The scaling hypothesis of Dao et at. in p + p → π− + X reactions has been used to derive the sea level spectrum of cosmic muons from the satellite data of primary cosmic ray nucleons. It is found that the derived pion production spectrum depends on [Formula: see text], the average value of the Feynman variable x. Taking as input the energy spectrum of primary cosmic ray nucleons determined by Grigorov et al., as well as the sea level muon spectrum determined by Allkofer, Carstensen, and Dau, the value of [Formula: see text] at different pion energies has been estimated. A fit to the calculated results gives the following energy dependence of [Formula: see text]:[Formula: see text]
