Aura (EOS CH-1)
|Mission type||Earth Observation|
|Launch date||July 15, 2004 10:02:00 UTC|
|Launch vehicle||Delta II|
|Launch site||Vandenberg AFB|
|Mass||2,970 kg (6,550 lb)|
|Apoapsis||688 km (428 mi)|
|Periapsis||684 km (425 mi)|
|Orbital period||98.5 minutes|
Aura (EOS CH-1) is a multi-national NASA scientific research satellite in orbit around the Earth, studying the Earth's ozone layer, air quality and climate. It is the third major component of the Earth Observing System (EOS) following on Terra (launched 1999) and Aqua (launched 2002). Aura follows on from the Upper Atmosphere Research Satellite (UARS).
In formation, in a "train" 
all satellites having an equatorial crossing time at about 1:30 in the afternoon.
Aura carries four instruments for studies of atmospheric chemistry:
- HIRDLS — High Resolution Dynamics Limb Sounder — measures infrared radiation from ozone, water vapor, CFCs, methane and nitrogen compounds. Developed jointly with the United Kingdom Natural Environment Research Council. The HIRDLS chopper shutdown on March 17, 2008 and has not produced science since.
- MLS — Microwave Limb Sounder — measures emissions from ozone, chlorine and other trace gases, and clarifies the role of water vapor in global warming.
- OMI — Ozone Monitoring Instrument — uses ultraviolet and visible radiation to produce daily high-resolution maps. Developed by the Finnish Meteorological Institute and the Netherlands Agency for Aerospace Programmes.
- TES — Tropospheric Emission Spectrometer — measures tropospheric ozone in infrared wavelengths, also carbon monoxide, methane and nitrogen oxides.
See also