Knowledge of missile infrared signature (IRS) is required for the design and performance assessment of Missile Warning Systems (MWS). Missile IRS comes mainly from the plume radiation and depends on the rocket motor features as well as the missile altitude, speed and viewing angle with respect to the sensor. The estimation of speed and altitude dependencies requires simulations in order to complete ground detailed measurements. ONERA developed a chain of simulation tools called PRECISE to achieve infrared signature prediction. The multi-disciplinary project SIMBA2 (acronym for Ballistic Missile Signature in French) was setup to validate simulated results by comparison with experimental results. Several trials were conducted featuring a solid rocket motor inside a supersonic annular free stream, in order to simulate the effect of a Mach 2 flying missile on the plume. The LP13 motor solid propellant contained no aluminum so as to get an alumina particle-free plume. A Medium-Wave and a Long-Wave Infrared (MWIR and LWIR) multispectral cameras and a MWIR spectrometer recorded the trials with and without free stream. In order to pre-calibrate all optical instruments, IRS plume simulations were performed on existing alumina-free plumes: - Static CRV7-C15: the plume was computed by DLR (German Aeronautic Research Center) with REP code as a NATO test-case - Dynamic CRV7-C15: the plume was computed by ONERA with REP code with a 256 m/s free stream as a NATO test-case - Static “Alumina-Free plume”: the plume was computed by ONERA with CFD code CEDRE for another motor, with the same propellant composition as LP13 motor. The paper will present the chain of simulation tools and the simulated results for all three plumes. Then the experimental setup will be described and the IR measurements will be compared, first against each other, then against the simulated results. The discrepancies will be discussed. Finally, perspectives on SIMBA2 project will be drawn.