Overview and reconstruction of the ASPIRE project's SR01 supersonic parachute test

Abstract

The Advanced Supersonic Parachute Inflation Research Experiments (ASPIRE) project is aimed at developing and exercising a capability for testing supersonic parachutes at Mars-relevant conditions. The initial flights for ASPIRE are targeted as a risk-reduction activity for NASA's upcoming Mars2020 mission. For this effort, two candidate DiskGap-Band (DGB) parachute designs are being tested at Mach number and dynamic pressure conditions relevant to Mars2020. The two parachutes under investigation are a build-to-print version of the DGB used by the Mars Science Laboratory and a strengthened version of this parachute that has the same geometry but differs in materials and construction. Starting in the fall of 2017, the parachutes are being tested at deployment conditions representative of flight at Mars by sounding rockets launched out of NASA's Wallops Flight Facility (WFF). The first flight test (SR01) of the build-to-print parachute took place on October 4, 2017. During that test, a Terrier-Black Brant sounding rocket delivered a payload containing the parachute pack, the deployment mortar, and the ASPIRE instrumentation suite to a peak altitude of 51 km. As the payload descended back down, an on-board computer calculated an estimate of the dynamic pressure and triggered deployment of the parachute once the targeted test condition was reached. At a Mach number of 1.77 and a dynamic pressure of 453 Pa, the 21.35-m parachute was deployed. The parachute deployed and inflated successfully, producing a peak measured load of 30.95 klbf. The onboard instrumentation suite included a GLN-MAC IMU, a GPS unit, a C-band transponder for radar tracking, three load pins at the parachute triple bridles, and three high-speed/high-resolution cameras trained on the canopy during inflation. In addition, the atmospheric conditions at the time of flight were characterized by means of high-altitude meteorological balloons carrying radiosondes. These data allowed the reconstruction of the test conditions, parachute loads, and parachute aerodynamic performance in flight. The imagery from the onboard cameras will allow the reconstruction of the three-dimensional geometry of the canopy during inflation. This paper describes the SR01 flight test and provides an overview of flight operations, the data acquired during testing, the techniques used for post-flight reconstruction, and the reconstructed performance of the test vehicle and parachute system.