FT meaning in Space Science ?

Flight testing is a branch of aeronautical engineering that develops and gathers data during flight of an aircraft, or atmospheric testing of launch vehicles and reusable spacecraft, and then analyzes the data to evaluate the integrity and aerodynamic flight characteristics of the vehicle in order to validate the design, including safety aspects.

The flight test phase accomplishes two major tasks: 1) finding and fixing any design problems and then 2) verifying and documenting the vehicle capabilities for government certification or customer acceptance. The flight test phase can range from the test of a single new system for an existing vehicle to the complete development and certification of a new aircraft, launch vehicle, or reusable spacecraft. Therefore, the duration of a particular flight test program can vary from a few weeks to many years.