Calcium and phosphorus change of the Apollo 17 crew members.

In association with the 12.6-day lunar flight of Apollo 17, calcium and phosphorus intake and excretion were determined for the crew members before and during the mission. The study showed increased urinary and fecal phosphorus and increased fecal calcium during weightlessness. The calculated mean calcium "loss" for the three crew members was 0.2 percent of estimated total body calcium and phosphorus "loss" was 0.7 percent of estimated total body phosphorus. The ratio of phosphorus lost compared to calcium indicated a reduction in both bone and soft tissue. These changes may be attributed not only to the hypogravia of the lunar and circumlunar environment, but possibly also to disturbances in gastrointestinal absorption.