James A. Bickford

Large scale deployment and operation of distributed sensor assets optimized for robust Mars exploration

The large scale dispersal of distributed sensor arrays across planetary surfaces has been proposed by several groups for the exploration of Mars. We survey a number of these concepts and discuss their intrinsic advantages as well as technical challenges relative to more traditional exploration modalities. Specifically, distributed sensors working in conjunction with traditional surface vehicles enable critical phenomena to be measured in previously inaccessible terrain over temporal and spatial scales not obtainable otherwise. We discuss how this strategy can be integrated into an overall science campaign and address several key issues in regards to returning the acquired data. Dispersion and data extraction studies performed for the global environmental micro sensors (GEMS) project will be presented in the context of Mars exploration and the search for life. The modeling results provide insight into optimum strategies for distributing probes and then extracting measured data either via an ad hoc network or direct exfiltration to an orbital asset.

GEMS: A Revolutionary Concept for Planetary and Space Exploration

A novel observing system known as Global Environmental MEMS Sensors (GEMS) offers the potential to significantly improve the ability to take in situ measurements for a variety of space missions. The GEMS concept features devices with completely integrated sensing, power, and communications with characteristic dimensions of just millimeters. Thousands of these low‐cost devices could potentially be deployed together from a spacecraft to enable distributed sensing in planetary and other space environments. The deployment of such probes is analyzed and discussed for various scenarios on Mars that would provide measurements with unprecedented spatial and temporal resolution. The extended coverage provided by the arrays would improve the ability to calibrate remote sensing data while also extending the areas traditionally measured by localized landers. The unique features of such a system could significantly improve the capabilities for planetary and space exploration in the near and far term.

Low frequency mechanical antennas: Electrically short transmitters from mechanically-actuated dielectrics

Antennas that operate in the low-frequency (LF) band and below are useful for a number of applications. However, the long wavelengths result in very low efficiency for antennas that could be made portable. This has motivated the need for novel approaches for electrically short antenna design. Here, we present the concept of an electromagnetic transmitter that operates by mechanically moving bound static charge. The resulting motion induces electromagnetic fields that are similar to a short dipole antenna. However, the voltage, current, and resistance of a conventional antenna are replaced by force, velocity, and damping in a mechanical system. The mechanical system offers very high efficiency at low frequencies where impedance matching naturally occurs and mechanical structures have very low losses. We present a basic proof-of-concept demonstration by rotating a charged electret material up to 167Hz and measuring the resulting time-varying magnetic field. This work is intended to lay the foundation for future tests involving the implementation of efficient, small form-factor, mechanically-actuated antennas.

Automated, On-Line Loss-on-Ignition (LOI) Sensor

Draper Laboratory has developed a prototype, automated system that measures on-line loss-on-ignition (LOI) in coal power plants. The system automatically extracts fly ash samples via a sample probe inserted into the flue gas stream and delivers them to an integrated thermo-gravimetric-analyzer (TGA) that analyzes the sample’s LOI according to the ASTM C311 standard. The integrated TGA is custom designed and built to be rugged and low cost relative to a laboratory grade instrument and can analyze samples every fifteen minutes. This LOI sensor is a major improvement in time and spatial resolution over the commonplace method of sampling fly ash from the bag house and sending it offsite for analysis. During field tests at actual power plants, the prototype system acquired ash samples and analyzed them while unattended. A proposed redesign for commercialization is also described.Copyright

GEMS: a mobile wireless network for atmospheric sampling

Large scale, mobile ad-hoc networks (MANET) are of great interest for a number of applications including battlesphere dominance and homeland security. ENSCO, Inc. is designing a system for profiling large regions of the atmosphere. The concept, known as Global Environmental Micro Sensors (GEMS), features an integrated system of airborne probes that will remain suspended in the atmosphere and take measurements of pressure, temperature, humidity, and wind velocity as they are carried by atmospheric currents. In addition to gathering meteorological data, the probes could be used for monitoring and predicting the dispersion of particulate emissions, organic and inorganic pollutants, ozone, carbon dioxide, and chemical, biological, or nuclear contaminants. Several functionality requirements are called into question when investigating a scalable mobile network protocol. For instance, periodic reporting may not always be required and can be abandoned in favor of event-driven reports. Similarly, network connectivity may not be required at all times. Instead of constant global connectivity, paths can be formed only when data packets are ready for transmission. For a successful GEMS system, the most important network function is to relay timely data to one or more receiving stations. We will present both the GEMS system and probe design as well as discuss the trade-offs associated with optimizing a three-dimensional, mobile, airborne network comprised of low-cost, low-power probes. We will also analyze and present measured data to determine the performance of a representative MANET under actual environmental conditions and various aspects of mobility.