With a journey predicted to take decades, if not centuries, one of the most important considerations of the engineers was the aging of the crew. Recent advances in cryogenics and chemical therapy have enabled scientists to chemically slow the metabolic process to a virtual standstill, which enables the scientists to then deep freeze the body without harm. Sensors regulate the zero-oxygen environment to ensure that the colonists will be kept as safe as possible, and a special warming system utilizing broad spectrum electromagnetic radiation is used to quickly and safely restore warmth to the body. The radiation also has the effect of breaking down the chemical agents that slow the colonists' metabolism, making them able to be thawed out in a matter of seconds and fully aware in a little over a minute. This is essential to the survival of the craft in a situation in which the computer is unable to determine a course of action and a pilot or navigator must be roused to assess the danger, or in a situation in which a technician must be roused to effect repairs. This system has been used very effectively in tests on pigs and monkeys, and it has been shown that such animals in deep cryogenic sleep have been able to be roused after three years with absolutely no visible side effects. A couple of military volunteers have also been frozen to test the system, but only for a matter of weeks. Although scientists have not yet tested the effects of long-term freezing on human beings, they are completely confident that there will not be any problems with the Stasis Chamber on the Space Ship. Completely confident.