Radiation-Hardened FPGA

Radiation-Hardened FPGAs (Field-Programmable Gate Arrays) are reconfigurable integrated circuits designed to operate reliably in the intense radiation environments of Earth orbit, cislunar space, and interplanetary trajectories.

In space, silicon electronics are bombarded by energetic particles from solar wind, galactic cosmic rays (GCR), and trapped radiation in planetary magnetospheres (Van Allen belts). These particles cause three primary failure modes: Single Event Upsets (SEU) - bit-flips in memory and logic cells; Single Event Latchup (SEL) - destructive high-current states; and Total Ionizing Dose (TID) degradation - cumulative damage that degrades transistor performance over mission lifetime.

Kepler Nav's Kalam Gen 1 silicon engine implements radiation hardening at the architectural level rather than relying solely on radiation-hardened manufacturing processes (which are expensive and generations behind commercial nodes). The key techniques include:

Triple Modular Redundancy (TMR): Every logic cell is triplicated, and a majority voter circuit masks single-bit upsets. This provides SEU immunity without requiring rad-hard foundry processes.

SRAM ECC Controllers: All on-chip memory uses Error-Correcting Code with continuous scrubbing, detecting and correcting multi-bit upsets in configuration memory.

The Kalam architecture is validated for Total Ionizing Dose resistance up to 100 krad(Si) - sufficient for 15+ year missions in Medium Earth Orbit or 5+ year missions in interplanetary space. The FPGA fabric allows in-orbit reconfiguration of navigation algorithms, enabling mission-adaptive software updates without hardware replacement.