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Planetary protection and organic contamination control, like many technologically rich areas, continually progress. As a result of the 2011 Planetary Science Decadal Survey Report, Vision and Voyages for Planetary Science in the D...
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Planetary protection and organic contamination control, like many technologically rich areas, continually progress. As a result of the 2011 Planetary Science Decadal Survey Report, Vision and Voyages for Planetary Science in the Decade 2013-2022, the future focus is now on proposed Mars sample return missions. In addition to Mars exploration we now have the exciting possibility of a potential mission to the outer planets, most likely Europa. This paper reassesses planetary protection and organic contamination control technologies, which were evaluated in 2005, and provides updates based on new science results, technology development, and programmatic priorities. The study integrates information gathered from interviews of a number of National Aeronautics and Space Administration (NASA) and European Space Agency (ESA) scientists, systems engineers, planetary protection engineers, and consultants, as well as relevant documents, and focuses on the technologies and practices relevant to the current project mission set as presented in the 2011 Planetary Science Decadal Survey. This paper provides the status of planetary protection and contamination control technologies as they apply to potential future missions, and provides findings and recommendations to improve our capabilities as we further explore our solar system. It has become clear that linking planetary protection and contamination control requirements and processes together early in mission development and spacecraft design is key to keeping mission costs in check and returning high-quality samples that are free from biological and organic contaminants.
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A key step of the mission development process is the selection of a system architecture, i.e., the layout of the major high-level system design decisions. This step typically involves the identification of a set of candidate archi...
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A key step of the mission development process is the selection of a system architecture, i.e., the layout of the major high-level system design decisions. This step typically involves the identification of a set of candidate architectures and a costbenefit analysis to compare them. Computational tools have been used in the past to bring rigor and consistency into this process. These tools can automatically generate architectures by enumerating different combinations of decisions and options. They can also evaluate these architectures by applying cost models and simplified performance models. Current performance models are purely quantitative tools that are best fit for the evaluation of the technical performance of a mission design. However, assessing the relative merit of a system architecture is a much more holistic task than evaluating the performance of a mission design. Indeed, the merit of a system architecture comes from satisfying a variety of stakeholder needs, some of which are easy to quantify, and some of which are harder to quantify (e.g., elegance, scientific value, political robustness, flexibility). Moreover, assessing the merit of a system architecture at these very early stages of design often requires dealing with a mix of: a) quantitative and semi-qualitative data; b) objective and subjective information. Current computational tools are poorly suited for these purposes. In this paper, we propose a general methodology that can be used to assess the relative merit of several candidate system architectures under the presence of objective, subjective, quantitative, and qualitative stakeholder needs. The methodology is called VASSAR (Value Assessment for System Architectures using Rules). The major underlying assumption of the VASSAR methodology is that the merit of a system architecture can be assessed by comparing the capabilities of the architecture with the stakeholder requirements. Hence for example, a candidate architecture that fully satisfies all critical stakeholder requirements is a good architecture. The assessment process is thus fundamentally seen as a pattern matching process where capabilities match requirements, which motivates the use of rule-based expert systems (RBES). This paper describes the VASSAR methodology and shows how it can be applied to a large complex space system, namely an Earth observation satellite system. Companion papers show its applicability to the NASA space communications and navigation program and the joint NOAA-DoD NPOESS program.
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The Soil Moisture Active Passive (SMAP) mission, one of the first-tier missions recommended by the 2007 U.S. National Research Council Committee on Earth Science and Applications from Space, was confirmed in May 2012 by NASA to pr...
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The Soil Moisture Active Passive (SMAP) mission, one of the first-tier missions recommended by the 2007 U.S. National Research Council Committee on Earth Science and Applications from Space, was confirmed in May 2012 by NASA to proceed into Implementation Phase (Phase C) with a planned launch in October 2014. SMAP will produce high-resolution and accurate global maps of soil moisture and its freeze/thaw state using data from a non-imaging synthetic aperture radar and a radiometer, both operating at L-band. Major challenges addressed by the observatory design include: (1) achieving global coverage every 2-3 days with a single observatory; (2) producing both high resolution and high accuracy soil moisture data,including through moderate vegetation; (3) using a mesh reflector antenna for L-band radiometry; (4) minimizing science data loss from terrestrial L-band radio frequency interference; (5) designing fault protection that also minimizes science data loss; (6) adapting planetary heritage avionics to meet SMAP's unique application and data volume needs; (7) ensuring observatory electromagnetic compatibility to avoid degrading science; (8) controlling a large spinning instrument with a small spacecraft; and (9) accommodating launch vehicle selection late in the observatory's development lifecycle.
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Seeking "nearby habitable worlds" was one of three science themes identified in the Astronomy Decadal Survey. Hundreds of extrasolar planets are known, but magnetic fields are likely required for these planets to be habitable. As ...
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Seeking "nearby habitable worlds" was one of three science themes identified in the Astronomy Decadal Survey. Hundreds of extrasolar planets are known, but magnetic fields are likely required for these planets to be habitable. As of today, no direct constraints on the magnetic field characteristics of extrasolar planets exist. The ExtraSolar Observing Low-frequency Array of Nano Satellites for Radio Astronomy (XSOLANTRA), formerly known as XSOLARA is a feasibility study of a student designed, built, and tested micro-satellite mission to a Distant Retrograde Orbit (DRO) around Earth. XSOLANTRA will look at the Electron Cyclotron Maser Emission generated by the interaction between stellar wind and a planetary magneto sphere from which interior composition and atmospheric shielding can be inferred. The science instrument for XSOLANTRA is the entire array of fourteen CubeSats operating together as an interferometer. The fourteen CubeSats will be stacked on a SHuttle Expendable Rocket for Payload Augmentation (SHERPA) vehicle as a payload and will be deployed once arrived at DRO. A feasibility study was conducted to demonstrate that a CubeSat mission with cost of no more than $60 million is capable of detecting extrasolar planets. The study showed that a CubeSat mission within these constraints is possible; however, some questions still remain unanswered. This paper summarizes the mission concept starting from the science requirements, key mission design decisions, component level feasibility analysis and management and cost analysis
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An effective approach to exploiting statistical differences between desired and jamming signals named adaptive robustness is proposed and analyzed in this paper. It combines conventional Bayesian, adaptive, and robust approaches t...
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An effective approach to exploiting statistical differences between desired and jamming signals named adaptive robustness is proposed and analyzed in this paper. It combines conventional Bayesian, adaptive, and robust approaches that are complementary to each other. This combining strengthens the advantages and mitigates the drawbacks of the conventional approaches. Adaptive robustness is equally applicable to both jammers and their victim systems. The capabilities required for realization of adaptive robustness in jammers and victim systems are determined. The employment of a specific nonlinear robust algorithm for anti-jam (AJ) processing is described and analyzed. Its effectiveness in practical situations has been proven analytically and confirmed by simulation. Since adaptive robustness can be used by both sides in electronic warfare, it is more advantageous for the fastest and most intelligent side. Many results obtained and discussed in this paper are also applicable to commercial applications such as communications in unregulated or poorly regulated frequency ranges and systems with cognitive capabilities.
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The tropospheric Infrared Mapping Spectrometers (TIMS) operating at 2.33 and 4.68 μm were developed to demonstrate retrieval of atmospheric CO in several layers. In this presentation we describe the architecture of the 2.33 TIMS ...
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The tropospheric Infrared Mapping Spectrometers (TIMS) operating at 2.33 and 4.68 μm were developed to demonstrate retrieval of atmospheric CO in several layers. In this presentation we describe the architecture of the 2.33 TIMS spectrometer, recap its development, develop its noise model, and validate that against TIMS demonstration data. We briefly describe a multi-channel geostationary space application, called geoCARB, of the TIMS technology and use the model to predict its signal to noise ratio (SNR).
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The unscented Kalman filter (UKF) is a useful alternative to the extended Kalman filter (EKF) for tracking with nonlinear dynamics models and when the measurements are nonlinear functions of the target state. In this paper, the pr...
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The unscented Kalman filter (UKF) is a useful alternative to the extended Kalman filter (EKF) for tracking with nonlinear dynamics models and when the measurements are nonlinear functions of the target state. In this paper, the problem of tracking using monostatic and bistatic measurements is considered. Previous work has demonstrated that the UKF does not always handle measurement nonlinearities in challenging monostatic scenarios better than the EKF, let alone considering more complicated bistatic scenarios. This paper reviews previous work showing that the UKF is one among many numeric integration-based filters. It is demonstrated that a general cubature Kalman filter outperforms the extended Kalman filter for multistatic tracking when cubature points of a sufficiently high order are used. Additionally, cubature-based measurement conversion for track initiation is discussed, and the posterior Cramér-Rao lower bound for basic multistatic tracker assessment is derived.
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NASA's long-range goal is focused upon human exploration of Mars. Missions to Mars will require campaigns of multiple launches to assemble Mars Transfer Vehicles in Earth orbit. Launch campaigns are subject to delays, launch vehic...
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NASA's long-range goal is focused upon human exploration of Mars. Missions to Mars will require campaigns of multiple launches to assemble Mars Transfer Vehicles in Earth orbit. Launch campaigns are subject to delays, launch vehicles can fail to place their payloads into the required orbit, and spacecraft may fail during the assembly process or while loitering prior to the Trans-Mars Injection (TMI) burn. Additionally, missions to Mars have constrained departure windows lasting approximately sixty days that repeat approximately every two years. Ensuring high reliability of launching and assembling all required elements in time to support the TMI window will be a key enabler to mission success. This paper describes an integrated methodology for analyzing and improving the reliability of the launch and assembly campaign phase. A discrete event simulation involves several pertinent risk factors including, but not limited to: manufacturing completion; transportation; ground processing; launch countdown; ascent; rendezvous and docking, assembly, and orbital operations leading up to TMI. The model accommodates varying numbers of launches, including the potential for spare launches. Having a spare launch capability provides significant improvement to mission success.
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Optical communication using space borne lasers has long promised to increase the amount of science data transmitted down to Earth. A first step in achieving operational capability is demonstrating the fundamentals of the optical l...
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Optical communication using space borne lasers has long promised to increase the amount of science data transmitted down to Earth. A first step in achieving operational capability is demonstrating the fundamentals of the optical link in an equivalent environment. The International Space Station, with its vast capability, is well suited to accommodate payloads aimed at advancing the readiness of such technologies. The Optical PAyload for Lasercomm Science (OPALS), to be launched to and operated on the ISS in late 2013, will attempt to downlink a short video to an optical ground station in California using a 1550 nanometer, 2.5 watt laser, over the course of a 90 day mission. To achieve this, in addition to designing and building the ISS payload, the OPALS team has increased the capability of the existing ground station, as well as developed the interface to the ISS infrastructure that will allow operators to command it. This paper will discuss the drivers and constraints created by designing to existing interfaces (ISS flight, ISS operational, ground system) while following a Class D payload implementation (NASA NPR 8705.4). The paper will also provide some specific examples of programmatic and technical areas that have been shaped by these drivers and constraints.
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Human space exploration has always been heavily influenced by goals to achieve a specific mission on a specific schedule. This approach drove rapid technology development, the rapidity of which added risks and became a major drive...
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Human space exploration has always been heavily influenced by goals to achieve a specific mission on a specific schedule. This approach drove rapid technology development, the rapidity of which added risks and became a major driver for costs and cost uncertainty. The National Aeronautics and Space Administration (NASA) is now approaching the extension of human presence throughout the solar system by balancing a proactive yet less schedule-driven development of technology with opportunistic scheduling of missions as the needed technologies are realized. This approach should provide cost effective, low risk technology development that will enable efficient and effective manned spaceflight missions. As a first step, the NASA Human Spaceflight Architecture Team (HAT) has identified a suite of critical technologies needed to support future manned missions across a range of destinations, including in cis-lunar space, near earth asteroid visits, lunar exploration, Mars moons, and Mars exploration. The challenge now is to develop a strategy and plan for technology development that efficiently enables these missions over a reasonable time period, without increasing technology development costs unnecessarily due to schedule pressure, and subsequently mitigating development and mission risks. NASA's Johnson Space Center (JSC), as the nation's primary center for human exploration, is addressing this challenge through an innovative approach in allocating Internal Research and Development funding to projects. The HAT Technology Needs (TechNeeds) Database has been developed to correlate across critical technologies and the NASA Office of Chief Technologist Technology Area Breakdown Structure (TABS). The TechNeeds Database illuminates that many critical technologies may support a single technical capability gap, that many HAT technology needs may map to a single TABS technology discipline, and that a single HAT technology need may map to multiple TABS technology disciplines. The TechNeeds Database greatly clarifies understanding of the complex relationships of critical technologies to mission and architecture element needs. Extensions to the core TechNeeds Database allow JSC to factor in and appropriately weight JSC core technology competencies, and considerations of commercialization potential and partnership potential. The inherent coupling among these, along with an appropriate importance weighting, has provided an initial prioritization for allocation of technology development research funding at JSC. The HAT Technology Needs Database, with a core of built-in reports, clarifies and communicates complex technology needs for cost effective human space exploration so that an organization seeking to assure that research prioritization supports human spaceflight of the future can be successful.
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