The Penetration of Planetary Atmospheres

Abstract

The problems of penetrating a planetary atmosphere are reviewed and techniques for penetration are discussed. These techniques are resolved into two general classes: (1) Gradual entry into the atmosphere with relatively low deceleration loads and heating rates low enough so that the heat may be rejected by thermal radiation from the surface; and (2) direct entry with higher deceleration loads and higher heating rates with the heat being absorbed by the body surface.

Extension and Enhancement of the Allen–Eggers Analytical Ballistic Entry Trajectory Solution

“…An atmospheric scale height H 8.5 km and reference density ρ ref 1.215 kg∕m 3 at reference altitude h ref 0 km are assumed [22]. While the analyses presented in this work are restricted to Earth, Gazley has applied the Allen-Eggers solution to Mars and Venus with good results, indicating applicability at the terrestrial planets with atmospheres [23]. Further evaluation of the efficacy of the Allen-Eggers approximate solution at other planetary destinations is left for future investigation.…”

“…The simplified expressions in Eqs. (20)(21)(22)(23)(24)(25)(26)(27)(28) are typically presented in texts on atmospheric entry [12][13][14]26,27], as they readily provide insight into several ballistic entry phenomena. First, the altitudes at which maximum acceleration and heat rate occur are not functions of velocity to first order: they are determined by vehicle parameters, planetary parameters, and the flight-path angle.…”

“…( 13) or the simplified expression, Eq. (23). Using the simplified expression for V a max yields a more compact expression for γ .…”