Mission Strategy Research Articles

Solar sail transfer strategy for long-duration multi-objective mission in cislunar space utilizing solar radiation and reflectivity control device

Abstract This study delves into the complexities of optimizing solar sail trajectories for long-duration multi-objective missions in cislunar space, focusing on orbital transfers between halo orbits and distant retrograde orbits. It presents an innovative transfer strategy that integrates solar radiation propulsion and reflectivity control devices to effectively adjust thrust force magnitude and direction, thereby improving maneuver capabilities. The optimization method is founded on the coupled dynamics of a solar sail, aiming to minimize the transfer time of flight using the Hermite-Simpson collocation method while ensuring optimal performance. Through thorough analysis and comparison, the research strives to determine the most efficient trajectory for solar sail orbital transfers in cislunar space.

An Assessment of the Socio - political and Economic impact of the Presbyterian Church of East Africa in the Eastern Region from 1915 to 2022

The Presbyterian Church of East Africa (PCEA) was brought to Kenya by the Church of Scotland Mission (CSM). The idea of the mission was initiated by the company directors of the Imperial British East African Company. The CSM had already settled in Central Kenya and established mission stations in Kikuyu and Tumutumu in 1901 and 1908 respectively. PCEA was established in the Eastern Region in 1915 by the Church of Scotland Mission (CSM). The Eastern Region was the third mission area to be established by the CSM. Their mission strategy was holistic in nature where they combined evangelism, education, medical and industrial work. Although the PCEA has been in Eastern region for more than a century, its impact has not been given much scholarly attention. This study was undertaken to in investigate the impact socio-political and economic of PCEA in the Eastern region since its inception in 1915. The study employed Descriptive survey research design. Questionnaires, oral interviews and document review were used to collect the data. The sample size for this study was 438 which included 9 presbytery moderators, 53 church ministers and 376 church members. From the 376 church members a category of 20 respondents who were identified through snow balling were engaged in oral interviews. The study established that PCEA has greatly impacted in the social, economic and political transformation in the Eastern Region over the last one century.

Detecting life by behavior, the overlooked sensitivity of behavioral assays

Detecting life has driven research and exploration for centuries, but recent attempts to compile and generate a framework that summarizes life features, aimed to develop strategies for life detection missions beyond planet Earth, have disregarded a key life feature: behavior. Yet, some behaviors such as biomineralization or motility have occasionally been proposed as biosignatures to detect life. Here, we capitalize on a specific taxis’ motility behavior, magnetotaxis, to experimentally provide insights in support of behavior as an unambiguous, sensitive biosignature, and magnetic forces as a prescreening option. Using a magnetotactic bacterial species, Magnetospirillum magneticum, we conducted a lab sensitivity experiment comparing PCR with the hanging drop behavioral assay, using a dilution series. The hanging drop behavioral assay visually shows the motility of MTB toward magnetic poles. Our findings reveal that the behavioral assay exhibits higher sensitivity in the detection of M. magneticum when compared to the established PCR protocol. While both methods present similar detection sensitivities at high concentrations, at ≥ 10–7 fold dilutions, the behavioral method proved more sensitive. The behavioral method can detect bacteria even when samples are diluted at 10–9. Comparable results were obtained with environmental samples from the Hula Valley. We propose behavioral cues as valuable biosignatures in the ongoing efforts of life detection in unexplored aquatic habitats on Earth and to stimulate and support discussions about how to detect extant life beyond Earth. Generic and robust behavioral assays can represent a methodological revolution.

Radio Occultation Modeling Experiment (ROMEX): Determining the Impact of Radio Occultation Observations on Numerical Weather Prediction

Abstract The international radio occultation (RO) community is conducting a collaborative effort to explore the impact of a large number of RO observations on numerical weather prediction (NWP). This effort, the Radio Occultation Modeling Experiment (ROMEX), has been endorsed by the International Radio Occultation Working Group, a scientific working group under the auspices of the Coordination Group for Meteorological Satellites (CGMS). ROMEX seeks to inform strategies for future RO missions and acquisitions. ROMEX is planned to consist of at least one 3-month period during which all available RO data are collected, processed, archived, and made available to the global community free of charge for research and testing. Although the primary purpose is to test the impact of varying numbers of RO observations on NWP, the 3 months of RO observations during the first ROMEX period (ROMEX-1, September–November 2022) will be a rich dataset for research on many atmospheric phenomena. The RO data providers have sent their data to EUMETSAT for processing. The total number of RO profiles averages between 30 000 and 40 000 per day for ROMEX-1. The processed data (phase, bending angle, refractivity, temperature, and water vapor) will be distributed to ROMEX participants by the Radio Occultation Meteorology Satellite Application Facility (ROM SAF). The data will also be processed independently by the UCAR COSMIC Data Analysis and Archive Center (CDAAC) and available via ROM SAF. The data are freely available to all participants who agree to the conditions that the providers be acknowledged, and the data are not used for commercial or operational purposes.

Pentecost Mission, Eschatology, and the Embodiment of the Full Gospel in a Wounded World

Abstract Pentecostal mission activity was initially motivated by a commitment to the premillennial return of Christ. This eschatological basis for mission was driven by a number of factors, not least being interpretations of Matthew 24:14, in which the gospel needed to reach every nation before the end would come. But a focus on the next world also led Pentecostal mission strategy away from this world concerns, and Pentecostals have long been criticized for a history of mission that involved proclamation of a future hope without any form of present-day relief. In an increasingly wounded world, such an approach becomes less and less palatable, which is why there has now been a significant shift towards social justice and welfare aspects of mission within Pentecostal efforts. However, it has been argued that the relegation of eschatological motivation to the periphery of mission has detrimental consequences for Pentecostal mission as a whole and therefore needs to be rethought (Ma and Ma 2010:280). This article endeavors to contribute to this discussion by drawing together theological and missiological reflections on the Pentecostal full gospel to reflect on whether such relegation is inevitable, or whether an amended eschatological vision is still helpful for mission efforts in a wounded world.

Research on Inter-Satellite Laser Ranging Scale Factor Estimation Methods for Next-Generation Gravity Satellites

The scale factor serves as a ruler for converting raw phase measurements into physical displacements and significantly impacts the preprocessing of data from the Laser Ranging Interferometer (LRI) in laser ranging systems. In the current GRACE Follow-On (GRACE-FO) mission for low–low tracking gravity satellites, most of the existing LRI scale factor estimation algorithms heavily rely on cross-calibration between instantaneous/biased ranges from the Ka-Band Ranging Interferometer (KBR) and the LRI. However, due to the nonlinearity of the objective function (which includes terms involving the product of scale and time shifts), the scale factor estimation may absorb errors from timing noise. Moreover, future gravity missions or gravity detection tasks may no longer incorporate KBR ranging instruments. To address these challenges, this paper proposes an energy-based method for scale factor estimation using inter-satellite baseline solutions. Comparative analysis indicates that the proposed method effectively disentangles two parameters in the objective function and can be applied in scenarios where KBR data are unavailable, demonstrating promising prospects for practical application. The experimental results show that when the KBR validation residuals are lower than 0.8 mm, the SYSU LRI1B V01 products exhibit residuals below the payload design accuracy thresholds in the frequency band of 2 mHz to 0.1 Hz. Additionally, the stability of the scale factors obtained from the baseline can reach 10−7. Although this is still below the required precision of better than 10−8 for the laser frequency stability in next-generation gravity satellites, advancements in orbit determination technology and the enhanced stability of GPS receivers offer potential for future precision improvements. Currently, this method appears suitable for roughly extracting the scale factor as a stochastic mean over several months or serving as a backup validation strategy for future missions, but it is not well suited to measure day-to-day variations.

A DIC-UAV based displacement measurement technique for bridge field testing

Load rating of old or deteriorated bridges is performed either analytically or experimentally to determine their safe passing loads. Due to high costs of field operations and testing, analytical load rating is currently the preferred method of practice. To promote experimental load rating through bridge field testing, a novel displacement measurement technique as an alternative to conventional sensor-based measurements is proposed in the present study incorporating digital image correlation (DIC), unmanned aerial vehicle (UAV or drone), opensource computer programs, and cost-effective cameras. The development of the proposed DIC-UAV displacement measurement method including mission strategy, camera system trade-off, DIC software, drone, and payload configuration is discussed. Furthermore, the accuracy of the proposed technique is evaluated by performing more than 70 tests on a scaled truss bridge in a laboratory. The proposed DIC-UAV based displacement measurement strategy and computational tools were found feasible with submillimeter accuracies, significantly advancing the state-of-the-art methodologies.

Imaging-based measurement of lunar dust velocity and particle size.

This paper introduces an optical-mechanical system designed for the dynamic detection and analysis of lunar dust, typically characterized as particles under 20micrometers on the lunar surface. The system's design is both compact and lightweight, aligning with the payload constraints of lunar exploration missions. It is capable of real-time tracking and recording the motion of lunar dust at various altitudes, a crucial capability for understanding the environmental dynamics of the lunar surface. By capturing images and applying sophisticated algorithms, the system accurately measures the velocity and size of dust particles. This approach significantly advances the quantitative analysis of lunar dust, especially during agitation events, filling a critical gap in our current understanding of lunar surface phenomena. The insights gained from this study are not only pivotal for developing theoretical models of lunar surface air flow disturbances and dust movement but also instrumental in designing effective dust mitigation and hazard avoidance strategies for future lunar missions, thereby enhancing both scientific knowledge and the engineering applications in lunar exploration.

A novel calculation method for low-thrust transfer trajectories in the Earth-Moon restricted three-body problem

This paper introduces a novel trajectory calculation method for achieving continuous low-thrust transfers from the geostationary orbit to libration point orbits within the Earth-Moon restricted three-body framework. Low-thrust engines can offer benefits such as high specific impulse and long operating lifetimes, making them suitable for deep space exploration. However, the primary challenge lies in the low thrust level, leading to prolonged flight duration for spacecraft to overcome Earth's gravitational pull. Furthermore, the transfer trajectories exhibit multiple revolutions around the Earth, adding complexity to the calculations. To solve these difficulties, a novel trajectory computation method is presented, which for the first time discusses dynamical evolution beyond a predefined time interval in the context of an optimal control problem specific to low-thrust engines. This method employs a backward integration technique applied to the known optimized solution, coupled with a deliberate extension of the flight time to generate an initial guess for subsequent trajectory optimization, significantly simplifying the computational procedure. Several application scenarios involving transfer from the geostationary orbit to libration point orbits are demonstrated. The results confirm the effectiveness of this method, providing a rapid computational strategy for similar low-thrust transfer missions.

Research on optimization method for flyby observation mission adapted to satellite on-board computation

In this paper, the optimization problem of orbital transfer strategy for orbital flyby observation missions is studied. A hybrid optimization method is proposed, which is improved to make it more suitable for satellite on-board computing. This new algorithm is designed to solve the initial value sensitivity problem of the sequential quadratic programming algorithm (SQP). It is consisted of the depth-first search algorithm (DFS) and the SQP algorithm and thus has the characteristics of fast convergence, high reliability, and good robustness. With this method, the DFS with a large step size is calculated first, and then the optimal value in the calculation result is used as the initial value of the SQP algorithm for further optimization. This method can obtain the approximate optimal solution available in engineering. The numerical simulation of an orbital transfer optimization problem is set to verify the effectiveness of the new hybrid algorithm. The simulation results compared with the genetic algorithm (GA) show that the proposed hybrid algorithm can effectively reduce the on-board resource occupation when getting similar results and thus can meet the needs of satellite on-board computing.

How the adaptation of the human microbiome to harsh space environment can determine the chances of success for a space mission to Mars and beyond.

The ability of human cells to adapt to space radiation is essential for the well-being of astronauts during long-distance space expeditions, such as voyages to Mars or other deep space destinations. However, the adaptation of the microbiomes should not be overlooked. Microorganisms inside an astronaut's body, or inside the space station or other spacecraft, will also be exposed to radiation, which may induce resistance to antibiotics, UV, heat, desiccation, and other life-threatening factors. Therefore, it is essential to consider the potential effects of radiation not only on humans but also on their microbiomes to develop effective risk reduction strategies for space missions. Studying the human microbiome in space missions can have several potential benefits, including but not limited to a better understanding of the major effects space travel has on human health, developing new technologies for monitoring health and developing new radiation therapies and treatments. While radioadaptive response in astronauts' cells can lead to resistance against high levels of space radiation, radioadaptive response in their microbiome can lead to resistance against UV, heat, desiccation, antibiotics, and radiation. As astronauts and their microbiomes compete to adapt to the space environment. The microorganisms may emerge as the winners, leading to life-threatening situations due to lethal infections. Therefore, understanding the magnitude of the adaptation of microorganisms before launching a space mission is crucial to be able to develop effective strategies to mitigate the risks associated with radiation exposure. Ensuring the safety and well-being of astronauts during long-duration space missions and minimizing the risks linked with radiation exposure can be achieved by adopting this approach.

Control System for Quadcopter UAV based SMC-RBFNN with External Disturbance

Unmanned aerial vehicles (UAVs) can either be flown autonomously or remotely by a pilot. Due to its many benefits, including the capacity to take off and land vertically and the ability to take off and land in a small space, this form of UAV quadcopter is currently the subject of extensive research. An autonomous UAV is being developed to reduce the likelihood of pilot operating errors when managing the UAV. The quadcopter dynamic system in this study was controlled primarily by a radial basis function neural network (RBFNN), and its performance was evaluated using simulation on a test track with outside disturbances. One test track is used for the simulation, and there are no outside disturbances. Input of external noise occurs concurrently for x, y, and z coordinates. The average of error for the control system SMC and SMC-RBFNN without disturbance is 0 according to the simulation results. Additionally, the SMC control system’s of error with external disturbances is 0.74, whereas it is 0.54 for the SMC-RBFNN control system. This is demonstrated by the system’s ability to return to the test track at the present within 9 seconds while employing the SMC-RBFNN controller. In contrast, the system can reach the test track in 18 seconds while using the SMC. The SMC- RBFNN is one of the suitable control strategies for flight missions with external disturbances, it may be inferred.

Multi-set based model predictive control to explore large freshwater resources

Unmanned surface vehicles can become cutting-edge aquatic laboratories for real-time water quality assessment, evaluating the physical, chemical, and biological profiles of water to detect degradation in freshwater resources. The development of control strategies for surface scanning missions is essential for efficient and effective water resource management. This paper introduces novel exploration methods for analysis experiments. Our approach is founded on an optimizing target-set tracking controller and innovates by adopting a dynamic target-switching method. The target transitions to a further objective once the current target is assured, result in smoother system behavior, as shown by the simulations using the nonlinear model of a commercial surface vehicle tasked with covering a designated area of Heron Lake, located in Villeneuve d’Ascq. The method is implemented in two distinct ways: the first prioritizes passing through all the sets, while the second compromises between passing through and computational cost.

Strategi Pelayanan Misi Kontekstual Terhadap Generasi Z Yang Percaya Dengan Memanfaatkan Teknologi Informasi Dan Komunikasi

Generation Z's tendency to leave the church could occur when the church does not answer the needs and accommodate the generation’s perpectuve . Therefore, mission services to generation Z need to be carried out contextually, requiring services that suit their needs. Contextual mission services must develop the right "strategy" to reach generation Z. The method used is literature study observing books and scientific journals to support research writing. The main topic discussed is contextual mission strategy, where it is necessary to understand culture, Generation Z problems and services for Generation Z in utilizing ICT. Thus, three things were found in this research, firstly, sharing spiritual content via social media, because generation Z can spend quite a long time playing social media. Secondly, carry out spiritual activities online that attract attention creatively and innovatively. Finally, involve generation Z in service, so interest and appreciation might occur in the activities.

“А Supervisory Type of Thing”: the Establishment and Impact of the Latter-Day Saint Mission in Postcolonial Southeastern Nigeria

This article analyzes the challenges that confronted the Church of Jesus Christ of Latter-day Saints (LDS Church) in establishing its official mission in southeastern Nigeria following the 1978 Priesthood Revelation, and the impact of its mission strategy on the religious and daily life of Nigerian adherents. The emergence of unofficial LDS congregations in Nigeria between the late 1940s and 1970s required the LDS Church to abandon its traditional mission focus on proselytization, and instead develop a strategy of supervision–a strategy geared towards appointing and training local church leaders, teaching adherents to be proper Latter-day Saints, and integrating congregations in the administrative hierarchy. Using documentary records and oral histories archived at the LDS Church History Library and L. Tom Perry Special Collections, this article highlights the reciprocal impact of cross-cultural encounters and the shortcomings of the LDS Church’s missionary training programs.

Earth-Venus Mission Analysis via Weak Capture and Nonlinear Orbit Control

Exploration of Venus is recently driven by the interest of the scientific community in understanding the evolution of Earth-size planets, and is leading the implementation of missions that can benefit from new design techniques and technology. In this work, we investigate the possibility to implement a microsatellite exploration mission to Venus, taking advantage of (i) weak capture, and (ii) nonlinear orbit control. This research considers the case of a microsatellite, equipped with a high-thrust and a low-thrust propulsion system, and placed in a highly elliptical Earth orbit, not specifically designed for the Earth-Venus mission of interest. In particular, to minimize the propellant mass, phase (i) of the mission was designed to inject the microsatellite into a low-energy capture around Venus, at the end of the interplanetary arc. The low-energy capture is designed in the dynamical framework of the circular restricted 3-body problem associated with the Sun-Venus system. Modeling the problem with the use of the Hamiltonian formalism, capture trajectories can be characterized based on their state while transiting in the equilibrium region about the collinear libration point L1. Low-energy capture orbits are identified that require the minimum velocity change to be established. These results are obtained using the General Mission Analysis Tool, which implements planetary ephemeris. After completing the ballistic capture, phase (ii) of the mission starts, and it is aimed at driving the microsatellite toward the operational orbit about Venus. The transfer maneuver is based on the use of low-thrust propulsion and nonlinear orbit control. Convergence toward the desired operational orbit is investigated and is proven analytically using the Lyapunov stability theory, in conjunction with the LaSalle invariance principle, under certain conditions related to the orbit perturbing accelerations and the low-thrust magnitude. The numerical results prove that the mission profile at hand, combining low-energy capture and low-thrust nonlinear orbit control, represents a viable and effective strategy for microsatellite missions to Venus.

Transformation of elementary Puang Matua in Toraja belief system into Christianity

This study aimed to examine missionaries’ success in transforming the elementary Puang Matua from the Toraja religion of Aluk Todolo into a Christian-based one. Puang Matua is the name of the Toraja people’s god that created the earth and everything. The concept was transformed into Christianity through contextualisation efforts to become a God of the Universe (YHWH). Descriptive analysis showed that the reconstruction was supported by the theological similarities between Puang Matua’s concept and the conception of God the Creator. The theological similarity is an absolute requirement for successful contextualisation to introduce Christianity into indigenous peoples strongly controlled by culture.Intradisciplinary and/or interdisciplinary implications: This research could be a model for formulating a cross-cultural mission strategy that unites missiology with biblical and cultural anthropology.

ESA's current approaches to end-of-life strategies for HEO missions

ESA's Space Debris Office (SDO) provides support and recommendations for the on-ground risk assessment at the satellite's end of life (EOL) to internal ESA missions as well as external partners. The support covers missions in Low Earth Orbit (LEO) and highly eccentric orbits (HEO), but also special cases such as a re-entry of interplanetary missions. While for LEO and Geostationary orbits (GEO), guidelines for disposal in terms of natural decays and graveyard orbit are available, HEO orbits require tailored strategies to guarantee limited interference with the protected regions and a safe re-entry. The present works aims to provide an overview and reflection on the current approaches for the end-of-life strategies for mission in HEO orbits, accounting for the main uncertainties.

STUDY OF PRAGMATIC DEVELOPMENT AND KNOWLEDGE DOMAIN THROUGH WEB SERIES AMONG YOUTH

Web series is an innovative revolution of digital world and become a new trend setter in entertainment industry. It‘s displayed over digital platforms and provides opportunity to deliver the structure of new text as well as multi-dimension of media and technology that construct modern network. On comprehensive learning perspective, web series programs are responsible for developing new breed and transferring knowledge, new aesthetic and semiotic that producing pragmatic values towards the viewers. Likewise, pattern of accessing and watching of web series is responsible for knowledge dissemination and pragmatic development. This study highlights the attributes that reflects knowledge domain towards viewers through watching perspective web series. Study is consolidated with primary data sources and executed in Bhopal and Indore, cities planning under Smart Cities Mission Strategy.

Global dose distributions of neutrons and gamma-rays on the Moon

Dose assessment on the lunar surface is important for future long-term crewed activity. In addition to the major radiation of energetic charged particles from galactic cosmic rays (GCRs), neutrons and gamma-rays are generated by nuclear interactions of space radiation with the Moon’s surface materials, as well as natural radioactive nuclides. We obtained neutron and gamma-ray ambient dose distributions on the Moon using Geant4 Monte Carlo simulations combined with the Kaguya gamma-ray spectrometer measurement dataset from February 10 to May 28, 2009. The neutron and gamma-ray dose rates varied in the ranges of 58.7–71.5 mSv/year and 3.33–3.76 mSv/year, respectively, depending on the lunar geological features. The lunar neutron dose was high in the basalt-rich mare, where the iron- and titanium-rich regions are present, due to their large average atomic mass. As expected, the lunar gamma-ray dose map was similar to the distribution of natural radioactive elements (238U, 232Th, and 40K), although the GCR-induced secondary gamma-ray dose was significant at ~ 3.4 mSv/year. The lunar secondary dose contribution resulted in an additional dose of 12–15% to the primary GCR particles. Global dose distributions on the lunar surface will help identify better locations for long-term stays and suggest radiation protection strategies for future crewed missions.