14 C.F.R. § 437.7
An experimental permit authorizes launch or reentry of a reusable suborbital vehicle. The authorization includes pre- and post-flight ground operations as defined in this section.
(a) A pre-flight ground operation includes each operation that—
(2) Meets the following criteria:
[Doc. No. FAA-2006-24197, Amdt. No. 437-0, 72 FR 17019, Apr. 6, 2007, as amended by Amdt. No. 437-4, 89 FR 76726, Sept. 19, 2024]