CubeSat (Student Satellite Program)

Overview

Led the programming team for BeliefSat, a student-built 2P PocketQube-class nanosatellite developed at K. J. Somaiya Institute of Engineering and Information Technology.

The project focused on demonstrating that a functional satellite could be built using constrained hardware and commercially available components. The satellite was designed around a custom open-source architecture, with an indigenous deployer called *SomaiyaPod- developed alongside it.

My Work

Flight Firmware

Directed and developed the firmware running on the satellite's onboard computer.

A major constraint was the extremely limited memory available on the flight computer. Instead of relying on feature-heavy libraries, we inspected the underlying sensor libraries and header files and implemented only the functionality required by the mission.

This required treating memory as a first-class engineering constraint and making deliberate tradeoffs between functionality, reliability, and resource usage.

Autonomous Camera Safety

Designed an optical safety algorithm for the satellite's camera.

The satellite was intended to capture images periodically, but pointing the camera toward the Sun could damage the sensor. There was no conventional way to determine the spacecraft's orientation precisely enough for this purpose.

The solution used eight light sensors positioned around the satellite. By comparing their readings and identifying the three brightest sensors, the firmware could estimate the general direction of incoming light and determine whether the spacecraft was oriented safely enough to capture an image.

Satellite Stabilization

Worked on the approach for stabilizing the satellite's orientation in orbit.

The design used *two perpendicular permanent magnets- to interact with Earth's magnetic field and constrain the satellite's orientation along an axis. Passive damping was also used to reduce rotational motion around that axis over time.

Deployer & Systems Engineering

The project had limited funding for research and development, making it difficult to compete with teams focusing heavily on sophisticated payloads.

Rather than competing purely on payload capability, our team developed SomaiyaPod, an indigenous PocketQube deployer designed to deploy the satellite into orbit. The deployer became a central part of the project's technology demonstration and differentiated the team's proposal.

BeliefSat was subsequently selected as part of ISRO's *PS4-Orbital Platform- program and was launched in 2025. The original camera subsystem was ultimately not part of the launched configuration.

Engineering Constraints

The project required solving hardware and software problems with limited resources:

• Extremely constrained onboard memory
• Commercial off-the-shelf sensors and components
• Limited funding for R&D
• Autonomous operation without direct human intervention
• Power, thermal, communication, and reliability constraints
• Designing firmware around the exact capabilities required by the mission

The satellite architecture included telemetry, watchdog-based recovery, power monitoring, communication subsystems, and automatic safeguards for conditions such as low battery voltage, thermal events, and controller failures.

Technical Details

BeliefSat was designed as a *2P PocketQube- with a 58 × 128 × 50 mm satellite body and an estimated mass of approximately 450 g.

The onboard software was responsible for functionality including:

• Periodic telemetry transmission
• Sensor data collection
• Satellite command handling
• Watchdog-based fault recovery
• Automatic operating-mode changes based on battery conditions
• Communication subsystem control
• Autonomous mission logic

The project also used an unusual PCB-based structural design rather than a conventional aluminium satellite structure. The PCBs incorporated solar cells and other components directly into the satellite structure, reducing assembly complexity.

Links

• BeliefSat GitHub Repository
• BeliefSat Technical Documentation