'Must-keep' prof sets tone

September 23, 2010 | UNIVERSITY COMMUNICATIONS

Erica Corral

Erica Corral's academic rise may seem as hypersonic as the spacecraft she researches, but she's actually on a carefully plotted trajectory that began in elementary school in El Paso.

Corral, 33, is just five years out of graduate school and she heads a lab where six students and researchers are developing materials to allow hypersonic spacecraft to survive Mach 20 speed and space vehicles to re-enter Earth's atmosphere without burning off their protective shields.

"It's not easy," said Corral, an assistant professor in the University of Arizona's department of materials science and engineering. "That's kind of why it's so interesting."

The "non-ablative thermal protection system" she is trying to invent for spacecraft would afford the same kind of protection as those ceramic tiles on the space shuttle, only her material wouldn't fall off on launch or burn off on re-entry.

It's not hard to beat what they're using now, she said.

"The space shuttle (nose cone) is 1970s technology," said Corral. "It was designed to burn up in a single use."

Her research seeks to link the high-temperature properties of ceramic materials with the toughness of metals using fiber reinforcements.

"Think of a fiber of hair," she said. "Make it 1,000-times smaller and 1,000-times stronger with densities a fraction of any lightweight material on the planet."

She is also investigating materials for hypersonic flight (above Mach 5) that would infiltrate and become part of a spacecraft's structure.

She calls it a "reverse infiltrated, fully incorporated, carbon-carbon, ultra-high-temperature ceramic composite."

She hasn't come up with a snappy acronym.

At Mach 20, or 20 times the speed of sound, the leading edge of a spacecraft meets temperatures up to 5,072 degrees Fahrenheit.

"The high temperature generated by the plasma at Mach 20 actually separates the molecules in the air," she said.

Scientists have a pretty good idea of what that extreme environment looks like but no way of knowing for sure, said Corral.

"There is no single land-based test or facility on Earth that will duplicate that process. We don't know how these materials will behave, period."

But she is getting a picture. She can heat her material to the requisite 2,800 degrees with an oxyacetylene torch, but she can't control the atmosphere while she does that. She can take her prototype materials to Sandia National Lab in New Mexico where a solar thermal test facility allows a cleaner test, but it's still not the extreme environment that hypersonic vehicles face.

Ultimately, the Department of Defense will have to build a test-flight vehicle to answer the question, she said.

There is much to do before then for Corral and other researchers working on the problem. "We've already shown some very promising results," she said.

Those results have attracted attention and grants, both government and private.

Corral has been named young researcher of the year by the Hispanic Engineer National Achievement Awards Conference.

She has gathered early career awards totaling more than $1 million over five years from the Air Force and the National Science Foundation. Last month she snared a $750,000 share of a $15 million five-year "multi-university" grant from the Air Force.

Jeffrey Goldberg, dean of the College of Engineering, said Corral is one of a handful of "must keeps" - young professors who represent the future of the college. "If she's not the top, she's right up there," he said.

Pushing scientific careers

For Enrique Barrera, who works with a National Science Foundation program to move underrepresented students on to doctoral degrees and academic careers, Corral is a needed example. Barrera was Corral's research director at Rice University in Houston, where she received her doctorate in 2005.

A study released last week by the Council of Graduate Schools said women received 50.4 percent of the doctoral degrees in 2008-09. In engineering, they were 22 percent of the total. The Hispanic/Latino share was 8.4 percent.

Sam Campos, who promoted science careers to minorities at Rice, said Corral remains committed to the work they began as graduate students. "She really wants to promote diversity in the hard sciences, but she also drives home the message that you don't get it handed to you, you really have to work hard."

Campos sees that dedication daily. He and Corral met and married when they were in graduate school at Rice. He is now an assistant research professor in virology at the UA's Bio5 Institute. The busy couple jokingly begins Mondays with the line: "See you next weekend."

Victoria Marotto also has a front-row view of Corral's drive. Corral recruited Marotto to work in her lab when she was a freshman at UA. She is now in her junior year.

Working for Corral, she said, "is not a job for the lazy or the weak."

That suits Marotto just fine. She is rather driven herself.

She picked the e-mail address "NASA girl" when she was in junior high in Bullhead City.

"Ever since I could remember, I've always wanted to be an astronaut. I always watched the shuttle launches and followed the mission and wanted to know 'What made all of this happen?' "

Her major is aerospace engineering, but she quickly agreed to work in Corral's materials science lab because the research there fits her single-minded goal.

She describes Corral as "very optimistic and very hard-working. She always works really, really hard for what she wants and she seems to get it. She's a very powerful woman."

"Happy to be a role model"

Working with students like Marotto is Corral's way of paying back.

She grew up in El Paso, the daughter of school teachers who modeled the value of hard work and education.

Her younger sister, Jessica Padilla, said their parents signed the girls up at a young age for problem-solving competitions such as Odyssey of the Mind. Those experiences, and hanging out in her sister's lab at the University of Texas at El Paso, steered Padilla toward engineering as well.

Padilla is still solving problems. Her group at NASA's Johnson Space Center in Houston creates the tools astronauts use on the shuttle and the International Space Station.

Corral parlayed her doctorate at Rice into a three-year, post-doctoral stint at Sandia National Laboratories. She landed a professorship at UA in 2008.

"The thing that's most important to me is I do good science and stay on the cutting edge," she said, but she also feels a responsibility to inspire Hispanics and women to choose careers in engineering and the other sciences, she said.

So she mentors students. She advises the UA chapter of the Society of Hispanic Professional Engineers. She gives talks across the country. She takes her traveling "Materials Magic" show into classrooms.

Her biggest contribution, though, said former mentor Enrique Barrera, is her example.

"I am happy to be a role model," said Corral.

"The thing that's most important to me is I do good science and stay on the cutting edge."

Erica Corral, assistant professor in the University of Arizona's department of materials science and engineering

Originally posted on News @ Arizona Daily Star