National Aeronautics and Space Administration (NASA) Headquarters is releasing an Appendix to the current Space Technology Research, Development, Demonstration, and Infusion 2014 (REDDI) NASA Research Announcement (NRA) for initial studies of visionary aerospace concepts. NNH14ZDA007L, entitled NASA Innovative Advanced Concepts: Phase II Studies, will be available as of April 18th, 2014 by opening the NASA Research Opportunities homepage at http://nspires.nasaprs.com/ and then linking through the menu listings "Solicitations" to "Open Solicitations." This solicitation represents continuation of the NASA Innovative Advanced Concepts (NIAC) program, which issued its first solicitation on March 1, 2011. More information is available at: http://www.nasa.gov/niac . This NRA will solicit multiple studies, each of which will investigate an architecture, mission, or system concept with the potential to enable a great leap in space or aeronautics. NIAC is part of the Space Technology Mission Directorate. Aerospace architecture, mission, or system concepts proposed for NIAC Phase II studies must be exciting, unexplored, far-term, and credible. Proposals for narrow technology or subsystem development, or incremental or near-term advancement, are explicitly out of scope for this program. Finally, while NIAC encourages daring vision and accepts the accompanying risk, proposals must be technically credible and plausibly implementable. This solicitation is open to any principal investigator or organization that has completed a NIAC Phase I study, but has not yet completed a Phase II study. Applicants from the prior NASA Institute for Advanced Concepts that have completed a Phase I study, but have not completed a Phase II study, are also eligible unless the reason for not completing a Phase II study was discontinuation at the midterm review. Affiliation with any educational institution, commercial or not-for-profit organization, research laboratory, government agency, or NASA Center (including the Jet Propulsion Laboratory) is permitted. Individuals may submit, as long as they meet the registration requirements for NSPIRES. Every organization that intends to submit a proposal in response to this NRA must be registered with NSPIRES, and such registration must identify the authorized organizational representative(s) who will submit the electronic proposal. Each electronic proposal system places requirements on the registration of principal investigators and other participants (e.g. co-investigators). Potential proposers and proposing organizations are urged to access the electronic proposal system(s) well in advance of the proposal due date(s) to familiarize themselves with its structure and enter the requested information. Specific proposal submission deadline dates, evaluation criteria, and submission information will be identified in the NRA. Proposals will be due on or before June 3rd, 2014. The number of awards will be subject to the availability of appropriated funds. Comments and questions may be addressed by e-mail to NIAC Program representatives at hq-niac@mail.nasa.gov. Responses to inquiries will be answered by e-mail and also included in the Frequently Asked Questions (FAQ) document located on the NSPIRES page associated with the solicitation; anonymity of persons/institutions who submit questions will be preserved.