This article presents ERB, the ESA Ravenscar Benchmark. ERB aims at providing a synthetic benchmark comparing the efficiency of various Ada Ravenscar implementations and the RTEMS C implementation featuring the native threading model. ERB is original compared to existing Ada benchmarks, such as the ACES or the PIWG, not only because it is the first Ada Ravenscar benchmark, but also because it provides at the same time measurement of exe- cution times and estimate of the memory footprint of the Ada runtime and stack size requirements. ERB intends to become the standard benchmark for embedded Ada Ravenscar applications. To facilitate this, the European Space AgencAdaCore plan to release it under the GNU GPL to interested third parties.