“I was always fascinated by the albatross.”
Just one question in, and my interview with a Nasa chief scientist about exploring Mars has already taken a surprising turn. But throughout Al Bowers’ career birds have been his inspiration.
“Once you get used to looking at bird wings properly it’s difficult to go back to aircraft wings,” says Bowers from Nasa’s Armstrong Flight Research Center at Edwards Air Force Base in California.
“The wing dominates all the characteristics of the albatross and they have very high efficiency,” he says, “and that’s what we’re trying to achieve with aircraft now – eliminating all the unnecessary parts like tails.”
Bowers calculates that designing aircraft without tails could reduce drag by some 20%. “Pretty soon you get down to a pretty minimal aircraft – a flying wing – with the minimum of parts, a minimum of drag and a very high efficiency.”
The flying wing isn’t a new idea. The first practical design was developed by engineers in Nazi Germany in the final months of World War Two. The reason we are still whizzing around the globe in aluminum tubes with tails bolted to the back is that flying-wing aircraft have had a tendency to fall out of the sky.
Not anymore. Bowers’ team has spent the last few years developing and successfully testing models of flying wing aircraft. But, as befits the world’s foremost air and space organisation, Bowers is not only looking at terrestrial applications. He aims to become the first person to fly an aircraft across the surface of Mars.
“Mars is an incredibly hard problem,” says Bowers. “Flying on Mars ends up forcing you to look at aerodynamics in a very different way.”
Although Mars has about one-third the gravity of Earth, it has very little atmosphere – around 1% of Earth’s. “You end up having to fly something very small in order to get some interaction with air molecules,” says Bowers. “It’s similar to flying at around 30,000 metres above the surface of the Earth.”
A traditional aircraft would have little chance of staying aloft but a flying wing, with its increased efficiency, should be able to drift high above the surface. It could transform Mars exploration.
“The big limitation for rovers is the amount of surface they can cover,” says Andy Ratcliffe, a systems engineer for Airbus’ future programmes. The aerospace company is currently developing a European Space Agency (Esa) Mars rover at its Stevenage site in eastern England. The vehicle is due to land on the Red Planet in 2020.
“The most recent rover that landed on Mars is Curiosity,” says Ratcliffe, “but since it landed in 2012 it was only travelled nine kilometres – that’s around two kilometres per year – and when we’re trying to do a lot of surface science it limits the amount we can explore.”
Rovers have their advantages. They can study the ground in detail, take samples and the Esa rover will even drill into the surface to investigate signs of life. But aircraft can cover much more terrain.
Bowers’ pioneering Mars mission involves an unpowered flying wing just 60cm across and weighing only 1.5kg, which will be folded up into a 30cm-long cubesat spacecraft. The idea is to carry this as ballast on a future rover mission. It would replace some of the mass commonly used on Mars missions to help give spacecraft spin during the long cruise to the planet.