Overview
Dates: November 2020 to Present
MoonRanger is a robotic lunar rover that will be flying the to Moon in 2022 to search for water on the South Pole. This is a cooperative science mission between Carnegie Mellon University, NASA, and Astrobotic. Its mission will last 2 weeks on Earth (one Lunar day), and will land on the Moon with Masten’s XL-1 lander. MoonRanger will be the first lunar rover to autonomously navigate through lunar craters in semi-darkness. It will also be the first rover to search for water on the Lunar South pole.
My Role
I joined the MoonRanger project in November of 2020. My primary focus has been development of various software modules, including the rover kinematics, rover executive, and flight software architectures. I also was able to practice my love of PCB design working with the avionics team. I designed a PCB that enables peripheral Wi-Fi communication with the Masten lander. I also designed a board that will provide power and heat sinkage to our IR dot projector, which allows MoonrRanger to see in the dark.
As of September 2021, I have become the lead software engineer for state estimation, which aims to localize the rover during its trek at any point.
Process
Software
I developed a 3D, 6 degree of freedom kinematics model for the robot in order to improve MoonRanger’s pose estimation abilities. The earliest development version is not a trade secret and therefore shown on my GitHub. I implemented this in C++ and then assembled a ROS node for integration with the development system. I also worked closely with the software leads to apply top-down systems engineering processes to develop the flight software system architecture. As of this writing, our flight software design is almost ready for implementation, and we are using the architecture to determine how we will use NASA’s Core Flight System (cFS) on our main computer.
The state estimation software uses an Extended Kalman Filter variant to track the orientation of the vehicle using the IMU. The translation is estimated using wheel data and a visual odometry solution. We implemented all of this in C.
Hardware
I designed a board that houses the Texas instruments CC3200 Wi-Fi transmitter chip. This board enables an RS422 communication bus with our central computer, and also utilizes an RF switch to swap between two antennas. I also designed a board that supports an infrared dot projector device, proving power, current limiting, and thermal management to support continuous operations in frigid operating temperatures.
Outcome
The rover project is ongoing, stay tuned for future updates!