Abort System Using Supersonic Aerodynamic Interaction for Capsule-Type Space Transportation System

The space transportation system using capsule/rocket configurations such as Apollo and Soyuz are simple compared with Space Shuttle, and have several merits from the viewpoint of reliability. The capsule/rocket system will take over the Space Shuttle, after it retires in 2010. As the Space Shuttle accidents had been caused by several factors, e.g., aerodynamic interaction of shock waves ahead of its wing, advanced abort systems such as LAS (Launch Abort System) are required for the capsule/rocket system. In the present study, as a baseline configuration, a combination of a cone and a cylinder is employed as a CEV (Crew Exploration Vehicle), which consists of a capsule (LAV: Launch Abort Vehicle) and a rocket (SM: Service Module). By changing the relative position of the two components as well as the profile area of the rocket, their effects on the capsule/rocket aerodynamic interaction and characteristics (drag and pitching moment) are experimentally and numerically investigated at a supersonic speed (M∞ = 3.0). It is found from the results that the clearance have little effects on the flow field for the case of the baseline configuration. The capsule always showed a positive drag (CD = 0.34), which means that thrust is required to overcome the drag. Otherwise the capsule will recontact the rocket. However in the case where the rocket contact area is 2.2 times as large as the capsule profile, more favorable effects were obtained. Especially in the case of a certain clearance (h/D = 0.40), the drag coefficient of the capsule is CD = −0.35, which means that the capsule suffers a thrust force from the aerodynamic interaction. Under this condition, if capsule has a pitch angle with 5 degrees instantaneously, then pitching moment coefficient becomes CMp = −0.41 therefore capsule stabilize. However, in the case of a very small clearance (h/D ∝ 0.00), the flow becomes unsteady involving pulsating shock wave, leading to a potentially risky separation of the capsule.

[1]  Shishir A. Pandya,et al.  Capsule Abort Recontact Simulation , 2006 .

[2]  B. V. Leer,et al.  Towards the ultimate conservative difference scheme V. A second-order sequel to Godunov's method , 1979 .

[3]  Thomas R. Yechout,et al.  NASA Crew Exploration Vehicle and Launch Abort Tower Aerodynamic Separation Characteristics , 2009 .

[4]  Keiichi Kitamura,et al.  Evaluation of Euler Fluxes for Hypersonic Flow Computations , 2009 .

[5]  A. F. Charwat,et al.  An Investigation of Separated Flows - Part I: The Pressure Field , 1961 .

[6]  Bernd Einfeld.  On Godunov-type methods for gas dynamics , 1988 .

[7]  Edney.  ANOMALOUS HEAT TRANSFER AND PRESSURE DISTRIBUTIONS ON BLUNT BODIES AT HYPERSONIC SPEEDS IN THE PRESENCE OF AN IMPINGING SHOCK. , 1968 .

[8]  Keiichi Kitamura,et al.  Very simple, carbuncle-free, boundary-layer-resolving, rotated-hybrid Riemann solvers , 2008, J. Comput. Phys..

[9]  M. Liou.  A Sequel to AUSM , 1996 .

[10]  A. Lanshin,et al.  Propulsion systems for TSTO airplane-accelerators of different types , 2001 .

[11]  Peggy S. Williams-Hayes.  Crew Exploration Vehicle Launch Abort System Flight Test Overview , 2007 .

[12]  John B. Davidson,et al.  Crew Exploration Vehicle Ascent Abort Overview , 2007 .

[13]  Richard A. Thompson,et al.  LAURA Aerothermodynamic Computations for Space Shuttle Columbia STS-107 Baseline and Damage Scenarios , 2004 .

[14]  Ken Badcock,et al.  Driving Mechanisms of High-Speed Unsteady Spiked Body Flows, Part 2: Oscillation Mode , 2004 .

[15]  Scott L. Lawrence,et al.  Simulation-Assisted Risk Assessment , 2006 .

[16]  Meng-Sing Liou,et al.  An Accurate and Robust Flux Splitting Scheme for Shock and Contact Discontinuities , 1997, SIAM J. Sci. Comput..