First Test Flight Thermal Performance of the Low Density Supersonic Decelerator (LDSD) Supersonic Flight Dynamics Test (SFDT) Vehicle

The first of three planned experimental flights of the Low Density Supersonic Decelerator (LDSD) Supersonic Flight Dynamics Test (SFDT) vehicle took place on the morning of June 28th, 2014 off the coast of Kauai, Hawaii. The goal of the first flight was to determine if the vehicle could reach the altitudes and airspeeds needed to test new technologies for decelerating supersonic vehicles destined for Mars. SFDT-1 was launched from the Navy’s Pacific Missile Range Facility (PMRF) on a 960,000 cubic meter helium carrier balloon provided by NASA’s Columbia Scientific Balloon Facility (CSBF). Once lifted to a stable float altitude of 36.4 km over the Pacific Ocean, the vehicle was dropped and a series of automated maneuvers began. First, the vehicle was spun up via small rocket motors to provide trajectory stability and then a third stage Star 48 solid rocket motor fired to accelerate the vehicle up to Mach 4.3 at an altitude of 54.2 km. After main engine burnout, the vehicle was spun down with another set of small rockets and testing of the new deceleration system in Mars analogous conditions began. A 6-meter doughnut shaped Supersonic Inflatable Aerodynamic Decelerator (SIAD-R) was successfully deployed around the test vehicle and performed flawlessly, slowing the vehicle to about Mach 2.5 before the second technology was deployed – an enormous Supersonic Disk Sail Parachute (SSDS) that had more than double the area of the most recent parachute used to land Curiosity. The parachute, however, did not inflate properly but it provided enough drag to allow the vehicle to survive a water impact largely intact. Despite the parachute anomaly, the test was still hailed as a success, and the engineering team is using all of the recovered vehicle hardware and data recorders to learn how to improve upon the technology for subsequent test flights scheduled in 2015 and 2016. The vehicle’s thermal control system effectively protected the avionics, batteries, cameras, data recorders, and composite core structure during both the cold ascent and powered flight which posed a high heating environment. The thermal telemetry from the first test flight, an assessment of post-flight inspections of the recovered vehicle, and a review of the thermal design and model of the vehicle will be presented along with several lessons learned.