Because manned spaceflight still imposes unknown stresses on the human body, NASA is seeking non-invasive technological approaches for intra-cranial pressure measurement. A baseline must be established on the ground, and then periodic measurements will be taken during flight — possibly over several months to a year. For consistency, it is important for the same technology to be used both on the ground and in space. The method and equipment must operate independent of gravity and acceleration. Materials and designs for spaceflight should anticipate the potential for high radiation exposure.