Editing Ames Research Center (section)

===Hypervelocity Free-Flight Range===
{{Unreferenced section|date=July 2024}}
The Hypervelocity Free-Flight (HFF) Range currently comprises two active facilities: the Aerodynamic Facility (HFFAF) and the Gun Development Facility (HFFGDF). The HFFAF is a combined Ballistic Range and Shock-tube Driven Wind Tunnel. Its primary purpose is to examine the aerodynamic characteristics and flow-field structural details of free-flying aeroballistic models.

The HFFAF has a test section equipped with 16 shadowgraph-imaging stations. Each station can be used to capture an orthogonal pair of images of a [[hypervelocity]] model in flight. These images, combined with the recorded flight time history, can be used to obtain critical aerodynamic parameters such as lift, drag, static and dynamic stability, flow characteristics, and pitching moment coefficients. For very high [[Mach number]] (M > 25) simulations, models can be launched into a counter-flowing gas stream generated by the shock tube. The facility can also be configured for hypervelocity impact testing and has an aerothermodynamic capability as well. The HFFAF is currently configured to operate the {{convert|1.5|in}} [[light-gas gun]] in support of continuing thermal imaging and transition research for NASA's hypersonics program.

The HFFGDF is used for gun performance enhancement studies, and occasional impact testing. The Facility uses the same arsenal of light-gas and powder guns as the HFFAF to accelerate particles that range in size from {{convert|3.2|to|25.4|mm|sp=us}} diameter to velocities ranging from {{cvt|0.5|to|8.5|km/s|mph}}. Most of the research effort to date has centered on Earth atmosphere entry configurations (Mercury, Gemini, Apollo, and Shuttle), planetary entry designs ([[Viking program|Viking]], [[Pioneer Venus]], ''[[Galileo (spacecraft)|Galileo]]'' and [[Mars Science Laboratory|MSL]]), and aerobraking (AFE) configurations. The facility has also been used for scramjet propulsion studies ([[Rockwell X-30|National Aerospace Plane (NASP)]]) and meteoroid/orbital debris impact studies ([[Space Station]] and [[Reusable launch vehicle|RLV]]). In 2004, the facility was utilized for foam-debris dynamics testing in support of the Return To Flight effort. As of March 2007, the GDF has been reconfigured to operate a cold gas gun for subsonic [[Crew Exploration Vehicle|CEV]] [[Space capsule|capsule]] aerodynamics.