Providing critical testing support to the nation's research and development activities in aerodynamics, aero-thermodynamics, flow-field structure and planetary impact physics.
The Ames Range Complex provides NASA, the US, and the global aerospace and planetary science communities with a suite of unique, critical and mission-enabling ground-test capabilities. The Complex boasts world-class test hardware and instrumentation, and a staff with extensive expertise garnered from decades of test experience. The Complex is comprised of three components: the Ames Vertical Gun Range (AVGR), the Hypervelocity Free Flight Facilities (HFFF) and the Electric Arc Shock Tube (EAST). The HFFF, in turn, consists of two aero-ballistic ranges: the Hypervelocity Free Flight Aerodynamics Facility (HFFAF) and the Gun Development Facility (GDF). Together, they offer support to a wide variety of science and aerospace engineering applications, from studying asteroid impacts on Mars, to determining the aerodynamic heating on, and stability of, a vehicle entering and descending through the atmosphere of Neptune. The three components of the Range Complex are discussed, individually, below.
The Ames Vertical Gun Range (AVGR) was designed to conduct scientific studies of lunar impact processes in support of the Apollo missions. In 1979, it was established as a National Facility, funded through the Planetary Geology and Geophysics Program. In 1995, increased scientific needs across various disciplines resulted in joint core funding by three different science programs at NASA Headquarters (Planetary Geology and Geophysics, Exobiology, and Solar System Origins). In addition, the AVGR provides programmatic support for various proposed and ongoing planetary missions (e.g. Stardust, Deep Impact).
Using its powder and light-gas guns, the AVGR can launch single, small groups, or even clusters of multiple projectiles at velocities ranging from 0.5 to nearly 7 km/sec. Single projectiles up to 6.4 mm in diameter can be tested. The projectile shape and material can also be varied widely. By varying the gun's angle of elevation with respect to the target vacuum chamber, impact angles from 0° to 90° relative to the gravitational vector are possible. This unique feature is extremely important in the study of crater formation.
The cylindrical target chamber is approximately 2.5 meters in diameter and height and can accommodate a wide variety of targets and mounting fixtures. It can maintain vacuum levels below 0.03 mm Hg, or can be back filled with various gases to simulate different planetary atmospheres. Impact events are typically recorded with high-speed video/film, or Particle Image Velocimetry (PIV).
The Hypervelocity Free-Flight Facilities (HFFF) include two aero-ballistic ranges, the HFFAF and the GDF.
The HFFAF is the only aero-ballistic range in North America with a controlled-environment (gas pressure and composition) test section. It has a variety of cold-gas, powder, and two-stage light-gas gun launchers, with bore diameters of 25 mm, 20 mm – 57 mm, and 7 mm – 38 mm, respectively. Models can be launched at velocities ranging from 100 m/s to 8,000 m/s. To test at even higher relative velocities (up to 12,000 m/s), the downrange end of the HFFAF can be connected to a 16-inch combustion-powered shock tunnel, which generates up to a 4,000 m/s counter-flow in the HFFAF test section. These features allow the HFFAF to simulate, for virtually any planetary atmosphere, an unparalleled range of descent-trajectory points. The HFFAF test section is equipped with 16 shadowgraph-imaging stations equally spaced along its 22.8-m length. Each station can be used to capture an orthogonal pair of images of a scale model in flight. These high-speed images, combined with the accurately recorded flight time history, can be used to obtain critical aerodynamic parameters for entry vehicles, such as lift, drag, static and dynamic stability. At hypersonic velocities, thermal imaging performed with intensified-CCD and IR cameras also allows determination of boundary layer transition points and global surface temperature distribution on the flying model.
The GDF can utilize the same gun launchers as the HFFAF, and it has a 4.9 meter-long atmospheric test chamber. What makes the GDF unique and invaluable is that the rectangular cross section of the facility is 1.8 meters wide by 2 meters high and has virtually continuous optical access. Equipped with 8 high-speed, gated, intensified CCD cameras (4 side-view and 4 top-view), the facility has the functional equivalent of approximately 50 shadowgraph stations (the actual number depends on model velocity, lighting conditions, and camera position and settings). The combination of the GDF's concentration of optical stations and its unusually spacious test section makes it an ideal facility in which to determine the aerodynamic characteristics of vehicles (or projectiles, as was done for Space Shuttle External Tank foam debris in the Shuttle Return to Flight effort) with unusually high, or unknown, rates of deceleration, swerve, or pitch-yaw oscillation.
The Electric Arc Shock Tube (EAST) Facility is used to investigate the effects of radiation and ionization generated by shock waves at very high speed atmospheric entry velocities. Gas compositions and shock wave velocities can be tailored to replicate entry into a variety of planetary atmospheres. The spectral and spatiotemporal characteristics of shock radiation are measured using imaging spectrographs spanning the mid-wave infrared through the vacuum ultraviolet. The facility has three separate driver configurations to meet a range of test requirements: the driver can be connected to either a 102mm (4 inch) or a 610mm (24 inch) shock tube. Energy for the drivers is supplied by a 1.25-MJ-capacitor storage system.
NASA Ames has a long tradition of leadership in the use of ballistic ranges and shock tubes for the study of the physics and phenomena associated with hypervelocity flight. The Range Complex has provided critical testing in support of many of NASA's Space Transportation and Planetary Programs including: Mercury, Gemini, Apollo, Shuttle, Viking, Pioneer Venus, Galileo, Cassini, Stardust, Mars Odyssey, Mars Exploration Rovers, Mars Science Laboratory, International Space Station, and the National Aerospace Plane.
This tradition of leadership in testing for aerodynamics impact physics and flow-field structure and chemistry, goes back to the NACA era of the 1940's. Today, the Range Complex continues to provide unique, mission-enabling support for the Nation's programs in planetary geology and geophysics, exobiology, solar system origins, earth atmospheric entry, planetary entry and aerobraking vehicles, and various vehicle configurations for supersonic and hypersonic flight.