The Earth Orbiter 1 satellite was part of NASA's New Millenium Program. Complementing the New Millenium's Deep Space series, EO-1 was a NASA-Goddard satellite which demonstrated technology for the next generation Landsat. It flew in formation with Landsat-7 for comparison purposes, using a hydrazine thruster to adjust its orbit. The satellite used a MIDEX-derived bus built by Swales Aerospace; dry mass was 566 kg. The main instruments were ALI (Advanced Land Imager) and the Hyperion 220-band imaging spectrometer.