Tanking with liquid nitrogen will be done to qualify the mechanisms before LOx is loaded, and so on throughout the flight test program. Whereas the regulatory environment for unmanned expendable vehicles is uncertain at present, the Pathfinder can be operated under current FAA regulations. There isn't any problem flying such an aircraft over populated areas. Unlike typical launch systems, Pathfinder is not designed with high reliability to carry people, but rather carries people to attain high reliability. The Pathfinder aircraft crew performs essential flight operations throughout its mission profile, these crew members are not merely cargo.
Pathfinder uses conventional airbreathing engines for takeoff and landing.
The rocketplane could even be flown to a satellite manufacturer's facility for satellite pickup. Liquid oxygen is only loaded in the air, significantly reducing launch site hazards. Apart from a liquid oxygen aerial propellant transfer, new technologies do not need development in order for Pathfinder to work. By using conventional, robust equipment, aircraft design practices, and modern thermal protection materials, turnaround time will be very short. Pathfinder can take off from any runway tanker aircraft can, potentially opening hundreds of new space launch facilities without any major new infrastructure.