A digital data processing unit for future X-ray observatories

Future space-based X-ray observatories will not only have increased sensitivity and energy resolution but will provide astronomers with high time resolution in the order of microseconds. The detection of millions of single photons per second with their precise energy and their time of arrival will produce unprecedented data rates that cannot be downlinked to Earth in their full extend due to telemetry limitations. We present the study of a very fast, lossless, on-board data compression implemented in an FPGA-based LEON3 microprocessor. We conclude with performance estimates done with a prototype board developed for the High Time Resolution Spectrometer (HTRS) on board the International X-ray Observatory (IXO). We also discuss a possible application of the Data Processing Unit (DPU) for the future X-ray mission Large Observatory for X-ray Timing (LOFT).