Revising satellite reentry design to mitigate orbital debris risks

In a controlled environment at the University of Stuttgart's High Enthalpy Flow Diagnostics Group (HEFDiG), a significant experiment is taking place. A reaction wheel, critical for adjusting a satellite's orientation in space, is being tested under simulated reentry conditions using a plasma wind tunnel. This device, capable of generating arc-heated gas streams at speeds of several kilometers per second, mimics the intense conditions of atmospheric reentry. Simultaneously, the reaction wheel is rotated to emulate the tumbling motion of satellites as they return to Earth.

Collins Aerospace in Germany, a long-time participant in Design for Demise (D4D) activities, has made key modifications to their TELDIX reaction wheel to enhance its demisability during reentry, aiming for a controlled disintegration.

The importance of such technologies was highlighted during this year's Space Mechanisms Workshop at ESA's ESTEC technical center. Attended by over 130 experts from European industry and academia, the workshop examined the growing challenge of orbital debris. Geert Smet, workshop co-organizer, emphasized the need for effective satellite mechanisms that can fully disintegrate upon reentry, thus reducing the risk of debris surviving the descent and posing threats on the ground.

Current efforts in D4D primarily focus on components such as reaction wheels and solar array drive mechanisms. However, plans are in place to extend these practices to all satellite mechanisms in the future.

Highlighting the tangible dangers, the workshop revisited an incident from 1997 when a woman in Oklahoma was struck by a piece of debris from a Delta II stage. Future strategies might consider keeping parts of a satellite together to reduce the ground footprint and impact risk if total disintegration isn't feasible.

Additionally, the workshop detailed new initiatives by ESA and various industry leaders to actively remove debris by deploying dedicated spacecraft to capture and safely deorbit defunct satellites. This approach underscores the critical role of specialized mechanisms in the ongoing battle against space debris.

Co-organizer Kobye Bodjona concluded by stressing the importance of complying with stringent debris mitigation regulations, particularly as satellite launches become more frequent.