Predicting the reliability of entry systems

The future of space exploration seeks to discover new information about the evolution of life and the Solar System through increasingly ambitious missions. Many of these missions involve the entry of a space vehicle into a gaseous atmosphere at very high velocity. Due to the extreme environments encountered, a space exploration vehicle requires an Entry System to protect its contents from very high temperatures and pressures.

Our research predicts the reliability of entry systems to ensure the success of future exploration missions.

we tackle the following challenges:

01.

Reliability for Earth Entry Vehicles

An Entry System consists of the Thermal Protection System (TPS), both a heat shield and backshell, and supporting structure. Entry Systems have been employed successfully on many prior exploration missions including Apollo, capsules returning from the International Space Station, and missions to the surface of Mars. However, future missions have extremely high reliability requirements for th Entry System for which there is no currently available approach.

One of our primary goals is to develop new analysis tools that can predict the reliability of an Entry System with greater confidence.

02.

An Integrated Simulation Framework

One major challenge for the prediction of Entry System reliability is the complexity and numerical cost of available analysis tools. Current tools are labor intensive to use, are not well integrated across different physical phenomena, and their computational performance is limited by not taking full advantage of emerging computer architectures. To address the very high reliability required from future Entry Systems, there is also a new requirement to propagate uncertainty across the various design components.

We are developing a robust integrated and interdisciplinary framework to meet these requirements and challenges.

To ADDress these challenges,
access is organized around four tasks:

This task will develop models of all gas-phase and gas-surface processes in Entry Systems for the atmospheres of Titan, Mars, and Earth. Processes to be studied include gas-phase chemistry, radiation, surface chemistry, and turbulence. A combination of high fidelity computational analysis and experimental data generated in world-class facilities will be used to quantify the uncertainty in the models.
This task addresses how the materials and structures of an Entry System respond to the high temperatures and pressures of the harsh entry environments. The task will study these processes by building up from the fiber scale, to an intermediate meso-scale, to the full system macro-scale. A combination of high fidelity computational analysis and experimental data generated in world-class facilities will be used to quantify the uncertainty in the models.
This task aims to quantify the uncertainty in our ability to predict all aspects of Entry System performance. It involves close collaboration with the tasks on hypersonic flow and materials and structural processes to quantify the accuracy of all models developed. This task will also develop efficient ways to apply the Integrated Simulation Framework to predict the reliability of Entry Systems.
The primary overall product of ACCESS is the Integrated Simulation Framework (ISF). This framework will couple together models for all flow, material, and structural processes developed in the other tasks. It will include the uncertainty of each component model and propagate them throughout the analysis to determine the reliability of an Entry System. Execution of the ISF on heterogeneous high performance computing architectures will also be studied. Through comprehensive integration of the modeling for all relevant processes including quantified uncertainty, and by harnessing the power of modern supercomputers, the ISF has the potential to completely change the paradigm for the analysis and design of Entry Systems.