim.com ACRIM Science Team homepage]
* [http://www.sciencedaily.com/releases/2005/05/050523153719.htm Press report at end of primary mission]
* [http://eospso.gsfc.nasa.gov/eos_homepage/mission_profiles/docs/ACRIMSAT.pdf Fact sheet on the mission]