Cryotubes

Cryotubes are often used by UNSC personnel toendure long space travel without aging to the body. Crytubes are seen in the first Level of Halo: CE when the Master Cheif is defrosted from the tube. Aparently htere can be adverse affects, hinted when the Cryo Bay Crewman says "... vitals look good .... no freezer burn." The master cheif recovers several cryotubes jetisioned from the Pillar of Autumn in the novel Halo: First Strike.