Making Contact: A Review Of Robotic Attachment Mechanisms For Extraterrestrial Applications

The space environment offers unique challenges for robotic grippers and controllable attachment mechanisms. Applications include satellite and orbital debris capture, perching for free-floating robots inside the International Space Station, climbing rocky surfaces in planetary exploration tasks, and grasping asteroids and other rough substrates for drilling and sample collection operations. Many traditional adhesive technologies, such as pressure-sensitive adhesives, suction, and electromagnetism, are not tenable in the space environment due to the lack of an atmosphere (e.g., pressure-sensitive adhesives outgas and suction requires a pressure differential) or suitable substrates (e.g., materials for space applications are rarely ferromagnetic). Instead, a number of other technologies have shown promise for space, including bio-inspired fibrillar dry adhesives that offer controllable adhesion on both flat and curved smooth surfaces, electrostatic adhesives that work on smooth surfaces but also rougher surfaces and fabrics, and microspines for rocky and rough substrates. Herein, a review of these technologies, focusing on their operation and providing examples of the technologies applied to space and other extraterrestrial missions is presented.