Summary of the First High-Altitude, Supersonic Flight Dynamics Test for the Low-Density Supersonic Decelerator Project

Abstract

NASA's Low-Density Supersonic Decelerator Project is developing and testing the next generation of supersonic aerodynamic decelerators for planetary entry. A key element of that development is the testing of full-scale articles in conditions relevant to their intended use, primarily the tenuous Mars atmosphere. To achieve this testing, the LDSD project developed a test architecture similar to that used by the Viking Project in the early 1970's for the qualification of their supersonic parachute. A large, helium filled scientific balloon is used to hoist a 4.7 m blunt body test vehicle to an altitude of approximately 32 kilometers. The test vehicle is released from the balloon, spun up for gyroscopic stability, and accelerated to over four times the speed of sound and an altitude of 50 kilometers using a large solid rocket motor. Once at those conditions, the vehicle is despun and the test period begins.The first flight of this architecture occurred on June 28th of 2014. Though primarily a shake out flight of the new test system, the flight was also able to achieve an early test of two of the LDSD technologies, a large 6 m diameter Supersonic Inflatable Aerodynamic Decelerator (SIAD) and a large, 30.5 m nominal diameter supersonic parachute. This paper summarizes this first flight.

Precision Guidance for Mars Entry with a Supersonic Inflatable Aerodynamic Decelerator

“…Therefore, a reasonable deployment condition for the SIAD is 3 ≤ MSIAD ≤ 5. In the flight test of the LDSD [7], the deployment Mach number is MSIAD = 4. However, a fixed deployment condition for the SIAD would eliminate a significant means of controlling the entry flight.…”

“…To increase the drag area and still meet launch vehicle constraints, a hypersonic inflatable aerodynamic decelerator (HIAD) and a supersonic inflatable aerodynamic decelerator (SIAD) are being investigated for future Mars missions [2][3][4][5][6]. One part of the low density supersonic decelerator (LDSD) system, the SIAD, had two test flights, one in 2014 and the other in 2015 [7][8][9]. In the testing, though the parachute was damaged, the SIAD performed well.…”