4 weeks ago

UAH modeling the spacecraft for NASA’s nuclear thermal propulsion idea

Successful human spaceflight to Mars and back is bound by basic rules of physics that any home garage hot rodder knows: mass, power and fuel consumption. To complete the mission, there must be enough thrust to propel a spacecraft’s weight to the target destination and enough fuel economy to ensure there is adequate propellant.

Nuclear thermal propulsion (NTP) can help achieve the goals of low weight, high power and good economy. An NTP engine uses low enriched uranium (LEU) to heat a lightweight propellant such as liquefied hydrogen to 2,800 degrees Kelvin through channels in the core.

The expanding gas exits the nozzle, providing thrust. If something goes awry and the craft crashes to Earth, the engine design and use of LEU reduce the chance of a catastrophic nuclear incident to near zero, as well as making flight safer for the crew.

NASA studied nuclear propulsion early on with the roughly two-decade-long Nuclear Engine for Rocket Vehicle Application (NERVA) program that ended in 1972. Current NTP research can be viewed as a modern-day progeny of NERVA.

“The heartbeat of the program at this time is demonstrating that the reactor elements can be manufactured such that they will function in and survive the intense environment internal to the engine,” says Dr. Dale Thomas, UAH’s eminent scholar in systems engineering, who is the principal investigator for a UAH research grant with NASA’s NTP Program Office.

Under the management of NASA researcher Dr. Bill Emrich, who teaches nuclear propulsion as an adjunct UAH faculty member, that testing is underway at NASA’s Marshall Space Flight Center (MSFC) in the Nuclear Thermal Rocket Element Environmental Simulator (NTREES) facility.

As all hot rodders know, swapping engines can pose technical challenges. That’s why NASA has a research grant with The University of Alabama in Huntsville (UAH) to model how a spacecraft might be engineered to work with NTP, en route to an eventual test flight. NASA is currently focused on determining the feasibility and affordability of an LEU-based NTP engine with solid cost and schedule confidence. The space agency has started looking into a potential flight demonstration as a follow-on project in the mid-2020s.

UAH’s Propulsion Research Center (PRC) manages the university’s role in the project. The university’s Complex Systems Integration Laboratory in its Rotorcraft Systems Engineering and Simulation Center (RSESC) is working closely with MSFC and private contractors to solve the challenges and exploit the opportunities created by a nuclear reactor at the heart of a rocket engine.

“We’re trying to figure out – assuming you can make the engine – can we fit it to the vehicle and make it work,” says Dr. Thomas, who incidentally is swapping engines to hot rod a classic pickup truck at home.

UAH’s research focus is not on the reactor design, but rather on modeling the spacecraft during a human mission to Mars.

“How does the utilization of NTP affect the mission architecture and the spacecraft design and operation within that mission architecture?” Dr. Thomas asks. “What all do we have to change in what we’re used to doing in designing a human crewed spacecraft?”

NTP is such a radical departure from liquid fuel rockets that even the NASA phrase “We have ignition” becomes obsolete because the propellant isn’t burning. The crew will be shielded from the LEU in the reactors and will “get more radiation from deep space than from this engine,” Dr. Thomas says. Yet the reactor poses other design challenges.

One of the first problems that NASA asked UAH to research is the heating effect that the NTP engine’s gamma ray and neutron emissions will have on the hydrogen stored in the propellant tanks.

“Hydrogen, which must be in its liquid state to be used as NTP propellant, must be chilled to near absolute zero,” Dr. Thomas says. “And it turns out that hydrogen is a great absorber of neutrons and a good absorber of gamma rays.”

As the hydrogen absorbs the particles, heat is generated.

A team led by Dr. Jason Cassibry, associate professor of mechanical and aerospace engineering, is modeling the behavior of the hydrogen in the system with the goal of keeping it liquid until the precise time it is to be expended.

“Storing hydrogen on a mission for months at a time is difficult, and every little thing that heats up the hydrogen is a problem,” says Dr. Cassibry.

His computer modeling explores the impacts of variables such as the craft’s trajectory and the design of the hydrogen tanks.

“Downstream of the reactor, we’re modeling the flows of hydrogen and using those to validate the data against the results from the NERVA rocket development in the ’60s and ’70s,” Dr. Cassibry says. “We’re looking at the fuel economy and the thrust that comes out of the cone.”

The initial modeling is being done at full power, but Dr. Cassibry expects that in a year or two, the team will begin to model the throttling process.

The stack of an NTP rocket begins with the nozzle, where liquefied hydrogen undergoes rapid expansion. Next up is the nuclear reactor, supplying heat to the nozzle. The reactor will only be powered up once conventional rockets have lofted parts of the craft into space so it can be assembled there. While on Earth, the reactor is in safe mode. Atop the reactor is the hydrogen storage, and atop that is the crew module.

Very cold and very light, liquid hydrogen is also a viscous fuel that can be hard to pump and utilize. UAH is investigating whether injection seeding the hydrogen with a noble gas such as argon would make it flow better. However, the argon seeding will affect engine performance.

“In rocket terms, you talk about specific impulse. How much energy can you get out of a fuel?” Dr. Thomas says. “When an engine is running hydrogen, it has one thrust level. If you seed it with argon, it generates more thrust, but at less efficiency.”

The researchers are investigating whether seeding improves thrust enough make up for the loss of efficiency, while at the same time conferring the benefit of better fuel flow.

NTP engines generate high thrust at over twice the specific impulse of the best chemical combustion engines. They also provide engineers with new opportunities for innovation.

“That’s why NASA brought us on board, to explore opportunities and to kind of look off into the distance to see what might be accomplished,” says Dr. Thomas.

One possibility that would appeal to a hot rodder: Add a conventional combustion component to the nuclear engine. Adding an oxygen tank to create an afterburner that ignites the hydrogen coming out of the nozzle could significantly boost thrust when needed.

Another intriguing opportunity lies in the reactor’s waste heat.

“When you look at it, a Mars spacecraft is going to require a big solar array to get its power, and that creates design challenges of its own in weight and strength,” Dr. Thomas says. “Plus, the farther away you get from the sun, the less efficient those arrays are going to be.”

Because it’s difficult to turn the reactor off and on due to the thermal effect on its materials, it has to idle when not in use. While idling, the reactor continues to generate heat. Perhaps hydrogen can be directed through the core to carry that heat to radiators coated with a thermoelectric compound that generates electricity, Dr. Thomas suggests. Or the heat could be used to run a mechanical generator.

“If we tap the power off the reactor, we may be able to do away with the array,” he says.

Exploring these kinds of design challenges and opportunities attracts graduate students to UAH from universities across the country, according to Dr. Thomas.

“It’s amazing, the team we have been able to build,” he says.

Besides Dr. Thomas and Dr. Cassibry, the NASA grant currently supports four graduate research assistants (GRAs). They are doctoral candidates Alex Aueron and Samantha Rawlins, and masters student Dennis Nikitaev. The team added another GRA position this fall and Dr. Thomas anticipates UAH’s role will expand in the future.

“My attraction to NTP research stems from the understanding that, from a technical standpoint, nuclear thermal propulsion is hands-down the best way to get humans to Mars in my lifetime,” Rawlins says. Because of their orbits, the energy required to travel from Earth to Mars reaches minimum expenditure every 16 years. The next opportunity is in 2033.

“We got to the moon in 8 years, so this is definitely possible, but it’ll require making sure we play our cards right,” Rawlins says.

“That’s what’s so exciting about working with Dr. Thomas on my research within the Complex Systems Integration Laboratory,” she says. “We’re using systems engineering to look ahead, question our current process and identify potential solutions or alternatives before they even become an issue.”

It’s the UAH team’s job to smooth the path for NASA to help it get to Mars, Rawlins says.

“With this research, it feels great to contribute to the next ‘giant leap for mankind,’ sending humans to Mars,” says Nikitaev. “The most challenging task is figuring out how to make all the components work together in a high fidelity NTP engine simulation.”

Being able to intellectually dream about possibilities “is one of the very best things I like about being at UAH,” says Dr. Thomas, who joined the university in 2015 after being associate center director (technical) at MSFC.

“What we’re doing here has wider implications for other areas,” he says. “NTP moves the ball on Dr. Cassibry’s work on PuFF (the Pulsed Fission-Fusion engine). It could even lead to a single stage to orbit engine.”

A hybrid NTP single stage to orbit engine could lead to the resurrection of a program similar to Lockheed Martin’s X-33, a NASA Reusable Launch Vehicle (RLV) testbed that was scheduled to fly 15 suborbital test hops before it was canceled in 2001.

“There’s potential to come up with an air-breathing engine in the thick atmosphere,” Dr. Thomas says, “and then use nuclear power once we get out of the atmosphere.”

(Courtesy the University of Alabama Huntsville)

11 hours ago

Ivey visits hometown Camden to commemorate bicentennial — ‘Y’all, Alabama has come a long way’

CAMDEN — On Friday, on the eve of the culmination of Alabama’s Bicentennial celebration set to take place in Montgomery, Gov. Kay Ivey paid a visit to her hometown to take part in an event marking the milestone in her home county of Wilcox.

Not far from where Ivey attended high school as part of Wilcox County High School’s class of 1963, the governor participated in a ceremony that also included Camden Mayor Bill Creswell and Wilcox County Commissioner Bill Albritton.

After offering a list of the state’s achievements, Ivey remarked on how far Alabama had come.

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“During these 200 years, Alabama has celebrated some pretty incredible people and milestones,” she said. “Building a rocket that took a man to the moon, our rich Native American history and culture, becoming the birthplace for civil rights, and becoming an international market for goods and products. Y’all, Alabama has come a long way.”

She also noted that the events leading up to the bicentennial celebration kicked almost immediately after she assumed the role governor in 2017 and led her to make at least one visit in all of Alabama’s 67 counties.

(Jeff Poor/YHN)

While speaking to the press at the return to her hometown, Ivey expressed how great she felt about being back in her hometown and what her goals were as the state heads into its third century.

“We’re proud to be here in Wilcox County and in my hometown of Camden to celebrate the bicentennial of Wilcox County, and tomorrow we’ll celebrate the bicentennial of Alabama. It is sure great to be home,” Ivey stated.

“Certainly, we want to keep the economy going, keep the everybody working, get more people that are not working to work,” she continued. “We just want to make the quality of life in our state really good, so everybody has an opportunity to be and do what they want to do.”

(Jeff Poor/YHN)

Ivey also offered some words of advice for her hometown and county in the pursuit of a better quality of life.

“Y’all just make this place an attractive place to live and do business, have a strong education system so people can put their children in schools, then in touch with the Department of Commerce to get prospects to look us over,” she said.

@Jeff_Poor is a graduate of Auburn University, the editor of Breitbart TV and host of “The Jeff Poor Show” from 2-5 p.m. on WVNN in Huntsville.

11 hours ago

Three Crimson Tide players, Auburn’s Derrick Brown named Walter Camp All-Americans

University of Alabama football players Xavier McKinney, Jaylen Waddle and Jedrick Wills, Jr. have been named to the Walter Camp All-America second-team, while Auburn University’s Derrick Brown made the first-team.

McKinney is a safety, Waddle is a wide receiver selected to the team as a returner on special teams, Wills is an offensive tackle and Brown is a defensive tackle.

The Walter Camp Foundation announced the honors Thursday evening at the ESPN Home Depot College Football Awards Show.

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McKinney, a junior, ranked 12th in the SEC in tackles with 85 through 12 games. He was also the Crimson Tide leader in tackles this season, including 4.5 for loss and two sacks. He forced four fumbles and added three interceptions to go with five pass breakups and four quarterback hurries. The star defensive back also returned one of his interceptions for an 81-yard touchdown.

Waddle led the nation in punt return average at 24.9 yards per return with 19 for 474 yards and a touchdown, including a long of 77. The sophomore also returned four kickoffs for 152 yards and one score and added more than 53 yards and six touchdowns on 32 catches at wideout this season. Earlier this week, he was selected as a first team All-American at returner by Pro Football Focus and named SEC Special Teams Player of the Year.

Wills anchored an offensive line that has surrendered only 12 sacks in 381 pass attempts this season. He graded out at over 91% for the Tide along the front allowing only one sack all season and only 3.5 quarterback hurries while missing only seven assignments in 714 snaps for a success rate of 99.9%.

Brown had a monster season on the defensive side of the ball and landed as a finalist for just about every national award possible. He was named the SEC Defensive Player of the Year by both the conference coaches and The Associated Press.

This is the 130th edition of the Walter Camp All-America team, the nation’s oldest such team.

Sean Ross is the editor of Yellowhammer News. You can follow him on Twitter @sean_yhn

11 hours ago

Marshall applauds federal court ruling that plaintiffs challenging Alabama’s minimum wage law lack standing

The 11th U.S. Circuit Court of Appeals ruled in favor of the State of Alabama on Friday, saying that the plaintiffs challenging Alabama’s 2016 minimum wage law lacked standing to file their racial discrimination claim against the Alabama Attorney General.

The law being challenged holds that no Alabama municipality can raise its minimum wage higher than the state of Alabama’s minimum wage. The law was enacted by the state legislature after Birmingham attempted to raise the minimum wage paid by businesses in the city to $10.1o per hour. The minimum wage in Alabama is $7.25 an hour. Twenty-two states have similar laws to the one on Alabama’s books.

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In response to Alabama’s new law, the plaintiffs in question from Friday’s ruling filed a civil rights action in federal court arguing the law perpetuated white supremacy and violated the equal protection clause of the 14th amendment.

Notably, the court did not rule on whether the equal protection claim had merit, but rather ruled that the suit was wrongfully being brought because their alleged damages were not “fairly traceable” to conduct by the AG.

“I am pleased with the 11th Circuit’s ruling today, which agreed with the State of Alabama that the plaintiffs had no standing to sue the Attorney General over their complaints about Alabama’s minimum wage law,” said Attorney General Steve Marshall.  “I also think the substance of the plaintiffs’ challenge lacked merit, but the court withheld judgment on that question because the plaintiffs failed to show that the Attorney General ever harmed them.”

Henry Thornton is a staff writer for Yellowhammer News. You can contact him by email: henry@yellowhammernews.com or on Twitter @HenryThornton95.

13 hours ago

Black Belt Workforce Center opens in Demopolis

Private and public officials gathered in Demopolis Friday to announce the opening of the Black Belt Workforce Center.

The center will provide training for job seekers and employers, job application assistance, resume help and a computer lab. The center will also provide retraining and retooling for job seekers who were previously in the workforce but need help competing for the jobs available today.

“We knew that we needed to serve some of our most critical areas in Alabama by creating a center in the Black Belt. This is a place for both job hunters and employers to find resources to help them succeed,” said West Alabama Works Executive Director Donny Jones.

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The center is a collaboration between West Alabama Works, the Southwest Alabama Workforce Development Council (SAWDC), Central Alabama Works, and numerous governmental and nonprofit stakeholders in the area. It will be helmed by Tammi Holley.

The center is very close to the Alabama Department of Labor’s facility in the area, a department with which the training center plans to work in concert.

Jim Page is the CEO of the West Alabama Chamber of Commerce, which houses West Alabama Works.

He told Yellowhammer, “Even though Alabama has got a very strong economy right now and we’ve got record low unemployment, there are still far too many people who are unemployed or underemployed.”

“A major reason for that is the lack of education, lack of training, and lack of certain skill sets needed to compete for jobs, or to get a better job. We’ve long felt it important to go into our more rural areas, particularly the black belt, to make the resources more readily available closer to the people, and meet them where they are,” Page added.

Unique among workforce development initiatives in Alabama is the partnership with a local drug prevention organization: The Parents Resource Institute for Drug Education (PRIDE). The Tuscaloosa-based PRIDE plans to work with the center to help increase drug prevention efforts in the surrounding community.

“One of the biggest problems that workforce development has is keeping kids where they can pass a drug screening,” Derrick Osborne, the Executive Director of PRIDE told Yellowhammer on the phone.

According to Osborne, PRIDE is “trying to help people understand addiction before they become addicted.”

He added, “We want to say, you don’t have to use a drug because you feel like there isn’t anywhere for you to go. There is hope, there are things to look forward to in your life.”

Henry Thornton is a staff writer for Yellowhammer News. You can contact him by email: henry@yellowhammernews.com or on Twitter @HenryThornton95.

14 hours ago

Watch: Alabamians line up with American flags to welcome slain Naval ensign home

As seen in a video posted on Twitter, people lined the streets of Enterprise on Friday to welcome home Navy Ensign Joshua Kaleb Watson.

Watson, a 23-year-old Coffee County native who also spent many of his formative years in Blount County, was killed in last week’s shooting at Naval Air Station Pensacola.

The hero’s body arrived at Dothan Regional Airport on Friday and then a procession took him to Searcy Funeral Home in Enterprise.

Considering Fort Rucker’s presence, the area has a high percentage of military families, making Watson’s murder that much harder on the Wiregrass community. People lined the procession route with American flags, honoring his service, sacrifice and life.

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A public memorial service for Watson will take place at the Enterprise High School Performing Arts Center at 11:00 a.m. next Saturday, December 21.

Burial will be the following day at the Alabama National Cemetery in Montevallo. Governor Kay Ivey has ordered flags to half-staff on that day of internment: Sunday, December 22.

RELATED: How the hometown of a NAS Pensacola shooting hero is paying tribute to one of their own

Sean Ross is the editor of Yellowhammer News. You can follow him on Twitter @sean_yhn