ˈɜːli ɛkspˈɛɹɪməntɚz ɪn ˈɛksɹˈeɪ ænd ɡˈæmɚɹˈeɪ ɐstɹˈɑːnəmi fˈaʊnd ðæt ðɛɹ dɪtˈɛktɚz, flˈoʊn ˌɔn bəlˈuːnz ɔːɹ sˈaʊndɪŋ ɹˈɑːkɪts, wɜː kɚɹˈʌptᵻd baɪ ðə lˈɑːɹdʒ flˈʌksᵻz ʌv hˈaɪˈɛnɚdʒi fˈoʊtɑːn ænd kˈɑːzmɪkɹˈeɪ tʃˈɑːɹdʒdpˈɑːɹɾɪkəl ᵻvˈɛnts.
Early experimenters in X-ray and gamma-ray astronomy found that their detectors, flown on balloons or sounding rockets, were corrupted by the large fluxes of high-energy photon and cosmic-ray charged-particle events.