Abstract
The current state of miniaturization already enables cost-effective space missions in the CubeSat format. Continued advances are pushing research toward even smaller femto-satellites. However, such highly miniaturized systems cannot be realized by simple geometric down-scaling; conceptually novel approaches are required. In this paper, we investigate the feasibility of a lensless star tracker as a selected subsystem for integration into foil-based femto-satellites. We implement a hardware-in-the-loop (HIL) setup that employs a low-cost image sensor (OV5647) with an added diffuser tape for image capture and a Raspberry Pi 5 single-board computer with a Full-HD display for pattern generation. Experimental results show that the system can successfully reconstruct star-like patterns and achieves an angular resolution of approximately 0.05°. Although this is above the accuracy of high-end star trackers \left(\leq 0.01^{\circ}\right) , the lensless approach offers advantages in mass, cost, and radiation tolerance. Moreover, its wide-angle characteristics may allow operation with a smaller star catalog. These findings confirm the viability of lensless imaging for spaceborne attitude determi-nation and provide a practical testbed for further investigations.