Solar Sail for Material Transport in Space



By Claire Cusick, September 2004



Ilinca Stanciulescu"Imagine a huge kite."

That’s how Ilinca Stanciulescu starts the conversation about her doctoral research.

Her research "focuses on the development and implementation of algorithms for nonlinear analyses in structural and solid mechanics".

But let’s hear more about that kite.

It’s actually called a solar sail, and one day it will be used to transport material in space, using for propulsion the photon energy from the sun. Building and testing a solar sail in the environment where it will eventually be used – outer space – is enormously expensive. So researchers, working on a grant from NASA, have to be especially confident that it will work before even creating the full-scale model.

That’s where Stanciulescu comes in. "We don’t have the luxury of doing all the testing here, so we have to have high confidence in our numerical models before sending it off for testing," she said. So she is using her background in applied mathematics and civil engineering to give the designers that confidence before they build it.

For the first few years she was here, she created frictional models for rolling tires. All the algorithms she developed have their place where the rubber meets the road. Since February 2004, she has been working with the solar sail project. It’s something totally different, and, unlike cars and tires, all new.

Back to that kite – the solar sail. It will be made of a framework that supports the sail material and whatever it needs to transport. The sail has to be really light, and have a reduced compacted volume, so as to optimize the efficiency with which a spacecraft can transport it into space. Also, it will have to deploy properly from its storage compartment into usable form. Researchers from several universities and research labs (including NASA Langley Research Center, Duke, Northwestern, the University of Kentucky, James Madison University, and the South Dakota School of Mines and Technology) are involved in a collaboration to develop computational tools for many different aspects of this problem. For her part, Stanciulescu is focused on creating numerical models for the framework – the booms, she calls them – that support the fabric. She is carrying this work out under the supervision of Professor Lawrence Virgin (of Mechanical Engineering and Materials Science) and Professor Tod Laursen (of Civil and Environmental Engineering).

There is no experimental or existing data on what the booms would need to be like – unlike tires – but she knows that the booms must be light, flexible and able to support the rest of the structure.

"At this stage, there’s nothing to compare it to," she said.

A native of Bucharest, Romania, Stanciulescu has always excelled at math and science. Her mother is also a civil engineer, although with a different specialty than Stanciulescu’s. Her mother taught at Technical University of Civil Engineering in Bucharest, where Stanciulescu earned a B.S. and an M.A.Sc. in civil engineering.

"I never took one of her classes," Stanciulescu said.

Growing up, Stanciulescu participated in math and science competitions, including the Math Olympiad. In high school, she won a county-wide prize – but not in math. It was in physics.

"That was kind of a surprise because I was more involved in math," she said.

She continued her studies in math. She had an encouraging professor who advised her to be more practical, to think about engineering, but not to forget about the math. So after earning two degrees in civil engineering, she went back to school again – for four more years – to earn an additional B.S. in Applied Mathematics from Bucharest University – all the while working as a lecturer in civil engineering at Technical University. She came to Duke in September 2000, and should finish her Ph.D. in 2005.

Professor Laursen, her supervising professor at Duke, finds that the combination of mathematical sophistication and engineering experience Stanciulescu possesses is a particularly valuable and rare combination in the structural engineering community.

"Ilinca represents the type of engineer who is uniquely qualified to analyze and design the broad range of modern engineering structures," says Laursen. "Both of the projects Ilinca has worked on while at Duke–— the deployable space sail booms and the sophisticated models she developed of tire-roadway interaction–— are tremendously difficult to analyze using traditional structural and solid mechanics analysis tools.

"Development of the new tools and techniques needed to analyze such systems requires strong background in mathematics and computer science as well as in engineering. Ilinca has excelled in her ability to apply her talents in these areas to a broad range of applications, while having the engineering insight also to make her results practical and readily applicable to the design process," Laursen said.