Instant Glider--Just Add Light.
May 2, 2003: Tomorrow a high-altitude balloon will rise to the edge of space, bringing with it a small glider. Under the space-black sky 100,000 feet above Earth, the glider will sprout a pair of inflatable wings from its sides. Ultraviolet rays from the Sun will harden them to flight readiness.
Above: A Mars glider may someday offer scientists a long, up-close look at the Red Planet's surface. Image courtesy NASA.
"Who knows? Some of the students who have really enjoyed this project may find themselves working professionally on a glider probe in the future to explore the Red Planet," says Suzanne Smith, associate professor of mechanical engineering at the University of Kentucky and one of the faculty advisers for the project called BIG BLUE--short for Baseline Inflatable Glider Balloon Launched Unmanned Experiment.
A glider soaring over the surface of Mars could take a much closer look than an orbiting satellite, while also covering much more territory than Sojourner-like rovers.
It's an elegant solution to the problem of bulk, but it presents a different problem of its own. Flexing of the inflatable wings during flight makes the glider unstable, and this flexing is particularly bad for the long, thin wings needed for Mars.
To get rigid wings out of an inflatable package, the students are using a little chemical wizardry to stiffen the wings after inflation.
All they need is a little help from the Sun.
Below: The wings consist of parallel, inflatable tubes that can be packed within the fuselage when deflated, as shown at left. Pictured here are Scott Massa, Aaron Welch and Nathan Shewmaker, UK undergraduate BIG BLUE team members. Photo courtesy UK.
"We're working with ILC Dover, Inc., to custom-tailor an epoxy material that hardens when exposed to UV light so that it cures properly at the temperatures and UV intensities at that altitude," says Smith, who oversees the project along with professors Jamey Jacob, James Lumpp, and William Smith, all at UK.
At the altitude where the glider will deploy its wings tomorrow the Sun's ultraviolet radiation is much more intense than here on the ground. Both the high radiation and the sparse air at 100,000 feet resemble conditions on Mars, thus making this test a reasonable approximation of what might happen on a real mission to the Red Planet. The radiation would be dangerous for you or me, but it comes in quite handy for transforming the balloon-like wings into structurally rigid flight surfaces.
"It's similar to the UV-hardened tooth fillings that dentists sometimes use," Smith explains. The details are complex, but basically when the photons of UV light strike the molecules of the epoxy material, they induce a chemical change that turns the goopy epoxy into a hard solid.
Presto! Instant glider.
Working with the pros
Beyond developing a potential Mars exploration technology, the idea behind the project is to give university students an enticing taste of working on real, ambitious aerospace projects.
The glider is much more than fancy wings and a body. Computerized autopiloting, electronic tracking and communication hardware, and optical measurement of wing shape and performance during flight are just a small part of the complexity of a workable glider designed to gather scientific data about itself.
Right: Electronic circuitry and optical surface-measurement equipment add to the complexity of the glider. Photo courtesy UK.
The 40-plus students have worked together with professional scientists and engineers at several NASA centers, the National Oceanic and Atmospheric Administration (NOAA), and ILC Dover, the company that makes astronauts' spacesuits and specializes in strong, inflatable fabrics.
ILC Dover is manufacturing the inflatable, self-hardening wings for the project--to match specifications provided by the students--and the balloon launch is being handled by Edge of Space Sciences, a non-profit group based in Denver, Colorado.
"All these professionals make a point of treating the students as peers working on a collaborative project--not like they're on a class field trip," Smith says.
For example, NASA's Langley Research Center worked with the students to incorporate advanced surface measurement technologies that use beams of light to measure the shapes of the wings during flight (called "photogrammetry"). It's the same technology that NASA engineers are developing for use with solar sails and other "gossamer" spacecraft. Other student teams worked with NOAA to predict UV intensities at the precise altitude, location, and time of year when the flights will be performed.
The test flight happening tomorrow over Colorado will only check the deployment of the wings and the operation of the onboard electronics; a parachute will bring the craft back down to earth. In the fall, a new group of students will pick up the project and refine the design.
All the hard work will culminate in a full-blown test flight this coming January, when the glider will actually fly back down. For the students who can't attend the test flights, and for anyone else who's interested in watching the progress of the flights, telemetry data will be broadcast live on the web.
For the students and their collaborators at NASA, watching their brainchild sprout wings and fly home from the edge of space will certainly be an unforgettable experience. And one day they just might get to see their concept spread its wings over a planet of a redder hue.
BIG BLUE -- home page from the University of Kentucky
Edge of Space Sciences -- detailed information about the high-altitude balloon launch that will carry the glider to the edge of space.
Live tracking of the flight -- from the EOSS Web site
NASA Mars glider prototype completes test flight (NASA Ames Research Center)
Design your own Mars glider -- educational activity from NASA Quest