You are presented with multiple paper abstracts, alongside the associated literature review and chapter titles. Given the provided information, you are going to do a literature review. Please generate a coherent literature review that synthesizes the content, draws connections between different works, highlights major findings, and identifies any gaps in the existing research.

Literature Review Title: Survey of Blunt Body Dynamic Stability in Supersonic Flow 
Chapter Title:  B. Free Oscillation Testing 
1. Abstract of Cited Paper (BIB001):  With the retirement of the Space Shuttle, NASA is designing a new spacecraft, called Orion, to fly astronauts to low earth orbit and beyond. Characterization of the dynamic stability of the Orion spacecraft is important for the design of the spacecraft and trajectory construction. Dynamic stability affects the stability and control of the Orion Crew Module during re-entry, especially below Mach = 2.0 and including flight under the drogues. The Launch Abort Vehicle is affected by dynamic stability as well, especially during the re- orientation and heatshield forward segments of the flight. The dynamic stability was assessed using the forced oscillation technique, free-to-oscillate, ballistic range, and sub-scale free-flight tests. All of the test techniques demonstrated that in heatshield-forward flight the Crew Module and Launch Abort Vehicle are dynamically unstable in a significant portion of their flight trajectory. This paper will provide a brief overview of the Orion dynamic aero program and a high-level summary of the dynamic stability characteristics of the Orion spacecraft.

Literature Review:
Free oscillation uses a transverse rod positioned through the center of rotation of the vehicle. This rod is set in low friction bearings that allow the model to pitch freely in response to the oncoming freestream flow. Following an initial oscillatory perturbation, the vehicle's natural dynamic damping response is measured. By observing the time history of the oscillatory growth or decay, the dynamic aerodynamic coefficients can be determined with parameter identification techniques. This technique was matured during the Apollo program and is still in use today. It allows for explicit determination of the reduced frequency inherent to the vehicle (as opposed to sweeping through various possibilities as in forced oscillation technique) BIB002 , is simple in its implementation, and requires only one measurement (oscillation amplitude as a function of time)  . Similar to the forced oscillation setup, free oscillation testing yields an average value of the damping over one oscillation cycle and suffers from the effects of having a sting present to modify the wake flow. Also, it has additional scaling requirements in that the center of gravity of the vehicle must be coincident with the center of rotation and the pitch moment of inertia must be scaled properly from the expected full scale vehicle for representative behavior to be obtained BIB001 . Finally, damping due to bearing friction must be accurately quantified so that it can be separated from the aerodynamic damping of the vehicle.