Spaceflight application of a high performance (high rate, high capacity) erasable optical disk recorder is discussed. NASA has estab-lished a program to develop an optical disk recorder focused on use aboard the unmanned polar orbiting Earth Observing System plat-forms. An expandable modular system concept is proposed consisting of multiple drive modules and a modular system controller. A drive contains two 14 inch magneto-optic disks and four electro-optic heads each con-taining a nine-diode solid state laser array (eight data tracks, one pilot track). The performance goals of the drive module are 20 gigabyte capacity, 300 megabit per second transfer rate, 10x(Exp-10) corrected BER, and 100 millisecond access time. The system goals are 120 gigabyte capacity at up to 1.8 gigabits per second rate, concurrent I/O, varying data rates, reconfigurable architecture, and 2 to 5 year operating life in orbit. The system environment and operational scenarios are presented.