The question of soft proton scattering efficiency under grazing angles raised in 1999 quickly after the Chandra X-ray observatory was launched. Since then, measurements could confirm a reduction of the large discrepancy between soft proton radiation effects seen in orbit and simulations. Nevertheless, a complete experimental coverage of the relevant parameter space is still pending.
Experimental and theoretical advancement in this field as well as validation and a possible extension of simulation codes are part of the currently running EXACRAD project, which is funded by ESA. Its major goal is to provide the foundations for the thorough assessment of the charged particle background of the upcoming ATHENA X-ray observatory. This contribution will summarize the soft proton measurement results so far, highlight the short-term plans for extending the experimental coverage, and draw comparisons between experimental and simulation results.