How to build the first extraterrestrial airplane.
- By Oliver Morton
- Air & Space magazine, January 2000
(Page 3 of 5)
Because of these advances in other fields, by the time NASA’s planetary exploration program started to pick up again in the early 1990s, it could draw on more expertise relevant to Mars aircraft than ever before. In 1992, at the first workshop devoted to NASA’s Discovery program of low-cost planetary missions, a Mars aircraft proposal was put on the table by John Langford, whose company, Aurora Flight Sciences, had developed high-altitude aircraft for NASA to use in programs much like the environmental impact study that had led Dale Reed to design the Mini-Sniffer. Langford had also managed the Daedalus project to build the human-powered aircraft that a cyclist flew 74 miles across the Sea of Crete in 1988.
As the Discovery program developed, more ideas for Mars airplanes surfaced. Larry Lemke’s team at the Ames center came up with a craft that was basically a scaled-down version of the Reed Marsplane of the 1970s. Weighing about 400 pounds, it would fly for six hours or so, land, study the surface, then take off a month later for more cruising. The Ames people even had a target in mind: Gusev Crater, which, evidence suggests, may have once been a lakebed. Water inside the crater might have been warmed by a large volcano more than 100 miles to the north. Many researchers—especially at Ames, where the crater has a particularly passionate set of advocates—think Gusev could hold traces of past Martian life.
Another Ames proposal, done in cooperation with planetary scientist Mike Malin’s small company (see “Getting the Picture,” Aug./Sept. 1999), was MAGE, a mission that used a graceful flying wing with a pusher propeller to carry a suite of geophysical instruments over the Martian canyons. At the same time, a team involving AeroVironment, JPL, and others suggested an even simpler mission, which flew a series of small gliders rather than a single powered aircraft. “We ended up in a situation where we more or less had to choose between carrying a propulsion system and carrying a scientific payload,” says Carlos Miralles of AeroVironment. Flying several vehicles instead of one added resilience. “You can tolerate failures, you can target them independently, you can cover a larger total range and get more diversity than if you are stuck with one airplane trying to fly for a long period of time,” he says. Six gliders would have been popped down at different sites in Valles Marineris. Although each would have flown for at most 60 miles, together they might have provided data on the whole length of the canyon system.
Clever as they were, these ideas were slightly ahead of their time. In November 1998, after the Discovery review panels worried about the risk involved in using unproven technologies, NASA turned down both MAGE and the fleet of gliders. But the December 2003 Wright centennial, which happens to coincide with a favorable launch opportunity for reaching Mars, had already begun to generate a buzz for Mars airplanes. Both proposals had used the name Kitty Hawk—MAGE viewgraphs even had the word proudly emblazoned on the wing.
Edgar Choueiri, a plasma physicist at Princeton University, had also noticed that the Wright anniversary coincided with a Mars launch window, and mentioned it to Norm Augustine, the former Lockheed Martin CEO who had moved to Princeton. Augustine became an enthusiastic proponent of the idea, talking it up to Dan Goldin and others in the space agency, who saw its potential as a Mars Pathfinder–like source of national excitement.
And so it was that the NASA budget came to include a bold, if modestly funded, new project: the Mars Airplane.
To the people at Ames, JPL, Langley, Dryden, Aurora, AeroVironment, and other places who had been thinking about Mars aircraft, the most striking thing about the proposal was how small the vehicle was. The Mars micromissions are parasites lifted to Earth orbit by a European Ariane 5 rocket. While going about its everyday business of launching communication satellites two at a time, the Ariane 5 has enough oomph left over to put very small payloads into highly elliptical orbits around Earth. From there, with the help of a couple of lunar swing-bys to pump up their velocity, such spacecraft can go on to Mars. French and American researchers have all sorts of tentative plans for little orbiters, penetrators, and communications relay satellites that could travel to Mars this way, all based on or carried by a standard “microspacecraft” that the Mars Airplane will be the first to use.
Because of the Ariane constraints, the aeroshell will be at most 30 inches across, meaning that the first Mars aircraft has to fit inside a container the size of a large wok. Even though the airplane will be small, weighing maybe 40 pounds, fitting it in such a tight space will require some clever origami. The designs that Langley worked on last summer had five separate folds. The outer segments of the wings fold in across the body. The vertical rudder flattens itself down onto the tailplane. And the two booms that attach the body to the tail assembly have to bend too (the booms fit on either side of the casing for the parachute, which sits in the small of the aeroshell’s back).