Corpuscular Radiation and the Acceleration of Artificial Satellites

Abstract

IN a previous connnunication¹ I showed that the secular accelerations of Satellites 1958 β 2 and 1958 δ 1 varied nearly in unison with the 10.7-cm. radiation from the Sun. This correlation sheds no light on the nature of the radiation responsible for the variations of density of the upper atmosphere, since the 10.7-cm. radiation—the variations of which are remarkably similar to those of the sunspot numbers—can obviously be considered only as a general index of solar activity. To obtain further clues on this subject I reduced anew all the available observations of these two Satellites (about 2,500 for 1958 β 2 and 9,000 for 1958 δ 1) with the best elements at hand and obtained more accurate accelerations at twice the original resolution. The results are plotted in Fig. 1, together with the 10.7-cm. solar radiation curve². As can be seen, the correlation with the solar radiation is remarkably good, even in details, for the high-flying, spherical Vanguard Satellite 1958 β 2, for which accurate, well-distributed Minitrack observations were available throughout. For 1958 δ 1 the observations are mostly optical, less accurate and more irregularly distributed, with occasional periods of near-invisibility; this fact, together with the elongated shape, may have contributed somewhat to the poorer correlation in its case.