DENVER, COLORADO -- To better reconnoiter the Red Planet, scientists and engineers see high-tech robotic aircraft offering unique advantages. One innovative glider design, currently undergoing trial runs, is built to deploy instruments in scientifically rewarding but tough-to-get-to spots on Mars.

The remotely operated 8-foot (2.4 meter) flying wing is one of several projects a group of independent scientists and engineers are working on preparing. The objective: to construct safe, smart, and autonomous landing vehicles and systems for investigating Mars and other worlds.

A second generation flying wing for Mars took to the skies here June 1, put through its paces just outside the borders of Denver International Airport. The craft made a series of low-altitude runs to check its stability and control at various speeds, including near zero velocity landings.

Berger has been working the glider design as part of a Mother Goose mission team -- a project to carry out astrobiology research on Mars -- led by Equinox Interscience of Golden, Colorado.

The prototype Mars wing features no tail, relying on only two control surfaces that handle both pitch and roll. "The reason it's appealing to us for Mars is packaging. All you've got to do is unfold wings. You've got everything you need to control the whole aircraft in just two controls," Berger said.

Dan Scheld, vice president of engineering for Equinox, said the team is now at work on giving the Mars wing built-in smarts to ferret out science targets while in flight.

"The idea is to give the plane science cues so it can land in an area of interest. That's really the key feature. To land safely where it counts and where the science demands," Scheld said.

Berger said the Mars wing idea is a multi-phase, step-by-step project.

As a next step, plans call for a Mars glider development model with a 21-foot (6.4-meter) wing span to be built and airborne later this year, Berger said.

An evolved ready-for-Mars craft would sport a nearly 65-feet (20-meter) wing span. Also, that wing would be inflatable and topped by energizing solar cells.

A technology push is underway to provide the Mars wing with a good dose of brainpower and sensitive sensors. On Mars, the plane would decide for itself where the best winds, thermals, and atmospheric conditions are in order to stay aloft for multiple hours.

That on-the-job, onboard intelligent decision-making would allow the Mars wing to remain in the air longer, carry out more science on the fly, and pick a top-notch landing site. Eyeing the Martian terrain from on high, the instrumented wing would make its robotic mind up about dropping down on the most scientifically rich real estate.

Berger said that the Mars wing, once landed, might be capable of relaunch using a foldable propeller. "If we're inventive enough, I think we could fly to another site. We certainly can use it as a ground-based power station for scientific payloads that can recharge, using the huge wing with its solar panels," he said.

In the near-term, simulated science mission scenarios are on tap, flying over Mars analog environments. An ultimate goal is to conduct a full Mars mission simulation using a balloon to drop test the wing from high-altitude.

"This plane shows that a good design can overcome brute force, complexity and mass," said Penny Boston, of Complex Systems Research, Inc. in Boulder, Colorado.

Boston is lead astrobiologist on the Mother Goose mission team. The proposed concept utilizes a Mars plane to deposit small-scale rovers and other gear in areas of high scientific interest, including micro robots that crawl into caves. She said that planetary landing systems are vital to future science studies on Mars.

Next generation landing systems, Boston said, must be an active extension of the field scientist. It should be autonomous, learn from the environment, deal with unexpected conditions, and make landing target decision based on science and safety inputs.

Boston said that the Mars wing could drop experiments as it coasts about. "I'm thinking numerous, cheap, and really small devices so you can carry a lot of them. You just throw them out like breadcrumbs, she said.

At present, NASA has no firm plan to dispatch robotic aircraft at Mars.

However, experts at several space agency facilities -- such as the Ames Research Center, the Jet Propulsion Laboratory, Langley Research Center, and the Glenn Research Center -- have blueprinted or have built Mars plane concepts.

In addition, one Mars aircraft scheme, among ten selected projects, was granted study money last year under the NASA Mars Scout program. Scientist Wendy Calvin at the University of Nevada, Reno, has proposed the "KittyHawk" mission - sending tiny, fold-up gliders into Mars' Valles Marineris Canyon.

NASA's Mars Exploration Program is to pick later this year a Mars Scout mission for possible 2007 launch to the Red Planet.