The sensor - called the Space Debris Sensor (SDS) - combines multiple technologies to measure the time, speed, direction, size, and density of objects as small as 50 µm and to collect statistics on objects below 1 mm in size. It will be attached to the ESA Columbus module facing the ISS velocity vector with a one-square-meter microsensor array detection area.
The sensor records the time and scale of impacts using dual-layer thin films, an acoustic sensor system, a resistive grid sensor system, and a sensored-embedded backstop. Data is automatically recorded when an impact occurs and then sent to the ground for analysis.
The data gathered will help measure the trajectories of the debris objects in orbit and provide information about their origins. For example, debris with an elliptical orbit suggests a meteoroid origin, while a circular orbit indicates that it probably came from a satellite.
NASA hopes to collect enough data over the sensor's planned minimum two-year mission to update the NASA Orbital Debris Engineering Model software for objects smaller than 1 mm near ISS altitudes. With lessons learned from the SDS experience, says the agency, a follow-on mission to place a second-generation sensor at higher altitudes will someday enable it to update the risk from small debris to many operational spacecraft in low Earth orbit.
Additional objectives of the SDS are to help define accurate spacecraft shielding requirements to enable effective impact shielding design for future spacecraft constructions. Development of effective spacecraft shielding systems depends on accurate estimates for the abundance and size distribution of orbital debris, and the quantitative information provided by the SDS is expected to improve risk management for the growing number of Earth-orbiting missions.