While most everyone has witnessed the spectacle of a rocket launch – at least on video, if not in person – have you considered the bone-jarring forces propelling that space vehicle?
It’s an everyday focus for NASA’s Armstrong Flight Research Center in California, where advances that have moved scientific and space exploration forward have become increasingly smaller, faster and lighter.
Consider the realities of achieving orbit: rocket engines ignite just seconds before liftoff. The forces at play sending vibrations coursing through the cabin as the vehicle begins to turn potential energy kinetic. The boosters fire, and the craft leaps off the launch pad, building up speed through the lower atmosphere.
Perhaps forty-five seconds in, the engines throttle down, reducing stresses on the shuttle’s structure to maintain “Max-Q” – maximum aerodynamic pressure. In a matter of minutes, the empty boosters separate and the main engines continue to push the craft steadily upward. Then comes the final thrust, propelling the payload to its indented orbit. And then silence. Main engine shuts down and the mission beyond Earth’s atmosphere begins.
What goes on behind the scenes of this incredible feat – through measurement and control – is some of the world’s most innovative, intricate and precise technology. And with the demands presented by that amount of energy expended in such a short burst, it had better be!
As America celebrated the Apollo 11 moon landing’s 50th anniversary last summer, space travel has been getting a renewed share of attention.
Among the advances in micro-technology that power NASA’s foray into new space frontiers is a Fiber Optic Sensing System (FOSS) developed for aeronautics research at this California center. FOSS is a high-density and high-speed monitoring and sensing system that collects aerodynamic data from research aircraft. The data is instantly fed into algorithms to determine the structural health of the vehicle, measuring parameters like strain and temperature and calculating others such as operational loads and shape – all in real time.
This is a game-changing measurement system, says Allen Parker, NASA Armstrong Senior Research Engineer and the primary developer of FOSS.
“When you’re flying, even on a commercial airline, the wings are undergoing aerodynamic loading that cause bending and can produce, in some cases, a large amount of strain,” Parker explains.
“And if they’ve been pushed too far, they can ultimately fail. So that’s what we’re trying to avoid – pushing our structures too far to where they fail and could possibly lead to loss of life. So, we monitor those strains, for example, to provide the feedback to make those important decisions.”
FOSS is a game-changer for flight instrumentation, he says, because of its density measurement parameters, compact size and lower installation requirements. Consider that conventional data systems on aircraft require large reduced wire runs, harnesses to fasten those wires into place, and bulky connectors and sensors, which all add weight and complexity.
But Parker’s team, with more than a dozen years of laboratory work and field testing, has excelled at downsizing. FOSS started out as the size of a large conference room table and is now the size of a small box that can easily fit inside your carry-on luggage. That’s packing lightly, whether you’re travelling across continents or direct to Mars.
The transformative piece in this shrinking technology?
“It was really the algorithms that were the large leap forward,” Parker says of the software that processes the vast amount of raw data into tangible engineering unit parameters. It’s much like a pulse check on flight-critical factors like wing flutter activity, shape and/or structural strains.
FOSS uses an optical fiber up to 40 feet long, as fine as a human hair, that weighs almost nothing and provides up to 2,000 data points. The system processes information at rates up to 100 times per second over multiple fibers simultaneously.
“Before, when you would push a button, you waited a couple of minutes and you got a response back. And so, we developed the initial algorithms to where we ultimately achieved a sample per second, and then 10 samples per second. Now we are currently at about 100 to 150 samples per second.”
Another aspect of advancing the project is reducing the cost of the technology and applying it in new ways. In space research, FOSS has the potential to monitor the state of a tank of cryogenic fuel that could be on a satellite, a rocket or positioned on a moon base. The system could monitor the structure of the tank, temperature, and liquid levels of the tank, and do it in a cost-effective manner, and with a relatively small form factor. “And those are some things that excite me – making sure that our technology is ready for opportunities like that,” he says.
Parker is in his element as the team lead for FOSS. He was programming computers when he was ten years old, growing up in Houston, Texas. “I’ve always enjoyed technology and my mom would always say, my son is going to be a NASA engineer one day. And back in those days you didn’t see black NASA engineers.”
Parker says he thought it was an impossible goal until he met a young NASA recruit, Charlie Bolden, who eventually became a full astronaut and the administrator of NASA.
“I had an opportunity in the early 80s to meet him at Johnson Space Center where he gave me a tour, and I thought to myself, if he can do it, then I could do it too. And so that’s when I set my sights on engineering. Once in college, I was privileged to interview for an internship at NASA Armstrong (then NASA Dryden) with another black engineer by the named of Charlie Brown. NASA hired me as an intern in 1987, and I have been a part of the NASA family since.”
FOSS has been a career achievement, he adds, with the satisfying result of ensuring safer transport with more exact monitoring and troubleshooting.
The technology also has the potential to solve a number of technical challenges for industries as diverse as medical, power, automotive, oil and gas and military. Companies are working on new medical tools incorporating fibers because of their small size and flexibility, which makes them perfect as a sensor for catheters, as one example.
In oil and gas, when operators are pulling crude out of the ground, they’re pulling more than just oil. Depending on the process, they could be extracting water, detergents, gravel and all sorts of elements and dumping it into a tank. Over time, that material settles and you would want to know how much oil you actually have.
In such a case, the only thing that really counts is the oil, Parker explains. “So you need a means of knowing just how much crude is in that tank. We’ve demonstrated in a preliminary sense, the ability to use fiber optic sensing technology to show the stratification of what’s in that tank, what part of that tank is crude, what part is water and so on. Then you can tell how much the contents within the tank are worth.”
There are also applications in automotive and military, and Parker’s team has a number of partner projects underway to transfer the technology.
Parker says what matters most to innovation are the people behind it, and those who will take it forward. And engineering students come from all walks of life. In fact, urban ski legend LJ Strenio has been pumping out code as an intern in Parker’s lab recently, along with three other worthy student engineers.
“We have been blessed over the years with great students, some of whom we have been able to offer fulltime engineering positions,” says Parker. “I really enjoy the work that we do and the accomplishments we have achieved, but what I’m most proud of are the students that I’ve been privileged to have helped along the way.”