KINGSTON, R.I. – Feb. 3, 2022 – Thirteen University of Rhode Island mechanical engineering students are working with NASA and other prestigious universities on a project that could cut in half the travel time for a human mission to Mars.
The project involves nuclear thermal propulsion, which scientists and engineers say can get astronauts to Mars more quickly and safely than they can with current chemical propulsion and technology. The students are enrolled in Professor Bahram Nassersharif’s senior capstone mechanical engineering class, which spends a year working on problems or projects from industry and then delivers design and/or production recommendations, prototypes and more.
When Nassersharif, distinguished university professor, capstone design director and professor and Nuclear Engineering Program director, first set up the project, he envisioned a four-student team.
“I introduced the project at the start of the class in September and there was so much interest, I decided to create three separate teams,” Nassersharif said. “Since the very beginning, they have been very dedicated to the project. The three teams all work well together and with their colleagues on the teams at other universities. I am very impressed with their communication and organizational skills.”
According to Nassersharif, the project involves a proposed nuclear thermal propulsion system with 19 fuel tubes partially filled with uranium metal. The uranium melts at a temperature of 2,070 degrees Fahrenheit. The work of the URI students centers on getting the fuel tubes to spin fast enough to spin the uranium liquid metal at startup, during the bulk of the journey, and at completion so that the liquid uranium stays attached to the walls of the tubes and does not escape. In other words, the students are working on a system that generates centrifugal force. To produce the necessary spinning, hydrogen would run through the walls of the rocket, cooling the fuel tubes. And as the hydrogen heats up, it becomes the propellant that exits out of the rocket’s nozzle and sends the spacecraft on its way.
Advantages of thermal nuclear propulsion
So what are the advantages of nuclear thermal propulsion over the current and best chemical rockets in use today?
- It needs far less fuel and therefore less weight to be transported during the journey.
- It can achieve as much as a 50% reduction in travel time when compared with chemical propulsion.
The Massachusetts Institute of Technology, Pennsylvania State University College of Engineering, University of Michigan College of Engineering and the University of Alabama, Huntsville, are the other academic collaborators.
The URI students are focused on three parts of the project, all of which are integrated with the work of the other collaborators.
- Team 1 is working on starting the rocket, which means melting the uranium fuel. But before that happens, the students will have to get the fuel tubes spinning, Nassersharif said. He said potential solutions could include an electric motor or using hydrogen in a turbine to get the tubes spinning. The goal is to get the tubes spinning up 200 revolutions per minute at the outset.
- Team 2 is working on the tubes’ normal operation during the flight, including increasing and decreasing speeds. The goal is to keep the tubes spinning synchronously, starting at around 250 revolutions per minute to several thousand per minute.
- Team 3 is developing a 3D, plastic, desktop model of the system so that teams across the project can examine the engine’s assembly and its geometry to see how it all fits together.
The URI teams made two presentations in class during the fall semester and will deliver two major design presentations during the spring semester, “a build-test report” and final design showcase, which will include a working model. Michael Houts, the nuclear research manager at NASA’s Marshall Space Flight Center, participated in the fall presentations by Zoom.
“URI students are performing important research related to the Centrifugal Nuclear Thermal Rocket (CNTR), and we are extremely glad they are part of the research team,” Houts said recently. “Their work is excellent, and they continue to make significant contributions to the advancement of the CNTR high performance space propulsion concept.”
Student Jacob Murphy of Coventry said, “The goal of his team is to develop, by the end of the spring semester, a prototype 3D model of the engine. Our entire group is only focused on the mechanical portion of the rocket.”
“Basically a nuclear reaction heats the uranium, which then heats the hydrogen, which then becomes the rocket’s propellant,” said Connor Venagro, also a member of the 3D model team from Cranston.
Seeds of the project
The seeds of the project were sown when Nassersharif met NASA’s Houts, the nuclear research manager at NASA’s Marshall Space Flight Center, at a conference of the American Nuclear Society. One of Nassersharif’s master’s degree students, Miguel Lopez, talked with the professor and Houts about the project, and then they decided to develop a proposal. It was submitted to NASA’s Rhode Island Space Grant Consortium at Brown University, which provided funding for the project. Houts is the NASA mentor to the URI students.
“One of the great things about this project is that our students meet (remotely) with students from the other schools and they talk about their projects, which are different from URI’s. But being able to share ideas helps connect all of the students to the wide ranging work being done on this,” Nassersharif said.
The buzz among students in the classroom in URI’s Fascitelli Center for Advanced Engineering was palpable one afternoon as they discussed the project and what it means to them.
“Part of the problem with a chemical rocket (traditional rocket) is the amount of time it would take to propel it to Mars,” said Marco DeFruscio, a mechanical engineering major from Providence. “Being able to get to Mars in an efficient manner is the goal of this project. There is lots of competition to prove that we can get humans to Mars.”
In the 1960s, NASA worked on nuclear propulsion for its rockets, but fears around putting astronauts next to a nuclear fuel source, and public controversies around nuclear power over the decades, made it difficult to proceed with that option, according to Zachary Hermanson of Woonsocket.
“But this technology is very similar to what we use already in our submarines and surface ships,” Hermanson said.
“All of us in Team 1 have worked in the nuclear submarine arena,” said North Kingstown’s Rachael Bjorn, another member of team one.
Nassersharif added that some of the 13 students have taken at least one of 10 nuclear engineering courses offered by the University and several are physics, mathematics, and nuclear engineering minors.
“Working with NASA has been a dream of mine since 9th grade when I did a National History Day Project on Neil Armstrong,” Hermanson said.
Bjorn, who is a mechanical engineering-German double major, said her mom told her when she was young that she wanted to be able to say, “My daughter, the rocket scientist.”
“And when this actually does happen, I can say I had a hand in that,” Bjorn said.
“Working on this project is very cool,” said Danny Kruzick of South Windsor, Connecticut. “Like most kids, I wanted to be an astronaut. The science of space and the engineering to get to space are two demanding disciplines. It’s not guesswork.”
Collin Treacy of Ballston Spa, New York, an applied mathematics and mechanical engineering student, said the course incorporates everything he and his fellow students have learned during their first three years in the mechanical engineering program. “This project brings together physics, chemistry, engineering and math.”
Honghao Zhen of Westerly, Rhode Island, knows that such a course is “important because it gives me a start in the space industry and it could lead to careers with NASA or aerospace firms. We have spent many late nights together in virtual and in-person meetings. We have even looked at old textbooks for background.”
Murphy and Venagro said among the most enjoyable parts of the project are working with students at the other schools and interns at NASA.
“This rocket is an entirely new concept,” Venagro said.