‘Jack-of-all-trades’ improves future spacefaring calculations

Sandia researcher Humberto “Tito” Silva III has been named ‘Engineer of the Year’ by the world’s largest aerospace technical society, the American Institute of Aeronautics and Astronautics.

Selected by a committee of his peers, Silva was honored for improving the prediction of failure rates for aerospace flight systems as they reenter Earth’s atmosphere. The work helps engineers solve the worst problems first for reentry rockets, spaceships and satellites.

Tito’s procedure, which he has dubbed “Tito’s full-circle analysis methodology,” uses computer modeling to determine the fewest number of computer simulations and physical experiments needed to get trusted data on a project.

“We were able to have high statistical confidence in our results. These were analogous to those achieved by researchers using many orders of magnitude more computational simulations and physical experiments,” he said. “Our method saves money and time.”

AIAA president Basil Hassan, who is also Sandia’s deputy chief research officer, said, “Tito’s work helps ensure the safety, security and reliability of the nuclear deterrent by helping to understand potential uncertainties in extreme thermal environments. The methodologies developed here could also be used for other entry and reentry-type applications that similarly concern engineers.”

Tito’s award will be presented in August at the AIAA Aerospace Spotlight Awards Gala, an annual event the organization describes as “recognizing the most influential and inspiring individuals in aerospace.”

Succeeding with failure

Tito credits his unusually varied background, which includes study in several engineering and science fields, for endowing him with a jack-of-all-trades outlook that connects with the deeper perspective of other researchers who self-confine to specific research areas.

“Many scientists deep-dive into subfields,” he said. “My bread and butter is that I bring a different perspective. Technical experts fill in my knowledge gaps, and I fill in ones they haven’t thought of.” Tito describes himself as an “inside consultant” who can bridge subcategories in computer science, project management, and in aerospace, mechanical, chemical and electrical engineering.

He said acting as a catalyst in a variety of fields doesn’t blur his research focus, which is thermal science, “pretty much the jell for all the work I’ve done.”

His teams feed data from modeling and physical experiments — limited in number to keep costs down — into computer models expected to simulate the actual effects. Results from the models are then used in experiments to see how the derived data matches physically harvested data.

The work often shows considerable overlap between theory-based and experimental graphs, which lends weight to Tito’s failure-rate predictions.

Super-sleuthing the cosmos

Working from an Earth-bound lab, Tito doesn’t minimize the difficulty of determining events in outer space. The sleuth-like deductions are similar, he says, “to determining why an iPhone thermally or electrically fails in a box, if the box is in a closet, the closet in a room, the room in a building, the building on a barge in the hold of an aircraft carrier.”

His first move is to simulate the environment, including the season of the year and time of day.

Then, there’s the equipment. “If the reentry body is made partly of stainless steel, we think we know its thermal conductivity. But there’s material variability from different factories, so we have uncertainty in how that affects our vehicle. So, we use a range of possible figures,” he said.

To solve questions about a particular system entering Earth’s atmosphere, subspecialists were needed to find the sweet spot between different forms of heat transfer. “So, we did a computational experiment on how to use all the test equipment most frugally,” Tito said. “We needed to determine the optimum amount of experiments and computer simulations, so we weren’t running, say, 5 million computer simulations and 5,000 experiments.”

Probabilities for all possible outcomes

Using these deliberately limited means, Tito’s team found a way to map the probability space of all possible outcomes.

“Then we found a condition with our model that stressed the system,” he said. “We used that in the computer domain and then again in the experimental domain in an iterative fashion. That gave us our result.”

Said Darcie Farrow, a former system engineer overseeing nuclear weapons sustainment, “The multiple technical advances initiated by Tito are improving nuclear safety assessments as well as aerodynamic models for a wide range of flight systems.”

Tito also has initiated collaborations with Los Alamos National Laboratory resulting in nuclear weapon system models that capture the response of both labs’ components in fire environments for the first time, she said.

Tito’s family worked long hours in the medical field. He jokes he was the black sheep for going into engineering because he suspected it must have a better work-life balance. His children show strong aptitudes in music, a field that the guitar-playing Tito has retained as a sideline.

Belying the future complexity of his work, Tito grew up in farming country around El Paso, Texas.

There were no big buildings, and he could see for miles.

The open fields contributed to his interest in outer space. “It’s easy to dream about the stars, growing up with only cotton fields in your backyard,” he said.

But his life grew more complicated when he left astrophysics as he started graduate school.

“At the time, there was too much uncertainty in that field,” he said. “You couldn’t experimentally prove that there is such a thing as black hole — or, at least, back then there wasn’t any experimental or tangible proof as there is now.” 

What got him back into studying space — specifically, aerospace engineering — to finish his graduate school education was the space shuttle Columbia disaster.

“I knew then that I wanted to apply uncertainty quantification to safety-driven problems and that aerospace engineering was a perfect field for that application.” 

“I saw it in real time across the sky as I was driving my sister across Texas back to Baylor Medical center in early February 2003,” he said.

The emotional impact of the sight was reinforced by Texas radio stations that repeatedly played Stevie Ray Vaughan’s song “The Sky is Crying,” and it created a memory that he felt forged his future life path.

“I knew then,” he said, “that I wanted to apply uncertainty quantification to safety-driven problems and that aerospace engineering was a perfect field for that application.  It was like a homecoming for me, coming back to what I always loved.”

The earlier space shuttle Challenger disaster was Tito’s initial propellant into thoughts of aerospace. “The memory of watching that disaster — also in real time with my principal and my classmates while in school — left a huge impression on me as a young boy.”

He maintains his interest in a number of academic fields in which he still takes classes and teaches “to this day,” he said.

But in Tito’s life, he said, “It’s clear that aerospace tragedies have had their way with my destiny.”