This amendment delays the proposal due date for C.17 Astrobiology: Exobiology and Evolutionary Biology Program. Programmatic schedule conflicts at NASA Headquarters have postponed the EXO peer review and hence the date when SMD must have proposals. A corresponding deferral of the EXO due date will provide the community additional time to prepare proposals. The proposal due date for EXO has been changed to Friday, October 22, 2010. Table 2 and Table 3 of the Summary of Solicitation for this NRA have been updated to reflect this change.