MMOD Impact Detection and Location

sensors
MMOD Impact Detection and Location (LAR-TOPS-245)
Micrometeoroid/Orbital debris impact detection and location using fiber optic strain sensing
Overview
Determination of micrometeoroid/orbital debris (MMOD) impact on orbiting spacecraft currently requires visual inspection. For human-rated spacecraft such as the ISS and, previously, the Space Shuttle Orbiter, this has required crew time as well as vehicle assets to identify damage due to MMOD strikes. For unmanned spacecraft, there are no human assets present to conduct detailed surveys to ascertain potential damage. NASAs Langley Research Center has developed a strain-sensing system that can be affixed to a spacecrafts micrometeoroid/orbital debris (MMOD) shielding layer or structure. This technology detects the occurrence, time, location and severity of a MMOD strike on the shield, allowing for detection and location of potentially harmful MMOD strikes on both crewed and unmanned spacecraft. This knowledge is important because prolonged exposure to the on-orbit MMOD environment increases risk to vehicles in this environment including commercial crew vehicles expected to visit and remain for considerable periods of time at ISS.

The Technology
Multiple strain sensors encoded into one or more optical fibers are affixed to a MMOD shield or structure. The optical fiber(s) is/are connected to a data collection device that records strain data at a frequency sufficient to resolve MMOD impact events. Strain data are processed and presented on a computer display. MMOD impact imparts a transient shock loading to a structure which is manifested as transient strain as the shock wave moves through the structure. MMOD impacts are determined from the time signature of, both, measured strain from multiple sensors on the optical fiber(s) as well as strain resulting from plastic strain induced in the MMOD shield and structure as a consequence of the MMOD impact (for materials exhibiting plastic strain). The array of strain sensors, encoded into one or more optical fibers using Fiber Bragg Grating (FBG) technology, records time varying strain to identify that a strike has occurred and at what time it occurred. Strike location information can be inferred from the residual plastic strain recorded by the multitude of strain sensors in the fiber(s). One or more optical fibers may be used to provide optimal coverage of the area of interest and/or to ensure a sufficient number of strain measurements are provided to accurately characterize the nature of the impact.
Fiber Optic Strain System Block Diagram. Image credit: NASA
Benefits
  • Fiber Bragg Grating sensors provide an efficient and easily implemented means of instrumenting MMOD shields and spacecraft structure
  • Can be manufactured from COTS or near-COTS components
  • This technology is apparently novel for spacecraft applications and could become one element in a suite of systems to monitor/assure a return-ready condition for manned spacecraft

Applications
  • Of possible interest to all aerospace companies engaged in spacecraft work, such as commercial crew providers and developers of elements of the Deep Space Gateway and transport system
  • Complex unmanned vehicles such as satellites and UAVs may also benefit from automated object impact detection
Technology Details

sensors
LAR-TOPS-245
LAR-18723-1
10,267,694
Rickman, S. L., Richards, W. L., Christiansen, E. L., Piazza, A., Pena, F., Parker, A., R., Micrometeoroid/Orbital Debris (MMOD) Impact Detection and Location Using Fiber Optic Bragg Grating Sensing Technology, 6th Asia Pacific Workshop on Structural Health Monitoring, December, 2016.
Similar Results
Damage Detection System Prototype
Multidimensional Damage Detection System
The Damage Detection System consists of layered composite material made up of two-dimensional thin film damage detection layers separated by thicker, nondetection layers, coupled with a detection system. The damage detection layers within the composite material are thin films with a conductive grid or striped pattern. The conductive pattern can be applied on a variety of substrates using several different application methods. The number of detection layers in the composite material can be tailored depending on the level of damage detection detail needed for a particular application. When damage occurs to any detection layer, a change in the electrical properties of that layer is detected and reported. Multiple damages can be detected simultaneously, providing real-time detail on the depth and location of the damage. The truly unique feature of the System is its flexibility. It can be designed to gather as much (or as little) information as needed for a particular application using wireless communication. Individual detection layers can be turned on or off as necessary, and algorithms can be modified to optimize performance. The damage detection system can be used to generate both diagnostic and prognostic information related to the health of layered composite structures, which will be essential if such systems are utilized to protect human life and/or critical equipment and material.
Meta Monitoring System (MMS)
Meta Monitoring System (MMS) was developed as an add-on to NASA Ames patented Inductive Monitoring System (IMS), which estimates deviation from normal system operations. MMS helps to interpret deviation scores and determine whether anomalous behavior is transient or systemic. MMS has two phases: a model-building training phase, and a monitoring phase. MMS not only uses deviation scores from nominal data for training but can also make limited use of results from anomalous data. The invention builds two models: one of nominal deviation scores and one of anomalous deviation scores, each consisting of a probability distribution of deviation scores. After the models are built, incoming deviation scores from IMS (or a different monitoring system that produces deviation scores) are passed to the learned model, and probabilities of producing the observed deviation scores are calculated for both models. In this fashion, users of MMS can interpret deviation scores from the monitoring system more effectively, reducing false positives and negatives in anomaly detection. Note: Patent license only; no developed software available for licensing
impactor device
A Portable Impactor Device
The NASA impactor is a fully portable device that propels an instrumented projectile so that it impacts a vehicle, structural component, or test specimen. The device includes a projectile inside an exterior tube. The projectile itself contains a commercial load cell designed to obtain the dynamic force response during the impact event. Furthermore, a digital oscilloscope and optical sensor are combined to measure the velocity just prior to impact so that the impact energy of the projectile onto the test surface can be calculated. In the current configuration, impacts with energies between 4 and 40 J (between about 3 and 30 ft-lbs) are obtainable, and could be adjusted by changing the spring to one with a different spring constant. The tube can be handheld or rigidly mounted at any angle such that the impact response can be evaluated at specified positions throughout the test article. The impactor device is primarily designed for use on composite structures to investigate the structural response from a low-velocity impact, as composite materials are highly susceptible to damage from low-velocity impacts where the damage may not be visible but results in great loss of strength. If the damage cannot be detected visually, it can be seen through nondestructive testing (ultrasonic, flash thermography or X-ray). However, the device may also be used on structures to evaluate and tune structural health monitoring systems. The technology has been designed, prototyped, and implemented in four military or government programs for impact testing on metallic and composite structures, including a helicopter roof in 2013. The cost of the parts for the prototype was approximately $9,000. Production costs are expected to be lower.
Spacecraft Reentry
Robust Sensors Detect Material Ablation and Temperature Changes
Glenn's breakthrough technology introduces batch-fabricated, miniature sensors embedded and distributed over a large surface area of a material or product during the manufacturing process. The sensors can be utilized for test instrumentation or as an integrated in-situ monitoring system. This integrated manufacturing approach preserves the structural and mechanical system integrity by eliminating the antiquated plug-in approach, invasive machining, manual insertion, and gluing processes currently required to implant sensors into a material. The sensor ladder network of resistors and capacitors breaks down as result of the thermo-physical effects caused by temperature, shock, radiation, corrosion, or other reactions, causing a change in the electrical properties. A processor interprets these changes in the electrical properties and generates a high-resolution, large-area surface profile. The profile demonstrates the amount or rate of material deterioration and temperature change, and is used to optimize geometric structural design, develop materials, predict performance, and make decisions. These sensors play an important role as industries work to realize material performance and product design. This type of monitoring is ideal for infrastructures, nuclear enclosures, or any system susceptible to surface deterioration.
Spacecraft to Remove Orbital Debris
An approach to mitigating the creation of additional orbital debris is to remove the sources of future medium debris by actively removing large spent objects from congested orbits. NASA has introduced the ADRV, an efficient and effective solution to remove large debris from LEO such as spent rocket bodies and non-functional satellites. The concept yields a single use, low-cost, lightweight, high mass fraction vehicle that enables the specific removal of large orbital debris (1000 - 4000 kg mass, 200 - 2000 km altitude, and 20 98-degree inclination). The ADRV performs rendezvous, approach, and capture of non-cooperative tumbling debris objects, maneuvering of the mated vehicle, and controlled, targeted reposition or deorbit of the mated vehicle. Due to its small form factor, up to eight ADRVs can be launched in a single payload, enabling high impact orbital debris removal missions within the same inclination group. Three key technologies were developed to enable the ADRV: - 1) The spacecraft control system (SCS) is a guidance, navigation, and control system that provides vehicle control during all phases of a mission; - (2) The debris object characterization system (DOCS) characterizes movement and capture of non-cooperative targets; and - (3) The capture and release system (CARS) allows the vehicle to capture and mate with orbital debris targets. These technologies can improve the current state-of-the-art capabilities of automated rendezvous and docking technology significantly for debris objects with tumbling rates up to 25 degrees per second. This approach leverages decades of spaceflight experience while automating key mission areas to reduce cost and improve the likelihood of success.
Stay up to date, follow NASA's Technology Transfer Program on:
facebook twitter linkedin youtube
Facebook Logo Twitter Logo Linkedin Logo Youtube Logo