Like many boys, Alexandre Martin often dreamed of exploring space as an astronaut. Then he grew up, and his work as a mechanical engineer veered instead to the study of electrical arcs in circuit breakers.
Now an assistant professor at the University of Kentucky, Martin's research has come back around to his childhood dream: He and a research team just received a $1 million grant from NASA to improve the heat shields for spacecraft as they enter a planet's atmosphere.
So while Martin won't be spacewalking himself, he'll be working on ways to improve the spacecraft that make it to distant planets like Mars and Venus.
As Martin explained it, vehicles in space have to go very fast but must slow down as they enter an atmosphere. That generates an enormous amount of energy that can heat up the craft and transform it into a fireball. So those vehicles need extra-thick exterior heat shields. But thick heat shields also take up the mass that could be used for more equipment, such as exploration robots or the specimens that could be brought back to Earth.
"If you're spending your usable mass in heat shields, that's mass you can't use for your robot," Martin said. "If it's three times as thick as it needs to be, you can't take as much equipment as you should."
The heat shield material is like a carbon matrix with little holes, and you fill the holes with resin. But there is still much about these materials that researchers don't understand, Martin said, especially how different materials might react with different atmospheres in space.
Martin will spend most of his time on a computer, doing numeric modeling of the different materials and how they will work. He will be helped by Shi Chen, a professor at Kentucky State University, who will interpret those algorithms for graphical processing. Fellow UK professors Sean Bailey and Michael Winter will work on the experimental materials themselves. The entire team, including graduate and undergraduate students, and two high school students from the Math, Science and Technology Center at Paul Laurence Dunbar High School, will be working with researchers at NASA sites in Ames, Calif., and Langley, Va.
The grant is being administered by the NASA Kentucky EPSCoR, or Experimental Program to Stimulate Competitive Research, which is housed at UK.
"What I hope is that one of those vehicles will use the research we did," Martin said. "It's so theoretical, I will never be able to think this my heat shield, but I hope we will have contributed to understanding the process."