NAND flash storage technology for mission-critical space applications

For more than 10 years, mass memories for space applications have taken the DRAM technology family as conventional semiconductor storage technology. DRAM technology is very fast, reliable, and provides a very high data rate, but needs power back up to retain data and tends to become very inefficient (on a watt/bit scale) with increasing capacity. This is why flash technology has been considered for replacing the well-established DRAMs. NAND flash is currently the most suitable solution for nonvolatile storage in embedded applications and it is gaining access to in safety critical applications, thanks to their high storage density, low power, low cost, and high data throughput. However, NAND flash research and literature in the safety-critical environment is not as established as in the commercial applications. As a matter of fact, for the specific case of space applications, NAND flash is struggling to keep pace with those advances for multiple reasons. This article provides an overview of these reasons. We discussed the most relevant design aspects to address when dealing with NAND flash memory for the critical space environment. Furthermore, the Sentinel-2 practical example lets the reader experience the advantages of adopting a NAND flash-based SSMM as opposed to a SDRAM-based device. In conclusion, if properly designed, NAND flash currently represents the most suitable candidate as future semiconductor storage technology of upcoming mass memories for space applications.