STEP (USA): 10-18    (10-17  from Phase A Studies in Europe)
(requires payload to be maintained close to absolute zero temperature)                                 In the SMEX competition
mSCOPE (France): 10-15                 Phase B  Study         
GG (Italy): 10-17                                    Advanced Phase A Study             
                            The costs  
        STEP : GG : mSCOPE=1 : 20% : 13%
The international context
GREAT (balloon test): 10-15 , competitive with mSCOPE, lower cost, repeatibility… (ASI-NASA study)