Multi-Parameter Aerosol Scattering Sensor
instrumentation
Multi-Parameter Aerosol Scattering Sensor (LEW-TOPS-19)
A highly accurate, lightweight, low-cost miniaturized environmental monitoring sensor system
Overview
Innovators at NASA's Glenn Research Center have developed the Multi-Parameter Aerosol Scattering Sensor (MPASS), an aerosol-detection system that characterizes atmospheric particles, enabling real-time environmental monitoring often critical for public safety. This optical sensor is superior to the present state-of-the-art in its ability to characterize virtually any particle, as small as nanometer-scale, without the need for calibration against a known aerosol. The universal sensor has the unique ability to measure total particle surface area and mass as well as particle count within the same system. Not only can the MPASS function as an independent portable sensor to quantify inaccessible conditions such as volcanic activity and wildfires through remote monitoring, it can also function as part of a sensor network within a factory or other facility for air quality and fire detection. Lightweight and compact, the unit is ideal for surveillance missions when integrated onto a drone or other unmanned aerial vehicle (UAV), or as a personal health monitoring device for first responders and public safety professionals.
The Technology
Originally developed to demonstrate a highly accurate, low-false-alarm, early fire detection system in space, this advanced technology level system utilizes a durable, low-cost, compact laser source and detector array, similar to CD/DVD player technology, to analyze the interaction of light with particles. The smart system is ideal for detecting a diverse range of particles found in pollution, emissions, fire and other atmospheric toxins while introducing a flexibility that enables its use in multiple environments, especially when coupled with UAVs or other remote platforms.
The MPASS contains a number of features that allow users to make the most of its pioneering capabilities. The self-contained system is lightweight and has been miniaturized and packaged to easily fit into the palm of your hand. A USB port enables the system to be powered, configured, and accessed through its onboard central processing unit. The advanced graphical user interface, custom software, and optimized algorithm allows the user to select known properties when applicable, and to program the system for maximum performance. The dashboard also provides visual feedback through graphical displays, making it easy to analyze the data and make real-time decisions. The system is designed with Bluetooth expansion capability, adding flexibility and communication through potential custom cellular phone applications. Once programmed, the battery-powered wireless sensor system opens the door to monitoring remote areas and extreme environments never thought possible.

Benefits
- Accurate: Customized algorithms optimize performance and maximize measurement accuracy
- Compact: The miniaturized packaged system fits in the palm of your hand
- Low power consumption: Powered through a USB or 4 standard AAA batteries
- Portable: Battery options and Bluetooth expansion capability for remote use
- Rugged: Ideal for harsh, extreme atmospheric conditions and environments
- Sensitive: Achieves a high level of sensitivity and reduces the occurrence of false alarms in fire detection
- Versatile: Measures total surface area, mass and particle count of various aerosols
Applications
- Environmental monitoring
- First responders
- Military
- Health monitoring
- Process control
- Protective gear
- Remote sensing
- Sensors
- Unmanned vehicles
- Security
Similar Results

Photo-Acoustic Sub Part-Per-Billion Chemical Sensing
The technology is a sensor for remotely detecting sub part-per-billion (ppb) levels of ambient trace gases and chemical species. The system includes a high-repetition-rate, pulsed laser module that is spectrally tuned to a desired chemical species. The photons from the laser are absorbed by the target chemical, creating an acoustic vibration that impacts a diaphragm (which acts like a speaker). A highly sensitive, photo-emf detector is then used to measure the magnitude of the vibration, which corresponds to the concentration of the target chemical. The technology is being developed for NASA's trace-gas measurement needs for validation and ground truth studies to support airborne and space-based LIDAR operations. The technology has application as a chemical sniffer to detect hazardous or toxic chemical species in the vicinity of IEDs, explosives, or other chemical agents. In such an application the sensor could detect chemical species hidden inside closed containers, bags, or car trunks.

Low Frequency Portable Acoustic Measurement System
Langley has developed various technologies to enable the portable detection system, including:
- 3-inch electret condenser microphone - unprecedented sensitivity of -45 dB/Hz
- compact nonporous windscreen - suitable for replacing spatially demanding soaker hoses in current use
- infrasonic calibrator for field use - piston phone with a test signal of 110 dB at 14Hz.
- laboratory calibration apparatus - to very low frequencies
- vacuum isolation vessel - sufficiently anechoic to permit measurement of background noise in microphones at frequencies down to a few Hz
- mobile source for reference - a Helmholtz resonator that provides pure tone at 19 Hz
The NASA system uses a three-element array in the field to locate sources of infrasound and their direction. This information has been correlated with PIREPs available in real time via the Internet, with 10 examples of good correlation.

Multi-Stage Filtration System
While HEPA filter elements can last for years without intervention, pre-filtering systems that remove larger particles before they reach the HEPA filter need to be treated (most often by cleaning or replacement) as often as once a week. These treatments can be resource-intensive and expensive, especially in extreme environments. Glenn's innovative system combines a pre-filtration impactor and a scroll filter that reduces the need to replace the more sensitive or expensive filters, extending the system's working life. The system uses an endless belt system to provide the impaction surface. A thin layer of low-toxicity grease is applied to the impaction surface to increase particle adhesion. A high flow turning angle near the impaction surface causes relatively large particles to impact and stick to the surface while smaller particles stay within the air flow. When the surface is covered with particles - or if a layer of particles has grown to a thickness that impairs adhesion - the surface is regenerated. The band is rotated so that the loaded surface passes by a scrapper, removing the layer of particles and a clean segment of the band revolves to become the new impaction surface.
A further innovation is the scroll filter which allows the filtration media to be rotated out of the airflow when fully loaded, providing multiple changes of the filter through a motorized scrolling or indexing mechanism. When nearly fully loaded with dust particles, the exposed media is mechanically rolled up on one side of the filter to both contain and compactly store the dust. The spools that hold the clean and spent filter media are mounted on roller bearings to facilitate the scrolling operation and reduce motor power requirements. Nearly any grade of filter media can be used to meet the desired filtration specification. Additional media rolls can be added after the original roll is spent to further increase filter life.

Wide Field Receiver Calibration Device for Micro Pulse LiDAR
Below an MPL’s minimum overlap range, the return signals are not completely in the instrument’s field of view, so the receiver only captures a portion of the backscatter laser pulse. MPL overlap ranges vary, but is usually between 4-8 km, encompassing the lower atmosphere where most aerosols reside. Commonly, correction entails recording horizontal profiles that require a ~10 km clear line-of-sight and homogenous atmospheric conditions, limiting the solution’s practicality.
In contrast, NASA’s WFR device corrects for the overlap using a second receiver co-aligned with the MPL that captures the same backscattered laser pulses as the MPL receiver, but with a ~20x wider FOV that enables a much shorter overlap range from ~6 km down to 250 m. Thus, the combination of the WFR and MPL can capture accurate signals from near surface to the stratosphere. The WFR utilizes the same detector as the MPL, enabling it to connect to the MPL data system for synced data acquisition. By eliminating the need for homogeneous horizontal measurements to determine the MPL overlap function, overlap corrections are more easily and more frequently obtained. Further, the WFR mount base was designed to easily integrate with MPLs.
NASA originally developed this device to improve accuracy of MPLs in the MPLNET, ensuring data collected are both accurate and reliable, thereby enhancing our understanding of atmospheric processes and contributing to more informed climate research and environmental modeling. The technology’s operational ease, flexibility, and cost savings are relevant to a wide range of scientific, environmental, and industrial applications. Companies that manufacture and sell MPLs may wish to offer this advanced calibration device as a product to enhance accuracy of MPL-based measurements. This NASA technology is at TRL 8 (Actual system completed and "flight qualified" through test and demonstration.) and is available for patent licensing.

Dust Accumulation Sensor Provides In Situ Monitoring
Previous techniques for measuring dust accumulation, mostly de-pendent on solar cell output, were limited by their inability to distin-guish dust effects from other factors like incident radiation and radiation damage. These techniques were less effective in environ-ments with inconsistent solar flux and future missions, such as the Lunar South Pole, and lacked versatility in adapting to diverse envi-ronmental conditions. The PADS device embraces success over these challenges, and reflects enhanced features over prior iterations to also allow for space environments.
Key design features begin with the customizable mechanical design of the PADS device for use in space environments, heaters with imbedded precision temperature sensors, a selected optical coating for the device coupons that are calibrated on high-fidelity thermal modeling and validated with ground-based testing to simulate the space environment of interest (including dusting with simulants representative of the planetary-body soil/regolith), and a control circuit for precision control/matching of the thermal inputs to the sensor via the heaters. Retainers with mount isolators are implemented to ensure the stacked layers within the device do not dislodge during high vibration or gravitational loads during launch.
For operation, the PADS device is installed at the point of interest (e.g., space vehicle surface, extraterrestrial equipment) to quantify dust accumulation. Power and data transfer are done through cabling to the space vehicle system or can be provided standalone. A control circuit/algorithm adjusts the power to the heaters to precisely match the temperature setpoints. Ground testing in the simulated space environment conditions of interest creates a calibration plot of effec-tive emittance versus dust density, and allows determination of the degradation in emittance as the dust increases on the surface.
Testing on the PADS device has been completed in a simulated lunar environment and data has been collected to enable sensor calibration for its use on the Moon. It is currently poised for integration into a lander for flight testing.
Although the PADS device is intended for use in a burgeoning space industry and requisite environments – but given that the PADS device is partially comprised of programmable sensors in conjunction with optically coated coupons that can be tailored for custom use - it or its constituent components could be modified for terrestrial applications such as surface dust monitoring on photovoltaic panels or potentially combustible dust on various industrial surfaces.