DURHAM – When NASA launches its 2020 Mars Rover Perserverance Thursday, July 30, it will include eight components used with 17 applications developed by the Sierra Nevada Corp’s (SNC) Durham office.
Sierra Nevada Corporation (SNC) is a privately-owned defense contractor (by a husband and wife team who are originally from Turkey), with an aerospace division based out of Louisville, Colorado.
This is not the SNC Durham operation’s first space rodeo. The 55-person Durham office has developed actuators and other components for almost all the Mars Rover missions, including for the Curiosity Rover currently on Mars. Altogether, SNC has participated in 14 NASA Mars Missioncounting this one.
Charlie Hughes, program manager at the SNC Durham office, is a North Carolina State University engineering grad and says about half the staff has been recruited from NC State.
One of Mars 2020’s main missions is to drill for rock and soil samples to send back to Earth, and it wouldn’t be able to do without the components SNC developed.
The eight components designed and built in Durham are used in the robotic arm, turret coring drill and caching assembly.
A SELF-DRIVING CAR ON MARS
Perseverance is different from previous Mars Rovers in a number of ways. Curiosity rover 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.
[In the video, the SNC SAS gearmotor built in Durham is causing movement from 0:56-1:06.]
Perseverance will spend its days drilling the Jezero Crater, an ancient Martian river delta, and the samples it collects may contain the first evidence of extraterrestrial life.
Perseverance, more autonomous than previous Rovers, has been described by a NASA robotics engineer as “as self-driving car” on Mars. It has a dedicated navigation computer to aid its movements. The distance between Mars and Earth means signals take 22 minutes one-way, which makes navigating from Earth clumsy and inefficient. For it to accomplish its primary mission in a year, its self-navigation will be critical.
Perseverance faces a busy schedule. It will launch a helicopter, do its sample collections, and find a spot to store them on Mars for collection by another mission about 2026.
THE EIGHT COMPONENTS MADE IN DURHAM
An engineer at Durham’s office provided these descriptions of the components the Durham office designed and built:
- 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.
[More Durham-made components are featured in this video above: Feed gearmotor is being used from 9:26-9:33, the SHACD is again being used from 9:44-9:53.]
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.
SNC is probably is best known for building the Dream Chaser spaceplane, an autonomous spacecraft that will launch to the International Space Station for NASA, delivering cargo and science experiments.
The Durham SNC office is also building components for Dream Chaser that help its wings deploy and lock into place on orbit and that move the flight control surfaces during reentry.
Dream Chaser also lands on a runway, much like the shuttles, and is reusable up to 15 times.
The launch window opens in late 2021. The Durham SNC office is also building components for Dream Chaser that specifically help its wings deploy on-orbit.
Original Article Source: WRAL TechWire