Draper Station Analysis Tool

Draper Station Analysis Tool (DSAT) is a computer program, built on commercially available software, for simulating and analyzing complex dynamic systems. Heretofore used in designing and verifying guidance, navigation, and control systems of the International Space Station, DSAT has a modular architecture that lends itself to modification for application to spacecraft or terrestrial systems. DSAT consists of user-interface, data-structures, simulation-generation, analysis, plotting, documentation, and help components. DSAT automates the construction of simulations and the process of analysis. DSAT provides a graphical user interface (GUI), plus a Web-enabled interface, similar to the GUI, that enables a remotely located user to gain access to the full capabilities of DSAT via the Internet and Webbrowser software. Data structures are used to define the GUI, the Web-enabled interface, simulations, and analyses. Three data structures define the type of analysis to be performed: closed-loop simulation, frequency response, and/or stability margins. DSAT can be executed on almost any workstation, desktop, or laptop computer. DSAT provides better than an order of magnitude improvement in cost, schedule, and risk assessment for simulation based design and verification of complex dynamic systems

Planet Hunters VII. Discovery of a New Low-Mass, Low-Density Planet (PH3 c) Orbiting Kepler-289 with Mass Measurements of Two Additional Planets (PH3 b and d)

We report the discovery of one newly confirmed planet ($P=66.06$ days, $R_{\rm{P}}=2.68\pm0.17R_\oplus$) and mass determinations of two previously validated Kepler planets, Kepler-289 b ($P=34.55$ days, $R_{\rm{P}}=2.15\pm0.10R_\oplus$) and Kepler-289-c ($P=125.85$ days, $R_{\rm{P}}=11.59\pm0.10R_\oplus$), through their transit timing variations (TTVs). We also exclude the possibility that these three planets reside in a $1:2:4$ Laplace resonance. The outer planet has very deep ($\sim1.3$), high signal-to-noise transits, which puts extremely tight constraints on its host star's stellar properties via Kepler's Third Law. The star PH3 is a young ($\sim1$ Gyr as determined by isochrones and gyrochronology), Sun-like star with $M_*=1.08\pm0.02M_\odot$, $R_*=1.00\pm0.02R_\odot$, and $T_{\rm{eff}}=5990\pm38$ K. The middle planet's large TTV amplitude ($\sim5$ hours) resulted either in non-detections or inaccurate detections in previous searches. A strong chopping signal, a shorter period sinusoid in the TTVs, allows us to break the mass-eccentricity degeneracy and uniquely determine the masses of the inner, middle, and outer planets to be $M=7.3\pm6.8M_\oplus$, $4.0\pm0.9M_\oplus$, and $M=132\pm17M_\oplus$, which we designate PH3 b, c, and d, respectively. Furthermore, the middle planet, PH3 c, has a relatively low density, $\rho=1.2\pm0.3$ g/cm$^3$ for a planet of its mass, requiring a substantial H/He atmosphere of $2.1^{+0.8}_{-0.3}$ by mass, and joins a growing population of low-mass, low-density planets.Comment: 21 pages, 10 figures, 5 tables, accepted into Ap

Robot configuration for subterranean modeling

Void models are invaluable for understanding subterranean conditions and guiding underground operations, but many maps are inaccurate, missing or difficult to acquire. Underground voids are inaccessible and often hostile to man and machine. Mapping and modeling of subterranean voids is a superb motivation for development of robots. Successful robot configurations for modeling subterranean worlds such as sewers, tunnels, mines and voids have yet to be created and characterized. This research identifies subterranean modeling tasks and exploration constraints. Modeling tasks range from limited two-dimensional cross sections to comprehensive, globally-referenced, three-dimensional coverage of vast voids. Entry constraints such as small diameter holes limit the size of robot configurations, but once inside, muck and obstacles require significant terrainability that only comes with larger size. Based on these conditions and constraints, robot configurations are conceived, developed, tested and classified. This research distinguishes three classes of robotic configuration for void modeling based on entry constraint and robot mobility. Portal Explorers are mobile robots featuring substantial locomotion, sophisticated sensing, and plentiful energy storage that can roam afar after being deployed via large diameter portals. Borehole Sensors provide exceptional modeling capability from fixed vantage points, while their miniaturization enables deployment down smallest diameter boreholes. Borehole Explorers combine some mobility with some borehole access miniaturization to acquire otherwise unobtainable model data. Mobility provides greater modeling coverage than possible with borehole sensors, while reconfigurability allows deployment via small diameter boreholes, enabling void access not possible with portal explorers. This research classifies subterranean modeling tasks, develops robots to address these tasks, and tests these robots by entering and modeling vast voids. Model data is used to evaluate the merits and limits of these important robot configurations. Additionally, field work provides insight into issues and operational approaches that are not otherwise apparent from lab work alone. Finally, future robot configurations and paradigms for subterranean robotics are envisioned

A System for Volumetric Robotic Mapping of Abandoned Mines

This paper describes two robotic systems developed for acquiring accurate volumetric maps of underground mines. One system is based on a cart instrumented by laser range finders, pushed through a mine by people. Another is a remotely controlled mobile robot equipped with laser range finders. To build consistent maps of large mines with many cycles, we describe an algorithm for estimating global correspondences and aligning robot paths. This algorithm enables us to recover consistent maps several hundreds of meters in diameter, without odometric information. We report results obtained in two mines, a research mine in Bruceton, PA, and an abandoned coal mine in Burgettstown, PA