Thermospheric Density Fluctuations Derived from the Atmospheric Neutral Density Experiment Missions

The Atmospheric Neutral Density Experiment (ANDE) flights consists of four spherical microsatellites launched in pairs in 2006 (ANDERR) and in 2009 (ANDE2). The primary scientific objectives of the ANDE flight is to monitor total neutral density along the orbit for improved orbit determination of resident space objects. The missions consisted of two spherical spacecraft fitted with retro-reflectors for satellite laser ranging (SLR). Each spacecraft contained a small lightweight payload designed to determine the spin rate and orientation of the spacecraft from on-orbit measurements and from ground based observations. The laser ranging data was combined with the radar observations and processed to generate SLR augmented orbit determinations. Thermospheric density fluctuations were then derived from these orbit determinations. This paper presents the observed thermospheric density fluctuations spanning the time period from 2006 to 2010. A comparison of these data with thermospheric models, solar and geomagnetic drivers as well as other neutral density measuring techniques is presented.