For just about any world you can name in our solar system that has an atmosphere, some future-minded engineer has proposed sending an airplane. Unfortunately, the list of such places is short: Earth, Mars, Venus, Titan, and possibly the outer gas planets.
Marco Quadrelli, a senior research technologist in the robotics section of NASA’s Jet Propulsion Laboratory, thinks he may have found a way for a CubeSat to “fly” over the airless surfaces of comets and asteroids, using electrical charge rather than aerodynamic lift. His “E-Glider,” as it’s called, just received a grant of $100,000 under the NASA Innovative Advanced Concepts program to explore the concept. The program is intended to examine far-out ideas to advance space technology, and generally focuses on ideas that are a decade or more from hitting the launch pad.
Only a handful of spacecraft have landed on the surfaces of comets or asteroids, which, despite their small size, are challenging targets to explore. When the European Philae spacecraft landed on Comet 67P/Churyumov–Gerasimenko in 2014, it encountered a wildly changing environment. Parts of the comet rapidly alternated between sunlight and darkness. 67P’s rotation kept changing with the pressure of the sun, and vents would appear on the surface in response to the heat. This made the landing—although not fully nominal, as Philae drifted far off course— a technological feat.
“These bodies are very complex, very exotic. They have strange physics, they steam, they tumble, they are small, they are of strange shapes,” says Quadrelli.
His E-Glider would use an electric field sensor to map the electrical charge at the surface of an asteroid or comet. That charge can cause dust to levitate off the object, and would do the same for a small, light spacecraft. A small camera on the E-Glider would keep an eye on the surface below for scientifically interesting landing spots. It would “fly” from spot to spot on the surface using very thin metallic wings, such as Mylar, to effectively repel the charge and stay aloft. When it needed to drop to the surface, the glider would simply furl its wings. To anchor in place, it could deploy a retractable harpoon. The light gravity of the small body would allow the E-Glider to lift off again by releasing the harpoon and unfurling the wings.
Quadrelli and his team intend to use their NIAC money starting this June to refine the concept by addressing such questions as what material the wings should be made of, which objects a glider might visit, and what instruments it could carry.