AAE faculty profile series: Steven Schneider

A curiosity and search for answers hasn't faded for Steven Schneider, more than 30 years into a career as a researcher and professor.
Steven Schneider (John Underwood/Purdue University)

Steve Schneider, apparently, was asking too many questions.

That wouldn’t surprise his mom, of course. As a kid, Steve couldn’t seem to refrain from asking “why?”

That curiosity didn’t fade by the time he was in seventh grade. And while mom Barbara may have found it endearing, the incessant search for answers, Steve’s seventh grade math teacher may not have agreed. He tried to be polite, of course, but he couldn’t quite understand why his teacher was making “mistakes.” So he asked why, and she didn’t seem to like that. Next minute, he was sent to the principal’s office.

“I think there’s a certain personality type where you just really enjoy learning things and doing things and the challenges,” Schneider says now, well beyond that middle school life.

That same search for answers, that same curiosity, led Schneider to Caltech for college because he wanted to go to a “really hard school.”

The curiosity didn’t fade when he spent two years after undergraduate school with the Naval Ocean Systems Center working to improve torpedo systems, soaking up as many technical papers as he could to better understand the science and engineering in an effort to build systems better.

It didn’t fade during his graduate school work at Caltech, studying boundary layer transition under an advisor who stressed that even the best paper would be a footnote in somebody else’s book, enforcing an emphasis to instead “go off and really do stuff.”

It didn’t fade during Schneider’s first year as an assistant professor at Purdue in 1989, as he evaluated and examined which research was worthy of devoting his life to.

Still hasn’t, actually, more than 30 years into a career as a researcher and professor in the School of Aeronautics and Astronautics.

And Schneider doesn’t expect to slow down anytime soon, considering the motivation for his insistence hasn’t faded a bit.

“If it’s easy, it’s boring. You feel like you’re wasting your life,” he said. “If something is really uncertain and really hard and it has a big effect and you can make some progress on it, then you’ll really make a difference.”

That’s been Schneider’s persistent pursuit.


He always liked to build things as a kid, and he enjoyed science and math in school. But his sense of responsibility toward doing things that matter, attaching value to pursuing something important, may have stemmed from being bullied as a kid in Chicago. A determination budded about standing up, defending what was right, an aspect that ultimately was pursued heavily in national defense work and weapons systems that offer protection from “bullies” and sustain freedom.

Schneider was pushed at Lane Technical High School, a magnet high school in the Chicago Public Schools district with a reputation for academic excellence and rigor. He actually didn’t eye engineering initially, even though he was intrigued by how things were built, worked together and questioned everything. Instead, he considered becoming a history major. Further evaluation revealed such a field may not be as inspiring —or lucrative — as engineering, so Schneider sought out colleges in which he could be challenged.

“I’m not all focused on winning, on getting the highest grades or the most contracts. I’ve never really been all that interested in that. I don’t really enjoy that sort of competitive side. So I wanted to go to a really hard school because I figured if I went to a hard school and I was with all the people who were the best students and the classes would be pitched at the highest level, I would learn the most,” said Schneider, the valedictorian in his graduating class, at the largest high school in the city. “So I applied to MIT and Caltech, and I got into both.”

Even after four years of undergrad at Caltech, Schneider still wasn’t sure of his path. Instead of choosing graduate school directly after he earned his bachelor’s degree, he accepted a position with the Naval Ocean Systems Center in San Diego. The first year, he rotated into different assignments every three months to get a feel for the lab and where he’d fit. In his second year, he worked in a group on torpedo development.

The work piqued Schneider’s interest enough to enroll in graduate school at Caltech for aeronautics, and he studied boundary layer transition. Transition, where the laminar boundary layer transitions into a turbulent one, is a classic problem that’s important for many applications. And it’s difficult to explain, which meant expertise was needed to help solve it. That appealed to Schneider.

After being hired by the School of Aeronautics and Astronautics in 1989, he made a list of several ideas for research.

The less-challenging ideas weren’t very interesting to sponsors because they didn’t promise much impact if successful, he said. The most difficult and challenging idea was the one that attracted some funding: Measurements of hypersonic instability and transition in a newly developed low-noise “quiet” tunnel.

Paul Lykoudis, a former aero professor and head of the Nuclear Engineering at the time, suggested Schneider seek guidance from colleagues in industry and government to try to think of ways to meet their needs. As Schneider was soliciting advice from distinguished senior colleagues in boundary-layer transition and high-speed flow, all seemed to say there was going to be a need, some day, for such measurements.

The applications were significant, too, relating to lifting reentry vehicles, ballistic reentry vehicles, hypersonic cruise vehicles, air-breathing vehicles, orbit vehicles, interceptor missiles and more.

And only NASA’s Langley Research Center had a high-speed facility. No University had one.

So even though Schneider never took a hypersonics course at Caltech because “it just seemed too exotic,” spurred by encouragement from colleagues, he opted to pursue it at Purdue.


“We went through this long list of applications for systems that the United States was going to need to build or maintain or someday develop and why they needed better understanding of boundary-layer transition in hypersonics, and they’re like, ‘There’s going to be a market for this,’” Schneider said. “The other thing that was really striking is all the people who knew stuff were all, like, 60-something. They’re like, ‘Somebody young has to do this, to take this over. If you do this, we’ll help you.’ So then it’s like, ‘OK, here’s a niche market opportunity where nobody else is doing this and there seems to be a market. I got a bunch of people willing to support me to try to do it. What else am I going to do that’s going to be worth doing?’

“I’d rather try to do something useful that the country really needs and fail than do a bunch of things that don’t seem like they’re really all that important just to skate through the system and get tenure and not feel like I was doing something that was really needed.”

Schneider couldn’t be afraid to fail, though he was entering a territory that was ripe for it, attempting to develop a tunnel and conduct experiments that few in the world had.

So Schneider dug in, poured over papers, soaked in knowledge from older colleagues who were nearing retirement, developed connections and a level of trust in the community. He accumulated a library of 8,000-plus papers, including reports that weren’t readily available. He taught a specialized course, became a Sandia Lab consultant and served a variety of programs as a technical expert, anything he could do to become a subject matter expert.

The design for the Mach-6 quiet wind tunnel started in 1994, was finished in 1998, and the tunnel was completed in 2001.

It took five more years until it would work.

Plenty of time for Schneider to ask “why?”

It was an anxious time, and Schneider admitted it tested him on emotional, psychological and spiritual levels. He eventually had to make peace with himself, forcing an attitude adjustment: There was a very real possibility this could fail. There were days he’d leave the lab in tears, frustrated he couldn’t figure out how to make it work.

But he was not going to quit.

Schneider often would gain encouragement from the picture hanging on the wall of his office at the Aerospace Sciences Laboratory, an under-construction Golden Gate Bridge.


Spouse Lynette; children Ariel and Katie; grandchildren Jacob, Owen and Brendan

Always makes time for ...

Backpacking, hiking, bicycling, camping and reading history books

More than research

"It's a blessing to be able to move into a new role supporting (Brandon) Chynoweth and (Joseph) Jewell, as I slow down with age and want to spend more time with my three small grandsons."

Did you know?

Schneider has a longtime friendship with Gregory Blaisdell, an AAE professor and associate head of the Gambaro Graduate Program of Aeronautics and Astronautics. Both attended Caltech – Blaisdell was a year older – and played basketball there. Blaisdell was starter on varsity, while Schneider was a “bench sitter” on varsity (after being a starter on JV). Basketball may have been how they met, but Blaisdell also offered a considerable resource to Schneider on math homework. “Greg was one of the people I’d go to when I’d get stuck and I couldn’t figure out how to solve the problems,” Schneider said. After Schneider had worked at the Naval Oceans Systems Center for about a year, Blaisdell was hired there. The pair wrote a short paper together on a particular piece of math related to the design of counter-rotating torpedo propellers. Blaisdell joined the AAE faculty in 1991.

“Everybody said they were crazy, too, when they started building that thing,” Schneider said. “They had lots of problems. Anything that you try to do that’s really new and meets a big need, if it was easy, somebody would have done it a long time ago. You get close to failing, sometimes you fail and you’re just out, and sometimes you get close to failing and solve the problems and end up being able to do something that’s really new that really works.”

The sponsor was nearly at the limit of its patience. Air Force Office of Scientific Research program manager John Schmisseur told his former PhD advisor they may need to think of alternative to the facility.

“It was difficult to talk about that with Steve because he’d been dedicated to that facility for so long. It was tough to have somebody that you believe in and someone who was so influential on you to be in a position where you had to have a conversation of ‘Hey, we’re not done yet, but if this doesn’t work, we’re going to have to think about other plans,’” said Schmisseur, who was a graduate student of Schneider’s from 1993-97.

Schneider and his group finally figured out the flaw — when the nozzle was machined, it was misformed. Gary Brown had an idea to build a surrogate nozzle throat, and Jerry Hahn machined an aluminum throat. They ran the tunnel after that, and it started to work. Then, they had to figure out why — and did.

“That was really exciting,” said Schneider, a smile creeping into his voice. “We were all pumped. Everybody was pumped.”

The results came quickly thereafter. Within a year, the team made measurements in support of DARPA’s Falcon Hypersonic Technology Vehicle 2 (HTV-2) program that “made a difference,” Schneider said.

Those kind of results continue, nearly 15 years after the tunnel’s first success.

“We’ve made all kind of measurements of things that couldn’t be made before that really help us understand the engineering science better that affects the design of U.S. missile and hypersonic systems, so that’s very gratifying,” Schneider said. “It’s really fun because you put stuff in there and most of the time, you don’t know what you’re going to see. It’s never been done before. You get surprised by stuff all the time. At least once a year, we get a pretty major surprise of seeing something that really we didn’t expect to see at all that has a pretty substantial impact on how people design things. That’s really gratifying, and it’s really fun you get to do stuff that’s never been done before.”

That kind of ground-breaking research has attracted talented graduate students, too.

Schneider makes sure to explain to them, though, that the work is often frustrating, and a lot of time is spent trying to figure out how to make things work. Patience is required. An ability to slog through challenges is necessary. But making measurements no one has before — producing results that truly matter — offers an incredible opportunity.

Schneider always has relished being a partaker in students’ successes. He’s always quick to share knowledge and has been especially drawn to graduate students who have the same insatiable thirst for tackling challenges. He’s graduated 18 Ph.D. and 36 MS students to date — nearly all of those Ph.D. students did MS degrees in AAE first — and all but one worked on high-speed transition experiments.

It’s been more than 20 years since Schmisseur was one of those graduate students, and he still recalls the time with fondness. Like when he was struggling with an alignment on a particular piece of equipment and Schneider, on his own, designed an improvement that allowed the rig to function better.

“I appreciated the attention Steve invested in his graduate students,” Schmisseur said. “As a PhD student when Steve was an assistant professor, I got an awful lot of dedicated attention from him. He was very interested in making it work. He, quite often, would get out and work with me side-by-side in the laboratory on projects and things. I think he was a very good advisor. I owe a lot of success I’ve had in my career to having a great start working in his group.”

Schneider is proud of his graduate students and has enjoyed seeing them grow and become successful in industry, government and academia. He hopes they can feel the satisfaction he’s had over the course of his career. Responding to the call of developing systems that matter has been its own reward.

But Schneider has gotten much more.

He’s been an invaluable resource to NASA, the Department of Defense and, on occasion, U.S. allies, impacting the nation and the defense of freedom around the world. He’s an AIAA fellow. He’s an internationally recognized expert.

“Particularly in the area of boundary-layer transition, Steve is among your top two or three people in the world. He’s definitely what I would consider to be an eminent scholar in the area in the United States and globally,” said Schmisseur, an incredibly accomplished expert in his own right, as an Outstanding Aerospace Engineer, an AIAA fellow and a professor who leads research at University of Tennessee’s Space Institute.

“He’s earned that through a really diligent and dedicated focus on the topic throughout his career. Steve is widely recognized as an internationally expert, and he earned that through all his hard work and all his study of the phenomenology and the science.”

It’s not surprising to hear one of the highlights of Schneider’s career thus far came during a classified meeting. At the final flight review of the HTV-2 program, Schneider was thanked for his contribution to identifying a solution to a flaw in the program.

Schneider simply did what he’d been doing since he was a kid: Asking “why?” and endlessly searching for answers, all in an effort to do work that carries weight.

“I had 200 people, all the leading hypersonics people in the country, turning around and looking at me. That particular thing, there was never a paper published out of it, there’s not really a dollar I’m going to get out of it, it didn’t get a student graduated, but leadership at the high levels at the U.S. Department of Defense, running hundred million dollar programs, acknowledged within that classified community something I really was able to do,” he said. “I really was able to help the nation. To me, that matters more than almost all the other stuff. You were really able to make a difference. It’s important.”

Stacy Clardie

I learned an awful lot about research, particularly in our field of boundary-layer transition from Steve. It was interesting because I was one of Steve’s students when he was an assistant professor, working his way through the process going up for tenure. So we worked very intensely to get the first generation of his facility going. We worked on a predecessor to the current Mach 6 facility, a Mach 4 tunnel, and it was very intense to try and get that lab up and going and to show that quiet tunnels were a viable academic research option. I think Steve had a lot of foresight to move into that area, and his determination was incredible in terms of being able to see the need for something and see it through to a very mature and internationally renowned capability now. It’s a real credit to Purdue now.” – AAE alumnus John Schmisseur (PhD ’97)

Professor Schneider is a world expert in hypersonic transition. Getting to learn from the best by working with him and with his unique facility is a privilege I am happy to have. He is extremely intelligent and honest, with high integrity and pride in his work. Despite having numerous demands for his time from a variety of government organizations and companies, Professor Schneider has always been available to his students. He has answered any questions I have had as well as offered constructive criticism when requested. Overall, he is a fantastic advisor and professor. " – AAE Ph.D. student Elizabeth Benitez

When Steve makes a commitment, he sees it through. He is loyal, focused and patiently persistent, whether as a college student spending a summer riding his bicycle coast-to-coast, as a son, brother, husband, father and grandfather caring for his family, or as a researcher developing a quiet-flow hypersonic wind tunnel when it wasn't clear it was going to work. " – AAE professor Gregory Blaisdell