During the transportation of any sample material, it is important to ensure that no damage or contamination of the sample occurs while in transit. This concept is extremely important within the sample caching rover sample return architecture. Adequately sealing the sample tubes is important because inorganic contamination of sample material will affect any potential science experiment upon return.
Torque plug sample tube seals have been specifically designed for the Mars sample return campaign that aims to collect Martian rock cores and return them to Earth for scientific study. Expanding torque plug sample tube seals will work to protect the Martian rock cores from varying types of gases that may leak into the sample tubes during the mission. These plugs work by expanding to close the void between the sample tube and the torque plug housing.
The torque plug actuator is comprised of a motor encoder/gearbox combination that produces 20 N·m of torque. The torque is transferred to the torque plug via an output drive shaft and torque reacting components. The hex key is driven by the output shaft, which interfaces to the torque plug and actuates it.
A torque plug actuator for sealing 1-cm-diameter tubes has never been designed and tested at Mars temperature and pressure. This actuator also can be used in sealing biological samples, pressurized liquids, or underwater samples.