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A Monte Carlo simulation was used to study the outflow of O+ and H+ ions along three flight trajectories above the polar cap up to altitudes of about 15 RE. Barghouthi (2008) developed a model on the basis of altitude and velocity-dependent wave-particle interactions and a radial geomagnetic field which includes the effects of ambipolar electric field and gravitational and mirror forces. In the present work we improve this model to include the effect of the centrifugal force, with the use of relevant boundary conditions. In addition, the magnetic field and flight trajectories, namely, the central polar cap (CPC), nightside polar cap (NPC), and cusp, were calculated using the Tsyganenko T96 model. To simulate wave-particle interactions, the perpendicular velocity diffusion coefficients for O+ ions in each region were determined such that the simulation results fit the observations. For H+ ions, a constant perpendicular velocity diffusion coefficient was assumed for all altitudes in all regions as recommended by Nilsson et al. (2013). The effect of centrifugal acceleration was simulated by considering three values for the ionospheric electric field: 0 (no centrifugal acceleration), 50, and 100 mV/m. It was found that the centrifugal acceleration increases the parallel bulk velocity and decreases the parallel and perpendicular temperatures of both ion species at altitudes above about 4 RE. Centrifugal acceleration also increases the temperature anisotropy at high altitudes. At a given altitude, centrifugal acceleration decreases the density of H+ ions while it increases the density of O+ ions. This implies that with higher centrifugal acceleration more O+ ions overcome the potential barrier. It was also found that aside from two exceptions centrifugal acceleration has the same effect on the velocities of both ions. This implies that the centrifugal acceleration is universal for all particles. The parallel bulk velocities at a given value of ionospheric electric field were highest in the cusp followed by the CPC followed by the NPC. In this study a region of no wave-particle interaction was assumed in the CPC and NPC between 3.7 and 7.5 RE. In this region the perpendicular temperature was found to decrease with altitude due to perpendicular adiabatic cooling.
Information Content (IC) analysis can be used before an instrument is built to estimate its retrieval uncertainties and analyse their sensitivity to several factors. It is a very useful method to define/optimise satellite instruments. IC has shown its potential to compare instrument concepts in the infrared or the microwaves. IC is based on some hypotheses such as the the gaussian character of the Radiative Transfer (RT) and instrument errors, the first guess errors (Gaussian character, std and correlation structure), or the linearisation of the RT around a first guess. These hypotheses are easier to define for simple atmospheric situations. However, even in the clear‐sky case, their complexity has never ceased to increase towards more realism, to optimise the assimilation of satellite measurements in the Numerical Weather Prediction (NWP) systems. In the cloudy/precipitating case, these hypotheses are even more difficult to define in a realistic way as many factors are still very difficult to quantify. In this study, several tools are introduced to specify more realistic IC hypotheses than the current practice. We focus on the microwave observations as this is more pertinent for clouds and precipitation. Although not perfect, the proposed solutions are a new step towards more realistic IC assumptions of cloudy/precipitating scenes. A state‐dependence of the RT errors is introduced, the first guess errors have a more complex vertical structure, the IC is performed simultaneously on all the hydrometeors to take into account the contamination effect of the RT input uncertainties, and the IC is performed on a diversified set of cloudy/precipitating scenes with well‐defined hydrometeor assumptions. The method presented in this study is illustrated using the HYperspectral Microwave Sensor (HYMS) instrument concept with channels between 6.9 and 874 GHz (millimeter and sub‐millimeter regions). HYMS is considered as a potential next generation microwave sounder.
This study investigates the benefits of a satellite HYper-spectral Microwave Sensor (HYMS) for the retrieval of atmospheric temperature and humidity profiles, in the context of Numerical Weather Prediction (NWP). In the infrared, hyper-spectral instruments have already improved the accuracy of NWP forecasts. Microwave instruments so far only provide observations for a limited number of carefully selected channels. An information content analysis is conducted here to assess the impact of hyper-spectral microwave measurements on the retrieval of temperature and water vapor profiles under clear-sky conditions. It uses radiative transfer simulations over a large variety of atmospheric situations. It accounts for realistic observation (instrument and radiative transfer) noise and for a priori information assumptions compatible with NWP practices. The estimated retrieval performance of the HYMS instrument is compared to those of the microwave instruments to be deployed on board the future generation of European operational meteorological satellites (MetOp-SG). The results confirm the positive impact of a HYMS instrument on the atmospheric profiling capabilities compared to MetOp-SG. Temperature retrieval uncertainty, compared to a priori information, is reduced by 2 to 10%, depending on the atmospheric height, and improvement rates are much higher than what will be obtained with MetOp-SG. For humidity sounding these improvements can reach 30%, a significant benefit as compared to MetOp-SG results especially below 250 hPa. The results are not very sensitive to the instrument noise, under our assumptions. The main impact provided by the hyper-spectral information originates from the higher resolution in the O2 band around 60 GHz. The results are presented over ocean at nadir but similar conclusions are obtained for other incidence angles and over land
Context. The ESA Rosetta probe has not seen direct evidence of a fully formed bow shock at comet 67P/Churyumov–Gerasimenko (67P). Ion spectrometer measurements of cometary pickup ions measured in the vicinity of the nucleus of 67P are available and may contain signatures of the large-scale plasma environment.
Aims. The aim is to investigate the possibility of using pickup ion signatures to infer the existence or nonexistence of a bow shock-like structure and possibly other large-scale plasma environment features.
Methods. A numerical plasma model in the hybrid plasma description was used to model the plasma environment of a comet. Simulated pickup ion spectra were generated for different interplanetary magnetic field conditions. The results were interpreted through test particle tracing in the hybrid simulation solutions.
Results. Features of the observed pickup ion energy spectrum were reproduced, and the model was used to interpret the observation to be consistent with a shock-like structure. We identify (1) a spectral break related to the bow shock, (2) a mechanism for generating the spectral break, and (3) a dependency of the energy of the spectral break on the interplanetary magnetic field magnitude and bow shock standoff distance.
Propulsion system testing before mission operation is a fundamental requirement in any project. For both industrial and commercial entities within the space industry, complete system integration into a static test platform for functional and performance testing is an integral step in the system development process. Such a platform - if designed to be relatively safe, uncomplicated and reliable - can be an important tool within academia as well, giving researchers and students a possibility for practical learning and propulsion technology research.
In this thesis, a preliminary design for a liquid-propellant rocket engine testing platform to be used primarily for academical purposes is developed. Included in the presented design is a bi-propellant Chemical Propulsion system, gas pressure fed with Gaseous Nitrogen and using Gaseous Oxygen as oxidiser and a 70 % concentrated ethanol-water mixture as fuel. The propellant assembly contains all necessary components for operating the system and performing combustion tests with it, including various types of valves, tanks and sensors. An estimation of the total preliminary cost of selected components is presented as well. Also part of the developed platform design is a small thrust chamber made of copper, water-cooled and theoretically capable of delivering 1000 N of thrust using the selected propellants.
A list of operations to be performed before, during and after a complete combustion test is presented at the end of the document, together with a preliminary design of a Digital Control and Instrumentation System software. Due to time limitations, the software could not be implemented in a development program nor tested with simulated parameters as part of this thesis project.
The "Ice Giants" Uranus and Neptune are a different class of planet compared to Jupiter and Saturn. Studying these objects is important for furthering our understanding of the formation and evolution of the planets, and unravelling the fundamental physical and chemical processes in the Solar System. The importance of filling these gaps in our knowledge of the Solar System is particularly acute when trying to apply our understanding to the numerous planetary systems that have been discovered around other stars. The Uranus Pathfinder (UP) mission thus represents the quintessential aspects of the objectives of the European planetary community as expressed in ESA's Cosmic Vision 2015-2025. UP was proposed to the European Space Agency's M3 call for medium-class missions in 2010 and proposed to be the first orbiter of an Ice Giant planet. As the most accessible Ice Giant within the M-class mission envelope Uranus was identified as the mission target. Although not selected for this call the UP mission concept provides a baseline framework for the exploration of Uranus with existing low-cost platforms and underlines the need to develop power sources suitable for the outer Solar System. The UP science case is based around exploring the origins, evolution, and processes at work in Ice Giant planetary systems. Three broad themes were identified: (1) Uranus as an Ice Giant, (2) An Ice Giant planetary system, and (3) An asymmetric magnetosphere. Due to the long interplanetary transfer from Earth to Uranus a significant cruise-phase science theme was also developed. The UP mission concept calls for the use of a Mars Express/Rosetta-type platform to launch on a Soyuz-Fregat in 2021 and entering into an eccentric polar orbit around Uranus in the 2036-2037 timeframe. The science payload has a strong heritage in Europe and beyond and requires no significant technology developments. © 2011 Springer Science+Business Media B.V.
The focus of the present master thesis is the automation of an existing controllerdesign for a missile using two aerodynamic actuating systems. The motivation isto evaluate more missile concepts in a shorter period of time.The option used is trimming and linearization of a highly nonlinear missile at specic conditions. According to these conditions, either a two-dimensional operatingpoint grid dened by Mach number and height or three-dimensional operatingpoint grid dened by Mach number, height and angle of attack is generated forthe whole operating range of the missile. The controllers are designed at thesepoints using convex optimization. The convex set denes the pole placement areawhich is constrained by linear matrix inequalities according to the dynamic behaviorof the missile at the operating point conditions. These controllers describea validity area where the missile can be stabilized. This area consists all neighboringoperating points and denes therefore the grid density which can dier atspecic regions of the operating range. Controlling the missile to the target makesit necessary to apply gain-scheduling in order to get the manipulated variable byinterpolation of adjacent operating points. During this blending of the controllersa problem called windup can occur when an actuator is saturated. This mightlead to instability in worst case but can be counteracted by a model-recovery antiwindupnetwork which guarantees stability in the presence of saturation. Thisanti-windup design is automated by an ane linear parameter dependency of thegrid parameters and has the same validity area like the controllers.The whole design was successfully developed and tested in MATLAB/Simulink onmissiles using one or two aerodynamic actuating systems. The controllers have agood performance at small and high acceleration steps and the anti-windup keepsthe missile stable even though the actuators are saturated. Stability and robustnessof the controllers and anti-windup networks was veried as well as an airdefense maneuver where the missile starts at the ground and intercepts a targetat high altitude was successfully simulated for dierent grids and missiles.
Atmospheric reentry is a challenging part of human space ight and planetary entry missions.At the Institute of Space Systems in University of Stuttgart the idea of projectCAPE was conceived in 2012. Project Cubesat Atmospheric Probe for Education aimsto demonstrate the capability of miniaturised technologies of the micro electric plasmathruster, reentry vehicle design and ablative shielding material developed in this institute.The mission scenario is such that the CAPE is being deployed from the InternationalSpace Station and needs to complete the de-orbit of the Service and deorbit module andre-entry of the Atmospheric entry module in less than 1 year. The Cube satellite weighs3.0 kg consisting of a 2+1 unit service design module with solar panels, pulsed plasmapropulsion system of the university of Stuttgart (PETRUS) and a micro atmosphericreentry module (MIRKA-2). This reentry vehicle is unique in its size and weighs 0.5kg. During its reentry phase, it will be subjected to the intense aero-thermal loads at theThermal Protection System front which are absorbed by its ablative heat shield. But thecharacteristics of the re-entry trajectory like the ight path angle, entry velocity and entrypoint greatly determine the survivability against the integral heat load for this ballisticreentry vehicle. Although the success of the mission is considerably higher when having acontrolled reentry, in case of ballistic vehicles it is solely determined by the mission design.The main task is to investigate and develop the optimal re-entry trajectories in thedesign-time phase of mission development for MIRKA-2 vehicle that satises the objectiveof minimizing heat loads and adhering to operational constraints. Thus, the aimof this thesis is to provide a novel solution and optimum trajectory of the de-orbit andre-entry ight to maximize the survivability of the reentry module. The con icting parametersin this mission would be the operational limit of the pulsed plasma thruster andminimum heat loads during reentry ight. The simulation of these trajectories is carriedout in MATLAB using the REENT software developed in the Institute of Space Systems,University of Stuttgart. Its source code is composed in Fortran 77 which is integratedinto MATLAB. A careful mission analysis with the constraints of the capacity of pulsedplasma thruster, impulse provided by the separation mechanism and survivability of thereentry vehicle is carried out to prove the feasibility of this mission. In order to accomplishthe survivability during re-entry the aspects that have been modelled are the ight dynamicsof the satellite, aerodynamic and aero-thermal loads, spacecraft behaviour underthe external loads and local heating process.
The Aurora is a visual manifestation of the complex plasma processes that occur as the solar wind interacts with the Earth's magnetosphere and ionosphere. Therefore, studies of the aurora can lead to better understanding of the near-Earth space environment and of fundamental physical processes.This thesis focuses on optical studies of the aurora, both ground-based observations using the Auroral Large Imaging System (ALIS) and measurements from instruments onboard the Japanese micro-satellite Reimei. Various properties of the aurora are studied, such as the characteristic energy of precipitating electrons and scale sizes of diffuse auroral structures. Our understanding of the ionospheric physical processes involved in a particular auroral emission is improved using conjugate particle and optical data.Auroral light is a result of radiative transitions between excited states of the ionospheric gases. These excited states are formed either by direct electron impact or by a series of more complicated processes, involving chemical reactions, where part of the energy is converted into auroral light. Studies of auroral emissions can therefore give information about primary particle fluxes, ionospheric composition, and the magnetospheric and ionospheric processes leading to auroral precipitation. One way of deducing the characteristic energy of the precipitating particles is by using intensity ratios of auroral emissions. To be reliable, this method requires a good understanding of the processes involved in the auroral emissions used. The method works well if the measurements are made along the geomagnetic field lines. Using data from ALIS, both in magnetic zenith and off magnetic zenith, this method is tested for angles further away from the direction of the magnetic field lines. The result shows that it is possible to use this technique to deduce the characteristic energy for angles up to 35 degrees away from magnetic zenith.Using ALIS we have also been able to study structures and variations in diffuse aurora. When mapped to the magnetosphere, this provides information about the characteristics of the modulating wave activity in the magnetospheric source region. A statistical study of the scale sizes of diffuse auroral structures was made and the result shows widths and separation between structures of the order of 13-14 km. When mapped to the magnetosphere, this corresponds to 3-4 ion gyro radii for protons with a typical energy of 7 keV. Magnetometer data show that the structures move southward with a speed close to zero in the plasma convection frame. Stationary mirror mode structures in the magnetospheric equatorial plane are a likely explanation for these diffuse auroral structures. In another study we use measured precipitating electron energy spectra to improve our understanding of how the auroral process itself relates to the 427.8 nm auroral emission, which is often used when studying intensity ratios between different emission lines. The 427.8 nm emission is a fairly simple emission to model, with only a few processes involved, but still has some uncertainties, mostly due to the excitation cross section. Simultaneous measurements of the intensity of this emission from ALIS and the intensity and electron flux from Reimei provide a way to evaluate different sets of cross sections in order to find the best fit to the experimental data. It also allows a comparison of the absolute calibration of ALIS and Reimei imagers, improving the possibility to use the space-borne data for other detailed quantitative studies.In order to compare absolute measurements of aurora using different imagers, optical instruments are usually absolute calibrated by exposing them to a calibration light source. In 2011 an intercalibration workshop was held in Sodankylä, Finland, where nine low light sources were compared to the radioactive Fritz Peak reference source. The results were compared with earlier calibration workshop results and show that the sources are fairly stable. Two sources were also calibrated with the calibration standard source at UNIS, Svalbard, and the results show agreement with the calibration workshop in Sodankylä within 15 to 25%. This confirms the quality of the measurements with ALIS and in turn also of the the Reimei imagers.
The auroral emission of the first negative system of N2 + at 427.8 nm is analyzed using simultaneous measurements from the ground with ALIS (Auroral Large Imaging System) and from space with optical (MAC) and particle (ESA) instruments of the Reimei satellite. The study has two main objectives. The first is validation of the absolute calibration of the ALIS and the Reimei MAC cameras. The other task is to evaluate different cross sections of the electron excitation of N2 + that are used for the modeling of the auroral 1N system emissions. The simultaneous measurements of the 427.8 nm emission by ALIS and Reimei imagers show excellent agreement, indicating that the calibration of the two instruments is correct. Comparison of the 427.8 nm emission intensity calculated using the incident electron flux measured by the Reimei particle instruments with intensities measured by the optical imagers show that the best match is reached with the cross section from Shemansky and Liu (2005).
We present the results of a statistical study using optical images from ALIS (Auroral Large Imaging System) to investigate the spatial and temporal variations of structures in diffuse aurora. Analysis of conjugate Reimei data shows that such fine structures are a result of modulation of high-energy precipitating electrons. Pitch angle diffusion into the loss cone due to interaction of whistler mode waves with plasma sheet electrons is the most feasible mechanism leading to high-energy electron precipitation. This suggests that the fine structure is an indication of modulations of the efficiency of the wave-particle interaction. The scale sizes and variations of these structures, mapped to the magnetosphere, can give us information about the characteristics of the modulating wave activity. We found the scale size of the auroral stripes and the spacing between them to be on average 13-14 km, which corresponds to 3-4 ion gyro radii for protons with an energy of 7 keV. The structures move southward with a speed close to zero in the plasma convection frame.
The intensity ratios of auroral emissions at different wavelengths are widely used for reconstruction of auroral electron parameters. This method works quite well if the measurements of the auroral emissions are conducted in the magnetic zenith direction. In this study we want to investigate the possibility to use the intensity ratio method in the case where the observations are made in a direction not parallel to the magnetic field. In particular, we want to check the possibility of using auroral data for deducing the 2D distribution of the auroral electron precipitation. We use ALIS multi-station measurements of the auroral red and green line emissions (6300 Å and 5577 Å) to get data in zenith and non-zenith directions. We also take into account that the red line emission peak and the green line emission peak are at different altitudes. The results of this investigation show we can obtain reliable results for angles up to 35º away from magnetic zenith.
Cubesats are picosatellites that have a mass of less than 1.3kg and have a shape of acube. As a result of their low cost of development and launch, cubesats are gainingpopularity in industry and academia. These satellites are also a cost-efective way forspace technology demonstrations. University of Würzburg has a longstanding cubesatprogram started with the launch of UWE-1 in 2005. This was followed by UWE-2 andUWE-3. Several technologies were tested and validated using the UWE platform. Thelast mission UWE-3 has successfully tested an attitude control system.In the next mission, UWE-4 will demonstrate an orbit control system.
Being a picosatellite as small as this one (10 x 10 x 10cm 3 and 1kg) brings new challenges intodi↵erent aspects of satellite design, development, control and operation. The orbit con-trol of such a satellite is one of the problems that should be tackled. Being such a smallsatellite means having less propellant mass and much smaller thrusters than conventionalsatellites. These should be addressed in the orbit control.
UWE-4 will take advantage of four NanoFEEP thrusters, on one side. Because of theiraccuracy and functionality, these thrusters can be used to implement a continuous thrustsystem. They are also a good choice because of their low energy usage. This work startswith the preparation that was needed to implement a control system. Then explains thestate of the art for continuous thrust control systems. Implements two di↵erent methods,based on perfect control and discusses the outcome. It discuses the limiting factors, likefuel mass, available electrical energy and their e↵ect on the controller performance andconcludes with recommendation for the future researches.
Here we inspect whether microbial life may disperse using dust transported by wind in the Atacama Desert in northern Chile, a well-known Mars analog model. By setting a simple experiment across the hyperarid core of the Atacama we found that a number of viable bacteria and fungi are in fact able to traverse the driest and most UV irradiated desert on Earth unscathed using wind-transported dust, particularly in the later afternoon hours. This finding suggests that microbial life on Mars, extant or past, may have similarly benefited from aeolian transport to move across the planet and find suitable habitats to thrive and evolve.
The influence of the solar proton event (SPE) 14-16 July 2000 on Polar Mesosphere Summer Echoes (PMSE) is examined. PMSE were observed by the Esrange VHF MST Radar (ESRAD) at 67°53'N, 21°06'E. The 30MHz Imaging Riometer for Ionospheric Studies IRIS in Kilpisjärvi (69°30'N, 20°47'E) registered cosmic radio noise absorption caused by ionisation changes in response to the energetic particle precipitation. An energy deposition/ion-chemical model was used to estimate the density of free electrons and ions in the upper atmosphere. Particle collision frequencies were calculated from the MSISE-90 model. Electric fields were calculated using conductivities from the model and measured magnetic disturbances. The electric field reached a maximum of 91mV/m during the most intensive period of the geomagnetic storm accompanying the SPE. The temperature increase due to Joule and particle heating was calculated, taking into account radiative cooling. The temperature increase at PMSE heights was found to be very small. The observed PMSE were rather intensive and extended over the 80-90km height interval. PMSE almost disappeared above 86km at the time of greatest Joule heating on 15 July 2000. Neither ionisation changes, nor Joule/particle heating can explain the PMSE reduction. Transport effects due to the strong electric field are a more likely explanation.
The theoretical PGI (Polar Geophysical Institute) model for the quiet lower ionosphere has been applied for computing the ionization rate and electron density profiles in the summer and winter D-region at solar zenith angles less than 80° and larger than 99° under steady state conditions. In order to minimize possible errors in estimation of ionization rates provided by solar electromagnetic radiation and to obtain the most exact values of electron density, each wavelength range of the solar spectrum has been divided into several intervals and the relations between the solar radiation intensity at these wavelengths and the solar activity index F10.7 have been incorporated into the model. Influence of minor neutral species (NO, H2O, O, O3) concentrations on the electron number density at different altitudes of the sunlit quiet D-region has been examined. The results demonstrate that at altitudes above 70 km, the modeled electron density is most sensitive to variations of nitric oxide concentration. Changes of water vapor concentration in the whole altitude range of the mesosphere influence the electron density only in the narrow height interval 73-85 km. The effect of the change of atomic oxygen and ozone concentration is the least significant and takes place only below 70 km. Model responses to changes of the solar zenith angle, solar activity (low-high) and season (summer-winter) have been considered. Modeled electron density profiles have been evaluated by comparison with experimental profiles available from the rocket measurements for the same conditions. It is demonstrated that the theoretical model for the quiet lower ionosphere is quite effective in describing variations in ionization rate, electron number density and effective recombination coefficient as functions of solar zenith angle, solar activity and season. The model may be used for solving inverse tasks, in particular, for estimations of nitric oxide concentration in the mesosphere
A 1-dimensional direct simulation Monte Carlo model is used to study the outflow of O+ and H+ ions from 1.2 RE to 15.2 RE along two flight trajectories originating from the polar cap, namely the central polar cap (CPC) and the cusp. To study the effect of varying geophysical conditions and to deduce the proper set of parameters. several parameters were varied and the results were compared to corresponding data from Cluster spacecraft. First, several sets of diffusion coefficients were considered based on using diffusion coefficients calculated by Barghouthi et al. [1998], Nilsson et al. [2013], and Abudayyeh et al. [2015b] for different altitude intervals. It was found that in the central polar cap using the diffusion coefficients reported by Barghouthi et al. [1998] for altitudes lower than 3.7 RE, zero diffusion coefficients between 3.7 and 7.5 RE and diffusion coefficients from Nilsson et al. [2013] for altitudes higher than 7.5 RE provide the best fit for O+ ions. For O+ ions in the cusp the best fit was obtained for using Barghouthi et al. [1998] diffusion coefficients for altitudes lower than 3.7 RE and Nilsson et al. [2013] diffusion coefficients for altitudes higher than that. The best fit for H+ ions in both regions was obtained by using the diffusion coefficients calculated by Abudayyeh et al. [2015b]. Also, it was found that along an ion's trajectory the most recent heating dominates. Second, the strength of centrifugal acceleration was varied by using three values for the ionospheric electric field namely: 0, 50, and 100 mV/m. It was found that the value of 50 mV/m provided the best fit for both ion species in both regions. Finally the lower altitude boundary conditions and the electron temperature were varied. Increasing the electron temperature and the lower altitude O+ parallel velocity were found to increase the access of O+ ions to higher altitudes and therefore increase the density at a given altitude. The variation of all other boundary conditions only affected the densities of the ions and not the other moments due to the overwhelming effect of wave particle interaction. Furthermore varying the parameters of one ion species has no effect on the other ion species. We also compared the energy gain per ion due to wave particle interaction, centrifugal acceleration, and ambipolar electric field and found that wave particle interaction is the most important mechanism, while ambipolar electric field is relatively unimportant especially at higher altitudes.
This paper describes the algorithms of the level-2 research (L2r) processing chain developed for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES). The chain has been developed in parallel to the operational chain for conducting researches on calibration and retrieval algorithms. L2r chain products are available to the scientific community. The objective of version 2 is the retrieval of the vertical distribution of trace gases in the altitude range of 18–90 km. A theoretical error analysis is conducted to estimate the retrieval feasibility of key parameters of the processing: line-of-sight elevation tangent altitudes (or angles), temperature and ozone profiles. While pointing information is often retrieved from molecular oxygen lines, there is no oxygen line in the SMILES spectra, so the strong ozone line at 625.371 GHz has been chosen. The pointing parameters and the ozone profiles are retrieved from the line wings which are measured with high signal to noise ratio, whereas the temperature profile is retrieved from the optically thick line center. The main systematic component of the retrieval error was found to be the neglect of the non-linearity of the radiometric gain in the calibration procedure. This causes a temperature retrieval error of 5–10 K. Because of these large temperature errors, it is not possible to construct a reliable hydrostatic pressure profile. However, as a consequence of the retrieval of pointing parameters, pressure induced errors are significantly reduced if the retrieved trace gas profiles are represented on pressure levels instead of geometric altitude levels. Further, various setups of trace gas retrievals have been tested. The error analysis for the retrieved HOCl profile demonstrates that best results for inverting weak lines can be obtained by using narrow spectral windows.
This paper describes the algorithms of the level-2 research (L2r) processingchain developed for the Superconducting Submillimeter-Wave Limb-EmissionSounder (SMILES). The chain has been developed in parallel to the operationalchain for conducting researches on calibration and retrieval algorithms. L2rchain products are available to the scientific community. The objective ofversion 2 is the retrieval of the vertical distribution of trace gases in thealtitude range of 18-90 km. An theoretical error analysis is conducted toestimate the retrieval feasibility of key parameters of the processing:line-of-sight elevation tangent altitudes (or angles), temperature and O3 profiles. The line-of-sight tangent altitudes are retrievedbetween 20 and 50 km from the strong ozone (O3) line at 625.371 GHz,with low correlation with the O3 volume-mixing ratio and temperatureretrieved profiles. Neglecting the non-linearity of the radiometric gain inthe calibration procedure is the main systematic error. It is large for theretrieved temperature (between 5-10 K). Therefore, atmospheric pressure cannot be derived from the retrieved temperature, and, then, in the altituderange where the line-of-sight tangent altitudes are retrieved, the retrievedtrace gases profiles are found to be better represented on pressure levelsthan on altitude levels. The error analysis for the retrieved HOCl profiledemonstrates that best results for inverting weak lines can be obtained byusing narrow spectral windows. Future versions of the L2r algorithms willimprove the temperature/pressure retrievals and also provide information inthe upper tropospheric/lower stratospheric region (e.g., water vapor, icecontent, O3) and on stratospheric and mesospheric line-of-sight winds.
This work presents the advancements in the development of simulation models of spacecraft components as part of a testbench for verification of onboard flight software. The satellite and its mission are briefly described as to give an idea of the conditions where the simulation has to run. The simulation environment, SimTG, is also introduced and a description of the developed models is presented. The models required interaction between different simulation environments, real hardware and simulated hardware, and also some data processing was necessary in order to filter undesired information. Finally, the performance of the models was tested and verified and a sensible improvement of the state of the testbench on the simulation side was achieved, although a considerable amount of work still lies ahead before a complete onboard software verification tool is ready.
In order to accomplish most asteroid redirection missions, rotational control of the asteroid body is required. Small near-Earth asteroids tend to exhibit a significant range of rotational and tumbling properties. This work provides an analysis of asteroid detumbling using a formation of spacecraft. Through an orbiter and three landed thruster spacecraft, a low-thrust detumbling maneuver is performed on two illustrative asteroids. The asteroid scenarios are designed such that they reflect the characteristics of possible redirection scenarios. In particular the geometries, densities, angular velocities, and masses of the asteroids are adjusted according to available asteroid data to provide two unique redirection scenarios. The asteroid and spacecraft specifications are outlined, as well as the formulations for the detumbling maneuver. The results of the maneuver are discussed along with the key detumbling parameters and timeframe required.
Executive Summary: Return of samples from the surface of Mars has been a goal of the international Mars science community for many years. Affirmation by NASA and ESA of the importance of Mars exploration led the agencies to establish the international MSR Objectives and Samples Team (iMOST). The purpose of the team is to re-evaluate and update the sample-related science and engineering objectives of a Mars Sample Return (MSR) campaign. The iMOST team has also undertaken to define the measurements and the types of samples that can best address the objectives. Seven objectives have been defined for MSR, traceable through two decades of previously published international priorities. The first two objectives are further divided into sub-objectives. Within the main part of the report, the importance to science and/or engineering of each objective is described, critical measurements that would address the objectives are specified, and the kinds of samples that would be most likely to carry key information are identified. These seven objectives provide a framework for demonstrating how the first set of returned Martian samples would impact future Martian science and exploration. They also have implications for how analogous investigations might be conducted for samples returned by future missions from other solar system bodies, especially those that may harbor biologically relevant or sensitive material, such as Ocean Worlds (Europa, Enceladus, Titan) and others. Summary of Objectives and Sub-Objectives for MSR Identified by iMOST: Objective 1 Interpret the primary geologic processes and history that formed the Martian geologic record, with an emphasis on the role of water. Intent To investigate the geologic environment(s) represented at the Mars 2020 landing site, provide definitive geologic context for collected samples, and detail any characteristics that might relate to past biologic processesThis objective is divided into five sub-objectives that would apply at different landing sites. 1.1 Characterize the essential stratigraphic, sedimentologic, and facies variations of a sequence of Martian sedimentary rocks. Intent To understand the preserved Martian sedimentary record. Samples A suite of sedimentary rocks that span the range of variation. Importance Basic inputs into the history of water, climate change, and the possibility of life 1.2 Understand an ancient Martian hydrothermal system through study of its mineralization products and morphological expression. Intent To evaluate at least one potentially life-bearing "habitable" environment Samples A suite of rocks formed and/or altered by hydrothermal fluids. Importance Identification of a potentially habitable geochemical environment with high preservation potential. 1.3 Understand the rocks and minerals representative of a deep subsurface groundwater environment. Intent To evaluate definitively the role of water in the subsurface. Samples Suites of rocks/veins representing water/rock interaction in the subsurface. Importance May constitute the longest-lived habitable environments and a key to the hydrologic cycle. 1.4 Understand water/rock/atmosphere interactions at the Martian surface and how they have changed with time. Intent To constrain time-variable factors necessary to preserve records of microbial life. Samples Regolith, paleosols, and evaporites. Importance Subaerial near-surface processes could support and preserve microbial life. 1.5 Determine the petrogenesis of Martian igneous rocks in time and space. Intent To provide definitive characterization of igneous rocks on Mars. Samples Diverse suites of ancient igneous rocks. Importance Thermochemical record of the planet and nature of the interior. Objective 2 Assess and interpret the potential biological history of Mars, including assaying returned samples for the evidence of life. Intent To investigate the nature and extent of Martian habitability, the conditions and processes that supported or challenged life, how different environments might have influenced the preservation of biosignatures and created nonbiological "mimics," and to look for biosignatures of past or present life.This objective has three sub-objectives: 2.1 Assess and characterize carbon, including possible organic and pre-biotic chemistry. Samples All samples collected as part of Objective 1. Importance Any biologic molecular scaffolding on Mars would likely be carbon-based. 2.2 Assay for the presence of biosignatures of past life at sites that hosted habitable environments and could have preserved any biosignatures. Samples All samples collected as part of Objective 1. Importance Provides the means of discovering ancient life. 2.3 Assess the possibility that any life forms detected are alive, or were recently alive. Samples All samples collected as part of Objective 1. Importance Planetary protection, and arguably the most important scientific discovery possible. Objective 3 Quantitatively determine the evolutionary timeline of Mars. Intent To provide a radioisotope-based time scale for major events, including magmatic, tectonic, fluvial, and impact events, and the formation of major sedimentary deposits and geomorphological features. Samples Ancient igneous rocks that bound critical stratigraphic intervals or correlate with crater-dated surfaces. Importance Quantification of Martian geologic history. Objective 4 Constrain the inventory of Martian volatiles as a function of geologic time and determine the ways in which these volatiles have interacted with Mars as a geologic system. Intent To recognize and quantify the major roles that volatiles (in the atmosphere and in the hydrosphere) play in Martian geologic and possibly biologic evolution. Samples Current atmospheric gas, ancient atmospheric gas trapped in older rocks, and minerals that equilibrated with the ancient atmosphere. Importance Key to understanding climate and environmental evolution. Objective 5 Reconstruct the processes that have affected the origin and modification of the interior, including the crust, mantle, core and the evolution of the Martian dynamo. Intent To quantify processes that have shaped the planet's crust and underlying structure, including planetary differentiation, core segregation and state of the magnetic dynamo, and cratering. Samples Igneous, potentially magnetized rocks (both igneous and sedimentary) and impact-generated samples. Importance Elucidate fundamental processes for comparative planetology. Objective 6 Understand and quantify the potential Martian environmental hazards to future human exploration and the terrestrial biosphere. Intent To define and mitigate an array of health risks related to the Martian environment associated with the potential future human exploration of Mars. Samples Fine-grained dust and regolith samples. Importance Key input to planetary protection planning and astronaut health. Objective 7 Evaluate the type and distribution of in-situ resources to support potential future Mars exploration. Intent To quantify the potential for obtaining Martian resources, including use of Martian materials as a source of water for human consumption, fuel production, building fabrication, and agriculture. Samples Regolith. Importance Production of simulants that will facilitate long-term human presence on Mars. Summary of iMOST Findings: Several specific findings were identified during the iMOST study. While they are not explicit recommendations, we suggest that they should serve as guidelines for future decision making regarding planning of potential future MSR missions. The samples to be collected by the Mars 2020 (M-2020) rover will be of sufficient size and quality to address and solve a wide variety of scientific questions. Samples, by definition, are a statistical representation of a larger entity. Our ability to interpret the source geologic units and processes by studying sample sub sets is highly dependent on the quality of the sample context. In the case of the M-2020 samples, the context is expected to be excellent, and at multiple scales. (A) Regional and planetary context will be established by the on-going work of the multi-agency fleet of Mars orbiters. (B) Local context will be established at field area- to outcrop- to hand sample- to hand lens scale using the instruments carried by M-2020. A significant fraction of the value of the MSR sample collection would come from its organization into sample suites, which are small groupings of samples designed to represent key aspects of geologic or geochemical variation. If the Mars 2020 rover acquires a scientifically well-chosen set of samples, with sufficient geological diversity, and if those samples were returned to Earth, then major progress can be expected on all seven of the objectives proposed in this study, regardless of the final choice of landing site. The specifics of which parts of Objective 1 could be achieved would be different at each of the final three candidate landing sites, but some combination of critically important progress could be made at any of them. An aspect of the search for evidence of life is that we do not know in advance how evidence for Martian life would be preserved in the geologic record. In order for the returned samples to be most useful for both understanding geologic processes (Objective 1) and the search for life (Objective 2), the sample collection should contain BOTH typical and unusual samples from the rock units explored. This consideration should be incorporated into sample selection and the design of the suites. The retrieval missions of a MSR campaign should (1) minimize stray magnetic fields to which the samples would be exposed and carry a magnetic witness plate to record exposure, (2) collect and return atmospheric gas sample(s), and (3) collect additional dust and/or regolith sample mass if possible.
In this thesis, we explore the dynamics of the solar wind as it perme-ates and flows through a tenuous cometary atmosphere, with a focuson the interaction observed at comet 67P/Churyumov–Gerasimenko.
Seven comets had already been visited by nine different probes when the European spacecraft Rosetta reached comet Churyumov–Gerasimenko in August 2014. The mission was however the first to orbit its host comet, which it did for a total duration of more than two years, corre-sponding to a large part of the comet's orbit around the Sun. This en-abled to study how the dynamics of the plasma environment evolvedas the comet itself was transformed from one of the smallest obstaclesto the solar wind in the Solar System when far away from the Sun, toa well-established magnetosphere at perihelion.
Most of our efforts tackle the early part of this transformation, when the creation of new-born cometary ions starts to induce significant disturbances to the incident flow. During this stage, a kinetic descrip-tion of the interaction is necessary, as the system of interest cannot be reduced to a hydrodynamic problem. This contrasts with the situation closer to the Sun, where a fluid treatment can be used, at Churyumov–Gerasimenko as well as at previously visited comets.
Rosetta was not a mission dedicated to plasma studies, however. It directly translates into a limited spatial coverage of the cometary plasma environment, which by its nature extends over several spatial scales. An approach solely based on the analysis of in-situ data cannot properly address the major questions on the nature and physics of the plasma environment of Churyumov–Gerasimenko. This thesis there-fore largely exploits the experimental–analytical–numerical triad of approaches. In Chapters 3 and 4 we propose simple models of the ion dynamics and of the cometary plasma environment, and these are tested against experimental and numerical data. Used together,they give a global description of the solar wind ion dynamics through the cometary atmosphere, that we explore in the 2-dimensional and 3-dimensional cases (Chapter 5). In Chapter 6, we propose a view onthe interaction and its fluid aspects when closer to the Sun.
Context. The first long-term in-situ observation of the plasma environment in the vicinity of a comet, as provided by the European Rosetta spacecraft. Aims. Here we offer characterisation of the solar wind flow near 67P/Churyumov-Gerasimenko (67P) and its long term evolution during low nucleus activity. We also aim to quantify and interpret the deflection and deceleration of the flow expected from ionization of neutral cometary particles within the undisturbed solar wind. Methods. We have analysed in situ ion and magnetic field data and combined this with hybrid modeling of the interaction between the solar wind and the comet atmosphere. Results. The solar wind deflection is increasing with decreasing heliocentric distances, and exhibits very little deceleration. This is seen both in observations and in modeled solar wind protons. According to our model, energy and momentum are transferred from the solar wind to the coma in a single region, centered on the nucleus, with a size in the order of 1000 km. This interaction affects, over larger scales, the downstream modeled solar wind flow. The energy gained by the cometary ions is a small fraction of the energy available in the solar wind. Conclusions. The deflection of the solar wind is the strongest and clearest signature of the mass-loading for a small, low-activity comet, whereas there is little deceleration of the solar wind
The Rosetta mission provided detailed observations of the growth of a cavity in the solar wind around comet 67P/Churyumov–Gerasimenko. As the comet approached the Sun, the plasma of cometary origin grew enough in density and size to present an obstacle to the solar wind. Our results demonstrate how the initial slight perturbations of the solar wind prefigure the formation of a solar wind cavity, with a particular interest placed on the discontinuity (solar wind cavity boundary) passing over the spacecraft. The slowing down and heating of the solar wind can be followed and understood in terms of single particle motion. We propose a simple geometric illustration that accounts for the observations, and shows how a cometary magnetosphere is seeded from the gradual steepening of an initially slight solar wind perturbation. A perspective is given concerning the difference between the diamagnetic cavity and the solar wind cavity.
Context.The first 1000 km of the ion tail of comet 67P/Churyumov–Gerasimenko were explored by the EuropeanRosettaspacecraft,2.7 au away from the Sun.Aims.We characterised the dynamics of both the solar wind and the cometary ions on the night-side of the comet's atmosphere.Methods.We analysed in situ ion and magnetic field measurements and compared the data to a semi-analytical model.Results.The cometary ions are observed flowing close to radially away from the nucleus during the entire excursion. The solar windis deflected by its interaction with the new-born cometary ions. Two concentric regions appear, an inner region dominated by theexpanding cometary ions and an outer region dominated by the solar wind particles.Conclusions.The single night-side excursion operated byRosettarevealed that the near radial flow of the cometary ions can beexplained by the combined action of three different electric field components, resulting from the ion motion, the electron pressuregradients, and the magnetic field draping. The observed solar wind deflection is governed mostly by the motional electric field−uion×B.
We study the dynamics of the interaction between the solar wind ions and a partially ionized atmosphere around a comet, at a distance of 2.88 AU from the Sun during a period of low nucleus activity. Comparing particle data and magnetic field data for a case study, we highlight the prime role of the solar wind electric field in the cometary ion dynamics. Cometary ion and solar wind proton flow directions evolve in a correlated manner, as expected from the theory of mass loading. We find that the main component of the accelerated cometary ion flow direction is along the antisunward direction and not along the convective electric field direction. This is interpreted as the effect of an antisunward polarization electric field adding up to the solar wind convective electric field.
When interacting, the solar wind and the ionised atmosphere of a comet exchange energy and momentum. Our aim is to understand the influence of the average Parker spiral configuration of the solar wind magnetic field on this interaction. We compare the theoretical expectations of an analytical generalised gyromotion with Rosetta observations at comet 67P/Churyumov-Gerasimenko. A statistical approach allows one to overcome the lack of upstream solar wind measurement. We find that additionally to their acceleration along (for cometary pick-up ions) or against (for solar wind ions) the upstream electric field orientation and sense, the cometary pick-up ions are drifting towards the dawn side of the coma, while the solar wind ions are drifting towards the dusk side of the coma, independent of the heliocentric distance. The dynamics of the interaction is not taking place in a plane, as often assumed in previous works.
Aims.We aim at analytically modelling the solar wind proton trajectories during their interaction with a partially ionised cometaryatmosphere, not in terms of bulk properties of the flow but in terms of single particle dynamics.Methods.We first derive a generalised gyromotion, in which the electric field is reduced to its motional component. Steady-stateis assumed, and simplified models of the cometary density and of the electron fluid are used to express the force experienced byindividual solar wind protons during the interaction.Results.A three-dimensional (3D) analytical expression of the gyration of two interacting plasma beams is obtained. Applying it to acomet case, the force on protons is always perpendicular to their velocity and has an amplitude proportional to 1/r2. The solar winddeflection is obtained at any point in space. The resulting picture presents a caustic of intersecting trajectories, and a circular regionis found that is completely free of particles. The particles do not lose any kinetic energy and this absence of deceleration, togetherwith the solar wind deflection pattern and the presence of a solar wind ion cavity, is in good agreement with the general results of theRosettamission.Conclusions.The qualitative match between the model and thein situdata highlights how dominant the motional electric field isthroughout most of the interaction region for the solar wind proton dynamics. The model provides a simple general kinetic descriptionof how momentum is transferred between these two collisionless plasmas. It also shows the potential of this semi-analytical modelfor a systematic quantitative comparison to the data.
Aims.Cometary ions are constantly produced in the coma, and once produced they are accelerated and eventually escape the coma.We describe and interpret the dynamics of the cometary ion flow, of an intermediate active comet, very close to the nucleus and in theterminator plane.Methods.We analysed in situ ion and magnetic field measurements, and characterise the velocity distribution functions (mostly usingplasma moments). We propose a statistical approach over a period of one month.Results.On average, two populations were observed, separated in phase space. The motion of the first is governed by its interactionwith the solar wind farther upstream, while the second one is accelerated in the inner coma and displays characteristics compatiblewith an ambipolar electric field. Both populations display a consistent anti-sunward velocity component.Conclusions.Cometary ions born in different regions of the coma are seen close to the nucleus of comet 67P/Churyumov–Gerasimenko with distinct motions governed in one case by the solar wind electric field and in the other case by the position relative tothe nucleus. A consistent anti-sunward component is observed for all cometary ions. An asymmetry is found in the average cometaryion density in a solar wind electric field reference frame, with higher density in the negative (south) electric field hemisphere. Thereis no corresponding signature in the average magnetic field strengt
Remote sensing is an efficient tool for temporal monitoring of inaccessible alpine glacial terrain. This study discusses the methods of remote sensing in visible and infrared (IR) wavelengths, which are helpful in providing important information about alpine glaciers. The scope of this study covers recent advances and prospects in optical and thermal remote sensing of glacier facies, glacier velocity, mass balance, glacial hazards and automated mapping techniques. The technology is ever evolving with the advent of new remote sensors capturing data in visible/IR wavelengths and better digital computing technology. An extensive list of significant studies further helps the reader to explore a particular topic of interest. We survey recent advances in this field and additionally highlight the emerging prospects
present work evaluates the applicability of operational land imager (OLI) and thermal infrared sensor (TIRS) on-board Landsat 8 satellite. We demonstrate an algorithm for automated mapping of glacier facies and supraglacial debris using data collected in blue, near infrared (NIR), short wave infrared (SWIR) and thermal infrared (TIR) bands. The reflectance properties invisible and NIR regions of OLI for various glacier facies are in contrast with those in SWIR region. Based on the premise that different surface types (snow, ice and debris) of a glacier should show distinct thermal regimes, the 'at-satellite brightness temperature' obtained using TIRS was used as a base layer for developing the algorithm. This base layer was enhanced and modified using contrasting reflectance properties of OLI bands. In addition to fades and debris cover characterization, another interesting outcome of this algorithm was extraction of crevasses on the glacier surface which were distinctly visible in output and classified images. The validity of this algorithm was checked using field data along a transect of the glacier acquired during the satellite pass over the study area. With slight scene-dependent threshold adjustments, this work can be replicated for mapping glacier facies and supraglacial debris in any alpine valley glacier
Supraglacial debris significantly hampers the mapping of glaciers using remote sensing data. A semi-automated approach for the mapping of debris-covered glacier was applied, which combined the inputs from thermal and optical remote sensing data and the Digital Elevation Model (DEM) derived morphometric parameters. A thermal mask that delineates the supraglacial debris extent was generated by the thresholding of surface temperature layer obtained from Landsat TM/ETM. + thermal band satellite data. The extent of clean glacier ice was identified by band ratioing and thresholding of TM/ETM. + 4 and TM/ETM. + 5 bands. Morphometric parameters like slope, plan curvature and profile curvature were rearranged in similar surface groups using the technique of cluster analysis. All these masks were vectorized and final classification maps were generated using geographic information system (GIS) overlay operations. The areal extent of semi-automated outlines of Hamtah and Patsio Glaciers derived from cluster analysis varied from manually derived outline using pan-sharpened Landsat ETM. + September 2000 image by -. 1.3% and -. 1.6%, respectively. Year 2011 classification map for Patsio Glacier was compared with the field observations and a high correlation and overall accuracy (~. 91%) were observed. The same classification methodology was adopted for images of years 2000 and 1989 for Patsio Glacier to observe the effects of varying snow cover patterns on adopted methodology. Also the methodology was adopted and verified for Hamtah Glacier, with different geometry and terrain conditions as compared to Patsio Glacier. Although the spatial resolution limitation of ASTER GDEM and Landsat TM/ETM. + thermal band limits the automated mapping of small debris-covered glaciers, the outcomes are still favorable enough to apply such methodologies for mapping different types of debris-covered glaciers in the future
This study demonstrates the effectiveness of remote sensing and analytical hierarchy process for avalanche hazard mapping. The layers incorporated in this study were of slope, aspect, profile curvature, ground cover and elevation. The accuracy of output was determined using the registered avalanche sites based on ground observations and field-based modelling techniques. 93.35% of avalanche-affected areas came under maximum and moderate hazard zones, thus proving the effectiveness of this technique for Gangotri glacier basin. A parallel study was done to observe the change in the results, if any, by using high-resolution DEM and Cartosat-1 imagery. Similar methodology was adopted and the outcome was having significant improvement over the previous result as 98.8% of the preregistered avalanche area falling within maximum and moderate hazard zones
This work investigates dengue affected localities of Delhi using static and dynamic environmental factors and their possible spatial relationships. The static variables include soil drainage, built-up area and vegetation. The dynamic variables represent seasonal precipitation and temperature data for past hundred years. Significance test (t-test) provided deterministic evidence of variable importance to model. Weighted sum and quantile classification helped to create a final risk map. The model indicated non-uniform distribution of risk across the state and showed elevated risk in urban built-up areas mainly alongside the river Yamuna. Three years (2007, 2008 and 2009) data for confirmed dengue cases for affected localities were obtained from Municipal Corporation of Delhi (MCD) for validation. 57.98% of the reported cases were observed under high risk category as modeled in this study. Modeling results indicate that environmental factors like Precipitation, temperature, soil drainage, built-up area and vegetation govern mosquito breeding and are correlated with human dengue risk The approach verified that dengue risk can be modeled at the state level and can be modified for risk predictions of other vector-borne diseases in varied ecological regions


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Tea & Talk / John Zickefoose
Tea & Talk at Terrace Hill
The Terrace Hill Partnership is proud to present four distinguished speakers who will bring timely programs to the Terrace Hill Drawing Room at 2 pm each Saturday in February, followed by tea and tasty tidbits. Tickets are $10 per program or $25 for a season pass. The speakers are donating their time and all proceeds will benefit the gardens of Terrace Hill. Tickets will be available at the door and on eventbrite.com.
For more information call: 515-281-7205.
Terrace Hill, Iowa Governor's Residence and National Historic Landmark, is located at 2300 Grand Avenue in Des Moines, Iowa.
February 2, 2019, 2 pm
John Zickefoose
John will talk about Terrace Hill's history and architect, William Boyington.
Tickets and speaker bio: https://teaandtalkjohnzickefoose.eventbrite.com

subset: commoncrawl


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The cause? Well, there was a great little fish store near my apartment in Westbury, and, during this period, I had developed a taste for clams, usually broiling them, but always dousing them in lemon juice or tabasco sauce. Good stuff. But it only takes one bad clam...
During that same month, the Yankees had jumped out to a three-game lead in the ALCS. With eight innings of Game 4 in the books, the good guys were a Mo save from the World Series. But it only takes one bad inning...
The blown save was followed by a Red Sox win in Game 5.
I honestly don't know if it was nerves or the clams, but I hurled before Game 6. More than once, I believe. An off-site meeting was on the docket for the next day. I remember getting sick in the office before leaving for the meeting, but I toughed it out and went, though I didn't mask my condition well: I was told that I looked greener than Kermit the Frog (or maybe it was greener than the Grinch. Or was it Gazoo?--anyway, someone green).
I did recover, but the Yankees didn't, and I didn't go near clams for several years after that.
So, what is it with our sports allegiances that can make us sick when things go wrong? And, what fuels the rivalries? The proximity of teams obviously enables them, as do playoff encounters, especially when these meetings occur several times within a few years.
For the most part, though, the rivalries reside with the fans, and not the players. Money drives players, and they switch to the uniforms of their rivals pretty easily. Further, I've been surprised at the camaraderie often evident from the players on "rival" teams. I'm not talking about sportsmanship like a handshake after a game. I'm referring to the commercials the players on these teams have done together, the pre-game embraces between the likes of the rather likable Big Papi and Yankees like A-Rod and Mo, and, most unsettling, a tender, hand on the shoulder, moment between Varitek and Jeter between pitches in the last series between these two teams (the announcers didn't comment on it, but it was a bizarre sight, albeit one that I think many missed). Sure, each team has players that the other team may not like, but any real contempt is between those players and the fans of the opponent. Red Sox players and Yankees players don't dislike each other nearly as much as Red Sox players and Yankees fans, and vice versa. Clearly, this dislike transcends across the four sports, for me anyway.
As the basketball and hockey seasons were nearing championships, it struck me how my dislike for teams in other sports influenced who I wanted to win and lose the two finals, and I became slightly disinterested when I realized that all four couldn't lose. A bit bitter? Perhaps. Still, as a Giants fan, how could I possibly root for a team from Dallas? Well, it was easy to root against Miami this year. The Canucks? Well, until the last Winter Olympic Games, I'd never have a problem with a Canadian team winning the cup. More than a bit bitter? Well, no not really: A grudge against any team or country can be washed away when the team faces one from Boston. Truth be told, I don't have any grudge against the Bruins either, other than their city (and I add that I have nothing against Boston other than their teams). With the recent multiple championships of the Red Sox and Patriots, and the frequent championships of the Celtics, the notion of a Stanley Cup going to the Bruins just wasn't palatable. Remarkably--enviably--Boston teams have won championships in all four major sports in the last six years. This gives them great claim to the "Title Town" billing.
Thinking about this for more than a couple of seconds reminds me of that October evening seven years ago, and I won't be eating clams for the next few weeks.
- Posted using BlogPress from my iPad


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Hundreds of LTTE war widows seek government assistance
Rehab Minister says Mrs. Balakumaran and Yogi among them
July 18, 2010, 9:33 pm
by Shamindra Ferdinando
Rehabilitation and Prisons Reforms Minister Dew Gunasekera says an urgent programme is needed to provide relief to war widows, including wives of the LTTE cadres killed during the war.
Speaking to The Island after meeting groups of war widows in Vavuniya, Jaffna and Kilinochchi over a week ago, Minister Gunasekera emphasized the importance of meaningful measures to alleviate their suffering.
General Secretary of the Communist Party of Sri Lanka, Gunasekera said that among the women whom he had met in Jaffna were the wives of K.V. Balakumaran and Yogiratnam Yogi, a member of the LTTE negotiating team for talks with the then President Ranasinghe Premadasa's government. The Army killed Balakumaran on the Vanni east front early last year.
Balakumaran was formerly the leader of the Eelam Revolutionary Organisation of Students (EROS) and joined the LTTE in the early 1990s.
Minister Gunasekera acknowledged that there had not been a detailed study on LTTE widows, though various NGOs and government officials from time to time had given different figures since the conclusion of the war in May last year.
He said that his ministry had called for applications from people of the Northern Province before meeting them in three separate groups in Jaffna (July 10), Kilinochchi (11) and Vavuniya (12). Responding to our query, he said that of the 8,000 who had responded to his ministry's call, about 98 per cent were young women.
Minister Gunasekera said that a considerable number of men and women, too, were held by the military since the conclusion of the war. As they had been members of the LTTE at the time of its collapse on the Vanni front, it would be natural for security forces to investigate their role and also rehabilitate them before their release, Minister Gunasekera said.
He said that he had had an opportunity to discuss the issue of war widows with UN Resident Representative in Colombo Neil Bhune before National Freedom Front (NFF) leader Minister Wimal Weerawansa launched a fast unto death outside the UN compound in Colombo. Minister Gunasekera regretted that their efforts to obtain UN assistance to help war widows could be delayed due to the on-going dispute between Sri Lanka and the UN.
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Last Updated May 24 2020 | 10:31 pm


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Advantage U.S. but China is in it for the long game. Both sides need to claim victory for a deal to succeed. Stocks continued their slide on Friday as rising interest rates continued to spook investors.
For years now, the Fed and markets have been disagreeing with each other. The Fed, through its FOMC meetings eight times a year, has been telegraphing 3-4 rate increases annually. But markets have been pricing in fewer. For quite some time the market has been right. The Fed went a full year between its first rate increase this cycle and the second. As recently as mid-2018, many questioned whether we would get more than two this year. Now it is increasing likely that we will get four, the last one in December. Moreover, the Fed for quite some time has been stating its expectations of at least three increases next year. Finally, markets are agreeing. This catch up, punctuated last week after the most recent FOMC meeting, has led to a sharp short term rise in rates. The 10-year Treasury yield has risen by about 40 basis points while the 2-year has risen by about 30. As a result, despite the sharp rise in rates, the yield curve has steepened a bit with the spread rising from just under 25 basis points before the last rate increase to about 35 basis points today. Prior to the FOMC meeting, there were many shouting that the yield curve would invert imminently if the Fed raised rates in September and preannounced several more rate increases in the meetings to come. The Fed did exactly that but the yield curve actually steepened. The message is that current economic strength offers no sign of a pending recession. However, one does have to raise the possibility that too much economic strength and the absorption of excess labor and productive capacity could ignite sharper inflationary pressures than presently expected. While no one, including us, expects an inflation spike in any realistic sense of the phrase, just a modest increase in expectations could allow interest rates to rise 25-50 basis points over a relatively short period of time.
In addition, the gradual withdrawal of quantitative easing reduces downward pressure on bond yields. As a result, yields could rise faster than one would expect simply from a modest increase in inflationary pressures. That, in turn, could have a real economic impact. In Germany, for instance, industrial production is now down for three consecutive months. Pressure on industrial production isn't just a function of ECB monetary policy. It also reflects trade uncertainty given the tariffs and tariff threats now hanging over the entire economic world.
If there is any category of factors that serves to dominate economic direction more than any other, it is demographics. Europe has mixed demographic trends, slightly positive in Germany and the more economically efficient northern European countries, poor in the larger southern European nations, and downright awful selectively in some of the weaker nations like Greece. China and Japan have terrible demographics. Japan has been experiencing negative population growth for many years and its population is aging as well. China, while better than Japan, is seeing worsening demographics accelerated by its one-child policy that existed for decades. That policy has also created a sexual imbalance with many more males than females. China has been lauded at times over the years for the efficiency and success of its state-run economic policies. For many years, it appeared China's evolution toward open markets and improved governance would accelerate its move toward world economic leadership. But under President Xi, the country has taken several steps backwards, especially related to the forced turnover of intellectual property to Chinese joint venture partners. President Trump has forcefully moved to reverse that trend. That has pushed China into an unwanted corner. While it knows that over time, it will have to move toward open markets and respect intellectual property fully, it wants to do so at its own pace. Part of its 5-year plan is to become a dominant factor in many key technology and medical fields. Said a bit differently, it has a goal of developing an intellectual property portfolio equal to or greater than any other nation. If it were there today, there would be little or no need to steel IP from others or to take other illegal shortcuts. But it isn't and, therefore, it will be loathed to agree to any treaty that slows its path to world leadership. On the other hand, if President Trump can get most, if not all, of the developed world behind it, the American side has most of the cards. China is much more dependent on exports than we are and it wants foreign investment to help develop its own strengths. Without the support of world markets, China isn't going to be able to grow anywhere near 6% with population growth below 1% and falling.
The question for China, therefore, is how does it extract itself from the vice the U.S. and others are tightening with tariffs. Obviously, in the short run, reduced trade with China and the need to reconfigure supply chains will be disruptive. Who blinks first? Obviously, after mid-term elections, there is little reason for us to blink any time real soon. Our stock and bond markets might get a bit more volatile but it has been Chinese markets that have been taking it on the chin so far this year. We know from just a few months of history, that President Trump's bark can be more fierce than his bite. Ultimately, he wants to be viewed as the President that forced Chinese compliance and set a path for American dominance, at least through the end of his Presidency. His end goal isn't tariffs for tariffs sake. He speaks of using tariffs to reduce our trade deficit but, so far, strong economic growth is raising deficits. The tariffs so far, including those that might be added in January, could reduce GDP by about a percentage point. We can all live with that assuming the rest of the underlying economy remains strong. China would have a tougher time.
With that said, Chinese trade issues go far beyond simply the forced transfer of IP to Chinese joint venture partners. Any serious agreement will take many months, possibly years. One should expect a protracted trade battle between the two countries. Some even suggest a new cold war, played out mostly (but not all) on the economic stage that could last for many years, possibly even decades as China fights for world economic dominance. One might also argue that our move away from the rest of the world toward a more protectionist, isolation society works in China's favor. Every time we lead, China is quick to try and fill the vacuum.
What this all means for markets is a mixed picture. On the one hand, our economy is very healthy and continues to grow at a nice pace. Confidence is high both among consumers and industry. But rising rates and a protracted trade battle with China are headwinds. Obviously, the forces of these counter pressures will determine the direction of markets over the next 12 months. My guess is that the end result will be a mild positive but I wouldn't be surprised, should rates rise further than currently expected, of a slight negative. The speed of the move upward in interest rates also reminds us of the illiquidity of markets at inflection points. Markets are all interrelated so a sharp move in bond prices carries over to other asset classes. Today, is the official celebration of Columbus Day. Banks and the bond markets are closed in the U.S. suggesting a more muted session. Chinese markets were closed last week for a holiday and reopened this morning with the Shanghai stock market down more than 3%.
Earnings season starts for real on Friday as several big banks report. Once again, remember it's all about results versus expectations. Expectations are high. As we have seen from some early reporting companies, simply matching expectations isn't enough as the good news is already priced in. Without raised guidance, there is little need for buyers to step in. I have found that often in earnings season, it is a good idea to have some cash available to buy stocks of companies that miss by a penny or two following by a significant correction on the order of 5-10%. Assuming the misses are easily explainable and one-off in nature, they can represent great buying opportunities.
Today, Matt Damon is 48. Chevy Chases turns 75. Reverend Jesse Jackson turns 77.
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text:
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A major update focused on content editing within the Customizer.
Customize Posts v0.5 Released
Customize Posts v0.5 Released
We're pleased to announce the v0.5 release of the Customize Posts plugin! Check out my rough release demo video: Key features in this release:
Postmeta support
A framework for registering postmeta types, adding controls, and previewing changes.
Page template
Changes to the page template can now be previewed, both in the Customizer and from the edit page admin screen. The Customizer now opens when clicking "Preview Changes" to preview the page. Further edits can be made from the page template control in this Customizer page preview, and the changes get synced back to the page template dropdown in the page attributes metabox on the edit page screen.
Featured image
Similarly to the page template, changes to the featured image can now be previewed where normally this is not possible in WordPress. The featured image selection on edit post screen has been improved to not update featured image in place, instead waiting until the post is saved before updating the featured image postmeta. The featured image can be set from the post edit screen and then previewed in the Customizer via the post Preview Changes button: the featured image can be further changed in the Customizer post preview, with
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Running PHPUnit Tests Outside VVV
Ideas for improving workflow and encouraging more PHPUnit test writing.
Running PHPUnit Tests Outside VVV
We use Varying Vagrant Vagrants (VVV) as the development environment for as many projects as we can. It provides a great foundation not only for developing client projects but also for core development itself. One great thing about VVV is that it installs all of the tools needed to run the core unit tests right out of the box. Our wp-dev-lib project has a PHPUnit plugin bootstrap that makes use of the core unit tests as installed by VVV, and we have a pre-commit hook which can run the plugin PHPUnit tests inside the VM even when making a commit from outside (on the host machine). This ability to run PHPUnit tests inside the VM makes it easy for getting developers quickly set up to run PHPUnit tests, and it's also something that is suggested for core's PHPUnit Grunt task (#36190).
Tests running outside of the VM are a fast and happy place.
— Jeremy Felt (@jeremyfelt) March 10, 2016
Even though VVV lets you run core's PHPUnit tests right out of the box, the tests can run more slowly in the box. If you have a pre-commit hook that runs unit tests with each commit, your workflow can be really slowed down (especially since the tests should eventually by run by Travis CI after
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- 23 votes | Comment this
Contributing to WordPress Core as a non-developer
Joshua Wold shares his thoughts / experience and lessons learned on contributing to WordPress as a non-developer.
Contributing to WordPress Core as a non-developer
What is Core contributing? Contributing to WordPress core as a non-developer can feel a little confusing. After 10 years of benefitting from the efforts of WordPress Core contributors, I was finally able to find a path toward giving back and making a meaningful impact.
WordPress is an Open Source project. It's maintained by folks around the world who care about its future and believe in a product that can be used and tweaked to meet the needs of countless individuals and organizations.
The beautiful thing about WordPress is we can help make it better. We've previously written about ways you can contribute to WordPress.
Barriers to contributing
In the past I tried to find ways to contribute. I even created an account for Trac, a place where much of the discussion and management of the WordPress project occurs, and wrote my first ticket.
But I felt blocked from going further by:
Time – It didn't make sense to try and figure out how to contribute to WordPress, since I didn't have a great starting point. There was no obvious path for digging in.
Experience – While I have experience as a designer, I wasn't sure how this could translate to working
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- 15 votes | Comment this
Running PHPUnit tests with VVV and PhpStorm
A guide to setting up the PHP interpreter and configuring PHPUnit settings.
Running PHPUnit tests with VVV and PhpStorm
PhpStorm has excellent out of the box support for running unit tests using the PHPUnit testing framework. It also provides you with great code coverage statistics of your unit tests. The challenge however is getting it setup properly and actually running your WordPress unit tests. On my local development environment, I specifically use VVV and ideally I wanted PhpStorm to run the tests from within the VVV virtual machine. Since PHP and PHPUnit are bundled with VVV, it makes sense to have PhpStorm utilise those libraries inside the virtual machine than for me to have to install the libraries independently on my Mac. I love having clear separation between my computer and development environments.
There is a downside to running your tests from inside a VVV virtual machine and that is that it can be a bit slower. This is because there is extra overhead involved with the communication over a SSH connection between your host machine and the guest/virtual machine. The virtual machine also does not have the same computing power as your host machine. The good news is that I've found that even though there is a slight reduction in speed, it's fast enough that it's not of concern to me.
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- 18 votes | Comment this
An interview with the Release Leads of WordPress 4.9
Interesting read, from the lead devs of WordPress! Mad props for all the work you guys do. Keep setting the bar high for WordPress.
An interview with the Release Leads of WordPress 4.9
WordPress 4.9 hit the shelves last week meaning 29% of the web woke to a nicely wrapped package of code filled with improvements to the way they work with the Customizer, safer and clearer ways to work with code in the admin, and new and upgraded widgets. To peek behind the curtain (which is nicely transparent in our world of open source), we've asked Weston, Mel, and Jeff, Co and Deputy Leads on the 4.9 release, some questions about their experiences on the project and their thoughts for where WordPress is heading in 2018.
Q: So how does one find themselves leading a release that impacts 29% of the web?
Mel: With a great sense of responsibility and a bit of trepidation. The customization focus has been somewhat "on hold" while work on Gutenberg progresses, but there's plenty of updates we can make while we wait. It made the most sense for Weston and I to co-lead 4.9, so we could concentrate on making some site customization improvements and lay some groundwork for Gutenberg in the future.
Weston: This year is somewhat different than previous years in how the WordPress project has been managed. This is the first year we've had dedicated focuses (Editor,
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- 11 votes | Comment this
Musings on Customizer as Future Admin Interface
Weston Ruter offers his thoughts on the Customizer as a future frontend-focused admin interface.
Musings on Customizer as Future Admin Interface
There has been a lot of (well-deserved) excitement over Automattic's Calypso project which largely re-implements the WP admin on WordPress.com as a JavaScript-driven REST API-powered single page application. (Reminder: WordPress.com is a service of Automattic that is built on the WordPress project, which I'll call "WordPress.org" to differentiate here.) It is great to see what is possible when JavaScript leveraged in this way with the REST API. The improvements to speed and overall user experience are much improved in the new WordPress.com admin interface. Calypso does not yet have a plugin architecture for extensions, but even when it does, it will be completely incompatible with all existing WordPress plugins that integrate with the WP admin. This works for WordPress.com because it doesn't support arbitrary plugins and so they have a fixed feature set that they have to account for. This is not the case for WordPress.org, so unfortunately there is no easy path toward adopting Calypso as the next-generation admin interface for WordPress.org.
How can we bring WordPress.org forward to feature a next-generation JavaScript-driven REST API-powered single page application (SPA) admin interface
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- 17 votes | Comment this
Previewing content changes across multiple site templates
Weston gives an overview of what's possible now with Customizer and explores the intersection with Gutenberg.
Previewing content changes across multiple site templates
A couple days ago Helen Hou-Sandí live tweeted her first time trying out Gutenberg, the feature plugin for the next generation WordPress editor. One of her tweets stood out to me and started a thread: 36) I still wish there was a good way to preview featured images in different contexts. What will this look like in an archive vs. single?
So how can I understand how a featured image is going to look in all those contexts? How multiple changes look all together?
— Helen 侯-Sandí (@helenhousandi) August 2, 2017
tl;dr You can use the Customize Posts plugin to add and edit posts in the Customizer and preview your changes—to the title, excerpt, featured image, etc—on any area of your site where the post may appear. Here is a demo video that shows the plugin in action along with the Customize Snapshots and Customizer Browser History plugins in a child theme of Twenty Seventeen:
Framework for Previewing
The problem of post previewing is something I'm really interested in. Post previews in core don't work for postmeta (like the featured image and page template) and you can't preview changes on anything other than the singular template. Actually,
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- 9 votes | Comment this
Integrating AMP into WordPress: A Comprehensive Guide
A comprehensive write-up on the what, why, and how of Google's AMP.
Integrating AMP into WordPress: A Comprehensive Guide
AMP is an emerging technology that's gaining the attention of online marketers in all fields. It formats content in a way that loads blazingly fast for mobile visitors, whose page load time expectations can be as little as three seconds. Abraham Lincoln has no patience for bad UX.
I recently worked with a client who wanted to improve their page load times by integrating the AMP project into their existing WordPress site. This was a great opportunity for me to expand my toolset, as well as learn something that I can now share with you.
Below you'll find (perhaps too much) information to get you rolling with AMP, as well as many code samples to help you include AMP in your WordPress projects.
What is AMP?
AMP stands for "Accelerated Mobile Pages." It is an Open Source project backed by Google that makes web pages load really, really fast. These pages are cached and served by Google itself, receive it's "Mobile-friendly" label in search results, and can even increase Search PageRank for these pages.
After all of the advances that have been made over the last 25 years to give users a rich web experience, AMP takes a huge step backward toward
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- 10 votes | Comment this
Bridging the Customizer and the WP REST API
An introduction, overview, and preview of the Customize REST Resources plugin.
Bridging the Customizer and the WP REST API
There's a lot of excitement in the WordPress community about the REST API. We'll be sending a couple representatives to the Day of REST conference coming up at the end of January, and I've been long-overdue to do a deep-dive in to the REST API: preparing for the conference is a great excuse. With a couple weeks off over the holidays, I took the opportunity to build something with the REST API. Naturally with the parallel excitement (and mandate) for JavaScript, I wanted to build something for WordPress's single page application: the Customizer. Inspired in part by Daniel Bachhuber's A more RESTful WP-CLI project, I set out to make a more RESTful Customizer and came up with the Customize REST Resources plugin. A more RESTful WP-CLI seeks "unlock the potential of the WP REST API at the command line" in that "all WP REST API endpoints registered via plugins and themes will automagically be usable as WP-CLI commands". In the same way, Customize REST Resources begins to unlock the potential of the WP REST API in the Customizer by automatically creating settings and controls for all REST resources that are used on a given page. In this way, anything developed for the REST API should automatically
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- 11 votes | Comment this
Streamlining Contributions to WordPress Core via GitHub
XML-RPC is now enabled for all Trac users, per Dev Chat Notes: June 29, 2016.
Streamlining Contributions to WordPress Core via GitHub
In Contributing to WordPress Core via GitHub, I detailed the somewhat-tedious workflow that I've been using for developing and collaborating on patches that get manually uploaded to Trac. Now that the topic of using GitHub for Core contributions is again up for discussion at the WordPress Community Summit, I wanted to jot down some ideas for how to automate the workflow I've been using; I'll be looking specifically at what a streamlined workflow for contributions looks like via a GitHub fork of the WordPress repo managed by a component maintainer, such as our XWP clone. (For how to set up a GitHub clone of develop.git.wordpress.org, see my previous post.) Caveat: This is intended for users in trusted contributor teams as it requires the user to open an internal (intra-repo) pull request from feature branch to master. It will not work when opening a pull request from a fork due to Travis CI's security restrictions on environment variables. So any pull requests from external contributors will need to be manually applied to a feature branch by a repo contributor and then open an intra-repo pull request (while closing the original inter-repo pull request).
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- 7 votes | Comment this
How you can contribute to WordPress (yes,
Jeff Paul, a deputy release lead for WordPress 4.7, offers a bunch of ideas for ways you can begin contributing to WordPress.
How you can contribute to WordPress (yes,
Me: Do you regularly use WordPress? You: Yes, I love it, it's fantastic!
Me: Have you ever thought about helping contribute to WordPress?
You: No, I am not a developer.
Me: Well, good news, you do not have to be!
You: Ok, tell me more…
Whether you have considered it or not, I am so certain that you CAN contribute to WordPress that I will personally offer to help you find a way to do so. I will outline some options below, but feel free to reach out to me directly and I promise to help!
But first, a little background on me…
I graduated from college in 2001 with a degree in Computer Science, but have not spent any significant time coding since then. I have held roles in project management, product management, and team and customer management. The way I tell it, no one would realistically hire me these days to do development. And yet, there has been a fantastic opportunity for me to help contribute to WordPress as a deputy release lead on WordPress 4.7. While this was a significant time commitment for me, there are ways you can contribute with minimal time commitment.
Now let us focus on how you could contribute…
I am going to give you some options to describe
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- 6 votes | Comment this


text: Merries 18 Posted December 18, 2016 Watching a video tutorial is a very helpful resource, however, having a written document with the same steps can often help even more. In most cases when recording you are referring to a document you have written, some people can do a video tutorial off the top of their heads. It does take quite some time to type out a document for a video tutorial so in that case perhaps providing a pdf/doc of the scripts with highlighting and good notes would be very helpful. Thank you! Quote Share this post Link to post