Rapid mechanism proven in practice
At the Thales Alenia Space workshops in Turin, a full‑scale model of the ExoMars lander unit demonstrated the automatic unfolding of its four legs. The pairwise deployment occurs after jettisoning the forward heat shield and takes less than one second. The system uses non‑explosive actuators, which operate without pyrotechnic charges and thus significantly reduce shock loads on the other subsystems.
Design and purpose
The tested legs match the structure and dimensions of the flight hardware planned for 2030. During the cruise phase they remain compactly stowed; they are only deployed during descent. Fast and synchronous extension is functionally necessary: wind loads, aerodynamic forces and thrust phases change rapidly in the final approach. A delayed or asymmetric deployment could overload damping elements or jeopardize landing stability.
Role at touchdown
The landing legs work in concert with parachutes and retrorockets. They absorb the remaining kinetic energy and compensate for irregularities of the often rocky, sloped Martian surface. Elastic supports and integrated dampers limit loads on the structure and payloads—crucial for protecting the Rosalind‑Franklin rover.
Advantages of non‑explosive actuators
Actuators without pyrotechnic charges allow repeated functional checks on the ground and reduce the risk of activation errors. At the same time they lower shock and vibration peaks, increasing the reliability of sensitive electronics.
Industry partnership and test campaign
Thales Alenia Space leads the industrial partnership, and Airbus is involved in the lander unit. The landing legs were developed and manufactured by the Spanish company Sener. Test campaigns—mechanical, thermal and functional—are being conducted in close coordination among the partners. Further steps include vibration tests, thermal cycling and simulations of deployment under reduced environmental conditions; the results will feed into redundancy concepts and release approvals.
Technology transfer
Low‑shock latches, compact stowage concepts and non‑explosive actuators are also being used in Earth‑orbit applications, for example in antenna and solar array deployments. This saves mass and increases operational lifetime—a particular advantage for environmental and climate satellites.
Outlook
The Rosalind‑Franklin rover touchdown is targeted for 2030. The successful Turin test boosts confidence in a central mechanism of the descent architecture and reduces risks for the critical final phase before touchdown.