Evolving the Ulysses Mission Control System - A Long Term Support Case Study

A Ground Support Biobarrier (GSB) for recontamination prevention

Hot dust-obscured galaxies (hot DOGs), selected from Wide-Field Infrared Survey Explorer’s all-sky infrared
\nsurvey, host some of the most powerful active galactic nuclei known and may represent an important stage in the
\nevolution of galaxies. Most known hot DOGs are located at z > 1.5, due in part to a strong bias against identifying
\nthem at lower redshift related to the selection criteria. We present a new selection method that identifies 153 hot
\nDOG candidates at z ~ 1, where they are significantly brighter and easier to study. We validate this approach by
\nmeasuring a redshift z = 1.009 and finding a spectral energy distribution similar to that of higher-redshift hot
\nDOGs for one of these objects, WISE J1036+0449 ( LBol ~= 8 x 10^46 erg s^-1). We find evidence of a broadened
\ncomponent in Mg II, which would imply a black hole mass of MBH ~= 2 x 10^8 M(solar) and an Eddington ratio of
\nLambdaEdd ~= 2.7. WISE J1036+0449 is the first hot DOG detected by the Nuclear Spectroscopic Telescope Array, and
\nobservations show that the source is heavily obscured, with a column density of NH = 2-15 x 10^23 cm^-2 . The
\nsource has an intrinsic 2–10 keV luminosity of ~ 6 x 10^44 erg s^-1, a value significantly lower than that expected
\nfrom the mid-infrared/X-ray correlation. We also find that other hot DOGs observed by X-ray facilities show a
\nsimilar deficiency of X-ray flux. We discuss the origin of the X-ray weakness and the absorption properties of hot
\nDOGs. Hot DOGs at z ~< 1 could be excellent laboratories to probe the characteristics of the accretion flow and of
\nthe X-ray emitting plasma at extreme values of the Eddington ratio.

The Landsat program is a joint United States Geological Survey (USGS) and National Aeronautics and Space Administration (NASA) enterprise for Earth Observation (EO), that represents the world’s longest running system of satellites for moderate-resolution optical remote sensing. The European Space Agency (ESA) has acquired Landsat data over Europe through the ESA ground stations over the last 40 years, in co-operation with USGS and NASA. A new ESA Landsat Multi-Spectral Scanner (MSS), Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) processor has been developed. This enhanced processor aligns the historical Landsat products to the highest quality standards that can be achieved with the current knowledge of the instruments. The updated processor is mainly based on the USGS algorithm; however the ESA processor has some different features that are detailed in this paper. Using this upgraded processor, ESA is currently performing for the first time a bulk-processing of its entire Landsat series MSS/TM/ETM+ historical archive to make all products available to users. Current achievements include the processing and online distribution of approximately 290 000 new Landsat 5 TM high-quality products acquired at the Kiruna ground station between 1983 and 2011. The Landsat 5 TM bulk-processed products are made available for direct download after registration at: https://earth.esa.int/web/guest/pi-community/apply for-data/fast-registration. The remainder of the ESA’s Landsat data, dating back more than 40 years, will gradually become available for all users during the course of 2014. The ESA Landsat processor algorithm enhancement, together with the results of the ESA archive bulk-processing, and an overview on the data quality on a subset of the Landsat 5 TM data are herein presented.

Personal computers of the past were limited to running computational fluid dynamics codes in serial mode. With the advent of multicore technology and suitable compilers, personal computers nowadays can execute codes in a parallel fashion similar to that of supercomputers and cluster computer systems. This article investigated what performance can be achieved when executing an aerodynamic code on an Intel quad core based personal computer with an OpenMP compiler in a Windows environment. The code solved the Euler equations to find the flowfield around a NACA0012 aerofoil on an O-type boundary fitted structured grid system. A speedup of up to 350% was obtainable in double precision accuracy. The reduced computation time means that, for small scale problems, more accurate Euler codes can replace commonly used transonic small disturbance codes. For larger problems, this information serves as a reference for developers of hybrid MPI/OpenMP algorithms for cluster computer systems. References Advanced Micro Devices (AMD), AMD FireStream 9170: Industry's First GPU with Double-Precision Floating Point, 2007, http://ati.amd.com/products/streamprocessor/specs.html Allmaras, S. R., Venkatakrishnan, V., and Johnson, F. T., Farfield Boundary Conditions for 2-D Airfoils, AIAA Paper 2005-4711, AIAA, 2005. Bailey, D., Barszcz, E., Barton, J., Browning, D., Carter, R., Dagum, L., Fatoohi, R., Fineberg, S., Frederickson, P., Lasinski, T., Schreiber, R., Simon, H., Venkatakrishnan, V., and Weeratunga, S., The NAS Parallel Benchmarks, National Aeronautics and Space Administration (NASA), Contractor Report 203186, USA, 1994, http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19970014936_1997021577.pdf Dong, S., and Karniadakis, G. E., Dual-Level Parallelism for High-Order CFD Methods, Parallel Computing, 30, Jan. 2004, pp. 1--20. Hirsch, C., Numerical Computation of Internal and External Flows (Volume 2): Computational Methods for Inviscid and Viscous Flows, John Wiley and Sons, Great Britain, 1992. Hoffmann, K. A., Computational Fluid Dynamics for Engineers, Engineering Educational System, Texas, USA, 1989. Intel, Tera-scale Computing Research Program, c.2007, http://www.intel.com/research/platform/terascale/ Jin, H., Frumkin, M., and Yan, J., The OpenMP Implementation of NAS Parallel Benchmarks and its Performance, National Aeronautics and Space Administration (NASA), Technical Report NAS-99-011, Moffett Field, USA, 1999. Liu, Y., and Vinokur, M., Nonequilibrium Flow Computations 1: An Analysis of Numerical Formulations of Conservation Laws, National Aeronautics and Space Administration (NASA), Contractor Report 177489, California, USA, 1988, http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19880021000_1988021000.pdf Lock, R. C., Test Cases for Numerical Methods in Two-Dimensional Transonic Flows, Advisory Group for Aerospace Research and Development (AGARD), Report Number 575, 1970. Ly, E., Improved Approximate Factorisation Algorithm for the Steady Subsonic and Transonic Flow over an Aircraft Wing, Proceedings of the 21st Congress of the International Council of the Aeronautical Sciences (ICAS98), ICAS and AIAA, Melbourne, Australia, 1998, Paper A98-31699. Ly, E., and Gear, J. A., Time-Linearized Transonic Computations Including Shock Wave Motion Effects, Journal of Aircraft, 39, 6, Nov/Dec. 2002, pp. 964--972. Ly, E., and Nakamichi, J., Time-Linearised Transonic Computations Including Entropy, Vorticity and Shock Wave Motion Effects, The Aeronautical Journal, Nov. 2003, pp. 687--695. Ly, E., and Norrison, D., Automatic Elliptic Grid Generation by an Approximate Factorisation Algorithm, ANZIAM Journal, 48 (CTAC2006), pp. C188--C202, July 2007, http://anziamj.austms.org.au/ojs/index.php/ANZIAMJ/article/view/48. Ly, E., and Norrison, D., Generating Elliptic Grids in Three Dimensions by a Method of False Transients, ANZIAM Journal, 49 (EMAC2007), pp. C170--C183, Nov. 2007, http://anziamj.austms.org.au/ojs/index.php/ANZIAMJ/article/view/313. Nvidia, The Era of the Personal Supercomputer, 2007, http://www.nvidia.com/content/events/siggraph_2007/supercomputing.html Pope, S. B., A Perspective on Turbulence Modeling, Modeling Complex Turbulent Flows, Kluwer Academic Publishers, The Netherlands, 1999. Pulliam, T., Kutler, P., and Rossow, V., Harvard Lomax: His Quiet Legacy to Computational Fluid Dynamics, 14th AIAA Computational Fluid Dynamics Conference, Norfolk, VA, 28 June-1 July, 1999, http://people.nas.nasa.gov/ pulliam/mypapers/lomax_la.ps Steger, J. L., and Warming, R. F., Flux Vector Splitting of the Inviscid Gasdynamic Equations with Application to Finite Difference Methods, National Aeronautics and Space Administration (NASA) Technical Memorandum 78605, California, USA, 1979, http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19790020779_1979020779.pdf Thompson, J. R., Warsi, Z. U. A., and Mastin, C. W., Numerical Grid Generation: Foundations and Applications, Elsevier Science Publishing Co. Inc., New York, USA, 1985. Van Leer, B., Flux-Vector Splitting for the Euler Equations, Proceedings of the 8th International Conference on Numerical Methods in Fluid Dynamics, Aachen, West Germany, 1982.

Imaging spectrometers are expected to play a crucial role in many upcoming unmanned planetary missions. The scientific goal of imaging spectrometry is to obtain compositional data about the target body by measuring the intensity and distribution of characteristic spectral signature features in the visible and infrared radiation reflected and emitted by surface materials. As part of the Planetary Instrument Definition and Development Program (PIDDP) sponsored by the National Aeronautics and Space Administration (NASA), a modular imaging spectrometer design with applicability to a diverse range of future planetery missions is being developed at the Jet Propulsion Laboratory (JPL). Derived from the near-infrared mapping spectrometer (NIMS) developed by JPL for the Galileo mission to Jupiter, the first version of the visual and infrared mapping spectrometer (VIMS) has been tentatively selected for NASA's recently approved Mars Observer mission.

In-situ exploration of Venus is seriously hampered by its severe environment, which is benign (28oC) at an altitude of 55 km, but rapidly becomes hostile, with increasing temperature and CO2 pressure at lower altitudes, eventually reaching ~465°C and 90 bars at the surface.1 These challenging conditions have limited the previous Venus surface missions, e.g., the Russian Venera series and Vega-2 Landers,2 to barely two hours after deployment with lithium-primary batteries, despite the use of considerable insulation, phase-change materials, and similar heat sinks to isolate batteries and avionics from high surface temperatures. The recent decadal survey, ‘Vision and Voyages for Planetary Science in the Decade as well as the more recent Venus Exploration and Analysis Group (VEXAG) study3 emphasized the need to gather basic information on the crust, mantle, core, atmosphere/exosphere, and bulk composition of Venus, to understand the evolutionary paths of Venus in relation to Earth and recommended long-duration landers and probes for future missions.In order to enable extended surface missions on Venus, e.g., landers, probes and seismometers, NASA has initiated the development of high temperature electronics and power technologies, under its ‘Hot Operating Temperature Technology’ (HOTTech) program. Under this program, we have been developing advanced primary batteries resilient to the hostile conditions on the Venus surface and operational for several days with high specific energy (>100 Wh/kg) and energy density (>150 Wh/l). Here, we will describe the development of high temperature batteries based on lithium alloy (e.g., Li-Al) anodes, molten salt electrolytes containing binary/ternary mixtures of alkali metal halides, cathodes consisting of transition metal sulfides, and designs similar to the aerospace thermal batteries.4 With FeS cathode and appropriate changes in the electrolyte, binder and active material ratios, we have demonstrated the operation of the high temperature battery in prototype cells for 30 days in primary mode, and >150 days in rechargeable mode at 475oC. Further, with suitable thin coatings of inorganic compounds, e.g., Al2O3, AlF3 and AlBO3 on the cathode particles, the utilization of the cathode, and hence the operational life of the cells have been improved by another 50%.AcknowledgementsThe work described here was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA) and supported by the NASA’s HOTTech project. The information in this document is pre-decisional and is provided for planning and discussion only.References Basilevsky, J. W. Head, "The surface of Venus". Rep. Prog. Phys. 66, 1699 (2003).Gilmore, et al., “Venus Surface Composition Constrained by Observation and Experiment”, Space Sci. Rev. 212, 1511–1540 (2017); doi:10.1007/s11214-017-0370-8.A. Bullock, et al., “A Venus Flagship Mission: Report of the Venus Science and Technology Definition Team," 40th Lunar and Planetary Science Conference (Lunar and Planetary Science XL), The Woodlands, TX, March 23-27 (2009).E. Glass, J.P. Jones, A. V. Shevade, D. Bhakta, E. Raub, R. Sim, R. V. Bugga, “High temperature primary battery for Venus surface missions”, J. Power Sources. 449, 227492 (2020). doi:10.1016/j.jpowsour.2019.227492.

Space environmental effects on materials are very severe and complex because of the synergistic interaction of orbital environments such as high-energy radiation particles, atomic oxygen, micrometeoroids, orbital debris, and ultraviolet irradiation interacting synergistically, along with thermal exposure. In addition, surface degradation associated with contamination can negatively impact optics performance. Materials flight experiments are critical to understanding the engineering performance of materials exposed to specific space environments. Likewise, the spacecraft designer must have an understanding of the specific environment in which a spacecraft will operate, enabling appropriate selection of materials to maximize engineering performance, increase mission lifetimes, and reduce risk. This article will present a methodology for assessing the engineering performance of materials baselined for a specific spacecraft or mission. In addition, an overview of the space environment, from low Earth orbit to interplanetary space, will be provided along with an overview on the effects of the space environment on materials performance. The majority of this article is devoted to materials flight experiments from the European Space Agency (ESA), the Japan Aerospace Exploration Agency (JAXA), and from the National Aeronautics and Space Administration (NASA). Some of the experiments reviewed include ESA's Materials Exposure and Degradation Experiment on the International Space Station (ISS), JAXA's Micro-Particles Capturer and Space Environment Exposure Device experiments on the ISS Service Module and on the ISS Japanese Experiment Module Exposed Facility, and NASA's Long Duration Exposure Facility satellite and the Materials International Space Station Experiment series flown on the exterior of ISS.

Space travel: medicine in extremes

The National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory, the Arizona State University (ASU), and Raytheon Space and Airborne Systems (SAS) Santa Barbara Remote Sensing (SBRS) have executed a series of successful Mars exploration missions. These have recently been publicized on television and the internet with the early 2004 Mars Exploration Rover (MER) mission geological robots that have revolutionized our detailed knowledge of the planet's geology and atmosphere. This latest mission success has its foundation in missions dating back to 1969. Over the past thirty-five years NASA has demonstrated a long-term commitment to planetary science and solar system exploration that continues with a commitment recently expressed by President Bush and codified in a reorganization of the NASA space sciences mission directorate. This paper reports on a small but exciting aspect of this sweeping NASA program, and illustrates the benefits and efficiency with which planetary and solar system exploration can be accomplished. Key in the success is the vision not only of NASA in general, but of the mission Principal Investigator, in particular. The specific series of missions leading to MER contains an underlying vision of carefully planned geological investigations using remote sensing instrumentation, starting with broad survey, leading to more finely resolved global imaging, and finally to landing instrumentation capable of detailed rock and soil analyses. The mission started with broad and relatively coarse spatial resolution orbital surveys with fine spectral capability focused on identifying the overall geological and atmospheric character of the planet accomplished from 1996 to the present conducted by the Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES). This led to the more detailed global imaging at finer spatial resolution offered by the Mars 2001 Odyssey Mission Thermal Emission Imaging System (THEMIS) which identified specific landing sites of interest for detailed exploration. The mission culminated in the recent MER lander geological analyses conducted by the mini-TES instruments carried by the rovers. This series of remote sensing investigations has set the stage for a new era in solar system exploration.

A number of applications under NASA’s Exploration Technology Development Program would benefit from high specific energy rechargeable batteries that have improved safety characteristics. To meet these objectives, lithium-ion battery chemistries have emerged as the most promising energy storage devices, due to their high specific energy, long life, and ability to operate over a wide temperature range. In recent years, advances in anode and cathode materials have created a number of lithium-ion chemistries that that have the potential of exceeded 150 Wh/kg at the cell level. However, owing to the fact that these chemistries employ the use of organic electrolytes, possessing flammable solvents, there is a desire to improve the safety characteristics of these devises. The flammability of these electrolytes is mainly due to the use of cyclic and linear organic carbonates, which are necessary to provide (i) sufficient conductivity of the media with the use of lithium electrolyte salts, (ii) adequate stability over a wide voltage range, and (iii) the formation of protective surface films at the electrolyte/electrode interfaces.A number of approaches can be employed to reduce the inherent flammability of the lithium-based electrolyte systems, including (i) the use of phosphorus-based flame retardant additives (FRAs), (ii) the use of ionic liquids, which possess extremely low vapor pressures, and (iii) the use of non-flammable co-solvents, such as fluorinated ethers, esters, and carbonates. Although the use of ionic liquids and highly fluorinated co-solvents has led to electrolyte formulations that can display dramatically lower flammability, these approaches typically suffer from poor compatibility with the electrode chemistries of interest and lead to a sacrifice in performance. In contrast, the use of flame retardant additives has proven to be a viable way of reducing the flammability of the electrolytes without compromising the performance of the system. Toward this end, a number of flame retardant additives have been identified in traditional lithium-ion chemistry with success, including triphenyl phosphate (TPP)1, tris(2,2,2-trifluoroethyl) phosphate2, and dimethyl methyl phosphonate (DMMP).3 After comprehensively investigating the compatibility of a number flame retardant additives in various chemistries, we have identified triphenyl phosphate (TPP) as being the most versatile, being compatible with traditional LiNi0.8Co0.2O2 and LiNi0.8Co0.15Al0.05O2 –based systems as well as with high voltage, lithium excess, mixed metal oxide-based cathode systems.4,5 We would like to describe our recent results with TPP-containing electrolytes in both traditional lithium-ion chemistries (i.e., MCMB carbon-LiNi0.8Co0.2O2 and graphite-LiNi0.8Co0.15 Al0.05O2) as well as in advanced lithium-ion chemistries that possess high capacity anodes and cathodes (i.e., Si/C-LiNi0.8Co0.15Al0.05O2 and graphite-Li1.2Ni0.13Co 0.13Mn0.54O2). Electrolyte formulations have been specifically tailored for each chemistry to achieve the desired benefit to safety without compromising performance. This was achieved by optimizing the FRA content, the use of fluorinated co-solvents in conjunction with traditional carbonate-based solvents, and the use of film forming electrolyte additives. The compatibility of the electrolytes with the various chemistries were investigated in experimental coin and three-electrode cells (equipped with lithium reference electrodes), which enable us to perform a number of electrochemical characterization techniques including EIS, DC micropolarization, and Tafel polarization. We will also describe the electrical performance of the most promising electrolyte formulations in prototype lithium-ion cells of varying capacity (0.25Ah to 8.0 Ah) manufactured by various battery vendors (Quallion, LLC, Yardney Technical Products, Inc. and Saft America, Inc.).ACKNOWLEDGEMENTThe work described here was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA) and under sponsorship of the NASA-Exploration Technology Development Program (ETDP). 1. Y. E. Hyung, D. R. Vissers, K. Amine, J. Power Sources, 119- 121, 383, (2003). 2. (a) K. Xu, M. S. Ding, S. Zhang, J. L. Allen, T. R. Jow, J. Electrochem. Soc., 149, A622, (2002). (b) K. Xu, S. Zhang, J. L. Allen, T. R. Jow, J. Electrochem. Soc., 149, A1079, (2002), (c) Kang Xu, Michael S. Ding, Shengshui Zhang, Jan L. Allen, and T. Richard Jow, J. Electrochem. Soc., 150, A161 (2003). 3. (a) J. K. Feng, X. P. Ai, Y. L. Cao, and H. X. Yang, J. Power Sources, 177, 194-198 (2008), (b) S. Dalavi, M. Xu, B. Ravdel, L. Zhou, and B. L. Lucht, J. Electrochem. Soc., 157, A1113 (2010). 4 K. A. Smith, M. C. Smart, G. K. S. Prakash, and B. V. Ratnakumar, ECS Transactions, 16 (35), 33-41 (2009). 5 R. P. Dunn, J. Kafle, F. C. Krause, C. Hwang, B. V. Ratnakumar, M. C. Smart, and B. L. Lucht, J. Electrochem. Soc., 159 (12), A2100-A2108 (2012).

This paper reports on the research done under a National Aeronautics and Space Administration (NASA) Research Announcement task, “Assessment of System Safety Risks for NextGen Concepts and Technologies.” We describe the methods and tools used in the task and results from first-order analyses of two NextGen ground-based automation concepts. The first-order results demonstrate the ability of the assessment method developed in previous NASA research to address NextGen concepts and to link research results rigorously to systemwide risk. The method explicitly addresses response times and failures, and the results, while first-order, specifically identify the time criticality of tactical conflict detection and resolution. I. Introduction n this research, we extended and applied to automated NextGen concepts the separation assurance safety risk assessment method we developed for the NASA Research Announcement task, “Conduct Safety Analysis of the Separation Assurance Function in Today’s National Airspace System (NAS)” (Ref. 1). As in our previous work, we addressed the task objective in two ways. First, we established functional and quantitative frameworks to allow integration of the results of all forms of safety and risk research into a single risk assessment. Second, we identified sources of data and developed and tested modeling tools to demonstrate the feasibility of our analysis approach. We conducted first-order risk assessments of two NextGen concepts: a Ground-Automation Controlled (GAC) concept based on the Advanced Airspace Concept (AAC) proposed by Erzberger in Ref. 2, and a near-term GroundAutomation Assisted (GAA) concept based on the concept proposed by McNally et al. in Ref. 3. Both concepts are based on managing traffic with ground-based automation using data link communications to control aircraft on timebased four-dimensional trajectories (4DTs). This paper describes analysis of the fully operational concepts plus two abnormal conditions. The first abnormal condition is a loss of intent data condition, which could be caused by a weather or emergency disruption leading to open 4DTs or by a hardware failure leading to loss of transmitted intent data; the second is a single aircraft inoperative transponder condition, which could be caused by hardware failure or by being turned off. Both concepts include a ground-based strategic element, a ground-based tactical element, an airborne Traffic Alert and Collision Avoidance System (TCAS) element, and an airborne see-and-avoid element. The AAC concept includes a monitoring human controller element, while the human-based GAA concept includes an active human controller in the strategic and tactical elements. The paper is organized as follows: 1) Section II presents our aviation safety risk analysis method and introduces the two NextGen concepts assessed. 2) Section III discusses the conflict modeling tool and the conflict probability data used for the risk assessments.

Estimation of the polarization orientation angle shifts induced by terrain azimuth slope variations is a recently developed application in radar polarimetry. In general, without any prior knowledge on the terrain, two polarimetric SAR (POLSAR) flight passes are required to derive terrain slopes in perpendicular directions for digital elevation model (DEM) generation. Moreover, we note that SAR intensity is a strong indicator of the range component of the terrain slopes. In this letter, we developed a method for DEM generation requiring only one POLSAR flight pass, by combining orientation angle estimation and a shape-from-shading technique. In particular, when limited POLSAR data are available, this POLSAR technique provides an alternative way for DEM generation. National Aeronautics and Space Administration Jet Propulsion Laboratory (NASA/JPL) AIRSAR L-band POLSAR data over Camp Roberts, California, is used to demonstrate the results of the method proposed in this letter, and a DEM derived from simultaneously measured C-band interferometric SAR from NASA/JPL topographic SAR instrument is selected as the comparative ground truth to validate the effectiveness of this single POLSAR method. Analyses and discussions are also included in this letter.

The National Aeronautics and Space Administration has formed the Advanced Space Transportation Program (ASTP) at the Marshall Space Flight Center to address advanced space transportation technologies. The main focus of the ASTP Office is directed to those technologies that will be needed to reduce the cost of both Earth-toorbit and in-space transportation. The current focus of the advanced reusable technologies (ART) Project is the development of those critical technologies required to enable a rocket-based combined-cycle (RBCC) engine and ultimately an RBCC-based reusable launch vehicle. Additional effort is also being expended to address those associated technologies that would be required to not only support an RBCC-based vehicle but other advanced reusable transportation systems as well. This paper will describe the work that has been performed since the last project status was presented to the 1997 Joint Propulsion Conference.' Currently, NASA and its industry partners are performing ground testing of hydrogen-fueled rocketbased combined-cycle flowpaths. Successful ramjet and scramjet testing at Mach 6 and scramjet testing at Mach 8 have been performed. Cold flow mixing tests have also been successfully performed as have inlet operability tests. Additional testing of RBCC flowpaths at air augmented rocket and rocket only modes is underway. Additional work will be performed on technologies that will support an RBCC-powered launch vehicle and will be focused in the following areas: structures and materials; avionics and operations; propulsion turbomachinery; and thermal protection systems. Chief Engineer, Advanced Reusable Technologies Project, NASA/ MSFC, Senior Member AIAA Project Manager, Advanced Reusable Technologies Project, NASA/MSFC, Member AIAA Copyright © 1998 by the American Institute of Aeronautics and Astronautics, Inc. No copyright is asserted in the United States under Title 17, U.S. Code. The U.S. Government has a royalty-free license to exercise all rights under the copyright claimed herein for Governmental Purposes. All other rights are reserved by the copyright owner. Introduction The National Aeronautics and Space Administration (NASA) Advanced Space Transportation Program (ASTP), part of the Space Transportation Program (STP) Office at the Marshall Space Flight Center (MSFC), is focusing on those technologies that will be needed to reduce the cost of both Earth-to-orbit and in-space transportation. NASA's strategy is to advance innovative space transportation technology development through the X-33, X-34, ASTP, and the Future-X programs to enable reduction of these costs. The ASTP consists of three major technology areas: focused, core, and research technologies. The ART project currently manages the work that is covered under NASA Research Announcements 8-16 and 8-21. The project's primary focus over the last 2 years has been on rocket-based combined-cycle (RBCC) technology development activities awarded under NRA 8-16. The current aerospace and academic organizations listed in Figure 1 are performing testing and analysis supporting the RBCC propulsion activities. The engine contractors, Aerojet, Pratt & Whitney, and Rocketdyne are currently either testing or preparing to test their RBCC engine flowpaths. Direct connect testing has been performed at Mach 6 flight conditions in both ramjet and scramjet modes and at Mach 8 flight conditions in the scramjet mode. Testing has also been performed at sealevel static conditions and at Mach 3.4 ramjet conditions.

This paper summarizes the results of an assessment performed by the Jet Propulsion Laboratory (JPL) in FY 77 of the technology readiness of ion propulsion technology to support a 1985 Halley Comet Rendezvous (HCR) mission. The assessment identifies the status of ion propulsion technology and risk of its utilization to perform the HCR mission as of July 1977 and provides projections of status and risk at the required date for an HCR project start, October 1978. These projections are based on the assumed completion of the development activities ongoing at the time of this assessment and the recommended new activities identified in this paper. The conclusions of the study indicate that a National Aeronautics and Space Administration (NASA) commitment to the performance-demanding HCR mission would involve significant risk, greater than that experienced in any post-1964 planetary mission, despite years of supporting research and advanced development funding for ion propulsion and even assuming the success of an ambitious, aggressive FY 78 pre-project advanced systems technology (AST) program proposed by JPL. Contributing principally to the identified risk are a marginal mass margin of 6.7%, driven by uncertainties in ion drive vehicle masses and an unconfirmed solar array power degradation model of 12%, and technology currently undemonstrated to meet HCR mission requirements in two of the six subsystems of the ion propulsion module: the thrust and solar array subsystems.

OCO-2 (Orbiting Carbon Observatory-2) is the first NASA (National Aeronautics and Space Administration) mission dedicated to studying atmospheric carbon dioxide, specifically to identify sources (emitters) and sinks (absorbers) on a regional (1000 km x 1000 km) scale. The mission is designed to meet a science imperative by providing critical and urgent measurements needed to improve understanding of the carbon cycle and global climate change processes. The single instrument consisting of three grating spectrometers was built at the Jet Propulsion Laboratory, but is based on the design co-developed with Hamilton Sundstrand Corporation for the original OCO mission. The instrument underwent an extensive ground test program. This was generally made possible through the use of a thermal vacuum chamber with a window/port that allowed optical ground support equipment to stimulate the instrument. The instrument was later delivered to Orbital Sciences Corporation for integration and test with the LEOStar-2 spacecraft. During the overall ground test campaign, proper function and performance in simulated launch, ascent, and space environments were verified. The observatory was launched into space on 02 July 2014. Initial indications are that the instrument is meeting functional and performance specifications, and there is every expectation that the spatially-order, geo-located, calibrated spectra of reflected sunlight and the science retrievals will meet the Level 1 science requirements.