Devices exist today that can electronically "strip-search" clothed passengers, sniff people for trace amounts of explosives, analyze the chemical composition of items stashed in luggage, and scan thumbprints and faces to verify a person's identity.
Some are still being tested; others are in use at a few airports and federal complexes. In the aftermath of the Sept. 11 terrorist attacks, Congress is working on legislation that would put new security equipment in 20 airports around the nation within a year. Those pilot projects would test the gear before allowing more-widespread use.
The hope is that new technology can make flying safer.
"We want to provide a gantlet" against terrorists, said Ralph Sheridan, chief executive officer of American Science and Engineering (AS&E), based in Massachusetts, which makes a scanning device that can peer through clothing.
Such security is costly.
Individual pieces of equipment range in price from $130,000 to $10 million. By comparison, the metal detectors and X-ray machines that have been at airports for decades cost about $5,600 and $45,000, respectively.
The tab for new devices would likely be picked up by travelers with a surcharge on tickets, said Gina Marie Lindsey, managing director of Seattle-Tacoma International Airport. The airport now has no plan to buy any of the new equipment.
There also are civil-liberty concerns. Do travelers really want their personal information — even their bodies — on display to security staffs?
The American Civil Liberties Union (ACLU) advocates a go-slow approach, saying that invasive technology must be proved effective before it is used and that even then its use should be limited.
"If there is a less-invasive alternative, it should be used," said Barry Steinhardt, associate director of the national ACLU office in New York.
"Don't pick the technology that most intrudes on our privacy."
And there's no guarantee spending millions on state-of-the-art technology would prevent future hijackings or terrorist attacks, said Edward Tenner, a visiting researcher at Princeton University and author of "Why Things Bite Back: Technology and the Revenge of Unintended Consequences."
At best, he said, "we would probably buy some time until terrorists could find a way to work around the system."
Researchers are approaching airport security on two fronts: detecting explosives or other weapons and identifying the bad guys.
Several new devices that scan people and containers for weapons are being discussed for use in airports and other public buildings. Here are a few:
• Neutron scanner: This device shoots neutrons through containers to measure the chemical composition of items. It can scan everything from cargo containers to suitcases.
The technology is so sophisticated, according to Ancore, the manufacturer, it can tell the difference between olive oil and motor oil. Or, more important, between a bottle of wine and a bottle of liquid explosives.
However, the scanner is the size of three tractor-trailers and costs $10 million. The California company says it would be good for airports and border crossings.
Ancore also makes a smaller device, the size of a double-wide filing cabinet, that scans for traces of explosives inside carry-on luggage. Cost: $150,000.
• BodySearch scanner: This is a more controversial technology. Made by AS&E, it uses special "backscatter" X-rays to see through clothing to spot weapons such as plastic guns or knives that would not be picked up by metal detectors. Cost: $130,000 to $150,000. The images seen through the machine resemble nude mannequins.
Concerns have been raised in the past about whether the technology is too revealing. While tattoos don't show up — the X-rays cannot distinguish differences in pigment — all other body features do.
"There was concern people might post pictures on the Web," said Harry Martz, a physicist at the Lawrence Livermore National Laboratory who has evaluated new security technologies for airports.
AS&E officials say no images are recorded by the device, and the equipment is designed so women screen women and men screen men. The company also makes larger scanners to peer inside luggage and vehicles.
The company says its technology is being used by more than 30 agencies of the federal government. The U.S. Customs Service has purchased 10 scanners for use at airports in eight locations, including Atlanta and Chicago. The device is used only on people entering the country who are suspected of smuggling. They are given a choice of getting a pat-down or being scanned.
Most people prefer a pat-down, but some have signed consent forms allowing a body scan. In one case, the scanner showed a man trying to hide 55 baby turtles in his pants, said Dean Boyd, a Customs spokesman.
• Explosives Detection Portal: This device, being developed at Sandia National Laboratories for the Federal Aviation Administration, collects air samples and analyzes them for trace amounts of explosives. A passenger stands inside a device that resembles a large metal detector equipped with a bunch of air nozzles. The nozzles emit puffs of air that pick particles off clothing, and then the samples are analyzed by the machine. The process takes about 12 seconds. A prototype has been built, but the portal is still in the testing stage.
By themselves, the new types of scanners would give airports a better chance of catching terrorists, but they likely would be enhanced by new methods of tracking passengers, security experts said.
Two technologies are getting a lot of attention: smart cards and facial-recognition software.
• Smart cards have been around for awhile but have become increasingly sophisticated. They're the size of credit cards and can store information such as flight schedules, a person's background information, photographs and thumbprints.
Some security experts are calling for airlines to test smart cards by using them as boarding passes for frequent fliers. An airline could issue a card that contains background information about a passenger and is keyed to the passenger's thumbprint.
When someone bought a ticket, the flight information would be downloaded to the smart card. At the airport, the card would be inserted in a reader at security checkpoints and at airline gates. There are two advantages: Frequent fliers could avoid most of the intensive security checks that slow down travelers, and the security staffs then would have more time to scrutinize people who travel less frequently.
"On a shuttle flight from Boston to Washington, D.C., more than 80 percent of the people are frequent business travelers who would qualify for this card," said AS&E's Sheridan, who has testified before Congress several times on airport security.
"Then you focus your security assets on the infrequent flier on whom you have no data."
• Facial-recognition software also is being promoted as a tool to keep terrorists off airplanes. Airports could install cameras in terminals that checked the faces of passengers against the faces of terrorists stored in a computer database.
Jim Wayman, director of the Biometrics Identification Research Group at San Jose State University, said the technology could be useful at airport-security checkpoints where people could be posed and the lighting controlled.
"In fact, I use facial recognition on the door to our laboratory," he said.
In an airport setting, there would be many false alarms because the software sometimes would identify innocent people as terrorists, Wayman said. Still, it could cull passengers down to a short list for security staff to check.
"If you have one terrorist in 10,000, he's going to be hard to find. If this technology can narrow a search to ... one in 100, you have a much better chance."
Visionics, which makes a facial-recognition system, contends the technology has advanced to the point it can pick out criminals from a distance. But Wayman said he doubts such software can randomly scan large crowds and identify individual suspects with much precision.
Even as devices grow more sophisticated, so do efforts to circumvent them, according to Princeton's Tenner. In fact, security staff could be lulled into a false sense of security thinking new gadgets had given them the upper hand, he said.
"Technology is very good at detecting and discouraging the amateur and the unprepared," he said. "What we've seen, unfortunately, is there are more cunning, well-prepared and patient terrorists than we had realized."
Andrew Garber can be reached at 206-464-2595 or firstname.lastname@example.org.