in ten months, the Portable Life Support System, aka "backpack", needed to be completed to support complete suit-system testing before the end of the twelfth month. Before the spacesuit contract was awarded, the requirement for normal life support per hour almost doubled. At this point, a maximum hourly metabolic energy expenditure requirement was added, which was over three times the original requirement. In late 1962, testing of an early training suit raised concerns about life support requirements. The concerns were dismissed because the forthcoming Apollo new-designs were expected to have lower effort mobility and improved ventilation systems. However, Hamilton took this as a strong indication that Apollo spacesuit life support requirements might significantly increase and initiated internally funded research and development in "backpack" technologies. In the tenth month, the first backpack was completed. Manned testing found the backpack to meet requirements. This would have been a great success but for the crewed testing confirming that the 1963 life support requirements were not sufficient to meet lunar mission needs. Early in 1964, the final Apollo spacesuit specifications were established that increased normal operations by 29% and increased maximum use support 25%. Again, the volume and weight constraints did not change. These final increases required operational efficiencies that spawned the invention of the porous plate sublimator and the Apollo liquid cooling garment. The porous plate sublimator had a metal plate with microscopic pores sized just right so that if the water flowing under the plate warmed to more than a user-comfortable level, frozen water in the plate would thaw, flow through the plate, and boil to the vacuum of space, taking away heat in the process. Once the water under the plate cooled to a user-comfortable temperature, the water in the plate would re-freeze, sealing the plate and stopping the cooling process. Thus, heat rejection with automatic temperature control was accomplished with no sensors or moving parts to malfunction. The Apollo liquid cooling garment was an open mesh garment with attached tubes to allow cooling water to circulate around the body to remove excess body heat when needed. The garment held the tubes against the body for highly efficient heat removal. The open mesh allowed air circulation over the body to remove humidity and additionally remove body heat. In 1966, NASA bought the rights to the liquid cooling garment to allow all organizations access to this technology. Before the first Apollo spacewalk,