Design of a rapid transit to Mars mission using laser-thermal propulsion

The application of directed energy to spacecraft mission design is explored using rapid transit to Mars as the design objective. An Earth-based laser array of unprecedented size (10-m diameter) and power (100 MW) is assumed to be enabled by ongoing developments in photonic laser technology. A phased-array laser of this size and incorporating atmospheric compensation would be able to deliver laser power to spacecraft in cislunar space, where the incident laser is focused into a hydrogen heating chamber via an inflatable reflector. The hydrogen propellant is then exhausted through a nozzle to realize specific impulses of 3000 s. The architecture is shown to be immediately reusable via a burn-back maneuver to return the propulsion unit while still within range of the Earth-based laser. The ability to tolerate much greater laser fluxes enables realizing the combination of high thrust and high specific impulse, making this approach favorable in comparison to laser-electric propulsion and occupying a parameter space similar to gas-core nuclear thermal rockets (without the requisite reactor). The heating chamber and its associated regenerative cooling and propellant handling systems are crucial elements of the design that receive special attention in this study. The astrodynamics and the extreme aerocapture maneuver required at Mars arrival after a 45-day transit are also analyzed in detail. The application of laser-thermal propulsion as an enabling technology for other rapid transit missions in the solar system and beyond is discussed.

Review of Mercury’s dynamic magnetosphere: Post-MESSENGER era and comparative magnetospheres

This review paper summarizes the research of Mercury’s magnetosphere in the Post-MESSENGER era and compares its dynamics to those in other planetary magnetospheres, especially to those in Earth’s magnetosphere. This review starts by introducing the planet Mercury, including its interplanetary environment, magnetosphere, exosphere, and conducting core. The frequent and intense magnetic reconnection on the dayside magnetopause, which is represented by the flux transfer event “shower”, is reviewed on how they depend on magnetosheath plasma β and magnetic shear angle across the magnetopause, following by how it contributes to the flux circulation and magnetosphere-surface-exosphere coupling. In the next, Mercury’s magnetosphere under extreme solar events, including the core induction and the reconnection erosion on the dayside magnetosphere, the responses of the nightside magnetosphere, are reviewed. Then, the dawn-dusk properties of the plasma sheet, including the features of the ions, the structure of the current sheet, and the dynamics of magnetic reconnection, are summarized. The last topic is devoted to the particle energization in Mercury’s magnetosphere, which includes the energization of the Kelvin-Helmholtz waves on the magnetopause boundaries, reconnection-generated magnetic structures, and the cross-tail electric field. In each chapter, the last section discusses the open questions related to each topic, which can be considered by the simulations and the future spacecraft mission. We end this paper by summarizing the future BepiColombo opportunities, which is a joint mission of ESA and JAXA and is en route to Mercury.

Determination of magnetopause and bow shock shape based on convolutional neural network modelling of MESSENGER data

<p><span id="E87">The magnetosphere of Mercury is relatively small and highly dynamic, mostly due to the weak planetary magnetic field. Varying solar wind conditions principally determine the location of both the </span><span id="E89">Hermean</span><span id="E91"> bow shock and magnetopause. In 2011 – 2015 MESSENGER spacecraft completed over 4000 orbits around Mercury, thus giving a data of more than 8000 crossings of bow shock and magnetopause of the planet, this makes it possible to study in detail the bow shock, the magnetopause and the </span><span id="E93">magnetosheath</span><span id="E95"> structures.</span></p> <p>In this work we determine crossings of the bow shock and the magnetopause of Mercury by applying machine learning methods to the MESSENGER magnetometer data. We attempt to identify the crossings during the whole duration of the orbital mission and model the average three-dimensional shapes of these boundaries. The results are compared with those previously obtained in other works.</p> <p><span id="E101">This work may be of interest for future Mercury research related to the </span><span id="E103">BepiColombo</span><span id="E105"> spacecraft mission, which will enter the orbit around the planet in December 2025.</span></p>

OBJECTIVES AND STRUCTURE OF SMART MONITORING OF SPACECRAFT STATUS IN THE COURSE OF MISSION CONTROL

The paper discusses objectives and structure of smart monitoring of spacecraft status in the course of mission control. It defines the place of the monitoring and the notion of analysis used in the context of solving mission control problems. It summarizes the current state of monitoring techniques used in the course of controlling the missions of modern spacecraft and orbital complexes. It provides data on the results of the use of computerized data analysis techniques for our country’s space assets that are currently in operation. It articulates major drawbacks in the monitoring process, which are getting more exacerbated with the current trends in space programs development. It proposes a remedy for the drawbacks by means of development and introduction of procedures that will make telemetry data analysis smarter. The paper introduces the notion of smart analysis and its key advantages in technical applications. It identifies the key prerequisites for expanding the computerization of the monitoring process involved in the spacecraft mission control. It outlines basic operational principles of a smart monitoring system taking into account its operational peculiarities. Key words: spacecraft, mission control, introduction of smart technologies, status analysis, monitoring system.

Objectives and structure of smart monitoring of spacecraft status in the course of mission control

The paper discusses objectives and structure of smart monitoring of spacecraft status in the course of mission control. It defines the place of the monitoring and the notion of analysis used in the context of solving mission control problems. It summarizes the current state of monitoring techniques used in the course of controlling the missions of modern spacecraft and orbital complexes. It provides data on the results of the use of computerized data analysis techniques for our country’s space assets that are currently in operation. It articulates major drawbacks in the monitoring process, which are getting more exacerbated with the current trends in space programs development. It proposes a remedy for the drawbacks by means of development and introduction of procedures that will make telemetry data analysis smarter. The paper introduces the notion of smart analysis and its key advantages in technical applications. It identifies the key prerequisites for expanding the computerization of the monitoring process involved in the spacecraft mission control. It outlines basic operational principles of a smart monitoring system taking into account its operational peculiarities. Key words: spacecraft, mission control, introduction of smart technologies, status analysis, monitoring system.

Automatic detection of magnetopause and bow shock crossing signatures in MESSENGER magnetometer data using Convolutional Neural Networks.

<p>During its 2011-2015 lifetime the MESSENGER spacecraft completed more than 4000 orbits around Mercury, producing vast amounts of information regarding the planetary magnetic field and magnetospheric processes. During each orbit the spacecraft left and re-entered the Hermean magnetosphere, giving us information about more than 8000 crossings of the bow shock and the magnetopause of Mercury's magnetosphere. The information obtained from the magnetometer data offers the possibility to study in depth the structures of the bow shock and magnetopause current sheets and their shapes. In this work, we take a step in this direction by automatically detecting the crossings of bow-shock and magnetopause. To this end, we propose a five-class problem and train a Convolutional Neural Network based classifier using the magnetometer data. Our key experimental results indicate that an average precision and recall of at least 87% and 96% can be achieved on the bow hock and magnetopause crossings by using only a small subset of the data. We also model the average three-dimensional shape of these boundaries depending on the external interplanetary magnetic field . Furthermore, we attempt to clarify the dependence of the two boundary locations on the heliocentric distance of Mercury and on the solar activity cycle phase. This work may be of particular interest for future Mercury research related to the BepiColombo spacecraft mission, which will enter Mercury’s orbit around December 2025.</p>

BepiColombo Science Investigations During Cruise and Flybys at the Earth, Venus and Mercury

The dual spacecraft mission BepiColombo is the first joint mission between the European Space Agency (ESA) and the Japanese Aerospace Exploration Agency (JAXA) to explore the planet Mercury. BepiColombo was launched from Kourou (French Guiana) on October 20th, 2018, in its packed configuration including two spacecraft, a transfer module, and a sunshield. BepiColombo cruise trajectory is a long journey into the inner heliosphere, and it includes one flyby of the Earth (in April 2020), two of Venus (in October 2020 and August 2021), and six of Mercury (starting from 2021), before orbit insertion in December 2025. A big part of the mission instruments will be fully operational during the mission cruise phase, allowing unprecedented investigation of the different environments that will encounter during the 7-years long cruise. The present paper reviews all the planetary flybys and some interesting cruise configurations. Additional scientific research that will emerge in the coming years is also discussed, including the instruments that can contribute.