16 U.S. Code § 5935 - Availability for scientific study
(a) In general
The Secretary may solicit, receive, and consider requests from Federal or non-Federal public or private agencies, organizations, individuals, or other entities for the use of any unit of the National Park System for purposes of scientific study.
A request for use of a unit of the National Park System under subsection (a) of this section may only be approved if the Secretary determines that the proposed study—
(c) Fee waiver
The Secretary may waive any park admission or recreational use fee in order to facilitate the conduct of scientific study under this section.