Long Fall Boot

"Gentleman, I give you the Long Fall Boot. Think of it as a foot based suit of armour for the Portal Device. I wont lie to you, it's expensive as hell!"

- Cave Johnson

The Long Fall Boot is a boot used by Aperture Science to prevent Test Subjects from injury from huge drops by lessening the impact.

Overview
During the testing of the ASHPD, the observers came across a reproducible human error - due to the conservation of the momentum of on object (or human) traveling through a portal, test subjects where reaching great heights, falling and dying on impact with the Chamber Floor, most likely due to damage to internal organs or because of huge blood loss. This meant that test subjects were letting go of their ASHPD's as they died, and the equipment hit the floor and breaking. The equipment was expensive, and was costing Aperture Science money, time and effort, so Cave Johnson devised the Long Fall Boot as a solution to the problem of falls from height leading to broken equipment, by a way of canceling out the momentum conserved between portals.

Trivia

 * The Long Fall Boot might be installed with a gyroscopic mechnaism of somekind as the boot aids the test subject in balance and from landing on their heads when falling or exiting portals. This feature is mentioned by Cave Johnson and demonstrated by Chell in Aperture Investment Opportunity #4: "Boots".