The University of Alabama in Huntsville (UAH) Space Hardware Club (SHC) is working steadily toward a latter November test of the liquid-fueled engine for its ambitious Tartarus rocket design, even as the COVID pandemic has thrown wrinkles into the effort.
“We have been strictly following COVID-19 guidelines from the university and the SHC,” says Project Manager Spencer Christian, a sophomore in aerospace engineering at UAH, which is a part of the University of Alabama System. Christian is from Nixa, Mo.
The project marks the first time SHC has attempted to engineer, construct and fire a liquid-fueled engine. An original goal is to fly a liquid bipropellant rocket up to 30,000 feet for the annual Spaceport America Cup in New Mexico, and the team is focusing now on the 2022 event. Equally important is that team members learn about the theory that drives the design of the rocket.
“Tartarus encourages all of its team members to learn about the science behind what we’re doing, and we have developed much more collective knowledge because of that,” says Christian. “This knowledge further fuels people’s interest in liquid rocketry, and many team members have secured internships or even full-time jobs at rocketry companies in part due to their time on Tartarus.”
The rocket’s payload is undecided but SHC is looking into payload partnerships with other SHC projects or with a group involved in the club’s outreach program.
Target date for the short duration static firing test is Nov. 21 on a rural property in Tennessee owned by Dr. Richard Tantaris, a lecturer in the Department of Mechanical and Aerospace Engineering (MAE) who along with Dr. Gang Wang, an associate MAE professor, advises SHC.
Others involved in project support are Dr. David Lineberry, a Propulsion Research Center research engineer; Scott Claflin, director of power innovations at Aerojet Rocketdyne; and former SHC members and UAH graduates McKynzie Perry, a propulsion engineer at NASA’s Marshall Space Flight Center; Aaron Hunt, an aerospace engineer at Dynetics; Michael Angeles, an engineer at QTEC Aerospace; Dalton Hicks, a test facilities engineer at Blue Origin; Daniel Corey, a test engineer at Blue Origin; and Corgi puppy Gemini Perry, called by Christian “a local canine space enthusiast.”
The test location SHC has selected is ideal since the team will be able to stand behind a hill during firing, mitigating all risk of an explosion shockwave injuring team members, says Christian.
“The Nov. 21 target date for the test is the last possible date it could have been scheduled,” he says. “I wanted to give the team as much time as possible to prepare for the test despite the COVID-19 situation, and thus far setting the date so far back has paid dividends.”
During testing, the engine will be stationary and will fire for just a few seconds – the amount of time it takes to open and close the valves that control propellant flow.
“It is absolutely necessary that this test is short, since things are more likely to go wrong if the test is longer,” Christian says. “Our No. 1 concern is safety, and having such a short test mitigates a plethora of risks.”
SHC’s testing system has 24 instruments to measure pressure and temperature.
“Our goal is to have total visibility of the pressures and temperatures throughout the system so we can more competently assess risk, and so that we can more easily abort the test if a dangerous pressure or temperature threshold is hit,” Christian says.
“Another incredibly important reason to have so many instruments is so that we can measure our engine’s performance and the overall performance of the ground system during the test.”
The team will monitor fuel tank mass flow rate, which is useful for calculating the oxidizer to fuel ratios in the combustion chamber, and the pressures and temperatures in the engine throughout the firing.
“All these numbers help verify that our system is safe, that our engine is performing as expected, and that the ground system is operating nominally,” Christian says. “It would not be feasible to test our engine without these instruments.” Before the actual static fire test, the team needs to run an inert integration test using anticipated test operating pressures for the system. That involves pressurizing the system to 10 times what it would see in normal operation – around 800 psi, using inert nitrogen.
“During the high-pressure test there are a lot of things that can go wrong, but if we can pull through and ensure the system functions as intended under these pressures we will have passed our biggest obstacle,” Christian says.
Also upcoming is a review of test and safety procedures with industry professionals and academic advisors to ensure that they provide for safety and efficiency.
“These are our main obstacles besides inclement weather, and if we can clear them then we will have the go-ahead to finally test the engine,” Christian says.
Since its start in 2017, the from-scratch nature of the project has presented SHC teams with numerous deep challenges, since there was no prior experience with the new and difficult challenges presented by liquid-fueled engines.
“Nobody in the club that had experience designing the components of a liquid rocket engine, like the injector or the nozzle,” Christian says. “Not only that, we had to design a ground system and test stand for the engine as well.”
The ground test system is still somewhat in flux, and he says it has been the most time-consuming and difficult part of the process.
“Even now, one month before the test, we are still making changes and it is very likely that we will continue to make changes after the first test.”
The system had to supply everything required for engine ignition and test firing plus be robust enough to keep it all anchored to the ground.
“Our ground system is incredibly safe, with no single-point failures and a very high factor of safety in the hold-down structure,” Christian says. “The fluid system is capable of running inert nitrogen through the engine at all times besides firing to keep the engine free of contamination, filling the tanks which supply the engine, supplying pneumatic pressure to valves across the system, and pressurizing the tanks with high pressure inert nitrogen.”
All of that is operated remotely for safety.
“Also, since we don’t really want the test stand to fly away during firing, we have a beast of a structure to hold down the engine during firing,” he says. “Weighing about 500 pounds total, not including the force from the cables that will be securing the stand onto the ground, the hold-down structure can stay structurally sound at up to seven times the force we are applying to it.”
The fluid system and hold-down structure were designed by past Tartarus team members and current members are still making productive changes.
“Our team members signed up knowing how difficult this project would be,” Christian says, “and everyone is always ready and excited to face these challenges.”
Besides Christian, the Tartarus team members are:
- Elias Perez, freshman, aerospace engineering, Bakersfield, Calif.
- Spencer Rubottom, junior, aerospace engineering, Waxhaw, N.C.
- Nathan Schmitz, sophomore, aerospace engineering, Oshkosh, Wis.
- Kenton Supplee, sophomore, mechanical engineering, Sevierville, Tenn.
- Jackson Miles, sophomore, aerospace engineering, Wausau, Wis.
- Luke Orwick, junior, aerospace engineering, Lexington, Ky.
- Jacob Jones, sophomore, aerospace engineering, Owensboro, Ky.
- Talon Safreed, sophomore, aerospace engineering, Owensboro, Ky.
- Megan Jordan, sophomore, aerospace engineering, Mobile, Ala.
- Sawyer Bryson, junior, aerospace engineering, Gadsden, Ala.
- Garett Ellis, sophomore, aerospace engineering, Bakersfield, Calif.
- Amber Porteous, sophomore, aerospace engineering, Mobile, Ala.
- David Tutunzhiu, senior, aerospace engineering, Raleigh, N.C.
- Manav Dave, sophomore, aerospace engineering, Herrin, Ill.
- Alexander Jones, freshman, aerospace engineering, Oneida, Tenn.
- Alexandra Fedrigo, freshman, aerospace engineering/mathematics, Grand Rapids, Mich.
- Tanner Jackson, junior, mechanical engineering, Cullman, Ala.
- Tung “Thomas” Nguyen, junior, mechanical engineering, Hanoi, Vietnam
- Noah Adams, sophomore, aerospace engineering, Birmingham, Ala.