February 29, 2024
Imagine being an astronaut on the Apollo 13 mission, launched on April 11, 1970, when an oxygen tank onboard explodes, sending the mission into chaos, coining the popular iteration of the famous phrase, “Houston, we have a problem.” To get the astronauts safely back home, NASA’s mission control teams fed data from the real spacecraft 200,000 miles from Earth into simulators to replicate what was happening aboard the aircraft. This scene, reenacted in the 1995 movie Apollo 13, helped NASA predict and execute the return of the astronauts back to Earth.
What does the above have to do with digital twins? The Apollo 13 mission, recalled by National Public Radio’s (NPR) host Manoush Zomorodi during her recent interview with Karen Willcox, a professor in the Department of Aerospace Engineering and Engineering Mechanics and the director of the Oden Institute for Computational Engineering and Sciences provides an early and relatable use of the ideas underlying digital twin technology.
Zomorodi, host of NPR’s TED Radio Hour, described digital twins as the modern digital version of NASA's physical simulators from the Apollo 13 days. The concept behind the term ‘digital twin’ isn’t new, having been in use for decades in aerospace engineering and weather forecasting. However, advances in computation are opening potential uses across disciplines not previously imagined.
Willcox, whose own TED Talk on digital twins debuted on TED.com in September 2023, was one of several guests featured on the TED Radio Hour Feb. 9, in an hour-long episode titled “Doppelgangers.” The episode featured four guests including Willcox, on topics from “our online mirror world to digital simulators, to the Earth's twin."
“What really makes the digital twin special is that the virtual representation is connected to the physical world and there is a bi-directional flow between the virtual and the physical. The digital twin is now becoming a personalized, dynamic virtual representation, which in turn can be used to drive new decisions,” explained Willcox, who said the applications for digital twins are endless.
While digital twins got their start in aerospace engineering, the concept is used in weather forecasting, including hurricane and storm prediction, and is expanding quickly into areas such as medicine and potential personalized cancer treatments, automotive design, urban infrastructure and smart cities, and climate modeling.
Quick to point out that she is an aerospace engineer and does not have a medical background, Willcox said the interdisciplinary nature of the Oden Institute at UT Austin provides for collisions of ideas, and recently led to a partnership with oncologists.
“Here at UT Austin, we started talking with the Center for Computational Oncology at the Oden Institute,” said Willcox. Those conversations led to the realization that even though “the physics and the biology is very different from what I do as an aerospace engineer, there are many common challenges,” in the idea of digital twins as a way to move towards personalized cancer care.
Willcox gives an example of a cancer patient, diagnosed with a tumor. “We have powerful models – mathematical models – that can represent a tumor, and make predictions on how that tumor is going to grow. The future vision is to have the digital twin work hand-in-hand with human clinician to try to achieve the best outcomes for that individual patient.” Willcox stresses that this technology is still a long way from being applicable because of the complexities of modeling the human body at the scale needed.
As with all new technology, concerns surrounding ethics and maintaining patient privacy (in the examples of medicine) are of real concern. The National Academies of Sciences, Engineering, and Medicine (NASEM) released a report on Dec. 15, 2023. The report is the result of a year-long consensus study that Willcox chaired. The study was sponsored by the U.S. Department of Defense, U.S. Department of Energy, National Institutes of Health, and National Science Foundation.
The report, Foundational Research Gaps and Future Directions for Digital Twins, sets down a cohesive definition for the term “digital twin,” urges responsible use of digital twin technology, and emphasizes the importance of establishing trust and embedding verification, validation, and uncertainty quantification in digital twin technologies from design to deployment.
“If you are going to use a computer model to drive a critical decision you need to know how good that model is and when you can trust it," explained Willcox. "How much can you trust it? How good are the predictions?” She went on to explain that in the context of digital twins, these questions about model trust become even more challenging because they must be asked continually, as the digital twin is evolving and changing in time.
The Oden Institute, which fosters interdisciplinary computing research, is uniquely positioned to collaborate on digital twin technologies. The Institute already has a number of ongoing research initiatives ranging from the development of digital twin mathematical foundations to new scalable algorithms to the applications of digital twins in computational oncology, storm mitigation, unmanned aerial vehicles, and space systems. In one major collaborative effort,
Oden Institute faculty member Omar Ghattas, a professor of mechanical engineering, co-leads with Willcox the Department of Energy Multifaceted Mathematics Integrated Capability Center on Multifaceted Mathematics for Predictive Digital Twins (M2dt). This center is advancing the mathematical foundations of digital twins and their applications in advanced manufacturing and climate modeling.
Willcox said a future vision could one day include a digital twin of planet Earth. “A digital twin at the scale of full planet Earth goes well beyond what we can do today with our models, our algorithms, and our data. But I think this is a fantastic vision because it also starts to think about integrating all those disparate pieces of our planet Earth that we know are connected, so that we start making decisions in a holistic way as a planet rather than as individuals or individual nations.”
Holistic is the vision that seems to capture the potential for digital twins. “It’s a huge challenge, but the good news is that we have a lot of hope for addressing this challenge, and a big part of this hope rests on this notion of predictive physics-based models that let us make predictions.”
To listen to the full NPR TED Radio Hour program “Doppelgangers,” follow this link. To watch Willcox’s original TED Talk, follow this link.
