Cryogenic Sleep is the process of freezing a person into a deep sleep for a long time with no supply of food and water. This process was proposed so as to pass time more quickly during the space travel. Cryogenic sleep also stops ageing. This is mostly addressed in science fiction movies.
During the space travel, the travelers need to take more materials such as food, water, exercise equipment, television etc. as they need to perform exercises to keep themselves healthy and also to keep themselves engaged, as sitting idle for hours would affect them mentally. Now, the weight of all these cargo increases the fuel consumption, while the fuel is quite expensive and volatile.
The aeronautical engineers say that a traveller doesn’t need any of these if he is put to sleep during this whole journey. Along with the food and cargo, the negative psychological and social aspects of prolonged space travel will also be pacified.
Putting humans to a hibernation-like state for long hours is the biggest challenge. The longest is 14 hours that a human can survive being in a state of stasis. But more than ten times of this time is taken even to reach our nearest planet Mars. Experiments are being made to make this work for space travellers.
Scientists are now considering the Therapeutic Hypothermia procedure an answer for this. However, experiments are being carried out, and we might see the practical possibilities in the next 30 years.