14 C.F.R. § 1217.102
In order to encourage and facilitate the use of NASA's launch services for the exploration and use of space, section 116 of Public Law 97-446 provided for the duty-free entry into the United States of certain articles imported by NASA for its space-related activities or articles imported by another person or entity for the purpose of meeting its obligations under a launch services agreement with NASA. Such articles were certified by NASA to the Commissioner of Customs for duty-free entry to be launched into space or space parts or necessary and uniquely associated support equipment for use in connection with a launch into space. This exemption from duty was provided for in Subheading 9808.00.80, Harmonized Tariff Schedule of the United States (HTSUS) (19 U.S.C. 1202 ) . Also, HTSUS, Chapter VIII, U.S. note 1, pursuant to the same law, provided that return of articles by NASA from space to the United States would not be considered an importation, and similarly not be subject to a duty.
As a result of the Uruguay Round agreements of the 1994 General Agreement on Tariffs and Trade, this authority was revised and expanded in scope. It now provides that imports of articles for NASA's use and articles imported to implement NASA's international programs, including articles to be launched into space, parts thereof, ground support equipment, and uniquely associated equipment for use in connection with NASA's international programs and launch service agreements would be eligible for duty-free customs entry upon certification by NASA to the Commissioner of Customs. The revised authorities also provided, in U.S. note 1 to subchapter VIII of chapter 98 of the HTSUS, that articles brought into the customs territory of the United States by NASA from space or from a foreign country as part of a NASA's international programs would not be considered imports or subject to customs entry requirements.
14 C.F.R. §1217.102