A University of Maine researcher and his team are studying ways to make inflatable structures rigid and durable, which could help make a lunar habitat for astronauts.
Vince Caccese, associate professor of mechanical engineering, is studying ways to rigidify inflatable structures and protect them from harsh environments in order to make materials that are strong and innovative in design. These materials could someday help NASA create a lunar habitat for its planned return to the moon in 2020.
"Our main thrust is on maybe coming up with an innovative concept or two that might help [NASA], and mostly education [of students]," Caccese said.
Among the problems involved in living on the moon is designing a building that can withstand the minus 243 degrees Fahrenheit temperatures, micrometeorite impacts, moonquakes, cosmic rays and solar radiation.
Caccese, along with help from professors in mechanical and civil engineering and students, is testing ways to eliminate shearing strain, which is inherent in inflatable structures, by making parts of them rigid. The method Caccese uses is similar to a composite resin-fiber coating that can be used to strengthen a material when a catalyst-such as heat-is applied. Caccese said the exact method he and his team are testing is slightly different.
Another aspect of the research was optimization and analysis of the structures designed, which Senthil Vel, associate professor of mechanical engineering, is working on, in conjunction with Caccese.
Vel uses computerized genetic algorithms, which select different structures from a "population," and then lets them evolve into better and better forms, and allow him to find the best way to optimize the design of a building. One algorithm can go through thousands of generations before it meets its desired solution.
"We use a certain process of selection based on fitness-basically a survival of the fitness philosophy-and fitness is defined as how well the structure performs. It's more or less mimicking nature," Vel said.
Vel said load-carrying capacity, reduced mass and a high stiffness are some of the main objectives in designing a lunar habitat.
Ali Abedi, assistant professor of electrical and computer engineering, also works with Caccese, by designing wireless vibration sensors that can be used to monitor a lunar habitat's reaction to micrometeorite impacts and other hazards. The space shuttle uses similar sensors in its impact detectors, but they require miles of wires to operate, making them expensive and heavy. Wireless vibration detectors, like the ones Abedi studies, eliminate wires, but problems arise from signal interference between them and similar technology.
"If we can successfully network all these different sensors, we can basically eliminate all those wires," Abedi said.
Abedi says that the sensors must be able to withstand contrasting hazards such as the intense heat of a space shuttle's engines, as well as the cold moon environment. Abedi's research also focuses on making sensors for detecting other environmental and mechanical factors, such as temperature, radiation, air quality and gas.
Caccese said he keeps in touch with NASA, which expressed interest in the research, but which has its own teams of engineers designing the lunar habitat. NASA has contracted with Bigelow Aerospace Corporation and ILC Dover to build its lunar habitat.
Caccese's research is funded through money from the Maine Space Grant Consortium.
Caccese worked at the Johnson Space Center two years ago, helping to design an impact detection system for the leading edge of space shuttle wings, which was used successfully on post-Columbia missions.