The ultraviolet photometer of the University of Iowa spin-scan auroral imaging instrumentation on board Dynamics Explorer 1 has returned numerous hydrogen Lyman alpha images of the geocorona from altitudes of 570 km to 23,300 km. Attempts were made to fit these observations with a spherically symmetric isothermal Chamberlain model of the exosphere using numerical solutions to the radiative transfer equation. The removal of a substantial portion of the satellite component at higher altitutes was necessary to obtain the required functional dependence of hydrogen density with radial distance. The optimum fit utilizes a Chamberlain model of temperature 1050 ¿K, with exobase rc at 1.094 RE (600 km altitude, exobase density of 40,000 cm-3, and a satellite critical level rcs equal to 3.5 rc. This model is accurate from the exobase to 4.5 RE, beyond which an exponential decrease in density N(r)=3300 exp (-r/1.46RE) cm-3 is found. This corresponds to the removal of an increasing percentage of the satellite component of the geocoronal population, ranging from 10% lost at 5 RE, through 50% at 6.5 RE, to 100% beyond 9 RE. Departures of the observed emission rates from the spherically symmetric model are consistent with a diurnal variation with lower densities on the dayside than on the nightside.