July 21, 2020
This summer, NASA’s newest Mars rover, Perseverance, is expected to take off for the red planet. SNC provided eight unique components that have been used in 17 applications on the rover. They’re used in the robotic arm, turret coring drill and caching assembly.
According to NASA, its Perseverance rover will, ‘look for signs of past microbial life, cache rock and soil samples and prepare for future human exploration’. It’ll be doing all of that with the help from crucial components Sierra Nevada Corporation (SNC) developed for the mission.
NASA’s Curiosity rover, which is currently on Mars, can only drill and analyze the dust of rocks. Perseverance will drill into rocks and take a core sample from them. The ability to take and process these samples, and prepare them for a future return mission, lies at the heart of this mission.
SNC’s eight components will directly help with the drilling and processing of those critical samples.
We caught up with SNC mechanical engineer, Dave, to explain them to us.
SHACD Gearmotor- SHACD stands for ‘sample handling arm, bit carousel and tube drop-off’. Without the function of this gearmotor, Perseverance would not be able to process the samples taken from the surface of Mars.
SAS Gearmotor- SAS stands for Sealing and STIG (Spindle Twin Input Gearing). The SAS gearmotor helps seal the sample handling tubes. If they aren’t sealed, they could get contaminated, contaminating important core samples in the process.
Another service the SAS gearmotor provides is the ability to shift the drill’s torque modes. This is similar to switching modes on your drill at home.
Lastly, without this gearmotor, Perseverance’s helicopter would not be able to deploy. The helicopter will be sent on scouting missions, directing the rover to new locations from above.
Chuck Gearmotor- The Chuck gearmotor allows for the rover to change drill bits depending on the type of rock that it’s drilling into. This is similar to the way a chuck is used to secure and release bits in a homeowner’s drill.
Feed Gearmotor- When the rover is drilling into a rock, this gearmotor feeds the drill in and out of the rock. It also holds the entire drilling assembly in place during launch and landing by acting as a lock. If the drill assembly were to move during those times, the drill would hit the aeroshell, preventing it from descending to the surface of Mars.
Percussion Gearmotor- This gearmotor is the driving factor behind the percussion mechanism in the turret coring drill. The percussion mechanism is like a jackhammer for the drill. Without the percussion gearmotor, the drill bit wouldn’t be able to drill into harder rocks.
ShEl Gearmotor- ShEl stands for ‘shoulder and elbow.’ It’s used in the rover’s robotic arm to help it move up and down and left to right. The SHEL gearmotor helps move the robotic arm to gather samples and make scientific measurements.
WAT Gearmotor- WAT stands for ‘wrist and turret’. This gearmotor is used in the rover’s robotic arm to help it twist and turn the drill turret. The WAT gearmotor helps move the robotic arm to gather samples and make scientific measurements.
Spindle Gearmotor- This is the core of the rover’s drill mechanism and part of the spindle twin input gearing (STIG) mechanism. The Spindle gearmotor actually spins the drill bit and breaks off the rock samples that will eventually be sent back to Earth to study.
This gearmotor is the most unique of all the SNC gearmotors. It has outputs to both spin the drill bit and break off core samples. Both of these outputs spin simultaneously, although the rover has the ability to select which one it wants using the SAS gearmotor along with a shifting mechanism.
The Spindle gearmotor had to be designed to withstand all the percussive forces and survive if a drill bit were ever to get stuck while drilling a rock, which creates very high torques.
NASA wanted to be able to start drilling early in the morning on Mars, when it is very cold, so SNC had to make sure the grease inside the gearmotor didn’t turn solid and could still spin at -94°F.