BILLIARDS: A Demonstration Mission for Hundred-Meter Class Near Earth Asteroid Disruption

Currently, no planetary defense demonstration mission has ever been flown. While Nuclear Explosive Devices (NEDs) have significantly more energy than a kinetic impactor launched directly from Earth, they present safety and political complications, and therefore may only be used when absolutely necessary. The Baseline Instrumented Lithology Lander, Inspector, and Asteroid Redirection Demonstration System (BILLIARDS) is a demonstration mission for planetary defense, which is capable of delivering comparable energy to the lower range of NED capabilities in the form of a safer kinetic impactor. A small asteroid (<10m) is captured by a spacecraft, which greatly increases the mass available as a kinetic impactor, without the need to bring all of the mass out of Earth's gravity well. The small asteroid is then deflected onto a collision course with a larger (approx. 100m) asteroid. This collision will deflect or disrupt the larger asteroid. To reduce the cost and complexity, an asteroid pair which has a natural close approach is selected

Satellite Servicing's Autonomous Rendezvous and Docking Testbed on the International Space Station

The Space Servicing Capabilities Project (SSCP) at NASA's Goddard Space Flight Center (GSFC) has been tasked with developing systems for servicing space assets. Starting in 2009, the SSCP completed a study documenting potential customers and the business case for servicing, as well as defining several notional missions and required technologies. In 2010, SSCP moved to the implementation stage by completing several ground demonstrations and commencing development of two International Space Station (ISS) payloads-the Robotic Refueling Mission (RRM) and the Dextre Pointing Package (DPP)--to mitigate new technology risks for a robotic mission to service existing assets in geosynchronous orbit. This paper introduces the DPP, scheduled to fly in July of 2012 on the third operational SpaceX Dragon mission, and its Autonomous Rendezvous and Docking (AR&D) instruments. The combination of sensors and advanced avionics provide valuable on-orbit demonstrations of essential technologies for servicing existing vehicles, both cooperative and non-cooperative

BILLIARDS: Baseline Instrumented Lithology Lander, Inspector and Asteroid Redirection Demonstration System

BILLIARDS Baseline Instrumented Lithology Lander, Inspector, and Asteroid Redirection Demonstration System Proposed demonstration mission for Billiard-Ball concept Select asteroid pair with natural close approach to minimize cost and complexity Primary Objectives Rendezvous with a small (10m), near Earth (alpha) asteroid Maneuver the alpha asteroid to a collision with a 100m (beta) asteroid Produce a detectable deflection or disruption of the beta asteroid Secondary objectives Contribute knowledge of asteroid composition and characteristics Contribute knowledge of small-body formation Opportunity for international collaboratio

Direct detection and measurement of wall shear stress using a filamentous bio-nanoparticle

The wall shear stress (WSS) that a moving fluid exerts on a surface affects many processes including those relating to vascular function. WSS plays an important role in normal physiology (e.g. angiogenesis) and affects the microvasculature's primary function of molecular transport. Points of fluctuating WSS show abnormalities in a number of diseases; however, there is no established technique for measuring WSS directly in physiological systems. All current methods rely on estimates obtained from measured velocity gradients in bulk flow data. In this work, we report a nanosensor that can directly measure WSS in microfluidic chambers with sub-micron spatial resolution by using a specific type of virus, the bacteriophage M13, which has been fluorescently labeled and anchored to a surface. It is demonstrated that the nanosensor can be calibrated and adapted for biological tissue, revealing WSS in micro-domains of cells that cannot be calculated accurately from bulk flow measurements. This method lends itself to a platform applicable to many applications in biology and microfluidics

Achievement of the planetary defense investigations of the Double Asteroid Redirection Test (DART) mission

NASA's Double Asteroid Redirection Test (DART) mission was the first to demonstrate asteroid deflection, and the mission's Level 1 requirements guided its planetary defense investigations. Here, we summarize DART's achievement of those requirements. On 2022 September 26, the DART spacecraft impacted Dimorphos, the secondary member of the Didymos near-Earth asteroid binary system, demonstrating an autonomously navigated kinetic impact into an asteroid with limited prior knowledge for planetary defense. Months of subsequent Earth-based observations showed that the binary orbital period was changed by –33.24 minutes, with two independent analysis methods each reporting a 1σ uncertainty of 1.4 s. Dynamical models determined that the momentum enhancement factor, β, resulting from DART's kinetic impact test is between 2.4 and 4.9, depending on the mass of Dimorphos, which remains the largest source of uncertainty. Over five dozen telescopes across the globe and in space, along with the Light Italian CubeSat for Imaging of Asteroids, have contributed to DART's investigations. These combined investigations have addressed topics related to the ejecta, dynamics, impact event, and properties of both asteroids in the binary system. A year following DART's successful impact into Dimorphos, the mission has achieved its planetary defense requirements, although work to further understand DART's kinetic impact test and the Didymos system will continue. In particular, ESA's Hera mission is planned to perform extensive measurements in 2027 during its rendezvous with the Didymos–Dimorphos system, building on DART to advance our knowledge and continue the ongoing international collaboration for planetary defense

Extracurricular L2 input in a Japanese EFL context: Exposure, attitudes, and motivation

This study presents empirical data collected from a survey of high-level and low-level, Japanese high school EFL students with a focus on L2 exposure, attitudes, and motivation. Specifically, the purpose of the survey was to determine which sources of L2 input—verbal, written, or mixed (verbal and written)—the students are exposed to outside of the English classroom, how much exposure they had to each source of input, their attitudes and beliefs toward those sources of input, and, in general, how motivated they are toward learning English. Qualitative data were also gathered from English teachers of surveyed participants as well as a focus group of Japanese ESL students used to inform the creation of the survey. The results show that Japanese high school EFL students have much more exposure to some extracurricular sources of English input than to others, including some sources of verbal and mixed (verbal and written) input, with relatively little exposure to extracurricular written English input. It is also shown that the amount of exposure is highly correlated with how enjoyable the students find each source of input. That students are motivated to seek out those sources of English media that they enjoy rather than those they believe would improve their English supports the English media orientation to learning English (Clement et al., 1994). This study extends previous findings to include a Japanese EFL context, provides implications for L2 pedagogy within that context, and calls for further research into the realities of incidental learning in SLA

Shoreline Change at Mañagaha, Saipan

MA University of Hawaii at Manoa 2012Includes bibliographical references (leaves 98–99).The coastlines of the world are the focus of population growth and urban development this century. It is projected that approximately 2.65 billion people will be living within the coastal zone by 2025. More than half of all Americans now live on or close to the coast with population density expected to increase. Within the Pacific Basin, population growth can increase the economic incentive to develop more land. On islands, this results in development pressures along the shoreline and into the active beach system. Chronic erosion of the shoreline increases resource and population vulnerability to inundation by storm surge, tsunami, and sea-level rise. As population increases along the coastline, the need to understand the highly dynamic coastal region becomes more important. The majority of shoreline change studies have been prompted by realization that coastal erosion threatens private property, public infrastructure, and natural ecosystems (National Academy Study, 1990). Improved understanding of detailed erosion patterns provides managers with a basis for planning appropriate coastal development and resource management, thus improving community resiliency and sustainability. Lack of robust physical processes modeling means that analysis of historical shoreline trends provides a practical, relatively affordable method of predicting future erosion hazards (National Academy Study, 1990). Typically, studies compile and analyze historic and modern shoreline position data to inform planning and policy about past shoreline variability. The methods used are designed to record, analyze, and predict patterns of shoreline change. These are largely dictated by the physical characteristics of the shoreline being studied and the type and quantity of shoreline position data available