were approved from the 1999 NRA solicitation. To estimate the expenditure on endocrine research, the fraction of a project that is endocrine related has been multiplied by the total dollar amount of the grant.

The total expenditure in FY 1999 on endocrine-related themes was about $1.225 million (~3.4 percent of total NASA expenditures). About half ($650,000) of the funds were used to support studies of the endocrine aspects of circadian rhythm dysfunction (three projects). The total expenditure in FY 1999 was unchanged from 1998, although there was a decrease in the number of projects funded (21 versus 16). Table 6.1 summarizes the funding and project distributions between subdisciplines and between the NRA and NSBRI programs for FY 1999.

The Strategy report (NRC, 1998) identified circadian rhythm dysfunction as being a high-priority area for investigation. Two circadian rhythm studies were included as part of the Bion program in 1998 but were discontinued in FY 1999 ($100,000). The current program encompasses three ground-based human studies. The total expenditure on the endocrine aspects of circadian rhythm and sleep studies ($650,000) was unchanged from FY 1998. (For additional discussion of circadian rhythms and the relevance of their study to NASA, see Chapter 9.)

Expenditure on the endocrine component of other programs with endocrine involvement was about $575,000 in FY 1999 (13 projects). No currently funded projects relate to the highest-priority objective, obtaining a baseline in-flight human hormone profile. The Integrated Testing Regimen (ITR) does not meet this requirement. The lack of activity is a consequence of the current lull in flight opportunities. The second objective, the refinement and development of ground-based models, is more nebulous because model development is not a specifically stated objective of any project. For the most part, endocrine measurements are secondary objectives. The endocrine components of currently funded studies are directed toward elucidating underlying mechanisms, as recommended in the Strategy report. The greatest number of interdisciplinary projects with an endocrine component in FY 1999 were in the areas of bone (five studies), muscle (five studies), sleep and circadian rhythm (three studies), and