Ewellix planetary roller screw lands on Mars
10 June 2021
Ewellix standard planetary roller screw evolved into a unique component to help test for signs of ancient life on Mars.
Ewellix has developed and manufactured a planetary roller screw that recently landed on Mars as part of NASA’s Mars 2020 Perseverance Rover Mission. Ewellix engineers worked in collaboration with NASA’s Jet Propulsion Laboratory (JPL) at the California Institute of Technology to develop a roller screw component for the Perseverance Rover that would be robust enough to withstand the extreme conditions of outer space and Mars, which can reach -80°C.
After a 203-day journey, the Perseverance Rover, the largest and most advanced rover NASA has sent to another planet, has touched down on Mars to search for signs of ancient microbial life. The Rover’s mission is to collect Martian rocks, extract and seal samples for testing and onboard storage. The mission team of NASA scientists will then decide when and where the Perseverance Rover will leave the samples for pick up by a future mission in approximately 2031, to bring them back to Earth for detailed analysis.
Ewellix’s planetary roller screw is housed inside the sealing station on the base of the Perseverance Rover and will generate the high force required to hermetically seal the 43 sample tubes on board. The Rover has a small servo motor that drives the roller screw nut. This rotational movement is converted into a linear displacement that pushes on a ram, which in turn presses the seal inside the open end of the sample tube with extremely precise force, speed, and position.
It was critical to save mass on the Rover and Ewellix’s roller screw provided a tremendous amount of force load in a small mechanism, making it an ideal rover component for load rating and weight. Other benefits are long service life by design, high reliability, and the ability to withstand frequent changes of loading direction, high linear speed, and some amount of contamination.
Ewellix’s planetary roller screw is a fully customised version of a standard SR/HR planetary roller screw product. All parts and materials have been adapted for the unique conditions through extensive analysis and testing. Adaptations include aerospace-grade materials and heat-treatment operations provided by suppliers with aerospace certifications.
This unique planetary roller screw took several years to develop, prototype, manufacture and test, from concept exploration to system validation, where one of the final product samples Ewellix provided was selected for the Mission. Extensive system testing including the roller screw was performed at JPL in California.
Jean-Pierre Collognat, Project Lead and Business Development Manager at Ewellix, explains some of the challenges of the project: “There were certainly some firsts for us along the way, due to challenging application conditions and environment, and the need to downsize our components as much as possible to reduce space and weight, yet still optimise the load rating and reliability. Plus, all materials have to work at all times at extremely low temperatures, hence all of the components materials were subjected to specific heat treatments.
“Ewellix has taken precision engineering and manufacturing to new levels on this incredible project, showing how a catalogue mechanical product can evolve into a unique component for use, quite literally, in another world.”
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