Getting to Know You

Trusted travelers, known shippers: Some ideas for airport security make common sense. Some, such as security systems built into airport structures, could be cost-prohibitive. Others are just plain icky, like a proposal to identify travelers by examining flakes of their skin. Still others are fascinatingly high-tech and could be coming to an airport near you.

The passenger screening devices discussed here are more likely than most to be adopted, because they all have one thing in common: a presence in airports already. Electronic noses are being put to the test this summer at security checkpoints across the country. A holographic scanner that underwent government research trials at Seattle-Tacoma International Airport more than a decade ago has been licensed to industry. Boston's Logan International Airport is considering whether to augment a traveler interview experiment with chillingly probing truth-verification software. A full-body X-ray scanner got a frosty reception during tests at Orlando International Airport two summers ago, but improvements are coming. "There's too many privacy issues to be able to image through clothing . . . unless we do some really effective methods of masking the private areas of the body," says Mark Laustra of Smiths Detection in Pine Brook, N.J., TSA's main supplier of luggage X-ray machines.

But the best way to prevent terrorism is to predict it, and being able to mine all sorts of data gives government that capability, argues Boeing's chief airport security technologist, Tony Swansson. So officials are seeking to collect and combine every kind of data, whether it's DNA, holographic images or flight itineraries. "You have to be sensitive to people's personal details," Swansson says, "but the ability to network sensors is a force multiplier in terms of detection."

Pieces of the technology necessary to balance seamless security with smooth travel in the future already are appearing in airports. Biometric identification will be deployed widely within six years and will become more accurate and less intrusive over time. The heating, air conditioning and ventilation systems of a few major airports have been equipped with large machines that sniff the air for harmful biological and chemical agents.

Underneath Your Clothes

SafeView Inc.'s holographic imaging system spots objects made of metal, plastic, ceramic and other materials under clothing without the use of potentially harmful ionizing radiation. It bounces radar waves off a person and reveals what she's carrying. The scanner can be programmed for privacy, to show just the objects and not the body. The Energy Department's Pacific Northwest National Laboratory developed the technology for the Federal Aviation Administration to screen passengers for concealed weapons, and licensed it to the Santa Clara, Calif., firm.

What's That Smell?

The first new technology to reach airport passenger checkpoints since the 1970s is explosive trace detection. Airports in Rhode Island, California, Florida and New York are getting the Entry-Scan3 machine from GE Ion Track of Wilmington, Mass., this summer for 45-day tests. A passenger enters the portal and stands still while several quick puffs of air are released. Sensors analyze the air for traces of explosives. A competing model from Smiths Detection can find concentrations as small as 30 parts per quadrillion. That's the equivalent of a milligram of aspirin in an Olympic-size swimming pool. "And we'll tell you the color of the aspirin," says researcher Kevin Linker of Sandia National Laboratory, which licensed the technology to Smiths.

Lie Detector Glasses

It's not about what you say but how you say it. Layered voice analysis technology from V LLC of Washington, D.C., is finding users among law enforcement officers and insurance investigators and is about to make its way into airports. It measures vocal wave frequencies. People boarding airplanes and cruise ships answer three to five yes-or-no questions, and V's Gatekeeper Security Access Control System screens the voice samples to determine whether the speaker intends to do harm. It clears legitimate passengers with a green light and signals questionable passengers with a red one. In times of high alert, the software can be incorporated into standard sunglasses, retrofitted with a tiny microphone and LEDs in the temples, and connected to a microcomputer worn on a belt.