Feasibility of Determining Aerodynamic Coefficients for a NASA Apollo Body With the Use of Telemetry Data From Free Flight Range Testing
Abstract
The U.S. Army Research Laboratory (ARL) was requested by the National Aeronautics and Space Administration's (NASA s) Langley Research Center to perform a free-flight experiment with telemetry (TM) instrumented sub-scaled re-entry vehicle in order to determine the feasibility of using TM to obtain aerodynamic coefficients. NASA s current ability to collect aerodynamics data of subscale re-entry vehicles has been limited to forced oscillation wind tunnel testing with a sting-mounted model or by free-flight testing in an indoor aeroballistic range. Both testing techniques have shortcomings. The presence of a rear sting and its effect on the capsule s aft-body flow field introduce uncertainties in forced oscillation test results, and aeroballistic testing provides a very limited set of data and relies on the ability to accurately measure small changes in the capsule s angle of attack, based on shadowgraph images. The current methods also limit NASA s abilities to test crew exploration vehicle (CEV) geometry variations such as offsetting the center of gravity and non-symmetrical mass distributions. ARL developed and demonstrated a unique experimental technique to capture the flight dynamics of sub-scaled re-entry vehicles while testing on an exterior ballistics range. This technique combines the gun launch of a projectile that uses a double-length 120-mm gun with an instrumentation package contained inside the re-entry vehicle. For the current phase 1 effort being described, a reduced size Apollo (see figure 1) shaped re-entry vehicle was used because of its similarity to the current CEV being proposed and the existence of vast empirical data available to validate this technique. Following muzzle exit, the sabot is discarded and an ARL-developed constellation of inertial and magnetic sensors generate raw data that is telemetered and captured via a ground station.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2007
- Accession Number
- ADA472739
Entities
People
- Benjamin Topper
- Bradford S. Davis
- Edward Bukowski
- Fred J. Brandon
- Peter C. Muller
- Rex A. Hall
- T. G. Brown
- Timothy T. Vong
Organizations
- United States Army Research Laboratory