Multistage Free-Flight Testing System

Aerospace
Multistage Free-Flight Testing System (TOP2-330)
Three-Stage System for Delivering Payloads to Supersonic Free-Flight Conditions — Stratospheric Projectile Experiment of Entry Dynamics (SPEED)
Overview
During atmospheric entry of blunt-body vehicles, such as a crew capsule or planetary probe, travel through the supersonic and transonic regimes can induce divergent instabilities due to dynamic stability issues, the fundamental understanding of which remains incomplete. Traditional qualification methods such as ballistic ranges, wind tunnels, and computation simulations can provide aerodynamic performance data for various flight conditions, but each has limitations or requires extensive validation. To address the need to understand dynamic stability issues of re-entry vehicles, NASA Ames has developed a multistage flight system architecture capable of testing vehicles through supersonic and transonic Mach numbers. This architecture enables the acquisition of rich, flight-relevant data related to dynamic stability and other key aerodynamic parameters.

The Technology
The disclosed technology provides a multistage system for evaluating the free-flight behavior of test articles across of the supersonic, transonic, and subsonic regimes. First, a drop platform is lifted to high altitudes using a lifting device, such as a stratospheric balloon. The drop platform houses multiple projectiles, each containing an ejection mechanism, an on-board avionics suit, and an instrumented test article. Upon reaching the target altitude via the lifting device, the drop platform releases the projectiles sequentially. Each projectile accelerates to a target speed and altitude before ejecting its test article into the freestream. The test articles, such as a scaled re-entry capsule, then collect flight data during their descent through the various Mach regimes, providing valuable insights into their flight performance under mission-relevant conditions. This innovative testing system offers several benefits. It enables the simultaneous testing of multiple vehicles, facilitating the evaluation of design variations as well as statistical analyses of vehicle behavior. This system also provides significant cost savings in comparison to other state-of-the-art testing methods, such as ballistic range testing. Additionally, the test articles within each projectile are easily interchangeable through a simple, modular change of a support surface in the ejection mechanism. This flexibility enables the system to accommodate a range of other aerodynamic technologies, including other vehicles, parachutes, propulsion systems, and defense technologies. This system can enhance the efficiency and robustness of reentry vehicle design, testing, and simulation operations through the collection of rich, flight-relevant data.
First stratospheric balloon demonstration A: The Stratospheric Projectile Experiment of Entry Dynamics (SPEED) Design Parameter Trade Space: shows achievable speed and altitude heat maps based on the Projectile and Capsule vehicle design. The current SPEED operating box is circled in each contour plot, but the potential to expand those bounds exist.
B: Anatomy of a SPEED flight unit.
C: Concept of Operations: A robust avionics system and comprehensive instrumentation package are critical to releasing entry capsules at the right time and capturing high-fidelity data throughout flight.
Benefits
  • The multistage system enables simultaneous testing of multiple flight vehicles, facilitating the evaluation of design variations and statistical analyses of vehicle behavior
  • The system captures rich, dynamically-scaled data in critical Mach number regimes that can be used in vehicle design and CFD validations
  • Modular design allows for easy customization to meet diverse testing requirements, supporting a wide range of applications
  • The technology facilitates the generation of flight-relevant data, offering valuable insights into the dynamic stability and performance of flight vehicles
  • The use of low-cost materials and additive manufacturing techniques enables economical and lightweight construction

Applications
  • Commercial Spaceflight industry (atmospheric entry capsules)
  • Aerospace industry (test article can be swapped at will for any vehicle design)
  • Parachute manufacturers
  • Propulsion System manufacturers
Technology Details

Aerospace
TOP2-330
ARC-19060-1
https://ntrs.nasa.gov/api/citations/20250006089/downloads/IPPW_Poster_SPEED_alpert2025_v2.pdf https://ntrs.nasa.gov/api/citations/20230011776/downloads/IPPW%202023%20-%20final.pdf https://ntrs.nasa.gov/api/citations/20240010385/downloads/SPEED%20Overview_2024%20Summer%20Seminar%20Series%20_Kazemba.pdf
Similar Results
Simple COBRA geometry shape
Co-Optimization of Blunt Body Shapes for Moving Vehicles
Vehicles designed for purposes of exploration of the planets and other atmospheric bodies in the Solar System favor the use of mid-Lift/Drag blunt body geometries. Such shapes can be designed so as to yield favorable hypersonic aerothermodynamic properties for low heating and hypersonic aerodynamic properties for maneuverability and stability. The entry trajectory selected influences entry peak heating and integrated heating loads which in turn influences the design of the thermal protection system. A nominal is used to compare each shape considered. The vehicle will be subject to both launch and entry loading along with structural integrity constraints that may further influence shape design. Further, such vehicles must be sized so as to fit on existing or realizable launch vehicles, often within existing launch payload shroud constraints.
Pterodactyl Baseline Vehicle (asymmetric aeroshell)
Aerospace Vehicle Entry Flightpath Control
This novel flightpath control system exploits the dihedral effect to control the bank angle of the vehicle by modulating sideslip (Figure 1). Exploiting the dihedral effect, in combination with significant aerodynamic forces, enables faster bank accelerations than could be practically achieved through typical control strategies, enhancing vehicle maneuverability. This approach enables vehicle designs with fewer control actuators since roll-specific actuators are not required to regulate bank angle. The proposed control method has been studied with three actuator systems (figure below), Flaps Control System (FCS); Mass Movement Control System (MMCS); and Reaction Control System (RCS). • FCS consists of a flap configuration with longitudinal flaps for independent pitch control, and lateral flaps generating yaw moments. The flaps are mounted to the shoulder of the vehicle’s deployable rib structure. Additionally, the flaps are commanded and controlled to rotate into or out of the flow. This creates changes in the vehicle’s aerodynamics to maneuver the vehicle without the use of thrusters. • MMCS consists of moveable masses that are mounted to several ribs of the DEV heatshield, steering the vehicle by shifting the vehicle’s Center of Mass (CoM). Shifting the vehicle’s CoM adjusts the moment arms of the forces on the vehicle and changes the pitch and yaw moments to control the vehicle’s flightpath. • RCS thrusters are mounted to four ribs of the open-back DEV heatshield structure to provide efficient bank angle control of the vehicle by changing the vehicle’s roll. Combining rib-mounted RCS thrusters with a Deployable Entry Vehicle (DEV) is expected to provide greater downmass capability than a rigid capsule sized for the same launch
front image
Transformable Hypersonic Aerodynamic Decelerator
The invention allows the deployment of a large aerodynamic decelerator relative to the size of its launch vehicle, which is controllable and can be transformed into a landing system. A structure composed of a radial assembly of ribs and struts in a four bar linkage arrangement fits inside a launch vehicle shroud, expands into a deployed size, and permits rotation about a pivot point along the vehicle axis. The mechanism that deploys the decelerator surface, doubles as the actuation/control mechanism, and triples as the payload surface leveling system. The design permits the use of conformable thermal protection systems at the central part and a flexible TPS, 3-D woven carbon fabric, as skin in the majority of the regions of the aeroshell entry system. The fabric handles both the heat and mechanical load generated during entry. This system is very mass competitive with other lightweight systems such as inflatable and rigid decelerators and is believed to be more reliable and testable at sub-scale. Once the payload reaches its destination, the decelerator structure leverages atmospheric drag to slow the craft from hypersonic travel speeds to an appropriate landing velocity. The decelerator can be actuated during descent to generate lift and steer the payload to its intended destination. Retro propulsion engines provide the final deceleration just before landing, and the decelerator structure is inverted to act as a landing platform and help minimize the impact of landing load.
NASA AAM
Aerodynamic Framework for Parachute Deployment from Aerial Vehicle
For rapid parachute deployment simulation, the framework and methodology provided by the simulation database uses parametrized aerodynamic data for a variety of environmental conditions, air taxi design parameters, and landing system designs. The database also includes a compilation of drag coefficients, thrust and lift forces, and further relevant aerodynamic parameters utilized in the simulated flight of a proposed air taxi. The database and framework can be constructed using simulated data that accounts for oscillatory breathing of parachutes. The methodology can further employ an overset grid of body-fitted meshes to accurately capture deployment of an internally-stored parachute, as well as descent of the air taxi and deployed parachute. The systems and methods of the disclosed technology can be utilized with existing CFD solvers in a plug-and-play manner, such that the framework can be integrated to directly improve the performance of these solvers and the machines on which they are installed. The framework itself can employ parallelization to enable distributed solution of intensive CFD simulations to build a robust database of simulated data. Further, as up to 90% of computational time is spent in the calculation of aerodynamic parameters for use in coupled trajectory equations, the framework can significantly reduce the computational costs and design time for safe landing systems for air taxis. These reductions can lead to lower costs for design processes, while enabling rapid design and testing prior to physical prototyping.
Rapid Aero Modeling for Computational Experiments
RAM-C interfaces with computational software to provide test logic and manage a unique process that implements three main bodies of theory: (a) aircraft system identification (SID), (b) design of experiment (DOE), and (c) CFD. SID defines any number of alternative estimation methods that can be used effectively under the RAM-C process (e.g., machine learning techniques, regression, neural nets, fuzzy modeling, etc.). DOE provides a statistically rigorous, sequential approach that defines the test points required for a given model complexity. Typical DOE test points are optimized to reduce either estimation error or prediction error. CFD provides a large range of fidelity for estimating aircraft aerodynamic responses. In initial implementations, NASA researchers “wrapped” RAM-C around OVERFLOW, a NASA-developed high-fidelity CFD flow solver. Alternative computational software requiring less time and computational resources could be also utilized. RAM-C generates reduced-order aerodynamic models of aircraft. The software process begins with the user entering a desired level of fidelity and a test configuration defined in terms appropriate for the computational code in use. One can think of the computational code (e.g., high-fidelity CFD flow solver) as the “test facility” with which RAM-C communicates with to guide the modeling process. RAM-C logic determines where data needs to be collected, when the mathematical model structure needs to increase in order, and when the models satisfy the desired level of fidelity. RAM-C is an efficient, statistically rigorous, automated testing process that only collects data required to identify models that achieve user-defined levels of fidelity – streamlining the modeling process and saving computational resources and time. At NASA, the same Rapid Aero Modeling (RAM) concept has also been applied to other “test facilities” (e.g., wind tunnel test facilities in lieu of CFD software).
Stay up to date, follow NASA's Technology Transfer Program on:
facebook twitter linkedin youtube
Facebook Logo X Logo Linkedin Logo Youtube Logo