Winner: Noël Bakhtian
Engineering Student of the Year seeks technological key to landing bigger mission payloads on Mars
Nothing bigger than a small car could be landed on Mars, at present. But Stanford University student Noël Bakhtian is pursuing research that might change all that.
Winner of the 2011 Boeing Engineering Student of the Year award, conferred in association with Flightglobal, she is closing in on a PhD focused on supersonic retro propulsion – which may be the key to resolving entry problems posed by the Red Planet.
NASA’s Mars rover Curiosity, to be launched on 25 November, is “about the size of a Mini Cooper”, says Bakhtian. “If we ever want to be able to land larger payload missions, such as human missions or sample-return missions, we’re going to need new technology to land these vehicles on the surface.”
The main issue is Mars’ very thin atmosphere – surface pressure is about 1% of Earth’s. “So we don’t have that big cushion of atmosphere to decelerate once we get to Mars,” says Bakhtian.
That’s where supersonic retro propulsion comes in. The concept is that the rocket thrust used to accelerate vehicles can be turned in the opposite direction for deceleration by directing the jets into the free stream flow. But it is the “supersonic” bit that distinguishes Bakhtian’s research, part of a wider project by NASA and collaborating universities.
“Everyone is familiar with seeing sci-fi films or even the Mars landers, where they land with retro propulsion, but at very low speeds,” she says. “We’re doing this in the supersonic phase of flight. If we want to land big-mass missions, we need to start decelerating much higher from the surface. We need to initiate it when the vehicle is going faster.”
Supersonic speeds bring their own flow physics, complicated by phenomena such as bow shocks. If methods based on engine thrust represent a brute-force approach to achieving deceleration, Bakhtian’s team is seeking to position jets as flow-control devices and to manipulate the vehicle’s shock structure to gain more drag in deceleration.
Her background is in fluid dynamics, specifically the computation of air or water flow around bird wings or aircraft. “But I’ve always been drawn to everything to do with space,” she says. “The problem is that space, by definition, doesn’t contain any fluid, it’s a vacuum, so there’s very little fluid dynamics to compute in space. But other planets have atmospheres, so landing on Mars is definitely a fluid dynamics research area.”
The area to which she gravitated is known as EDL (entry, descent and landing). “I was actually searching for a PhD topic for about a year trying to find something I would love so much that I wouldn’t mind spending x years of my life working on,” she says. “One day I got an email from my NASA supervisor, Michael Aftosmis, and he mentioned a new NASA project on SRP – supersonic retro propulsion – for high-mass EDL, and that was it. I was hooked.”
Growing up in Tennessee and Florida, Bakhtian developed a love of science and maths but “didn’t really know what engineering was until senior year” at high school. “Even back then, I loved space and aerospace, but I didn’t have a name for it,” she says.
She opted to go to Duke University in North Carolina to study mechanical engineering. “I didn’t want to specialise too fast, in case I didn’t like it,” she says. “I actually got into MIT and Caltech and decided, ‘Wow, that’s specialising’.