bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure, variability, and origin of the low-latitude nightglow continuum between 300 and 1800 nm: evidence for HO2 emission in the near-infrared
Authors: Noll Stefan , Plane John M. C. , Feng Wuhu , Kalogerakis Konstantinos S. , Kausch Wolfgang , Schmidt Carsten , Bittner Michael , Kimeswenger Stefan 
Published: January 2024

Abstract. The Earth's mesopause region between about 75 and 105 km is characterised by chemiluminescent emission from various lines of different molecules and atoms. This emission was and is important for the study of the chemistry and dynamics in this altitude region at nighttime. However, our understanding is still very limited with respect to molecular emissions with low intensities and high line densities that are challenging to resolve. Based on 10 years of data from the astronomical X-shooter echelle spectrograph at Cerro Paranal in Chile, we have characterised in detail this nightglow (pseudo-)continuum in the wavelength range from 300 to 1800 nm. We studied the spectral features, derived continuum components with similar variability, calculated climatologies, studied the response to solar activity, and even estimated the effective emission heights. The results indicate that the nightglow continuum at Cerro Paranal essentially consists of only two components, which exhibit very different properties. The main structures of these components peak at 595 and 1510 nm. While the former was previously identified as the main peak of the FeO “orange arc” bands, the latter is a new discovery. Laboratory data and theory indicate that this feature and other structures between about 800 and at least 1800 nm are caused by emission from the low-lying A′′ and A′ states of HO2. In order to test this assumption, we performed runs with the Whole Atmosphere Community Climate Model (WACCM) with modified chemistry and found that the total intensity, layer profile, and variability indeed support this interpretation, where the excited HO2 radicals are mostly produced from the termolecular recombination of H and O2. The WACCM results for the continuum component that dominates at visual wavelengths show good agreement for FeO from the reaction of Fe and O3. However, the simulated total emission appears to be too low, which would require additional mechanisms where the variability is dominated by O3. A possible (but nevertheless insufficient) process could be the production of excited OFeOH by the reaction of FeOH and O3.
Impact-based flood forecasting in the Greater Horn of Africa
Authors: Alfieri Lorenzo , Libertino Andrea , Campo Lorenzo , Dottori Francesco , Gabellani Simone , Ghizzoni Tatiana , Masoero Alessandro , Rossi Lauro , Rudari Roberto , Testa Nicola , Trasforini Eva , Amdihun Ahmed , Ouma Jully , Rossi Luca , Tramblay Yves , Wu Huan , Massabò Marco 
Published: January 2024

Abstract. Every year Africa is hit by extreme floods which, combined with high levels of vulnerability and increasing population exposure, often result in humanitarian crises and population displacement. Impact-based forecasting and early warning for natural hazards is recognized as a step forward in disaster risk reduction, thanks to its focus on people, livelihoods, and assets at risk. Yet, the majority of the African population is not covered by any sort of early warning system. This article describes the setup and the methodological approach of Flood-PROOFS East Africa, an impact-based riverine flood forecasting and early warning system for the Greater Horn of Africa (GHA), with a forecast range of 5 d. The system is based on a modeling cascade relying on distributed hydrological simulations forced by ensemble weather forecasts, link to inundation maps for specific return period, and application of a risk assessment framework to estimate population and assets exposed to upcoming floods. The system is operational and supports the African Union Commission and the Disaster Operation Center of the Intergovernmental Authority on Development (IGAD) in the daily monitoring and early warning from hydro-meteorological disasters in eastern Africa. Results show a first evaluation of the hydrological reanalysis at 78 river gauging stations and a semi-quantitative assessment of the impact forecasts for the catastrophic floods in Sudan and in the Nile River basin in summer 2020. More extensive quantitative evaluation of the system performance is envisaged to provide its users with information on the model reliability in forecasting extreme events and their impacts.
TARGETED IMMUNOTHERAPY FOR HEPATOCELLULAR CARCINOMA: A CLINICAL CASE
Authors: Kashakov B. , Akbarova M. 
Published: January 2024

Relevance: Hepatocellular carcinoma (HCC) is the most common malignant tumor of the liver. HCC is one of the most important problems of the oncology service of Kazakhstan, as it has a progressive course, late detection, low survival, and unfavorable prognosis.
The study aimed to evaluate the use of targeted immunotherapy in treating hepatocellular carcinoma in a clinical example.
Methods: The paper presents a clinical case of targeted immunotherapy in combination with Atezolizumab 1200 mg + Bevacizumab 800 mg, once every 3 weeks, in treating HCC in the Regional Oncology Center in Kyzylorda.
Results: The first symptoms of liver damage appeared in 2018, at which time HCC was discovered. Viral hepatitis B was diagnosed in 2016. MRI OBP from 15.08.20: a picture of the right lobe of the liver in S5 – 9×7×6 cm, in S3 – 3.7 cm, in S7 – 3.0 cm, in S8 – 2.5 cm. During the follow-up examination (July 2021), the enzyme immunoassay revealed a high angiotensin-converting enzyme (ACE) level of 450.56 IU/ml; the abdominal CT scan showed no deterioration. Later, despite the therapy, ACE increased rapidly: 2,595.3 IU/ml (August 2021) and 2,142.25 IU/ml (September 2021), and the therapy was changed to Regorafenib. ACE continued to rise to 4,405 IU/ml (November 2021) and 18,005 IU/ml (December 2021). A control abdominal CT scan showed a moderate reduction in the size of the tumor.
Taking into account a steady ACE increase, in February 2022, the patient was recommended therapy with Atezolizumab and Bevacizumab. In January 2023, the patient has already received 13 courses, and ACE continued to decrease: 1,932 IU/ml (January 2023), 53.38 IU/ml (February 2023), 16.07 IU/ml (March 2023), and the abdominal CT scan showed positive dynamics.
Conclusion: Targeted immunotherapy showed its effectiveness in the described case of inoperable HCC and allowed the patient to continue living, working, and leading an active lifestyle for more than 18 months.
Design of the MMX Rover Attitude Control System for Autonomous Power Supply
Authors:   Centre National d’Etudes Spatiales (CNES), Toulouse, France, Lagabarre Sandra , Goulet Sébastien , Tardivel Simon , IJpelaan Frans , Buse Fabian , Barthelmes Stefan , Skibbe Juliane 
Published: January 2024

The Martian Moons eXploration (MMX) mission led by the Japan Aerospace Exploration Agency (JAXA) aims at studying Phobos and Deimos, with a launch planned mid-2024. It includes a small rover (about 30kg) carried out jointly by the French Space Agency (CNES, Centre National des Etudes Spatiales) and the German Aerospace Center (DLR, Deutsches Zentrum für Luft- und Raumfahrt), released from the main spacecraft to explore the surface of Phobos.
The MMX rover survival depends on its ability to charge its battery, powered by a solar array (SA) fixed with respect to the rover body. For that purpose, the attitude control system‎ (SKA, System für die Kontrolle of the Attitude) manages the orientation of the rover, using the locomotion system‎ (its "legs") and based on a sun sensor measurements. Conceptually, the system stems from a classic Attitude Determination and Control System‎‎ (ADCS), but the specifics are due to the dynamic interaction between the wheels and the regolith: mouvements limitation to avoid sinkage, delays in the control loop.
This paper presents the SKA architecture, through the various challenges encountered: limited design flexibility with major changes during the development, small knowledge of Phobos' expected soil, "nanosatellite philosophy" constraints and in particular very tight schedule to meet the JAXA delivery date (mid-2023). The design drivers were to create the most simple, robust and efficient system to orient the rover in order to maximize the battery charge, while ensuring the rover stability and addressing all of the above issues. A particular focus is made on the preliminary simulation results. Finally, the way forward is outlined with the development and validation steps.
AOCS FINE POINTING TECHNIQUES FOR ESA PLATO MISSION
Authors:   Thales Alenia Space France, Cannes, France, Kutrowski Nicolas , Cruciani Pietro 
Published: January 2024

Planned for a launch in December 2026, PLATO is the 3rd medium mission of the Cosmic Vision ESA program.
Based on a payload consisting of 26 cameras that will look at transit of exoplanets in front of their stars, the pointing requirements of PLATO are very stringent.
In order to fulfill the required pointing performances, the AOCS is relying on the use of a Fine Guidance System (FGS), which is part of the payload and on different fine pointing techniques, some of which were developed by Thales Alenia Space in the frame of PLATO.
In the first part, the presentation will recall the objectives and constraints of the PLATO mission, while presenting the AOCS main pointing requirements (APE, MPE, PDE, RPE, performance in frequency domain) and the design of this “payload in the loop” AOCS.
In the second part, the different fine pointing techniques will be presented. A focus will be done on the different Kalman filters used for the attitude and angular rates estimation, reaction wheels friction torque estimation, and also how the AOCS is compensating for misalignment between attitude sensors (FGS and Star trackers) and the effect of the kinematic aberration of stars on the FGS line of sight.
Propellant sloshing effect modelling of spacecraft with Machine Learning
Authors:   Airbus Defence And Space, Toulouse, France, Denis Jules-Edouard , Ortiz Casanova Oscar , Manuel Juanpere Xavier , Coustie Oihana , Thevenot Claire , Evain Hélène , Standarovski Denis 
Published: January 2024

The sloshing effect of liquids occurring within spacecraft’s fuel tanks is a determinant factor in the pointing performance of space missions with high-reactivity needs. Accurately modelling this phenomenon allows anticipating its detrimental effects on satellite control, and thus possibly improve the tranquillisation time.
This paper examines a modelling trade-off between the quick but low performance analytical approaches and the slow but accurate CFD simulations. Based on the hypothesis that the problem presents underlying regularity characteristics, and considering that dataset can be generated thanks to CFD simulations, Machine Learning techniques are explored, from a Proof of Concept approach to a fully representative agile space mission.
Using Machine Learning techniques such as Multi-Layer Perceptron (MLP), Long-Short Term Memory (LSTM) or Convolutional Neural Network (CNN), this study demonstrates high-accuracy results whilst remaining efficient in terms of computation time. Furthermore, its industrialization capability for future missions is assessed, providing promising results. For instance, it is shown that a relatively small dataset is needed to reach high representativeness and robustness. Besides, a methodology is developed to implement these models into a Guidance, Navigation and Control (GNC) closed loop simulator based on Matlab/Simulink.
High-Accuracy Star Tracker ASTRO XP
Authors:   Chief Engineer Star Sensors, Jena, Germany, Schmidt Uwe , Würl Richard , Griebel Martin , Reichardt Jörg , Adolf Daniel , Kühn Thomas , Kirschstein Steffen , Steinbach Ingolf 
Published: January 2024

Jena-Optronik GmbH, located in Jena/Germany, has profound experience in designing and
manufacturing star trackers since the early 80ties. Today, the company has a worldwide leading
position in supplying satellites and other spacecraft for telecom, earth observation, science and all
kind of missions in various orbits with versatile and reliable star tracker systems. The future ESA
science missions require high accuracy star trackers in the 0.1arcsec accuracy class to achieve
the envisaged pointing budgets. Jena-Optronik received a pre-development contract (ESA
Contract No. 4000112514/14/NL/BW) from the European Space Agency in order to demonstrate
the feasibility of such a high accuracy star tracker within the challenging performance, mass and
envelope requirements. The here identified key-enabling optics technology in terms of a compact
4-times folded fully reflective optical system opened the way forward to a second contract (ESA
Contract No. 4000126831/19/NL/GLC/hh) to establish an engineering model optical head in form,
fit and function, able to undergo pre-qualification tests.
The star tracker optics consists of a full catoptric design and is therefore free of any chromatic
aberration. This is essential for a high accuracy star tracker, which uses guide stars from a wide
range of different spectral classes. The only four optics main parts are made from fused silica and
build in the final assembly a self-sustaining optical system with a total lack of CTE mismatches.
The high performance imaging system is completed with a FaintStar2 CMOS APS based focal
plane. The FaintStar2 is the most advanced and space-qualified APS star tracker imager as a
result of the ESA detector development roadmap. This detector comprises a complete system-on-
chip including a space-wire interface. This minimizes the power consumption of the ASTRO XP
optical head ensuring an excellent thermal-mechanical stability.
The ASTRO XP EM optical head was integrated in Q4/2022 so that the test readiness review with
the agency could be successfully performed. The paper presents insights in the optics and focal
plane technology and design. In addition, the first test results from the engineering model test
campaign will be published and discussed. The ASTRO XP optical head manufactured is the most
innovative star tracker ever designed at Jena-Optronik GmbH and beyond. This design applies
novel technologies and utilizes the most innovative high-technology assembly processes.
Determining Dimorphos' mass from the wobble of Didymos
Authors:   Aurora Technology B.V. for the European Space Agency (ESA), Villanueva de la Cañada, Spain, Grieger Björn , Küppers Michael 
Published: January 2024

In order to demonstrate of the feasibility of the deflection of an Earth threatening asteroid, the DART mission impacted Dimorphos, the asteroid moonlet of Didymos, on 26 September 2022. For the assessment of the efficiency of the momentum transfer, the mass of Dimorphos needs to be known.
Around October 2026, the Hera mission will reach the Didymos binary system and inspect closely its properties and the consequences of the DART impact. The mass of Dimorphos is so small that it will only marginally be possible to measure its gravitational impact by tracking of the spacecraft trajectory. However, images taken by the Asteroid Framing Cameras aboard Hera will make it possible to measure the wobble of Didymos introduced by its common orbiting with Dimorphos around the barycenter of the binary system. This will enable the estimation of Dimorphos' mass.
In 2016, we discussed the expected accuracy of such a mass reconstruction under different assumptions (EGU2016-12296). So far, we had skiped the process of actually defining landmarks and measuring their pixel positions in images. From the Rosetta mission we know that this can be done with about one pixel accuracy. We just assume landmark positions in the body fixed frame randomly distributed over the surface of Didymos. The available measurements are then inertially referenced directions from the spacecraft to the landmarks at different times (images).
In the reconstruction process, we assume that we do not know anything about the true landmark positions, the spacecraft trajectory, and the orientation of Didymos. Image by image, we estimate the pose (position and attitude) of the asteroid relative to the spacecraft. Through many iterations over all images, the landmark positions in the body fixed frame are optimized. Because the attitude of the spacecraft is known, this provides the trajectory of the spacecraft relative to Didymos. The trajectory reconstructed in this way is falsified in the sense that it comprises the wobble of Didymos around its common barycenter with Dimorphos.
In a second step, we filter the wobble out of the spacecraft trajectory and estimate its size. Here, we assume that the orbit of Dimorphos is known, so we know the period of the wobble and its direction at all times.
So far, each time point had been treated separately. With the additional assumption of a continuous asteroid rotation and its appropriate modeling, the accuracy of the mass estimation can be improved. Moreover, with the new data from the DART mission and the matured design of the Hera mission, we are now able to refine the predictions and prepare in more detail the strategy for the reconstruction of the mass of Dimorphos.
INTEGRAL operations and mission rescue without thrusters
Authors:   Airbus Defence and Space Ltd., Stevenage, United Kingdom, Chapman Patrick , Southworth Richard , Martin Jim 
Published: January 2024

The INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) is an operational European space observatory mission. It was launched in 2002, and has exceeded its original mission duration by a long margin, and has had several mission extensions approved.
In recent years several events have created interesting challenges for attitude control. In 2020 the fuel unexpectedly depleted earlier than predicted, making normal thruster-based angular momentum off-loading impossible. It was possible to devise a workaround for this, managing momentum using solar torque and "Z-flip" slews. The slew algorithm was redesigned by ESOC and industry to remove a previous constraint that can require momentum off-loading.
In Sep. 2021 a major anomaly put the spacecraft into an uncontrolled tumbling state for several hours. This paper describes the successful improvised recovery of attitude control using reaction wheels, and the subsequent development of procedures and a completely new AOCS mode, a wheel-based New Safe Mode (NSM) to prevent a recurrence of loss of control. With NSM, the mission will have the ability to be safely operated without thrusters and with redundancy for any further unit failures until predicted re-entry in 2029.
Assisted Reentry for All-Electric LEO Spacecraft
Authors:   Airbus Defence And Space, Toulouse, France, Lagadec Kristen , Gegout Dorian 
Published: January 2024

There have historically been only two strategies to choose from when designing a deorbiting capability for future LEO missions: controlled reentry requires a very large deorbit boost and thus a powerful propulsion system, while uncontrolled reentry is only allowed for small satellites that (almost) entirely burn up when reentering.
Assisted Natural Reentry (or assisted reentry for short) intends to fill the continuum between these two extremes, thus offering more design flexibility to comply with the 1/10,000 rule in terms of ground risk.
The main rationale is that if the orbital plane can be phased correctly with the Earth and the distribution of potential reentry locations can be confined to at most a couple of revolutions, the vast majority of reentries will occur above oceans, reducing the casualty risk by an order of magnitude with respect to uncontrolled reentry.
We present the design and performances of an assisted reentry strategy tailored for an all-electrical LEO satellite, i.e. one with a very low thrust/mass ratio which only allows quasi-static perigee lowering and offers minimal control authority. We demonstrate with extensive simulation campaigns that despite high uncertainty in aerodynamic and atmospheric models and large density swings due to unpredicted changes in solar activity, the final dispersion can be kept within 2 orbits of the nominal reentry location, reducing casualty risk by a factor >5.
AQUILA and 3AA: design and test results of high-accuracy accelerometer sensor and equipment
Authors:   Innalabs Ltd, Blanchardstown, Ireland, Torasso Alberto , Francis Rabin , Vandersteen Jeroen 
Published: January 2024

InnaLabs Ltd, a privately held limited company incorporated in Ireland in 2011, is producing European ITAR-free Quartz Pendulous accelerometers since 2013, achieving top-end navigation performance with its AI-Q-2000 series of accelerometers. Thousands of those accelerometers have been since integrated into a wide range of land, marine, and aerospace platforms. These accelerometers have recently been successfully used in rocket launchers to support inertial navigation, demonstrating compatibility of the technology with space applications.
AQUILA is a very high performance rad-hard accelerometer based on Innalabs quartz-pendulum accelerometer technology. It uses the same pendulum subassembly as the AI-Q-2000 family, but electronics have been developed to meet space PA/QA standards. A hybrid electronics component populated with thoroughly-selected high-reliability EEE parts has been designed for that purpose. Furthermore, performance is specified to meet the most demanding space navigation applications, in particular with the objective of supporting delta-v manoeuvres measurement.
AQUILA was developed with the primary goal of qualifying an alternative to non-EU Navigation Grade Space accelerometers currently used on board ESA missions and other European Primes’ platforms (with similar fit, form and function). Performance specifications include, among others, very low noise, stringent bias and scale factor stability (i.e. 0.1µg short term stability, 2µg over 1 hour, 50µg over 1 month, and scale factor stability over 1 month of 100ppm) under full operating conditions (i.e. temperature, time, launch environment), including more than 15-years exposure to Space radiations (100krad goal). AQUILA is re-using the electro-mechanical cell used in the InnaLabs AI-Q-2000 series of COTS accelerometers which are proven insensitive to radiations and robust to stringent mechanical shock and vibration levels.
3 Axis Accelerometer (3AA) is a new equipment designed to provide acceleration and delta-v measurement on boards satellites and space systems. It includes 3 AQUILA accelerometers mounted in orthonormal orientation to provide measurement along 3 axes. 3AA is equipped with a standard 28V power interface and UART communication bus to easily interface with the main on board computer. The equipment allows for accelerometer compensation and calibration in flight (temperature, misalignment, etc.), providing the main on board computer with a high precision acceleration and delta-v measurement.
This paper describes the specification and design of AQUILA Dry Pendulous Servo accelerometer and of the 3 Axis Accelerometer. The paper will also present testing results from AQUILA development models built so far, showing that the product meets the specified performance. Schedule of the development till completion of the qualification will be presented.