Drag-Enhancing Deorbit Devices for Mid-Sized Spacecraft Self-Disposal

The benefits and uses of drag devices for self-disposal of mid-sized spacecraft (~400 kg) in low Earth orbit are analyzed in this paper. Our analysis suggest that drag devices are well suited for small as well as for mid-sized spacecraft. The suitability and feasibility of drag devices for small spacecraft (<50 kg) is already well established. However, the use of drag devices for mid-sized spacecraft has not yet received the same level of attention. Here we show that for mid-sized spacecraft only moderate increases in cross-sectional areas, in the order of ten square meters, are required to reduce the orbital lifetime below the prescribed 25-year limit. Drag devices with such areas have been demonstrated, albeit not on mid-size spacecraft. Furthermore, these devices would offer attractive options to either offset fuel reserved for deorbit operations, or to extend mission life. In addition to the potential fuel-mass savings, drag devices can also offer other system-level advantages which we articulate. In order to advance the technology readiness level for use on mid-size spacecraft, we offer a conceptual design of a modular drag device integrated on a mid-size spacecraft. We chose an existing spacecraft (NASA's EO-1), whose operators were faced with the difficult decision to deorbit with remaining fuel on-board or extend mission life. We posit, and demonstrate with a realistic conceptual design, that a modular drag device could have allowed the desired life extension and enabled self-disposal.