RETHI

Banner image: The environment on the surface of the Moon is a great deal more extreme and hazardous than anything on Earth.

Creating safe and comfortable habitations is one of humankind’s oldest activities. Millennia of experimentation on Earth have brought the design and maintenance of our habitats to a high degree of sophistication. However, moving beyond the Earth’s relatively benign surface and out into space, new obstacles related to these harsh and unknown environments — from limited or absent oxygen to extreme temperature fluctuations, radiation, meteoroids, dust and moonquakes — will impede safety and progress.

The vision of the Resilient ExtraTerrestrial Habitats institute (RETHi), launched in 2019, is to establish the know-how to design and operate resilient and autonomous SmartHabs. NASA selected Purdue to lead RETHi as a new multi-university Space Technology Research Institute (STRI), with Shirley J. Dyke, professor of mechanical engineering and civil engineering, as its director. The institute is to receive up to $15 million from NASA over five years.

SmartHabs, or smart habitats, will need to have appropriate defenses that combat the hazards, deterioration, and commonplace faults that may occur in all electro-mechanical systems, while specifically incorporating principles of resilience to reduce and control emergent behaviors that complex systems exhibit. RETHi is not designing a habitat; rather, it is conducting the fundamental research needed to provide techniques and technologies to support SmartHabs’ resilience in deep space environments where resources are extremely limited and mission-critical activities must be the priority.

RETHi is learning to establish the principles for a smart habitat system architecture, while developing autonomous smart habitat interventions that enable response, repair and recovery, especially with support from robots. Awareness is supplied by an intelligent health management system that will make decisions that reflect both the importance and complexity of the SmartHab, while also exploiting the prediction of future behaviors, needs and responses.

To provide the means to study these research questions, the RETHi team is developing three versatile testing environments for exploring these concepts:

• The modular coupled virtual testbed (MCVT): This plug-and-play simulation environment provides a physics-based computational model that allows researchers to examine many SmartHab configurations while exploring how to make complex systems resilient and autonomous.
• The control-oriented dynamic computational modeling platform (CDCM): This platform enables the team to rapidly establish a coarse model that captures the essential dynamics of the interconnected systems — even those with different configurations. By running thousands of realizations, researchers can assess the performance of each configuration and rapidly perform trade studies to compare various alternatives.
• The cyber-physical testbed (CPT): This testbed merges physical experimentation with numerical simulation to provide controlled experimentation with realistic uncertainty. The CPT is based on the concept of real-time hybrid simulation in the structural engineering community, and it can readily be reconfigured to include different subsystems in different ways.

Developing these testbeds requires participation of the entire RETHi team and serves as a major mechanism for team integration.

RETHi’s robotics team also is working to provide robust and resilient capabilities, from two directions. A soft manipulator, along with associated controllers, is being developed to make it possible to handle a broader class of objects than traditional rigid robotics. The researchers also are exploiting robot factors, which consider redesign of components aimed to enable robots to work the various mechanisms and perform tasks related to SmartHab maintenance. Modular end-effector system work also is being performed to look at how robots can switch among a range of tools so they can use the right one for the job.

As the entire RETHi team continues to pursue this groundbreaking research, it also aims to contribute to NASA’s mission to educate the next generation of engineers and scientists, while building partnerships with U.S. industries and organizations, and other nations.