Southern Research engineers conducted tests that advanced an experimental NASA technology designed to solve a tough challenge in landing people and cargo on Mars – slowing down a spacecraft entering the Red Planet’s thin atmosphere to permit a safe touchdown.

The Hypersonic Inflatable Aerodynamic Decelerator, or HIAD, is essentially a doughnut-shaped heat shield made of soft, flexible materials. The system is like a cone of inflatable inner tubes that’s packed tightly into a spacecraft and automatically deployed to use atmospheric drag to slow a fast-moving capsule during descent.

The innovative HIAD system is being examined for possible uses such as manned missions to Mars and landing cargo weighing more than 20 metric tons on other worlds.

“NASA was able to land the Mars Rover, but that is a pretty small device,” said Jacques Cuneo, a Southern Research engineer involved in the testing of HIAD’s materials. “If humans ever go to Mars, we will need to land many things with lots of mass – structures, supplies and other vital items.

“NASA will need to land large payloads, and, right now, they just can’t do it.”

When it comes to Mars, NASA’s mission planners must contend with an atmosphere that is roughly 100 times thinner than Earth’s and composed mostly of carbon dioxide, which can float to the planet’s frigid surface as snowflakes.

FOLDING TESTS

Southern Research’s assigned task in HIAD’s development centered on a key question posed by NASA’S Langley Research Center in Hampton, Virginia, according to Cuneo.

The HIAD’s inflatable structure is fashioned from a fastened series of pressurized concentric tubes, or tori, that form an exceptionally strong cone-shaped shield. The tori’s braided synthetic fibers are 15 times stronger than steel, according to NASA.

But would packing the inflatable aeroshell’s flexible materials into the tight confines of a spacecraft threaten the system’s performance and doom the mission?

“When they fold this complex item, when they crunch it down, there is no way for them to get a regular fold,” Cuneo said. “It’s going to end up crumpled, it’s going to have kinks. There is definite randomness in what happens.

“It’s not like a parachute where they nicely fold it up and pack it in every time,” he added. “After they fold HIAD up, they compress it, so there is going to be some damage. The question is whether it can withstand this damage.”

The Southern Research team designed an extensive series of tests to provide an answer.

The engineers conducted folding studies meant to generate a wide range of creases and folds in the flexible HIAD materials during the packing process. They then evaluated specimens of the materials in strength-retention and permeation tests.

“We were looking to see what kind of property retention it has and what kind of damage occurred while it was folded up,” Cuneo said. “We folded it up loosely, we folded it up tightly. We introduced a lot of different conditions to see how it was going to perform, and the material actually did really well.

“That gave NASA confidence that what they are doing makes sense, and that catastrophic damage was not going to result from the folding operation,” he added.

COMPRESSION TESTS

Last year, NASA put HIAD through a key field test. Engineers used a vacuum pump to compress a 9-foot diameter prototype of the inflatable heat shield into the tight confines of a spacecraft. They then checked the materials for leaks and damage.

After that successful test, NASA said its engineers will move forward with the development of a larger HIAD that can withstand the stress of being tightly packed in a rocket and the challenges experienced when it descends through the atmosphere of a planet such as Mars.

Cuneo said the innovative technology holds promise as NASA contends with the challenges of landing large volumes of supplies, scientific instruments and equipment on worlds with thin atmospheres.

“HIAD has an excellent shot at being utilized down the road for these types of missions,” he said. “It might be Mars or a moon of Jupiter. The technology is there to utilize.”

NASA PARTNERSHIP

Birmingham-based Southern Research has a long history of collaboration with NASA, dating back to the early days of the Apollo program. As part of that work, engineers analyzed the thermal and mechanical properties of potential shield materials and developed mathematical models to predict their performance in re-entry conditions.

Southern Research conducted similar work for the Space Shuttle program, while also remedying a potentially catastrophic rocket nozzle problem and helping the NASA “Return to Flight” missions after the Columbia accident.

Today, the organization is involved in the Space Launch System, or SLS, the massive rocket NASA is developing for planned Mars missions.

“The unique talents of Southern Research’s engineers have contributed to many of NASA’s most significant projects over the decades, and that’s continuing today as the space agency plans epic missions to land astronauts on Mars,” said Michael D. Johns, the organization’s vice president of Engineering.

When a NASA probe launching in mid-2018 approaches its final destination – the roiling upper atmosphere of the Sun – the spacecraft’s heat shield will encounter temperatures hot enough to melt steel.

Testing conducted by Southern Research engineers demonstrated that the carbon composite materials selected for the Solar Probe Plus’ thermal protection system will protect the craft and its instruments from the relentlessly brutal conditions.

“The probe is going to be getting pretty hot, pretty toasty, and it’s going to be hot for a while,” said Jacques Cuneo, a member of Southern Research’s

engineering team who worked on the project. “It’s not a transitory thing; it’s going to be baking for a while.”

The Johns Hopkins Applied Physics Laboratory in Maryland is managing the mission and building the spacecraft. The lab brought in the Southern Research team to conduct high-temperature evaluations of the heat shield materials – a task the Birmingham non-profit organization has been performing since the early days of NASA.

Making sure the Solar Probe Plus can handle the hazards of intense heat and radiation is crucial. Scientists have imagined a mission to the Sun since 1958, and data collected by this probe will yield important new insights about the sun’s atmosphere – known as the corona – and its role in producing fierce solar winds.

Scientists want a deeper understanding of solar activity so they are better able to predict space-weather events that can impact life on Earth and disrupt the operations of orbiting satellites.

“The talented engineers and technicians at Southern Research have made many important contributions to the nation’s space program over several decades,” said Michael D. Jones, vice president of Engineering. “Solar Probe Plus is an exciting mission, and we are proud to have been part of an endeavor that will advance scientific knowledge about the Sun.”

REVOLUTIONARY MISSION

The Solar Probe Plus will travel closer to the Sun than any previous spacecraft, approaching as close as 3.9 million miles as it hurtles past the star at 450,000 miles per hour. That will put the craft well within the orbit of Mercury, the planet nearest to the sun.

Over seven years, the probe will complete two dozen solar orbits, using seven gravity-assisted flybys of Venus to skirt continually closer to the Sun’s blazing corona.

So it can perform this revolutionary investigation, the spacecraft and its instruments will be protected from the heat by a 4.5-inch-thick carbon composite shield capable of withstanding temperatures climbing to more than 2,000 degrees Fahrenheit, according to the Applied Physics Laboratory.

“As you can imagine, the heat shield is a big article,” Cuneo said. “It’s made up of carbon-carbon sheets on the top and the bottom, and in the middle, there’s a rigid carbon foam.”

The Southern Research engineering team was asked to determine the mechanical and thermal properties of the heat shield materials. The carbon composite used in the sheets represented familiar ground for testing, thanks to Southern Research’s longstanding involvement in the space program.

The carbon foam, however, was different. Just figuring out how to the test the relatively brittle open-cell foam was technically challenging, Cuneo said. The issue: How can you measure strain when you can’t even touch the specimen?

“When you pressed on the foam, it would create dust. It wouldn’t actually break, it just kind of machined itself down,” Cuneo said. “Anything that generated compression was a real issue with the foam, so we developed a way to stiffen the ends by impregnating them.

“We were able to figure out how to grab and pull or torque a specimen, and develop ways to measure strain because you couldn’t mount anything on the specimens,” he added.

The Southern Research engineers generated a database of the carbon foam properties, and the material passed muster.

“The foam fit what they thought it was going to do – particularly at high temperatures, which is what they were concerned about — and it’s on track for launch,” Cuneo said.

In July 2016, NASA said the Solar Probe Plus is slated to launch during a 20-day window that opens on July 31, 2018. The spacecraft has passed NASA’s design review stage, meaning it is has moved to final assembly. Engineers at the Johns Hopkins Applied Physics Laboratory are now finishing assembly and installing spacecraft systems and science instruments.

Southern Research’s Stuart Starrett, who has made many significant contributions to the nation’s defense, aerospace and energy industries, is being inducted into the State of Alabama Engineering Hall of Fame at a ceremony this Saturday.

During a career that began in the 1960s, Starrett has built a formidable international reputation as an expert in the behavior of materials in extreme environments such as atmospheric reentry and rocket propulsion systems.

Those who worked with Starrett say his technical insights were vital to the development of reentry nosetips for advanced defense systems, including the U.S. Navy’s C4 and D5 Submarine-Launched Ballistic Missiles and the Air Force’s Minuteman III Ballistic Missile.

“His efforts helped win the Cold War without much official recognition,” said John K. Shigley, Ph.D., of defense contractor Orbital ATK.

Added Keith Bowman, Ph.D., of the Air Force Research Laboratory at Wright-Patterson Air Force Base: “I equate what Stuart did for the nation’s defense to what the engineers working for NASA in the 1960s did for space exploration.”

They say Starrett also provided valuable insights into engineering challenges ranging from composite materials to hypersonic vehicles.

“What makes me proud is just being involved in programs that I thought were important to the U.S.A. and to national defense. That was sort of a mission for me, I guess,” Starrett said.

SOLVING COMPLEX CHALLENGES

Starrett joins Coultas “Colt” Pears, an innovator who led the development of Southern Research’s high-temperature materials laboratory, in the Alabama Engineering Hall of Fame. Southern Research and the high-temperature lab, renamed for Pears, have also been inducted into the Hall of Fame.

“Stuart’s technical excellence allowed Southern Research to become the leader in high-temperature materials. His quiet leadership also inspired those around him, leading to programs in aero-propulsion, reentry systems, heat shields, ground-based turbines, and nuclear power,” said Art Tipton, Ph.D., president and CEO.

“This honor is richly deserved, and recognizes the Stuart’s legacy of impressive technical expertise and his many achievements that have strengthened national defense,” he added.

Starrett, who received bachelor’s and master’s degrees in mechanical engineering from the Georgia Institute of Technology, joined Southern Research in 1965 as an associate engineer. He soon progressed to head the Solid Mechanics Section, then the Mechanics Division. In 1990, he was named Director of the Materials Research Department, a post he held for 16 years.

Officially in retirement, Starrett remains an active consultant on a variety of engineering projects.

“From the beginning, Stuart was able to use his love of mathematics to solve some of the most complex materials challenges of his day,” said Michael D. Johns, vice president of Southern Research’s Engineering division.

“He was a pioneer in the development and understanding of carbon-carbon composites, which are a foundational technology for human space flight, atmospheric reentry, and many other extreme-environment applications,” he added.

Johns said Starrett’s work helped to establish Southern Research’s high-temperature materials lab as one of the few locations in the world capable of conducting thermal and mechanical tests at temperatures ranging from 70 to 5,500 degrees Fahrenheit.

While much of his work has concentrated on U.S. Department of Defense projects, Starrett also used his extensive materials and engineering know-how to help solve challenges for the energy industry. For example, he was involved in the development of material systems for the filtration of hot gases from boilers to be used in the recovery of the energy in a gas turbine – a technology being deployed today.

Starrett has made many technical presentations, primarily in the U.S. but also overseas, and published scientific papers on a wide variety of topics related to materials research.

HALL OF FAME

The State of Alabama Engineering Hall of Fame is overseen by engineering colleges and schools at Auburn University, Alabama A&M University, the University of Alabama, Tuskegee University, University of Alabama at Birmingham, University of Alabama in Huntsville and the University of South Alabama.

Since its inception 30 years ago, the Engineering Hall of Fame has honored 168 individuals. Saturday’s induction ceremony will take place at the Renaissance Montgomery Hotel & Spa.

Southern Research has been selected by NASA’s Johnson Space Center for work under a specialized engineering, aeronautic, and manufacturing (SEAM) contract to support the Houston center’s Flight Operations Directorate, which performs critical functions for the space agency.

Under the contract, Southern Research will provide services associated with aero avionics, electrical and software systems to the Flight Operations Directorate (FOD), which manages the center’s aircraft fleet and trains astronauts and flight directors.

Southern Research is also positioned to perform aero structural engineering and analysis work for the Johnson Space Center’s FOD as a major subcontractor to another firm selected for SEAM tasks.

The work extends Southern Research’s decades-long collaboration with NASA, which began with high-temperature testing of heat-shield materials for the Apollo program and continues to this day with support of the Space Launch System (SLS) and other critical programs.

The SEAM contract award also builds on the Birmingham-based organization’s relationship with the Johnson Space Center, which has responsibility for planning and executing human space flight missions.

“This is a really great opportunity for us because it expands on the work and support we have been providing to the Johnson Space Center over the past 10 years,” said John Collier, director of the Systems Development Department for Southern Research’s Engineering division.

“We will now have a role in supporting multiple aircraft types for the FOD, and we will support aero avionics as well as participating in structural analysis and flight qualification,” Collier added.

The FOD air fleet includes NASA’s Super Guppy, an oversize cargo aircraft, and the WB-57, a high-altitude research plane and technology platform that has deployed the Airborne Imaging and Recording System (AIRS) developed by a team that included Southern Research.

COLLABORATION

The Johnson Space Center’s SEAM contracts are multiple-award, indefinite-delivery/indefinite-quantity (IDIQ) contracts, with firm-fixed-price and time-and-materials task orders. The SEAM contracts have a combined maximum potential value of $49.5 million over five years.

Houston-based QTS is working with Southern Research on the aero avionics, electrical and software systems contract as a major subcontractor.

In addition, Southern Research is a major subcontractor for Huntsville-based FMS Aerospace on aero structural engineering and analysis work at Johnson Space Center as part of the SEAM contract. This involves a wide range of aircraft support, engineering services, testing, and system integration, among other tasks.