Development of Models for Disk-Gap-Band Parachutes Deployed Supersonically in the Wake of a Slender Body

The Advanced Supersonic Parachute Inflation Research
and Experiments (ASPIRE) project will investigate the
supersonic deployment, inflation, and aerodynamics of Disk-
Gap-Band (DGB) parachutes in the wake of a slender body.
The parachutes will be full-scale versions of the DGBs used by
the Mars Science Laboratory in 2012 and planned for NASA’s
Mars 2020 project and will be delivered to targeted deployment
conditions representative of flight at Mars by sounding
rockets launched out of NASA’s Wallops Flight Facility. The
parachutes will be tested in the wake of a slender payload whose
diameter is approximately a sixth that of entry capsules used
for Mars missions. Models of the deployment, inflation, and
aerodynamic performance of the parachutes are necessary to
design key aspects of the experiment, including: determining
the expected loads and applicable margins on the parachute
and payload; guiding sensor selection and placement; evaluating
the vehicle trajectory for targeting, range safety, and
recovery operations. In addition, knowledge of the differences
in the behavior of the parachutes in the wake of slender and
blunt bodies is required in order to interpret the results of the
sounding rocket experiment and determine how they relate to
expected performance behind blunt bodies at Mars. However,
modeling the performance of a supersonic DGB in the wake of
a slender body is challenging due to the scarcity of historical
test data and modeling precedents. This paper describes the
models of the aerodynamic performance of DGBs in supersonic
slender-body wakes being developed for the ASPIRE sounding
rocket test campaign. Development of these models is based on
the four available flight tests of DGBs deployed in supersonic
slender-body wakes as well as on data from past flight and
wind-tunnel experiments of DGBs deployed in the wake of blunt
bodies, on the reconstructed at-Mars DGB performance during
past missions, and on computational fluid dynamics simulations.
Simulations of the wakes of blunt and slender bodies in supersonic
flow have been conducted in order to investigate the
differences in the flowfields encountered by parachutes deployed
in both wake types. The simulations have allowed the project
to investigate the fundamental differences between the sounding
rocket tests and the flight of a DGB during a Mars mission and
to assess the limitations of the sounding rocket test architecture
for evaluating flight performance at Mars.