The PanelSat® system will be designed with two main implementation paths:
a space-qualified version manufactured from radiation-resistant materials (e.g., Ultem 1010), and a ground-based demonstrator using low-cost materials and COTS components. Both share the same functional architecture but serve different purposes and development speeds.
1. Ground-Based Demonstrator
This model is optimized for fast and affordable testing under Earth's gravity. It serves two core demonstration purposes:
Gravity-and Motion-Guided Attitude Control
Without requiring any panels, the suspended satellite model can demonstrate self-alignment and pointing purely through internal mass shifting. The satellite rotates and tilts in response to changes in its mass distribution and mass movement, aligning itself along a virtual thread axis when hung on a thread.
Sensor-Based Light Tracking
When equipped with panels and illuminated by a moving light source, the model can autonomously follow the light by dynamically shifting its internal mass. This simulates orientation changes caused by differential radiation pressure in space.
2. Space-Qualified PanelSat®
The space-grade version is intended for actual space deployment. It is printed in high-performance materials such as Ultem 1010, which offer excellent resistance to thermal stress and radiation.
Before launch, this version can be tested in a vacuum chamber equipped with directional light sources to validate both its radiation-pressure-based panel steering and mass-shifting mechanisms under near-orbital conditions.
Dual Axis Control System
PanelSat® uses two complementary mechanisms for attitude control around its longitudinal (thread) axis:
A. Gravity-Guided Attitude Control
Mass Shifting Units (MSUs) actively displace small weights to shift the satellite's center of mass.
This may causes the system to tilt or to rotate along a virtual gravitational thread.
However, it may be too strong or imprecise for continuous fine adjustments.
B. SoSo-Steering – Switch-On / Switch-Off Panel Control
Each panel is normally oriented toward the Sun to maximize power generation.
Two small solar sensor cells per panel, mounted at opposite angles (e.g., +22.5° and –22.5°), measure sunlight asymmetry.
If the panel is not perfectly sun-facing, one sensor produces more voltage than the other.
The local controller (Arduino Nano BLE Sense) automatically adjusts the panel rotation to equalize the readings, thus maintaining constant solar alignment.
To perform fine control around the thread axis, select panels can be rotated edge-on to the Sun, reducing solar radiation pressure on one side.
This temporary "Switch-Off" creates minute differential torque, allowing precise and slow reorientation.
After adjustment, panels return to full exposure ("Switch-On") to resume power generation.
Each panel operates autonomously:
It measures sensor voltages and orientation data (IMU),
Transmits signals via Bluetooth to the central motor controller in the MotorCase.
This enables decentralized, automatic sun-tracking across the entire structure — no external commands are needed during operation.
Note on Operational Validation
The above-described behavior represents the intended operational concept of PanelSat®.
Whether the interaction of mass shifting and SoSo-Steering can achieve reliable and precise attitude control under real space conditions can only be verified through actual spaceflight testing.
