Speaker
Description
NASA Ames and Langley are partnering with DLR to propose a comprehensive instrumentation suite known as the Dragonfly Entry Aerosciences Measurements (DrEAM). DrEAM will provide key aerothermodynamic data and performance analysis for Dragonfly’s forebody and backshell Thermal Protection System (TPS), and also includes a DLR-provided Data Acquisition System (DAS). Titan’s atmosphere predominantly consists of nitrogen (~98% by mole) with small amounts of methane (~2% by mole). CN is a strong radiator and is found in nonequilibrium concentrations for Titan entry, the modeling of which has proven to be a difficult task. The DrEAM instrumentation suite will significantly advance the state-of-the-art not only by documenting the environment and performance of Dragonfly’s entry system but also by making key measurements in Titan’s atmosphere for the first time, thus providing new benchmark data applicable to entry science more generally.
Aerodynamic and aerothermal environments and TPS response will be measured using sensors similar to the Mars Entry, Descent, and Landing Instrumentation 2 (MEDLI2) Instrumented Sensor Plug (MISP) and the COMbined Aerothermal and Radiometer Sensor (COMARS) suite, with the latter supplied by DLR. For MEDLI2, MISP used embedded thermocouples (TCs) to directly measure in-depth temperature of the TPS at several locations, which can also be used to infer surface environments via inverse analysis. For DrEAM, the MISP style plugs will be known as Dragonfly Sensors for Aero-Thermal Reconstruction (DragSTR) plugs. Atmospheric density measurements and capsule aerodynamic data will be obtained through the onboard Inertial Measurement Unit (IMU), supplemented by hypersonic pressure transducers similar to those used by the MEDLI Mars Entry Atmospheric Data System (MEADS). The DrEAM pres-sure sensors will be known as Dragonfly Atmospheric Flight Transducers (DrAFT) On Schiaparelli, the COMARS suite included three total surface mounted heat flux sensors, three pressure sensors, six narrowband radiometers (provided by CNES) and one broadband radiometer. For DrEAM, a similar sensor package will be used with all sensors provided by DLR which is called COmbined Sensor System for Titan Atmosphere (COSSTA), see Fig. 1 showing the C3 being calibration at NASA Ames.
Figure 1: Angular characterization of the COSSTA sensors using the Laser Driven Light Source
The presentation will detail the various sensors to be included at each location around the aeroshell as well as provide a status on the current design, do-no-harm testing and flight hardware delivery.
Aerothermal analysis for the Dragonfly mission involves predicting the coupled convective and radiative heating environments the aeroshell will experience during entry into Titan’s dense, nitrogen‑methane atmosphere. This work integrates high‑fidelity CFD and nonequilibrium radiation modeling, drawing on assessments of turbulence behavior, roughness effects, wall‑temperature sensitivities, and species contributions such as $C_2N_2$, to characterize the flow field and heating across the forebody, shoulder, and aftbody regions. Iterative margin development, informed by wind‑tunnel comparisons, shock‑tube bias analysis, and parametric uncertainty studies, ensures that thermal protection system (TPS) sizing accounts for model uncertainty and mission risk. The resulting environments and status leading into aeroshell fabrication will be discussed.
Brief Presenter Biography:
Dr Brandis is a senior research scientist employed in the aerothermodynamics branch at NASA Ames. He is the DrEAM lead investigator, Dragonfly aerothermal lead and PI for NASA’s Entry Systems Modeling project.
References
[1.] A. Gülhan. et al. “Aerothermal Measurements from the
ExoMars Schiaparelli Capsule Entry,” Journal of Spacecraft and Rockets, 2018. https://doi.org/10.2514/1.A34228
Summary
The presentation will detail the various DrEAM sensors to be included at each location around the aeroshell as well as provide a status on the current design, do-no-harm testing and flight hardware delivery.