1
Capsule Abort Recontact Simulation
Shishir Pandya*, Jeffrey Onufer†, William Chan‡, Goetz Klopfer§
NASA Ames Research Center, Moffett Field, CA, 94035
A study is performed to ascertain the validity of the use of inviscid and viscous simulation
methods to predict the axial and normal forces during a launch abort scenario for manned
space flight vehicles. The proximity drag character of the Apollo launch escape vehicle
(LEV) was studied in detail in a wind tunnel during the Apollo program. Simulation results
obtained during the present effort are compared to the Apollo era wind tunnel experiments.
The validated simulation techniques are applied to assess the possibility of recontact between
the crew capsule and the service module after a launch abort is initiated. The natural
extension of the method is to assess the risk associated with the new Crew Launch Vehicle’s
escape system.
Nomenclature
Cp
= Pressure coefficient
CA
= Axial-force coefficient
CN
= Normal-force coefficient
CAj
= Thrust coefficient
!
= Angle of attack
d
= Service Module diameter
x
= Longitudinal distance from apex; positive rearward
l
= Length of the command module measured from the apex
!x
= Longitudinal displacement
!z
= Lateral displacement
!"s
= Relative angle between command module and service module
I.
Introduction
As NASA approaches the end of the Space Shuttle era, a new era of space exploration with an Apollo-type
launch system is on the horizon. The proposed Crew Launch Vehicle (CLV) is a design that combines elements of
the Saturn V vehicle used during the Apollo program with some of the components used in the Space Shuttle. The
new vehicle’s first stage is the Space Shuttle’s Solid Rocket Booster (SRB). The second stage utilizes a LH2/LOX
stage that uses a derivative of the Saturn rocket’s J2 engine. Atop the liquid stage is a service module (SM) and a
capsule, which holds the astronauts similar to the Apollo program. The capsule and the SM together are called the
Crew Exploration Vehicle (CEV). As in the