ANDE-2 (IMAGE) Naval Research Laboratory Caption ANDE-2 consists of two spherical microsatellites, Pollux and Castor, that are both 19" in diameter but have different masses. ANDE-2 is a low-cost mission designed to study the atmosphere of the Earth from low-Earth orbit by monitoring total atmospheric density between 300 and 400 km altitude. Credit NRL photo Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.