One of the most promising new wilderness-rescue devices now being perfected is the product of twin teenaged sisters who attend high school in Alaska.
Weighing 23 pounds, the 4-foot-long Ice Crawler can be sent into situations deemed too dangerous for man or beast -- out onto thin ice or treacherously soft snow -- to deliver a rope to a stranded victim.
Hanna and Heather Craig, 17, built the prototype robot to cope with the most vigorous terrain, whether it be rough snow or icy slopes.
The Ice Crawler is operated by a control panel that allows the rescue team to remain at a safe distance from the victim.
The control panel's wiring is encased in a plastic tube that runs from the control panel to the robot body.
The tube also holds the rope used to haul the victim back to safety.
"How far the Ice Crawler can go depends on the length of the tether -- on ours it's only 30-feet-long but could be hundreds of feet long," Heather Craig said.
The control panel consists of a small box that measures approximately 6 by 4 by 4 inches.
It's made up of a joystick to direct the robot, an on-off switch, a forward and reverse switch and a mechanical override switch.
The override switch allows the robot to be operated without speed control in case the speed program fails. As the robot only has a top speed of 3 miles per hour, speed control is not essential to the robot's performance.
The robot is run on two 12-volt drive motors -- one on each of the Ice Crawler's tracks.
The Ice Crawler is powered by a 12-volt portable battery.
A video camera, mounted on the front of the crawler, helps the rescue team spot the victim when vision is poor.
"The camera sends visual feedback to a receiver with a small TV screen, so you can see where the Ice Crawler is going in snowy conditions or when your vision is blocked by rough terrain," Heather said.
The two Anchorage East High School girls were resourceful in finding parts for their invention.
Finding the right material for the job was one of the main challenges of the project.
"Most of its parts needed to be redesigned -- it was a trial-and-error project," Heather said.
They used bicycle sprockets found in their garage to pull the track system and keep the track in place, while the robot's steering motor is a car window motor that the two salvaged from a used car lot.
The joystick in the control panel came out of a remote control unit of a toy airplane.
The Ice Crawler's body, which is padded to avoid further injuring the victim, consists of two tracks made of silicon reinforced rubber.
"Silicon reinforced rubber remains flexible even under extremely cold temperatures and is very strong. Then aluminum strips cover the track to provide traction," Heather said.
The two tracks are attached at a central pivot point, allowing the crawler to bend and mold itself to the land.
This, coupled with the robot's low center of gravity, means the robot can deal with any kind of snowy terrain without tipping or getting stuck.
"It works really well on different terrain -- on hard ice or on soft snow, it won't fall through," Heather said.
Another problem was accommodating the weather conditions. The material had to be flexible but still function at sub-zero temperatures.
The first year of the project was spent building the robot, the second tweaking it to get it just right.
The Craigs did have some help with their endeavor.
John Pursley, president of Envision Product Design and mentor in the school district program, served as the twins' adviser throughout the project.
"They were 15 at the start, so they didn't have any experience and needed guidance in assessing the scope of the project and the specific objective, what sort of material they would need, the electronics and software," Pursley said.
But, Pursley maintains, the Craigs built the whole robot and wrote all the software themselves.
"They are very talented, very bright girls. They are very fast at picking things up and were very easy to work with," Pursley said.
Apart from trying out the robot on test runs, with Hanna posing as the stranded victim, the Ice Crawler has yet to make its debut in a real search-and-rescue operation.
Despite its inexperience, the Craigs are confident in the robot's ability to perform.
Pursley shares their confidence.
"It's been assessed by many different people in all the competitions it has been entered in and, most importantly, it has been assessed by search-and-rescue people, and they were very interested in it," he said.
In one of these competitions, the National Siemens Westinghouse Science and Technology Competition, the Craigs received the second-place trophy and $50,000 in prize money.
First place, with a $100,000 prize, went to a New York team that developed a means to measure the viscosity of lubricants used in artificial limbs and computer disc drives.
Retired state trooper Bob Sanders believes the Ice Crawler could come in handy.
"If it was too hazardous for a person to go out and get the victim, then a mechanical device carrying a tether may be useful. But only if time were not a critical aspect -- a person in freezing water is not going to last long enough to wait for one to arrive," Sanders said.
While Sanders believes the Ice Crawler may be impractical for mountain rescue -- where a search and rescue team can be over 24 hours away -- he thought it might come in handy in the city.
"If you had one of these on hand at each fire department and could respond to someone falling through ice and could reach them in minutes, then this could be used to run out a rope to him," Sanders said.
