As scientists continue to sift through the treasure trove of data sent back from the New Horizons probe and its exploration of the confines of the solar system, a key component of this historic NASA mission will soon reside a lot closer to home.
Florida Tech is in the final stages of installing a key test apparatus used in the testing and design of the New Horizons mission: The Spin Slosh Test Rig, or SSTR.
Three years ago, professors Hector Gutierrez and Daniel Kirk from the College of Engineering and Science drove a 26-foot rental truck from the Southwest Research Institute in San Antonio, Texas, back to Melbourne, bringing with them this unique experimental apparatus used for the analysis of liquid slosh on spin-stabilized upper stage missions such as New Horizons. (Upper stage spin-stabilization analysis is essential for the design of deep-space missions, or those beyond earth’s geosynchronous orbit.) Nine such missions were designed by NASA using SSTR –New Horizons was the final one – before the unit was decommissioned.
The donation of SSTR to Florida Tech bolsters the unique capabilities of the university’s Aerospace Systems and Propulsion (ASAP) Laboratory to support liquid slosh research in spacecraft fuel tanks, which now include not just the SSTR but also the heavy slosh linear stage developed with funding from Orbital-ATK (now part of Northrop Grumman), which can be used for slosh studies in tanks up to 5,000 pounds.
“This is a unique experimental facility: it enables slosh research, mission planning and validation, and provides excellent opportunities for students,” Gutierrez said, adding, “We are in contact with interested parties both in NASA and aerospace companies for future use of SSTR.”
Understanding the dynamic effect of liquid slosh on the stability of upper-stage vehicles is critical for the success of deep-space missions. Unlike orbital missions, deep-space upper stages use passive (spin-based) stabilization, instead of thruster-powered vector control. The upper stages of spacecraft such as New Horizons are stabilized based on inertia and conservation of momentum, so precise analysis of liquid slosh is essential.
“The dynamics of upper stages are heavily affected by the distribution of liquid in the fuel tank. This has been a major issue since the early days of spaceflight,” Gutierrez said.
In 2014, Kirk and Gutierrez were principal investigators in the SPHERES-SLOSH experiment – this included the design, construction, deployment and testing on the International Space Station of a zero-gravity experiment to capture liquid slosh data that can be used to benchmark numerical models of the slosh dynamics. The experiment was funded by NASA Kennedy Space Center.
SSTR was originally built under contract from NASA at the Southwest Research Institute, one of the oldest and largest independent, nonprofit, applied research and development organizations in the United States.
“When and if any space agency or aerospace company plans for a deep-space mission, we have the only machine at this time to do the slosh analysis for the upper stage stabilization,” Gutierrez said. “In the meantime, it can be used for several other slosh studies.”
The SSTR installation is in progress and will be completed this year at the ASAP Lab at the University’s Center for Advanced Manufacturing and Innovative Design in Palm Bay.