A team from Air Force Research Laboratory (AFRL), Deutsches Zentrum für Luft- und Raumfahrt – Mobile Rocket Base (DLR-MORABA) and the Swedish Space Corporation (SSC) conducted the launch of the Hypersonic Flight Research Experiment (HIFLIER) from the Esrange test center in Kiruna, Sweden.
At 10:00 CEST Tuesday October 10, the single stage Black Brant sounding rocket was launched and successfully reached the desired velocity during both an ascent test window and a reentry test window. During the two experiment windows between 15km and 35km altitudes a maximum velocity of Mach 6 was attained. Between the two experimental windows the rocket was de-spun and re-oriented by an attitude control system (ACS) in order to be aligned with the vehicle’s velocity vector during reentry. The yoyo despin, ACS, and the motor separation were also perfectly executed. Two primary experiments were flown and received all telemetry data.
The AFRL primary experiment aims to measure the effects of aerodynamic heating by measuring the instabilities that precipitate the transition of the boundary layer from laminar to turbulent flow on the conical forebody geometry. The boundary layer is the thin layer of air near the vehicle’s surface where the airflow is decelerated by frictional forces which causes high aerodynamic heating and increased drag on the vehicle. Over 250 sensors consisting of thermocouples, pressure sensors, heat flux sensors, and accelerometers were employed to measure the surface conditions. In addition, a custom designed high-speed data acquisition system utilizing high frequency pressure and heat flux sensors was flown. This system, designed by GoHypersonic Inc, sampled 45 sensors at a rate of 2.5 million samples per second and recorded data onboard at a rate of 1,575 million bits per second. Some onboard data was processed during flight and sent with telemetry as a backup in the event that the payload could not be recovered.
The DLR FINEX experiment tested the application of transpiration cooling technology on fins with sharp leading edges during these hypersonic flight conditions. The fins were manufactured with a new porous carbon/carbon silicon-carbide (C/C-SiC) material by the DLR Institute of Structures and Design. Moreover, while one fin was cooled with constant coolant mass flow rate, an active control system, designed at the Institute of Space System of the University of Stuttgart, was employed on another fin to efficiently regulate the mass flow rate according to the real time thermal load. Two additional fins were un-cooled to act as a baseline.
All experimental payload flight and data systems were fully operational for the experimental system and transmitted data till post separation. Based on initial flight data the rocket motor systems performed as expected. Data analysis is ongoing.
HIFLIER Flight test
Image: Mattias Forsberg, SSC
Project lead science:
David Adamczak, AFRL/RQHV
Project lead MORABA:
Johannes Göser, DLR MORABA