The Soft X-ray Imager(SXI)on the SMILE Mission

The Soft X-ray Imager(SXI)is part of the scientific payload of the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission.SMILE is a joint science mission between the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS)and is due for launch in 2025.SXI is a compact X-ray telescope with a wide field-of-view(FOV)capable of encompassing large portions of Earth’s magnetosphere from the vantage point of the SMILE orbit.SXI is sensitive to the soft X-rays produced by the Solar Wind Charge eXchange(SWCX)process produced when heavy ions of solar wind origin interact with neutral particles in Earth’s exosphere.SWCX provides a mechanism for boundary detection within the magnetosphere,such as the position of Earth’s magnetopause,because the solar wind heavy ions have a very low density in regions of closed magnetic field lines.The sensitivity of the SXI is such that it can potentially track movements of the magnetopause on timescales of a few minutes and the orbit of SMILE will enable such movements to be tracked for segments lasting many hours.SXI is led by the University of Leicester in the United Kingdom(UK)with collaborating organisations on hardware,software and science support within the UK,Europe,China and the United States.

Ground-based and additional science support for SMILE

The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will explore global dynamics of the magnetosphere under varying solar wind and interplanetary magnetic field conditions,and simultaneously monitor the auroral response of the Northern Hemisphere ionosphere.Combining these large-scale responses with medium and fine-scale measurements at a variety of cadences by additional ground-based and space-based instruments will enable a much greater scientific impact beyond the original goals of the SMILE mission.Here,we describe current community efforts to prepare for SMILE,and the benefits and context various experiments that have explicitly expressed support for SMILE can offer.A dedicated group of international scientists representing many different experiment types and geographical locations,the Ground-based and Additional Science Working Group,is facilitating these efforts.Preparations include constructing an online SMILE Data Fusion Facility,the discussion of particular or special modes for experiments such as coherent and incoherent scatter radar,and the consideration of particular observing strategies and spacecraft conjunctions.We anticipate growing interest and community engagement with the SMILE mission,and we welcome novel ideas and insights from the solar-terrestrial community.

Some Aerothermodynamic Aspects of ESA Entry Probes

Two different entry vehicles are presented here： the Inflatable Reentry and Descent Demonstrator （IRDT）, and Huygens. Both missions involve （re）entries at conditions close to orbital, and have been performed in 2005. Specific aspects of the design and the mission of IRDT are briefly outlined. The preliminary results of the recent flight of IRDT and the methodology followed at ESTEC for the assessment of radiative fluxes for Huygens are summarised.

Atmospheric Remnants in the Low Earth Orbit Region around 200 km Altitude

Study of atmospheric remnants in the low Earth orbit region (~200 km altitude) using Global Models, with application to electric thrusters of in situ resources utilization type.

Diagnostics of Air-Breathing Electric Thrusters

Air-Breathing Electric Thrusters (ABET) diagnostics is addressed, with on-ground prototypes in mind. It is based on detailed volume averaged Global Models and focuses on emission spectroscopy. Notably, the obtained optical emission spectroscopy diagnostics tools give important information about the thruster propellant constitution and also the ionization degree of each constituent. This allows for trade-off between various prototypes on the basis of their characterization and optimization.

Magnetospheric Boundary Layer Structure and Dynamics as Seen From Cluster and Double Star Measurements

In this review,we discuss the structure and dynamics of the magnetospheric LowLatitude Boundary Layer(LLBL)based on recent results from multi-satellite missions Cluster and Double Star.This boundary layer,adjacent to the magnetopause on the magnetospheric side,usually consists of a mixture of plasma of magnetospheric and magnetosheath origins,and plays an important role in the transfer of mass and energy from the solar wind into the magnetosphere and subsequent magnetospheric dynamics.During southward Interplanetary Magnetic Field(IMF)conditions,this boundary layer is generally considered to be formed as a result of the reconnection process between the IMF and magnetospheric magnetic field lines at the dayside magnetopause,and the structure and plasma properties inside the LLBL can be understood in terms of the time history since the reconnection process.During northward IMF conditions,the LLBL is usually thicker,and has more complex structure and topology.Recent observations confirm that the LLBL observed at the dayside can be formed by single lobe reconnection,dual lobe reconnection,or by sequential dual lobe reconnection,as well as partially by localized cross-field diffusion.The LLBL magnetic topology and plasma signatures inside the different sub-layers formed by these processes are discussed in this review.The role of the Kelvin-Helmholtz instability in the formation of the LLBL at the flank magnetopause is also discussed.Overall,we conclude that the LLBL observed at the flanks can be formed by the combination of processes,(dual)lobe reconnection and plasma mixing due to non-linear Kelvin-Helmholtz waves.

Neutralized solar energetic particles for SEP forecasting:Feasibility study of an innovative technique for space weather applications

Energetic neutral atoms(ENAs)are produced by the neutralization of energetic ions formed by shock-accelerated gradual solar energetic particle events(SEP).These high-energy ENAs(HENAs)can reach the Earth earlier than the associated SEPs and thus can provide information about the SEPs at the lower corona.The HENA properties observed at Earth depend on the properties of the coronal mass ejection(CME)-driven shocks that accelerate the SEPs.Using a model of HENA production in a shock-accelerated SEP event,we semi-quantitatively investigate the energy-time spectrum of HENAs depending on the width,propagation speed,and direction of the shock,as well as the density and ion abundances of the lower corona.Compared to the baseline model parameters,the cases with a wider shock width angle or a higher coronal density would increase the HENA flux observed at the Earth,while the case with an Earthpropagating shock shows a softened HENA spectrum.The comparison of expected HENA fluxes in different cases with a flight-proven ENA instrument suggests that solar HENAs can feasibly be monitored with current technologies,which could provide a lead time of 2−3 hours for SEPs at a few MeV.We propose that monitoring of solar HENAs could provide a new method to forecast shock-driven SEP events that are capable of significant space weather impacts on the near-Earth environment.

开发供空间用的MIL—STD-1750微处理器系统

引言微处理器被大量用于当今航天器上,而且将来会更广泛。其应用已经扩展到航天器的主要分系统和有效载荷及科学实验。要用在航天器上的微处理器应在空间环境下长时间可靠地工作(直至10年)。空间辐射环境限制更大:累积剂量(由于捕获电子影响)和单粒子翻转/锁定(由于宇宙射线和质子的影响)。随着已用于航天器上的微处理器的逐渐过时,80年代末,欧洲决定着手开发一种高性能空间用的抗辐射微处理器。

An Event Horizon Imager(EHI) Mission Concept Utilizing Medium Earth Orbit Sub-mm Interferometry

Submillimeter interferometry has the potential to image supermassive black holes on event horizon scales,providing tests of the theory of general relativity and increasing our understanding of black hole accretion processes.The Event Horizon Telescope(EHT) performs these observations from the ground,and its main imaging targets are Sagittarius A~* in the Galactic Center and the black hole at the center of the M87 galaxy.However,the EHT is fundamentally limited in its performance by atmospheric effects and sparse terrestrial(u,v)-coverage(Fourier sampling of the image).The scientific interest in quantitative studies of the horizon size and shape of these black holes has motivated studies into using space interferometry which is free of these limitations.Angular resolution considerations and interstellar scattering effects push the desired observing frequency to bands above 500 GHz.This paper presents the requirements for meeting these science goals,describes the concept of interferometry from Polar or Equatorial Medium Earth Orbits(PECMEO) which we dub the Event Horizon Imager(EHI),and utilizes suitable space technology heritage.In this concept,two or three satellites orbit at slightly different orbital radii,resulting in a dense and uniform spiral-shaped(u,v)-coverage over time.The local oscillator signals are shared via an inter-satellite link,and the data streams are correlated on-board before final processing on the ground.Inter-satellite metrology and satellite positioning are extensively employed to facilitate the knowledge of the instrument position vector,and its time derivative.The European space heritage usable for both the front ends and the antenna technology of such an instrument is investigated.Current and future sensors for the required inter-satellite metrology are listed.Intended performance estimates and simulation results are given.

Remote sensing and its applications using GNSS reflected signals:advances and prospects

The Global Navigation Satellite Systems(GNSS),including the US’s GPS,China’s BDS,the European Union’s Galileo,and Russia’s GLONASS,offer real-time,all-weather,any-time,anywhere and high precision observations by transmitting L band signals continuously,which have been widely used for positioning,navigation and timing.With the development of GNSS technology,it has been found that GNSS-reflected signals can be used to detect Earth’s surface characteristics together with other signals of opportunity.In this paper,the current status and latest advances are presented on Global Navigation Satellite System-Reflectometry(GNSS-R)in theory,methods,techniques and observations.New developments and progresses in GNSS-R instruments,theoretical modeling,and signal processing,ground and space-/air-borne experiments,parameters retrieval(e.g.wind speed,sea surface height,soil moisture,ice thickness),sea surface altimetry and applications in the atmosphere,oceans,land,vegetation,and cryosphere are given and reviewed in details.Meanwhile,the challenges in the GNSS-R development of each field are also given.Finally,the future applications and prospects of GNSS-R are discussed,including multi-GNSS reflectometry,new GNSS-R receivers,GNSS-R missions,and emerging applications,such as mesoscale ocean eddies,ocean phytoplankton blooms,microplastics detection,target recognition,river flow,desert studies,natural hazards and landslides monitoring.

Surveys on magnetospheric plasmas based on the Double Star Project (DSP) exploration

The equatorial and polar satellites of the Double Star Project (DSP) were launched successfully on December 29, 2003 and July 25, 2004, respectively, and both of them are operating smoothly. The DSP provides a good opportunity for investigat-ing the structure of the magnetosphere. Based on the DSP data collected during 2004, we have surveyed the distribution of the magnetic fields and plasmas in the magnetosphere. It is found that: (1) Near the Earth’s equatorial plane within geo-centric distances of less than 7 RE, the Earth’s magnetic field is dipolar. In the vi-cinity of the magnetopause, the magnetic field is enhanced by a factor of about 1.5, and on the nightside, the magnetic field can vary significantly from the Earth’s di-pole field, likely caused by the presence of the near-Earth tail current sheet. (2) In the day-side magnetosheath, the electron and ion densities are usually both in the range of 10―30 cm?3; the ion and electron temperatures are usually about 200 and 50 eV, respectively. The flow pattern is usually smooth, with a low velocity in the subsolar region and with significantly higher velocities in the dawn and dusk flanks. (3) In the region between the magnetopause and plasmasphere the density is low, approximately 0.5―5 cm?3, and the temperature is high, about 1―10 keV for ions and 0.1―5 keV for electrons. The ion temperature has an apparent anisotropy, with the ratio of the perpendicular and parallel temperatures being about 1.0―1.3 for the night- and dusk-side magnetosphere and about 1.3―2.0 for the day- and dawn-side magnetosphere. There is an evident sunward convection of about 50 km/s in the magnetosphere. On the dawn side, the flow becomes somewhat turbulent, and in the vicinity of the night-noon meridian plane, the convection is rather slow. (4) The high-energy electrons with energies higher than 2 MeV are mainly located in the regions with 3 < L < 4.5; the size of the high-energy electrons area varies with time, it may expand and shrink occasionally according to different solar wind conditions and magnetic activities.

Tendril-Based Climbing Plants to Model, Simulate and Create Bio-Inspired Robotic Systems

Bioinspiration can be considered one of the keys for future smart and versatile robotic systems. Plants could be an im- portant source of ideas despite the fact that they have not yet been deeply observed and considered. In this paper, climbing tendril-bearer plants that, by means of irritable filiform organs called tendrils, search for a support, grasp it and climb to gain height, have been used to study and develop an effective climbing robot. The study aimed first to evaluate the main movements and behaviors of the tendril from a biomimetic point of view. The tendril complexity was then simplified, a robotic model was developed and a kinematic simulator was designed and implemented to visualize and evaluate the chosen system. Finally, based on the biological, technical and numerical evaluations, the main tendril behaviors were replicated by proof of concept devices made of smart materials to move towards a practical realization and to replicate the simulated results. The designed proof of concept prototypes showed food repeatability and feasibility.

Space Habitat Astronautics:Multicolour Lighting Psychology in a 7-Day Simulated Habitat

During space missions,astronauts live in a confined technological environment,completely isolated and deprived of the variety and variation found in the environment on Earth.This circumstance has a strong impact on the psycho-physiological states of the crew.Particularly in light of the plans for long-duration missions,new research needs to be carried out.The goal of this study,conducted at Xiangtan Central Hospital in China,was to test whether multicolour lighting can improve people’s psychological state in an isolated and confined environment over a period of seven days.Twenty participants(10 male and 10 female)were randomly divided into two groups:one group that was exposed to multicolour lighting and a control group,which was exposed to a static,monotonous white interior.The participants’psychological state was recorded on the first day,the fourth day,and the seventh day.The results of the control group showed that the participants’negative emotions and anxiety continued to increase over time,whereas the group randomly exposed to multicolour lighting that changed every three hours did not show any significant increase in negative emotions and anxiety.Moreover,the random change of light colour in the isolated environment appeared to help the participants increase their sense of surprise,thereby counteracting monotony.Finally,during this experiment,it was observed that when people who are accustomed to being connected to social networks were deprived of this,they experienced insomnia and unaccustomed reactions,in particular on the first days of deprivation.This article contributes to future space exploration and to social and psychological support of life in isolated and confined environments.

When It Strikes,Are We Ready?Lessons Identified at the 7th Planetary Defense Conference in Preparing for a Near-Earth Object Impact Scenario

Near-Earth object(NEO)impact is one of the examples of high impact and low probability(HILP)event,same as the Covid-19 pandemic the world faces since the beginning of 2020.The 7 th Planetary Defense Conference held by the International Academy of Astronautics(IAA)in April 2021 included an exercise on a hypothetical NEO impact event,allowing the planetary defense community to discuss potential responses.Over the span of the 4-day conference this exercise connected disaster response and management professionals to participate in a series of panels,providing feedback and perspective on the unfolding crisis scenario.The hypothetical but realistic asteroid threat scenario illustrated how such a short-warning threat might evolve.The scenario utilized during the conference indicates a need to prepare now for what might come in the future,because even with advance notice,preparation time might be minimal.This scenario chose Europe for the impact,which may likely cope with such a disaster,through the Union Civil Protection Mechanism(UCPM)and other solidarity and support mechanisms within the European Union(EU),as well as with potential support from international partners.This short article raises concern about other areas in the world on how they may access NEO impact information and cope with such disasters.It also provides an idea on vast scale of such disaster vis-a-vis the current capacity of response systems to cope with a larger event in Europe or elsewhere.This scenario showed that planetary defense is a global endeavor.Constant engagement of the planetary defense and disaster response communities is essential in order to keep the world safe from potential disasters caused by NEO impacts.

Accretion in strong field gravity with eXTP

In this paper we describe the potential of the enhanced X-ray Timing and Polarimetry(eXTP) mission for studies related to accretion flows in the strong field gravity regime around both stellar-mass and supermassive black-holes. eXTP has the unique capability of using advanced "spectral-timing-polarimetry" techniques to analyze the rapid variations with three orthogonal diagnostics of the flow and its geometry, yielding unprecedented insight into the inner accreting regions, the effects of strong field gravity on the material within them and the powerful outflows which are driven by the accretion process.