- The Announcement of Opportunity (AO) - This is generally used to solicit proposals for unique, high cost research investigation opportunities that typically involve flying experimental hardware provided by the proposer on one of NASA's Earth-orbiting or free-flying space flight missions. Selections through AO's can be for periods of many years, involve budgets of many millions of dollars for the largest programs, and usually are awarded through contracts, even for non-profit organizations, although occasionally grants are also used.

- The NASA Research Announcement (NRA) - An NRA is used to announce research interests in support of NASA's programs, and, after peer or scientific review using factors in the NRA, select proposals for funding. Unlike an RFP containing a statement of work or specification to which offerors are to respond, an NRA provides for the submission of competitive project ideas, conceived by the offerors, in one or more program areas of interest. NRAs may result in grants, contracts or cooperative agreements.

-The Cooperative Agreement Notice (CAN) - This is used to solicit ground-based research opportunities in which a fairly high degree of cooperation and interaction is expected between NASA and the selected institutions for completion of proposed research activities that further one of NASA's strategic objectives (e.g., to develop a research institute, an extensive educational/public outreach activity or provide technology transfer to develop a capability to enhance U.S. competitiveness). Further, the announced program intends a level of sponsorship, in the form of cost or resource sharing from both parties of the agreement. A CAN results in the award of a cooperative agreement.

- The NASA Announcement (AN) - This announcement is for a program in which non-funded selections of investigations are made on a competitive basis (e.g., to acquire new data from an operating space science mission). Typically, the AN have been used to award observation time on still-operating astronomical satellites, where due to imposed budget policies, funds were not available for continued data analysis. There is no official award instrument. Recipients receive a letter from NASA indicating that their proposal was selected and that there will be further contact with the NASA Program Office.