Space Research Research Articles

High-resolution mascon solutions reveal glacier-scale mass changes over the Greenland Ice Sheet from 2002 to 2022

SUMMARY As the main contributor to global sea-level rise, the Greenland Ice Sheet (GrIS) has undergone significant mass change over the last two decades. The satellite mission of GRACE (Gravity Recovery And Climate Experiment) and its follow-on mission (GRACE-FO) provide accurate observations but low-spatial resolution. In contrast, satellite altimetry provides observations at a high-spatial resolution but with large uncertainties, limiting the understanding of glacier-scale mass change. To derive accurate and high-spatial resolution mass change estimates from GRACE/GRACE-FO observations, we present a novel constraint mascon method in which the regularization matrix is constructed with the signal variances from satellite altimetry. Based on the proposed method, we derive a series of high-resolution (25 km × 25 km) monthly mascon solutions from 2002 April to September. The glacier-scale estimates from the input–output method agree better with those from our mascon solutions than those from the global mascons of CSR (Center for Space Research, the University of Texas), JPL (Jet Propulsion Laboratory), and GSFC (Goddard Space Flight Center), with a higher linear regression coefficient of 0.71. Benefitting from the greatly improved spatial resolution, our estimates provide the first accurate monthly glacier-scale mass change estimates from GRACE/GRACE-FO observations over the GrIS, to our knowledge. The results show that 20 of the 260 glaciers contributed to more than 42 per cent of the ice loss in the GrIS from 2002 to 2022. Most strikingly, the mass loss of Jakobshavn Isbrae was the most significant at –18.7 ± 0.05 Gt yr−1, accounting for 7.4 per cent of the total in the GrIS during the study period. Furthermore, we find that the SMB (surface mass balance) and ice-dynamics-related mass changes contribute nearly equally to the observed mass changes, but the corresponding spatiotemporal characteristics differ. SMB contributed the most to the mass change in 2019, while ice dynamics played the most dominant role in 2018. Moreover, the SMB effect is widespread, and ice-dynamics-related mass loss is mainly concentrated in five small areas.

Immunological Aspects of Reactivation of Latent Infections in Space Flight and Antarctica

The complex of space flight (SF) factors can have a negative impact on the human organism, including the innate and adaptive immunity. One of the negative effects of impaired functional activity of the immune system is a decrease of latent infections immunological control. During short- and long-term SF, reactivation of latent viruses was shown, while the virus was detected in body fluids for some time after returning to Earth. Despite the fact that in most cases reactivation was asymptomatic, there are fears that during long expeditions into deep space, reactivation of latent pathogens can lead to the development of diseases that are dangerous to the crewmembers health. There is a lot of data about the viral pathogens reactivation in SF, but the reactivation of bacterial agents in cosmonauts has received almost no attention. Due to the complexity of conducting research in space, an important role is played by ground-based analog experiments that simulate the space station conditions. One of the most significant analogues of SF is the long-term Antarctic expedition, which makes it possible to obtain unique information about the effect of isolation, increased mental and physiological stress on the latent pathogens reactivation. Currently, latency is increasingly considered as a symbiotic existence of a pathogen and host, during which the human body acquires additional resistance to certain infectious agents. Thus, an important task of the upcoming research is a comprehensive analysis of the personal immunological status in the SF, establishing its relationship with the latent infections reactivation and developing systems for monitoring, preventing and treating the negative consequences of reactivation.

Equity Crowdfunding and Offering Page Disclosure

ABSTRACT This paper provides descriptive evidence about how startup firms communicate with investors on their Regulation Crowdfunding offering page. I find evidence, consistent with prior theory about processing costs and information salience, that a firm’s prior revenues relate strongly to the discussion of financial information on its offering page. This runs counter to indications from Reg CF founders that they think financial information is of less importance to these investors than other information about the company. Consistent with founder beliefs that investors place little weight on firm financials, I find no consistent relation between financial disclosure and a firm meeting its offering goal. Offering success appears more closely related to other elements of disclosure that tell the “story” of the company. The results of this paper can help inform future research in the crowdfunding space, as well as contribute to the literature on how investors process information and disclosure. Data Availability: Publicly available from Regulation Crowdfunding filings on SEC Edgar. JEL Classifications: G23; G24; M13; M41.

A Multi‐Source GRACE Fusion Solution via Uncertainty Quantification of GRACE‐Derived Terrestrial Water Storage (TWS) Change

AbstractIn analyzing terrestrial water storage (TWS) data observed by Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow‐On satellites, quantifying uncertainties proves challenging due to the scarcity of sufficient independent observations of mass changes at scales commensurate with these missions. Moreover, owing to the diverse geophysical background models and processing techniques utilized by data processing centers, reaching consistent mass change estimations within specific regions of published solutions often proves arduous. We, therefore, quantified the uncertainty of the GRACE‐derived TWS changes by using the generalized three‐cornered hat method without relying on any prior knowledge and fused it to generate a higher‐quality solution. The findings reveal that of the six solutions, the Center for Space Research spherical harmonics (SH) solution exhibits the lowest uncertainty and highest signal‐to‐noise ratio (SNR) at both global and basin scales, and the Goddard Space Flight Center Mascon solution outperforms other Mascon counterparts. The fusion solution has an average 36.56% reduction in uncertainty and a 1.92‐fold improvement in SNR at the basin scale, and the improvement in SNR is particularly significant in regions with drastic mass changes. The global distribution patterns of the uncertainties associated with Mascon and SH solutions exhibit distinct differences. Mascon solutions result in significant signal leakage around regions characterized by the most substantial global mass variability. Additionally, transient mass changes triggered by super earthquake events in the ocean also produce similar “scars” in the global spatial distribution of uncertainties. The analysis of 142 basins worldwide shows that basins with more significant TWS annual oscillations have larger uncertainties but also better SNR.

Establishing scientific educational space within the university: factors contributing to successful Eurasian integration

Introduction. The problem of the article is to focus on a range of aspects in the field of integration of science and higher education, which play an important role in the process of establishing the Eurasian scientific and educational space. The purpose of the article is to identify factors contributing to successful Eurasian integration in the process of establishing scientific educational space within the university. Materials and Methods. The theoretical and methodological basis of the study is made up of general scientific (philosophical) methods and a systematic approach. The subject of the study required the use of a combination of different approaches, primarily systemic, which allowed to conduct the correct analysis of applying historically established and modern educational technologies and practices in Eurasian education, as well as to describe some aspects of the effective integration of science and education in the Eurasian space. The object of the study is the experience of the University under the IPA EurAsEC on developing a system of scientific, organizational, research, publishing and educational activities in the Eurasian space. The authors used the following research methods: comparative, historical, interdisciplinary, content analysis method, etc. Results. The article considers the experience of using methods of ethno pedagogy in preparing innovative staff for the Eurasian space as a means of developing scientific and educational cooperation, expanding Eurasian integration, and giving it a humanitarian dimension. The authors substantiate the idea that strengthening and expanding the capabilities and needs of a unified Eurasian scientific and educational space should be considered as conditions for achieving effective cooperation in the field of science and education, allowing to restore professional communication of researchers from different Eurasian countries, update the content of higher education and contribute to bringing new scientific knowledge to the scientific community. The authors emphasize that a significant contribution to the development of the Eurasian integration process is made by the University under the IPA EurAsEC, which initiated a number of international projects contributing to the inclusion of new scientific knowledge and methods in the educational process within the framework of Eurasian economic integration. Conclusions. The article concludes about the values of higher education and about a need for integrating science and education as a basis for further development of Eurasian integration process. The authors draw the conclusion that today integration must be based on the historical experience of cooperation between Eurasian states in the field of science and education. Such interaction is considered to be the basis for further successful integration.

La photométrie des éclipses de Lune, vue par František Link : commentaire historique

In a 1933 article, Link (1906–1984) shows how to calculate the lunar disc irradiance during a total eclipse, by taking in account the refraction and extinction of light in the Earth’s atmosphere, as well as the limb darkening of the Sun. Hence, he deduces some properties of the terrestrial ozone layer. This article illustrates how Hausdorff’s research on the upper atmosphere, based on the study of refraction and photometry, was extended during the first half of the 20th century, before space research emerged.

Surface Degradation of Thin-Layer Al/MgF2 Mirrors under Exposure to Powerful VUV Radiation.

Thin-layer Al/MgF2 coatings are currently used for extraterrestrial far-UV astronomy as the primary and secondary mirrors of telescopes (such as "Spektr-UF"). Successful Hubble far-UV measurements have been performed thanks to MgF2 on Al mirror coatings. Damage of such thin-layer coatings has been previously studied under exposure to high-energy electrons/protons fluxes and in low Earth orbit environments. Meanwhile, there is an interest to test the stability of such mirrors under the impact of extreme radiation fluxes from pulsed plasma thrusters as a simulation of emergency onboard situations and other applications. In the present studies, the high current and compressed plasma jets were generated by a laboratory plasma thruster prototype and operated as effective emitters of high brightness (with an integral overall wavelength radiation flux of >1 MW/cm2) and broadband radiation. The spectrum rearrangement and hard-photon cut-off at energy above Ec were implemented by selection of a background gas in the discharge chamber. The discharges in air (Ec ≈ 6 eV), argon (Ec ≈ 15 eV) and neon (Ec ≈ 21 eV) were studied. X-ray diffraction and reflectometry, electron and atomic force microscopy, and IR and visible spectroscopy were used for coating characterization and estimation of degradation degree. In the case of the discharges in air with photon energies of E < 6 eV, only individual nanocracks were found and property changes were negligible. In the case of inert gases, the energy fraction was ≈50% in the VUV range. As found for inert background gases, an emission of such hard photons with energies higher than the MgF2 band gap energy of ≈10.8 eV caused a drastic light-induced ablation and degradation of the irradiated coatings. The upward trend of degradation with an increasing of the maximum photon energies was detected. The obtained data on the surface destruction are useful for the design of methods for coating stability tests and an understanding of the consequences of emergencies onboard space research stations.

Multi-mission, multi-sensor study of the Shackleton Crater constrained for volatiles with emphasis on albedo distribution of the Lunar South Pole

Shackleton Crater on the Moon is named in honor of a pivotal figure of the Heroic Age of Antarctic Exploration Sir Ernest Henry Shackleton. The Crater was formed about 3.6 billion years ago at the Lunar South Pole. Due to the low (1.5°) tilt of the lunar axis of rotation, the interiors of the crater receive almost no direct sunlight and observations by passive hyperspectral sensors are only possible due to reflected light. Active sensors are however able to illuminate the interior surface of the crater and make observations. Here we present the results of study of the crater using data from multiple sensors onboard two missions of Indian Space Research Organization (ISRO) and National Aeronautics and Space Administration (NASA). Hyperspectral observations from Moon Mineralogy Mapper (M3) on-board Chandrayaan-1, temperature from Diviner Lunar Radiometer Experiment (DLRE), albedo from Lunar Orbiter Laser Altimeter (LOLA) and Off/On band ratios from Lyman-Alpha Mapping Project (LAMP) on board Lunar Reconnaissance Orbiter (LRO) have been used. Permanently Shaded Regions (PSRs) are identified and Shackleton has been found, as reported, to be a PSR. Emphasis has been laid on LOLA albedo analysis of lunar south pole (80°-90° South). It is observed that the Shackleton Crater exhibits significantly higher albedo compared to its surrounding regions. Some regions exhibit albedo even higher than the Shackleton Crater in the lunar south pole region. The findings of high albedo, coupled with high Off/On band ratio of LAMP, extremely low DLRE temperatures in the permanently shaded regions and detection of hydration features in the M3 hyperspectral data suggests higher probability of hydration in the Shackleton Crater.

Critical Issues in the Methods of Data Collection in Geoinformatics and Environmental Sciences

A successful geographic or environmental research is partly dependent on the sources and methods of data collection, data analysis and result presentation. This study examined two broad sources of data collection to include (i) primary: direct field or in-situ measurements, count, observation, administration of questionnaire, use of check list and Focus Group Discussions, and (ii) secondary: documented materials (including published and unpublished statistics/materials) residents in government and Non-Governmental Agencies (such as World Health and Food and Agricultural organizations), and private geoinformation organizations. Other sources of secondary data collection identified include research institutes such as the National Space Research and Development Agency (NASRDA) for the provision of Satellite Images for landuse and environmental studies, and Universities that deals with science and technology issues such as the Departments of Geography, Environmental Sciences, Urban and Regional Planning and Surveying/Geoinformatics. The evaluated major materials/tools/equipment used for data collections. The findings revealed that although primary data seems more reliable because of the close watch and methods of their collection, the cost and time it takes to generate them are very expensive hence, most people tend to rely on secondary sources of data for their use. The secondary sources may be relatively cheap but may be fraught with Spatial Data Quality issues. The study demonstrated that both primary and secondary datasets proved very useful in geographic and environmental change studies. A review of an empirical study of ‘urbanization impact on climate change in West Africa city of Warri, Delta State, Nigeria’ was used to validate this study.

Study of the hydrological impact of the growth of a residential neighborhood on urban drainage – A case study at the city of Macaé, Rio de Janeiro, Brazil

This paper aimed to study the drainage system of a residential neighborhood through a case study. Thus, a sensitivity analysis of drainage was carried out considering the progress of the urbanization process in the Imboassica district, in the municipality of Macaé, Rio de Janeiro. It was possible to evaluate the model’s response to different land use planning, represented with variations in the Manning coefficient and also in the Curve Number. The MOHID platform was used along with the OpenFlows FLOOD® software interface to elaborate scenarios with different soil characteristics, and distinct Digital Elevation Model (DEM) were adopted. In the first evaluation, three simulations (1, 2 and 3) were performed considering the natural topography of the terrain, using altimetry data obtained from the TOPODATA project of the National Institute for Space Research (INPE). Afterwards, the elevation quota represented in the Digital Elevation Model (DEM) was raised by 10 meters in the locations corresponding to the location of the houses and by 1 meter in the roads of the residential condominium, and then the three simulations (4, 5, and 6) were performed. The six simulations adopted the 10 years return period Rain Design. After that, another set of six simulations were performed, adopting the 50 years return period Rain Design. It was possible to observe that in the simulations considering the change in the elevations due to the presence to the houses and the road, the calculated value of the water depth increases in the drainage channels. The effect of the Curve Number changes was observed in the flood peak simulation, which is reduced due to the presence to greater vegetation. And finally, it was possible to observe the effect of the change in the Manning’s Coefficient, whose increase caused a delay in runoff.

INTERNATIONAL RELATIONS IN OUTER SPACE: FROM THE COLD WAR ERA TO FEBRUARY 24, 2022

The article reviews the changing landscape of international relations in the space sphere; examines the history of international cooperation in outer space: from the Cold War era to the beginning of Russia's large-scale invasion of Ukraine; examines key partnerships and initiatives, the advantages of such cooperation and challenges. The author proves that international relations in the field of space exploration and research are dual in nature. On the one hand, countries form international alliances to implement large-scale space projects, on the other hand, states strive to have independent access to space to ensure national security. The author's periodization of the development of international relations in the space sphere is given: 1) the first decade of space exploration – during this period, international cooperation in outer space was completely missing, but it was during these years that the foundations of the international legislative framework were laid; it is still in force today; 2) since the 70s of the twentieth century, the number of states that explore space has been growing and the first international space organization, the European Space Agency (ESA), is being formed; 3) after the end of the Cold War, US cooperation with the former Soviet republics intensified, which further led to US dependence on third countries in the space sphere; 4) in the early 2000s, the number of participants in space activities increased at the expense of private companies, which became possible due to a technological leap, in particular the miniaturization of space technology and the cheapening of electronics; 5) Russia's war against Ukraine has changed the international landscape of space activities, strengthened public-private partnerships and demonstrated the growing role of satellite technologies in national security issues.

Improved Drought Characteristics in the Pearl River Basin Based on Reconstructed GRACE Solution with Enhanced Temporal Resolution

As global warming intensifies, the damage caused by drought cannot be disregarded. Traditional drought monitoring is often carried out with monthly resolution, which fails to monitor the sub-monthly climatic event. The GRACE-based drought severity index (DSI) is a drought index based on terrestrial water storage anomalies (TWSA) observed by the gravity recovery and climate experiment (GRACE) satellite. DSI has the ability to monitor drought effectively, and it is in good consistency with other drought monitoring methods. However, the temporal resolution of DSI is limited by that of GRACE observations, so it is necessary to obtain TWSA with a higher temporal resolution to calculate DSI. We use a statistical method to reconstruct the TWSA, which adopts precipitation and temperature to obtain TWSA on a daily resolution. This statistical method needs to be combined with the time series decomposition method, and then the parameters are simulated by the Markov chain Monte Carlo (MCMC) procedure. In this study, we use this TWSA reconstruction method to obtain high-quality TWSA at daily time resolution. The correlation coefficient between CSR–TWSA and the reconstructed TWSA is 0.97, the Nash–Sutcliffe efficiency is 0.93, and the root mean square error is 16.57. The quality of the reconstructed daily TWSA is evaluated, and the DSI on a daily resolution is calculated to analyze the drought phenomenon in the Pearl River basin (PRB). The results show that the TWSA reconstructed by this method has high consistency with other daily publicly available TWSA products and TWSA provided by the Center for Space Research (CSR), which proves the feasibility of this method. The correlation between DSI based on reconstructed daily TWSA, SPI, and SPEI is greater than 0.65, which is feasible for drought monitoring. From 2003 to 2021, the DSI recorded six drought events in the PRB, and the recorded drought is more consistent with SPI-6 and SPEI-6. There was a drought event from 27 May 2011 to 12 October 2011, and this drought event had the lowest DSI minimum (minimum DSI = −1.76) recorded among the six drought events. The drought monitored by the DSI is in line with government announcements. This study provides a method to analyze drought events at a higher temporal resolution, and this method is also applicable in other areas.

Smart Surveillance: A Review &amp; Survey Through Deep Learning Techniques for Detection &amp; Analysis

Big data applications are consuming most of the space in industry and research area. Among the widespread examples of big data, the role of video streams from CCTV cameras is equally important as other sources like social media data, sensor data, agriculture data, medical data and data evolved from space research. Surveillance videos have a major contribution in unstructured big data. CCTV cameras are implemented in all places where security having much importance. Manual surveillance seems tedious and time consuming. Security can be defending in different terms in different contexts like theft identification, violence detection, chances of explosion etc. In crowded public places the term security covers almost all type of abnormal events. Among them violence detection is difficult to handle since it involves group activity. The anomalous or abnormal activity analysis in a crowd video scene is very difficult due to several real world constraints. The paper includes a deep rooted survey which starts from object recognition, action recognition, crowd analysis and finally violence detection in a crowd environment. Majority of the papers reviewed in this survey are based on deep learning technique. Various deep learning methods are compared in terms of their algorithms and models. The main focus of this survey is application of deep learning techniques in detecting the exact count, involved persons and the happened activity in a large crowd at all climate conditions. Paper discusses the underlying deep learning implementation technology involved in various crowd video analysis methods. Real time processing, an important issue which is yet to be explored more in this field is also considered. Not many methods are there in handling all these issues simultaneously. The issues recognized in existing methods are identified and summarized. Also, future direction is given to reduce the obstacles identified. The survey provides a bibliographic summary of papers from Science-direct, IEEE Xplore and ACM digital library.

DMD Based Multi-Object Spectrograph for INdian Spectroscopic and Imaging Space Telescope: INSIST

INdian Spectroscopic and Imaging Space Telescope (INSIST) is the next-generation UV-Optical space mission proposed by the Indian Astronomical community motivated by the great success of India’s first multi-wavelength Astronomical satellite (ASTROSAT) where Ultra Violet Imaging Telescope (UVIT) was one of the main payload launched in 2015 by Indian Space Research Organisation. INSIST is primarily designed for photometry observation in three bands (g-[400[Formula: see text]nm–550[Formula: see text]nm], u-[300[Formula: see text]nm–400[Formula: see text]nm] and UV-[150[Formula: see text]nm–300[Formula: see text]nm]) simultaneously over 0.25 sq.degree field of view. INSIST is equipped with a low resolution [[Formula: see text]] spectrograph for multi-Object slitless spectroscopy over the imaging field of view and also has a medium resolution [[Formula: see text]] spectrograph for multi-object slit spectroscopy in UV-band over ∼6 sq.arcmin sky. MEMS-based Digital Micromirror Device [DMD] is used to form configurable slits for the selection of objects at the focal plane of the telescope for multi-object slit spectrograph. Multi-Object spectrograph with DMD as a re-configurable slit for INSIST is designed and the performance of the spectrograph is presented.

Monitoring the cerebral venous drainage in space missions: the Drain Brain experiments of the Italian Space Agency

It is well known that the space environment induces major alterations to various human physiological systems, determining a general deconditioning of the body. Medical research programs aim to keep the astronaut’s health status during the mission, enable their ready operation once they arrive at their destination, and allow their safe recovery when returned to Earth. Among the programs coordinated and supported by the Italian Space Agency (ASI), the experiments called Drain Brain, performed by the University of Ferrara, are particularly relevant in this respect. The project, which began with the collaboration of Samantha Cristoforetti in 2014, has demonstrated the capability of a plethysmograph system to study the cerebral circulation and the venous return from the brain to the heart, onboard the International Space Station (ISS). Demonstrating the progressive reduction of the cross-sectional area of the internal jugular vein, particularly significant between pre-flight data collection and the last assessment after 6 months of flight on the ISS (p&lt;0.001). Over the next two years, thanks to the Drain Brain 2.0 project, crews of the International Space Station will be studied with a new version of the plethysmograph, synchronized with the electrocardiogram, to assess cardiac efficiency and brain drainage in relation to symptoms such as blurred vision, numbness, or the feared onset of jugular thrombosis, that is linked to blood flow slowdown due to the absence of the gravitational gradient. Drain Brain 2.0 will also generate important returns to Earth, closing the virtuous circle of terrestrial application of space research.

Chandrayaan-3 Mission: Decoding the Culture and Leadership at ISRO

While organisation culture is crucial for innovation to foster, leadership is the key to promoting a conducive culture. In the present study, I focused on the Indian Space Research Organisation (ISRO), to understand the facets of an innovation-led organisation and the role of leadership. Based on in-depth interviews with a unique set of respondents within the age range of 66–94 years, I pulled out the facets of ISRO culture. I further explored the leadership qualities that enable the formation of such a culture.

Using solicited research diaries to assess the restorative potential of exposure to inland blue space across time

Inland blue spaces, or freshwater environments, have been shown to provide people with positive mental health and wellbeing outcomes. Most inland blue space research focusing on wellbeing outcomes has so far been cross-sectional, utilising questionnaires and interviews. Therefore, there is significant uncertainty regarding the potential for inland waterways to benefit human populations over longer-term time scales. Across a sixteen-month data collection period, this study recruited four distinct sample groups to complete diaries for periods of three-months, focusing on inland blue space experiences in Scotland. The aim of the study was to use solicited diary methods to establish whether restorative exposure outcomes gained from visiting blue spaces may vary across time. Results from the diary data show that visiting freshwater areas consistently led to positive restorative outcomes, with minimal variation in restorative outcomes observed across time. Participants recorded three principal categories of blue space experiences; routine visits, getting fresh air; and day trips, with each visit type providing a range of restorative benefits. The findings highlight the potential for inland blue spaces to act as versatile public health resources and the need to consider long-term strategies to ensure these environments benefit populations across time.

A Quest?!: The Secret Life of Gameworld Punctuation

At times, the interfaces of videogames -- gameworlds -- contain tiny details that go unnoticed. One such detail is how designers employ ! and ? to communicate to players. These punctuation marks have existed in videogames since their creation, yet remain undiscussed by designers. They are used as ways to promote curiosity, as objects, as ways to symbolize excitement, and as a prompt to react. Their varied history is deserving of attention, so we present a chronicle of two pieces of gameworld punctuation: ! and ?. We discuss current and past uses and identify more ways that these could be used in the future. These symbols may present a useful space of inquiry not only for games and games research, but more generally, in terms of the rapid communication of complex information.

A bibliometric study of research output of ISRO's space science and exploration missions

Chandrayaan-1 and Chandrayaan-2, the Indian Mars Orbiter Mission (MOM), and a multi-wavelength astronomical observatory (AstroSat) are the missions launched by the Indian Space Research Organisation (ISRO) under the broader category of space science and exploration. The results generated from the periodically released data from these missions, are published in the form of journal articles, conference papers, The Astronomer's Telegrams, GRB Coordinates Network circulars, etc. The goal of this study is a bibliometric analysis of 592 journal articles on ISRO's four space science and exploration missions which were published between 2002 and 2021 (20 years). The Web of Science Core collection database and Google Scholar are used to retrieve the data needed for the study. Bibliometric indicators like mission-wise distribution of articles; year-wise distribution of articles, relative growth rate and doubling time of publications; prolific authors; leading institutions; international collaboration; highly ranked journals; highly cited articles and keyword occurrences were considered for analysis. The doubling time of publications of those missions which yielded the highest number of articles were separately calculated using an exponential equation and built in algorithms in Python. Advanced data visualization tool such as VosViewer was used for generating the network maps. The bibliometric analysis revealed the usage of mission output data not only by ISRO scientists but also by academia, research labs, etc. Overall, the study can be considered as a comprehensive reference source for information on research trends related to the four Indian space science and exploration missions.

Some Common Fixed Point Results in Modular Ultrametric Space Using Various Contractions and Their Application to Well-Posedness

The aim of this study is to prove the existence and uniqueness of fixed point and common fixed point theorems for self-mappings in modular ultrametric spaces. These theorems are proved under varying contractive circumstances and without the property of spherical completeness. As a consequence, the examples of fixed point and common fixed point problems are correctly formulated. As an application, the well-posedness of a common fixed point problem is proved. This study expands on prior research in modular ultrametric space to provide a more comprehensive understanding of such spaces using generalized contraction.