What does "static fire test" mean?

A "static fire test" refers specifically to the procedure where a rocket's engine is ignited while the rocket is secured in a stationary position. The primary purpose of this test is to evaluate the performance and reliability of the rocket's propulsion system without the complexities and potential risks associated with an actual launch. During this test, engineers monitor various parameters such as thrust, fuel flow, and engine temperature to ensure that everything functions as intended before proceeding to an actual launch.

Unlike the other options, this definition aligns perfectly with the concept of a static fire test, as it emphasizes the stationary context of the rocket during engine firing. The other choices either reference actions or properties that do not directly relate to the nature of static fire testing. For instance, launching the rocket into the sky or assessing aerodynamic properties involves movements and conditions not present in a static setup, while determining speed is a separate consideration that is not the focus of a static fire test.