In this work a chaincode-based lossy compression algorithm is designed and implemented specifically for the purpose of encoding particle event images in the context of "Antiproton Flux In Space" (AFIS) mission of the laboratory for rapid space missions. The mission's goal is to launch a small satellite equipped with a novel cosmic particle detection device, previously tested on the ISS, for the purpose of investigating antimatter in earth's orbit. The expected large number of events requires a lossy data compression for the bulk of non-antimatter events, which is what this work tries to solve. The algorithm, called particle chaincode or "paincode" for short, is designed based on the missions requirements which need paincode to feature control over the introduced compression error and to preserve specific important aspects of the data. The encoder is also implemented on AFIS' target platform, an FPGA, with the help of a High-Level-Synthesis framework, allowing C/C++ code to be synthesized to VHDL and integrated into the FPGA's hardware design. The implementation meets requirements, is configurable in two aspects of its compression and error behaviour and has a working realtime-capable hardware implementation. The last section of this work identifies multiple areas of potential future improvement that seem to be promising next steps for future work.