NASA has specific definitions for principal investigators. Contact your RAS contract administrator with any questions.
MIT has always agreed with NASA’s assessment that PI status for the Co-Investigator is not needed.
NASA Definitions
Principal Investigator (PI)
A Principal Investigator is the individual(s) a research organization designates as having an appropriate level of authority and responsibility for the proper conduct of the research, including the appropriate use of funds and administrative requirements such as the submission of scientific progress reports to the agency. Every proposal shall identify a PI who is responsible for the quality and direction of the proposed research and for the proper use of awarded funds regardless of whether or not he/she receives support through the award.
Co-Investigator (Co-I)
A Co-I is a member of the proposal’s investigation team who may hold either a full-time or limited-term appointment and who is a critical “partner” for the conduct of the investigation through the contribution of unique expertise and/or capabilities. A Co-I must have a well-defined, and generally sustained, continuing role in the proposed investigation, serve under the direction of the PI, and may or may not receive funding through the award. Only an individual who has formally agreed to the role may participate as a Co-I even if the Co-I's participation is at no cost (i.e., contributed) to the proposal. Each Co-I must demonstrate the Co-I's commitment to participate in the proposed investigation by way of a brief, signed statement from the Co-I even if they are from the proposing organization.