S. A. Curtis

ANTS for Human Exploration and Development of Space

The proposed Autonomous Nano-technology Swarm (ANTS) is an enabling architecture for human/robotic mission envisaged by NASAs mission for the Human Exploration and Development of Space (HEDS). ANTS design principles draw on successes observed in the realm of social insect colonies, which include task specialization and sociality. ANTS spacecraft act as independent, autonomous agents for specific functions, while cooperating to achieve mission goals. For example, the Prospecting ANTS Mission (PAM) is a long-term mission concept for the 2020-2025 time frame involving individual spacecraft agents that are optimized for specific asteroid prospecting functions. The objective of PAM is to characterize at least one thousand asteroids during each year of operations in the main belt. To achieve this objective, PAM spacecraft, individually and as a group, must achieve a high level of autonomy. This high degree of autonomy opens the possibility of a new kind of interaction between humans and these spacecraft, where human explorers and developers could interact with ANTS enabled resources by communicating high-level goals and data products. Thus ANTS enables new kinds of missions in which human and robotic agents work together to achieve mission goals. In this paper we review and discuss the ANTS architecture in the context of the HEDS mission.

Magnetospheric Multiscale Mission

The physical processes in the magnetosphere span a wide range of space and time scales and due to the strong cross-scale coupling among them the fundamental processes at the smallest scales are critical to the large scale processes. For example, many key features of magnetic reconnection and particle acceleration are initiated at the smallest scales, typically the ion gyro-radii, and then couples to meso-scale and macro-scale processes, such as plasmoid formation. The Magnetospheric Muliscale (MMS) mission is a multi spacecraft mission dedicated to the study of plasma physics at the smallest scales and their cross-scale coupling to global processes. Driven by the turbulent solar wind, the magnetosphere is far from equilibrium and exhibits complex behavior over many scales. The processes underlying the multi-scale and intermittent features in the magnetosphere are fundamental to sun-earth connection. Recent results from the four spacecraft Cluster and earlier missions have provided new insights into magnetospheric physics and will form the basis for comprehensive studies of the multi-dimensional properties of the plasma processes and their inter-relationships. MMS mission will focus on the boundary layers connecting the magnetospheric regions and provide detailed spatio-temporal data of processes such as magnetic reconnection, thin current sheets, turbulence and particle acceleration. The cross-scale exploration by MMS mission will target the microphysics that will enable the discovery of the chain of processes underlying sun-earth connection.

Tetrahedral Robotics for Space Exploration

A reconfigurable space filling robotic architecture has a wide range of possible applications. One of the more intriguing possibilities is mobility in very irregular and otherwise impassable terrain. NASA Goddard Space Flight Center is developing the third generation of its addressable reconfigurable technology (ART) tetrahedral robotics architecture. An ART-based variable geometry truss consisting of 12 tetrahedral elements made from 26 smart struts on a wireless network has been developed. The primary goal of this development is the demonstration of a new kind of robotic mobility that can provide access and articulation that complement existing capabilities. An initial set of gaits and other behaviors are being tested, and accommodations for payloads such as sensor and telemetry packages are being studied. Herein, we describe our experience with the ART tetrahedral robotics architecture and the improvements implemented in the third generation of this technology. Applications of these robots to space exploration and the tradeoffs involved with this architecture will be discussed.

Small‐scale plasma irregularities in the nightside Venus ionosphere

The individual volt-ampere curves from the Pioneer Venus orbiter electron temperature probe showed evidence for small-scale density irregularities, or short-period plasma waves, in regions of the nightside ionosphere where the orbiter electric field detector observed waves in its 100-Hz channel. A survey of the nightside volt-ampere curves has revealed several hundred examples of such irregularities (approximately 2% of all the current-voltage (I-V) sweeps from below 2000 km and 7% of those below 200 km). The I-V structures correspond to plasma density structures with spatial scale sizes in the range of about 100–2000 m, or alternatively they could be viewed as waves having frequencies extending toward 100 Hz. They are often seen as isolated events, with spatial extent along the orbit frequently less than 80 km. The density irregularities or waves occur in or near prominent gradients in the ambient plasma concentrations both at low altitudes where molecular ions are dominant and at higher altitudes in regions of reduced plasma density where O+ is the major ion. Electric field 100-Hz bursts occur simultaneously, with the majority of the structured I-V curves providing demonstrative evidence that at least some of the E field signals are produced within the ionosphere. Potential sources for the irregularities are extraionospheric particle precipitation and spatial structures and turbulence resulting from the day to night ion transport within the ionosphere.

Onboard science software enabling future space science and space weather missions

On the path towards an operational Space Weather System are science missions involving as many as 100 spacecraft (Magnetospheric Constellation, DRACO, 2010). Multiple spacecraft are required to measure the macro, meso, and micro scale plasma physics that underlies Geospace phenomena. To be feasible, however, multiple spacecraft missions must be no more costly to operate than single spacecraft missions are today. Furthermore, communication availability places severe constraints on an entire mission architecture and hampers the resolution, coverage, timeliness, and hence, usefulness of spacecraft data. To address some of these constraints, we have been studying the possibility of performing some science data processing functions on board a pathfinding mission in NASAs Solar-Terrestrial Probe Line, Magnetospheric Multi Scale (MMS, 2008). Our multi level approach to developing an onboard science analysis system for potential use onboard the MMS mission will enhance MMS science by improving sensor coverage and by returning to Earth high-resolution data that would otherwise be discarded or not generated. Results of our work using Space Physics data sets from previous missions illustrate our approach.

Neural Basis Function Control of Super Micro Autonomous Reconfigurable Technology (SMART) Nano-Systems

** Nanotechnology, taken to its full three-dimensional potential, will place within the volume of a cube of sugar systems of vast complexity that far exceed the quantitative and qualitative capabilities of today’s largest supercomputers. Currently, the uncertainty and imprecision of the real world is tamed, rigidly fixed, by addressable, digital techniques and the careful orchestration of digital patterns within our machines. How to handle the interaction between our digitally implemented systems and continuous, disorganized nature is a key question. NASA is currently researching ways to move beyond autonomy implemented as bruteforce control over every degree of freedom we can discover in our systems. Our systems operate in natural environments: inhumanly harsh, unfamiliar, unknown, and uncontrolled environments. Nature often surprises us, and so we turn to natural systems for clues about how to make massively complex systems more robust, reliable, and truly autonomous. Turning to Computer Science we draw on what we’ve learned about multi-agent systems running continuously and autonomously to understand information flow at the highest semantic levels. From physics we recall that the behaviors of systems may often be enumerated in a basis of fundamental behaviors. Non-linear physics contains clues about how to connect the physical world with the patterns of electric signals that make up the soft, information component of the systems. Genetics and control theory instruct how to handle long and short-term feedbacks throughout the system. Chemistry and biology provide important guiding principles governing system functions.

A theory for narrow‐banded radio bursts at Uranus: MHD surface waves as an energy driver

We describe a possible scenario for the generation of the narrow-banded radio bursts (n bursts) detected at Uranus by the Voyager 2 planetary radio astronomy experiment. This particular radio emission is suspected to originate within the Uranian northern polar cusp region. In order to account for the emission burstiness which occurs on time scales of hundreds of milliseconds, we propose that ULF magnetic surface turbulence, generated at the frontside magnetopause, propagates down the open/closed field line boundary and mode converts to kinetic Alfven waves (KAW) deep within the polar cusp. The oscillating KAW potentials then drive a transient electron stream (beam or loss cone) that creates the bursty radio emission. To substantiate these ideas, we show Voyager 2 magnetometer measurements of enhanced ULF magnetic activity at the frontside magnetopause. We then demonstrate analytically that such magnetic turbulence should mode convert deep in the cusp at a radial distance of 3 RU. A condition for mode conversion from magnetic surface waves to KAW is ƒpe/ƒce < 0.2, which is also a condition favorable for the generation of the R-X mode radio bursts. The fact that a similar plasma condition is required for both processes lends strong support that the active regions for mode conversion and R-X mode wave generation are one and the same.

Measurement Strategies for Future Missions to Understand Geospace Dynamics

Geomagnetic storms and substorms are dramatic reconfigurations of the magnetosphere resulting from fundamental processes that control its dynamics and structure. Improvements in our understanding of these processes require new information on the temporal evolution of the spatially-structured magnetospheric plasma, as well as the variable solar drivers of the connected sun-earth system. A successful approach will consist of an appropriately balanced combination of: a) measurements of the global magnetospheric configuration by widely-distributed spacecraft or by imagers that reveal the connections between different regions; b) comprehensive detailed measurements at important geospace boundaries and regions; c) dense networks of measurements that provide sampling consistent with the coherence length of the plasma; d) measurements of the inner and outer boundaries of the magnetosphere (i.e. the solar wind and the high-latitude ionosphere); e) measurements of the solar plasma and solar processes as a variable driver of geospace dynamics. Several missions have been strategically designed to supply these needed measurements, some of which are enabled by technology innovations. The measurement capabilities and specific approach of the missions that can resolve fundamental questions of storm-substorm relationships are identified, including some of the new missions planned for the NASA Sun Earth Connection program and for the Russian space research program.

SPARCLE: Electrostatic Dust Control Tool Proof of Concept

Successful exploration of most planetary surfaces, with their impact‐generated dusty regoliths, will depend on the capabilities to keep surfaces free of the performance‐compromising dust. Once in contact with surfaces, whether set in motion by natural or mechanical means, regolith fines, or dust, behave like abrasive Velcro, coating surfaces, clogging mechanisms, making movement progressively more difficult, and being almost impossible to remove by mechanical means (brushing). The successful dust removal strategy will deal with dust dynamics resulting from interaction between Van der Waals and Coulombic forces. Here, proof of concept for an electrostatically‐based concept for dust control tool is described and demonstrated. A low power focused electron beam is used in the presence of a small electrical field to increase the negative charge to mass ratio of a dusty surface until dust repulsion and attraction to a lower potential surface, acting as a dust collector, occurred. Our goal is a compact device of...

SPARCLE: Electrostatic Tool for Lunar Dust Control

Successful exploration of most planetary surfaces, with their impact‐generated dusty regoliths, will depend on the capabilities to keep surfaces free of the dust which could compromise performance and to collect dust for characterization. Solving the dust problem is essential before we return to the Moon. During the Apollo missions, the discovery was made that regolith fines, or dust, behaved like abrasive velcro, coating surfaces, clogging mechanisms, and making movement progressively more difficult as it was mechanically stirred up during surface operations, and abrading surfaces, including spacesuits, when attempts were made to remove it manually. In addition, some of the astronauts experienced breathing difficulties when exposed to dust that got into the crew compartment. The successful strategy will deal with dust dynamics resulting from interaction between mechanical and electrostatic forces. Here we will describe the surface properties of dust particles, the basis for their behavior, and an electro...