Airships may be the key component in a new robotic system for exploring the celestial bodies most likely to harbor life like Mars and Jupiter's moon, Titan.

The dirigibles would provide regional observations and autonomous command for ground-based vehicles, while maintaining contact with orbiters.

It'd be a new role for airships, which were the wonder of the aerial world in the days before airplanes (and rockets and space shuttles).

"The balloon or airship has a lot of advantages: It's buoyant, so it keeps its altitude and you do not need to invest energy to keep it afloat," said Wolfgang Fink, who led the work at Cal Tech's Visual and Autonomous Exploration Systems Research Laboratory, before accepting an appointment at the University of Arizona. "It has a lot of advantages, especially in places like Titan, which has a dense atmosphere that's perfect for an airship."

Current robotic exploration missions are limited. Orbiting telescopes like the Mars Reconnaissance Orbiter provide low-resolution views of vast swaths of a celestial body while rovers and landers provide detailed observations of a tiny region. Fink argues that we'll need teams of robots to do any serious exploration looking for interesting features that might tip us off to the presence of life or geological activity.

And on planets with atmospheres, airships are the ideal middle layer for "tier-scalable reconnaissance," a vision Fink has spelled out in a series of papers over the past several years.

To test how teams of autonomous robots working together could explore an area, Fink's team built a miniature lab version of the system, as seen in the image above. At just 4 feet by 5 feet, it's not exactly the surface of Mars, but it allowed the team to test a piece of software that picks out anomalous objects in a landscape, the Automatic Global Feature Analyzer.

The software doesn't try to place what it reads in images into known categories. Surveying a scene, it doesn't try to identify certain kind of rocks or geological features. Instead, it just looks for the odd stuff out — the Waldo — in the scene. For a place like Mars, where we know a lot of the territory is similar and seemingly lifeless, the weird stuff is probably the good stuff.

"If you do not know what you will encounter, you have to embrace the unknown," Fink said.

With the miniature lab tests complete, Fink plans to take his show on the road, probably to the Arizona desert. Over a large geographic region, they'll float an airship with on-board camera and release rovers controlled by the feature analyzer software.

"For initial test purposes, we could put a Coke can and see if the science algorithms will flag these anomalies," Fink said, "And then, once they are flagged, generate the navigation commands that are issued from the airships to the ground."

They plan to try the Coke can test in the next year. As time goes on, they will try more difficult terrains out because ultimately, it's the extreme areas of other planets that could prove the most interesting. By keeping the ground units cheap, they can also have more of them, allowing the missions to take greater risks.

"Mountain ranges, canyons, cliffs – those are the locations where interesting stuff might happen," Fink said. "You need to be able to get into those high-risk areas to get a nice and interesting science return. You might lose some of these agents you deploy, but because they are simplified, you can deploy more of them and still afford to lose some of them."

The entire system — satellite, airships and ground rovers — could be ready to go in the next decade, which would be long before NASA could actually use it.

Image: 1. NASA/JPL. 2. Wolfgang Fink. 3. The invasion of Normandy, U.S. Coast Guard Collection.

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