Current Orbit Determination (OD) solutions for CubeSats generally rely on onboard GNSS or ground-based tracking, which can be costly and complex. Argus is a 1U CubeSat that addresses these challenges by demonstrating a low-cost, autonomous, vision-based onboard OD system, addressing the lost-in-space problem for small spacecraft. Two identical Argus CubeSats are scheduled to launch this July aboard SpaceX Transporter-17.

Onboard cameras capture photos of the Earth that inference models use to detect a given region, classify landmarks, and produce bearing measurements. These measurements are then processed in tandem with the output of an inertial measurement unit through a batch nonlinear least squares estimator to determine orbit and attitude over a given time frame. The OD results are evaluated against an onboard GNSS receiver used as a reference.

In addition to OD, the satellite will also carry out two secondary experiments. The first experiment will study ground-based orbit determination through Doppler measurements obtained from GMSK signals, with the goal of determining how signal characteristics such as SNR, bandwidth, and duty cycle affect orbit determination precision. The second experiment will test an amateur radio packet repeater.

The satellite’s avionics are designed around a fully open-source hardware and software stack built entirely from commercial off-the-shelf components. A low-power Raspberry Pi RP2350 microcontroller serves as the onboard computer for low-level control, housekeeping, and system management, while an NVIDIA Jetson Orin Nano provides high-performance onboard compute for camera interfacing, vision model inference, and batch least-squares orbit determination.

The Argus CubeSat mission is being carried out in a joint effort between the Carnegie Mellon Nanosatellite Lab and the Instituto Superior Técnico NanoSatLab. The mission is entirely student-built. Development is primarily conducted in the context of CMU’s “Spacecraft Design-Build-Fly” graduate-level course, serving an educational purpose and more broadly contextualizing technical work on the satellite. This mission demonstrates a low-cost, reproducible approach to deploying advanced onboard autonomy and optical navigation capabilities on resource-constrained CubeSat platforms.