Search

This paper investigates different strategies for end-to-end flight software development that support having both desktop and embedded environments while minimizing the existing gap between them, in...

The purpose of the study is to consider the issues of forecasting the electromagnetic environment and assess the compatibility of onboard radio-electronic equipment of interplanetary spacecraft. Methodology and Approach. It is shown that well-known standards for assessing electromagnetic compatibility are not applicable for determining the electromagnetic fields generated by spacecraft equipment. Taking into account the results of bench tests conducted, theoretical and theoretical models of sources of electromagnetic fields near spacecraft have been developed. Results. The features of interaction in the electromagnetic fields of the plasma of electric jets with the radio-electronic means of spacecraft are investigated. The results of the analysis of electromagnetic compatibility of airborne electronic systems are presented. Theoretical and Practical implications. The results of the study provide the choice of the optimal frequency range for radio communications used on interplanetary spacecraft. In this case, it is necessary to take into account the various effects of the anomalous interaction of electromagnetic fields with plasma formations created by the electroreactive engines of spacecraft.

A sophisticated interplanetary spacecraft, Cassini–Huygens was launched on 15 October 1997. After achieving orbit at Saturn in 2004, Cassini collected science data throughout its four-year prime mi...

The United Arab Emirates’ Hope orbiter is the Arab world’s first interplanetary spacecraft — and has jump-started science in the country. Will the momentum last? The United Arab Emirates’ Hope orbiter is the Arab world’s first interplanetary spacecraft — and has jump-started science in the country. Will the momentum last?

The problem on providing the most accurate measuring information of an elastic aerospace vehicle (AV) state in real time is discussed. Such elastic AV can be large interplanetary spacecraft, a WIG-craft, or an airplane. For this purpose, it is proposed to place a sufficiently large number of inertial measuring modules along the AV body and perform verification and correction of their parameters during the flight. Such measuring modules should provide the necessary accuracy for a long time interplanetary flights. Micromechanical gyroscopes are used as the main measures. The results of digital modeling confirm the effectiveness of the proposed algorithms for verification of such important parameters of micro gyroscopes as the difference in the natural frequencies of primary and secondary oscillations and their Q-factor.

Tomas Kohout1 and Antti Näsilä2 Tomas Kohout and Antti Näsilä Tomas Kohout1 and Antti Näsilä2 1University of Helsinki, Faculty of Science, Helsinki, Finland (tomas.kohout@helsinki.fi) 2VTT Technical Research Centre of Finland Ltd, Espoo, Finland (antti.nasila@vtt.fi) 1University of Helsinki, Faculty of Science, Helsinki, Finland (tomas.kohout@helsinki.fi) 2VTT Technical Research Centre of Finland Ltd, Espoo, Finland (antti.nasila@vtt.fi) Hide Introduction We introduce a novel concept for miniaturized spectral imaging instrument which can be used for planetary exploration missions. Key component in the spectral imager is a tunable Fabry-Perot Interferometer (FPI) developed at VTT (Fig. 1). It can be fitted in ca. 1 CubeSat unit (CU), thus making it suitable for all CubeSat sizes from 2U upwards. Depending on the mission requirements, the instrument can perform measurements from 0.5 µm up to 7 µm (Table 1). The visible and near-infrared (0.5 µm - 1.6 µm) components have already been flown and validated in low Earth orbit. Planetary missions Knowledge of planetary compositions is of a key importance in planetology. It enables us to determine the origin of solid material in different zones of our Solar System, as well as to understand current processes such as space weathering. Reflectance spectroscopy is one of the widely used tools to determine the composition of planetary surfaces. The key diagnostic features in the planetary spectra are Fe2+ (~ 1 and 2 µm) and Fe3+ absorptions (~ 0.7 µm) in silicates, H2O and –OH features (~ 1.4, 1.9 or 2.7-3 µm), C-H bonds in organics (~ 3-3.6 µm), Si-O silicate vibration bands in visible – near-infrared (VIS-NIR), or various ices and gases in mid-infrared (MIR). Hyperspectral imaging enables spatial resolution of these features, and thus mapping of composition of planetary surfaces in order to determine homogeneity of the target body or distribution of various minerals or volatile compounds. The continuous spectra measurement over broad wavelength enables determination of spectral continuum essential for determination of surface grain size, or in detection of the space weathering or shock effects. The capability to combine different wavelength ranges in a compact volume makes the instrument highly useful in modern planetary exploration missions. Many larger space missions are planning to use smaller secondary spacecraft (InSight, Hera, Comet Interceptor) to perform secondary functions or to address different science objectives. As the larger missions are targeting very different objects (inner planets, outer planets, asteroids, comets) the required instrumentation differ. With standard CubeSat platforms and our modular instrumentation approach, it is easy to tailor an instrument suite for all types of targets and science cases. CubeSat for Hera mission The first mission for the modular spectral imager is European Space Agency’s Hera mission (launch in 2024). Part of this mission is a CubeSat with Asteroid Spectral Imager ASPECT as one of the payloads. Hera will study binary asteroid Didymos (primary 780 m and secondary 170 m in size) – target of the NASA DART (Double-Asteroid Redirection Test) kinetic impactor test mission. DART will impact the secondary asteroid, and create approx. 2-4 m sized crater with associated ejecta. ASPECT will map the composition of both asteroids, distribution of impact ejecta, space weathering effects on the asteroid surface, and impact-induced changes. ASPECT has four measurement channels: VIS (500 - 900 nm), NIR1 (850 - 1275 nm), NIR2 (1225 - 1650 nm) and SWIR (1600 - 2500 nm). VIS and NIR channels have imaging capability, while the SWIR channel is a single point spectrometer. All channels have good overlap with each other, so it is possible to construct the complete spectral slope from 500 nm up to 2500 nm. Comet Interceptor mission Comet Interceptor is a newly selected ESA F-mission (launch in 2028) to a dynamically new comet from Oort cloud. One of the key payloads is a modular hyperspectral imaging system MIRMIS (Modular Infrared Molecules and Ices Sensor) to detect the mineral, ice, and gas compounds in the comet nucleus and coma in NIR-MIR range, as well as to map temperature of the nucleus. The mission is first-of-its-kind to study the pristine material from the outer Solar System. Two of the MIRMIS channels, NIR and MIR, are based on VTT’s modular instrument concept. The NIR channel, measuring at ca. 1-1.6 µm has the same design as the NIR channels used for ASPECT. The MIR channel is a new development, and it will measure from 2.5 µm up to 7 µm. Atmospheric science missions Another important topic is the abundance of gases or substances in planetary atmospheres. Capability to identify different gas species can bring insight to the evolution of the planetary body and to the processes related to the climate. One of the most useful techniques for performing atmospheric measurements from a small spacecraft is solar occultation. In this method, the instruments look directly at the Sun during sunsets and sunrises. There are two great benefits: the Sun is the most powerful source of light in our Solar System, and the method is self-calibrating as the measurement signal is always divided by the out-of-atmosphere signal. With this technique, it is possible to identify many gases in the atmosphere based on their absorption spectra and at the same time the vertical profiles can also be generated. PICASSO mission The PICo-satellite for Atmospheric and Space Science Observations (PICASSO) is an ESA mission (launch in 2020) led by the Belgian Institute for Space Aeronomy. VTT has developed one of the payloads, VISION, for the mission. VISION has two scientific objectives: to study the ozone distribution in the stratosphere and to measure the atmospheric temperature profile up to the mesosphere. VISION is a spectral imager operating between 430 - 800 nm, and it is capable of taking 2D snapshots of the Sun at freely selectable wavelengths. VISION instrument will observe the atmospheric limb during orbital Sun occultation. By addressing the radiation absorption in the Chappuis band for different tangent altitudes, the vertical profile of ozone can be retrieved.

Accepted: 2018-04-09, 資料番号: SA1180078000

Earth–Mars cycling spacecraft have been proposed as potentially beneficial to Mars exploration. There are many types of cyclers, but their common characteristic is that they have a heliocentric tra...

A Lunar Microbial Survival (LMS) model (Schuerger et al., 2019) was developed to estimate the persistence of spacecraft bacteria over long periods of time on the Moon. Recently, we were extending the LMS model to include predictions for microbial survival on interplanetary spacecraft (Moores and Schuerger, 2020) and detected errors in Eqs. [2.a] and [2.b] in the original LMS paper. The following text describes the errors and how the corrected equations and MatLab programs changed the results given in Table 2 and Figure 5.

Cassini is one of the most sophisticated interplanetary spacecraft that humans have ever built and launched. Since achieving orbit at Saturn in 2004, Cassini has collected science data throughout i...

Telemetry data from three 445 N engine burns of the Cassini spacecraft are used to characterize the high-g slosh characteristics of bipropellants in cylindrical tanks with spherical end domes. Comp...

Accepted: 2016-12-30, 資料番号: SA1160369000

The Deep Space Network (DSN) is a worldwide array of radio telescopes that supports NASA's interplanetary spacecraft missions. When the DSN antennas are not communicating with spacecraft, they provide a valuable resource for performing observations of radio magnetars, searches for new pulsars at the Galactic Center, and additional pulsar-related studies. We describe the DSN's capabilities for carrying out these types of observations. We also present results from observations of three radio magnetars, PSR J1745-2900, PSR J1622-4950, and XTE J1810-197, and the transitional magnetar candidate, PSR J1119-6127, using the DSN radio telescopes near Canberra, Australia., Comment: 14 pages, 8 figures, Accepted for publication in Advances in Astronomy on 2019 January 27 (Invited paper for a special issue on magnetars)

Disk-integrated time-resolved photometric observations have been performed for 25 irregular moons of Saturn with the ISS camera of the Cassini spacecraft in a wide range of solar phase angles. From the derived lightcurves, synodic rotation periods were determined, ranging from ~5.5 h to ~76 h; the fastest observed spin rate is much slower than the disruption rotation barrier of asteroids at ~2 h. The lightcurves show very different structures which indicates that Saturn's irregular moons have a large variety of shapes. All lightcurves except for Phoebe and Paaliaq show 2-maxima/2-minima or 3-maxima/3-minima patterns. The lightcurve amplitudes range between 0.1 mag and > 2 mag, the latter is measured in observations of objects Ymir, Kiviuq, and Siarnaq at phase angles α > 60°. While most lightcurve amplitudes from observations obtained at α 50° are >0.5 mag. This campaign marks the first utilization of an interplanetary spacecraft for a systematic photometric survey of irregular moons.

Aerocapture is the maneuver by an interplanetary spacecraft to fly through the atmosphere of a planet with the aim of attaining a specified orbit around the planet. By appropriately controlling the...

SPEX (Spectropolarimeter for Planetary EXploration) is an innovative, compact remotesensing instrument for measuring and characterizing aerosols in the atmosphere. The shoebox size instrument is capable of accurate full linear spectropolarimetry without moving parts or liquid crystals. High precision polarimetry is performed through encoding the degree and angle of linear polarization of the incoming light in a sinusoidal modulation of the spectrum. Measuring this intensity spectrum thus provides the spectral dependence of the degree and angle of linear polarization. Polarimetry has proven to be an excellent tool to study microphysical properties of atmospheric particles. Such information is essential to better understand the weather and climate of a planet. Although SPEX can be used to study any planetary atmosphere, including the Earth's, the current design of SPEX is tailored to study Martian dust and clouds from an orbiting platform. SPEX’ 9 entrance pupils can simultaneously measure intensity spectra from 0.4 to 0.8 microns, in different directions along the flight direction (including two limb viewing directions). This way, the scattering phase functions of dust and cloud particles within a ground pixel are sampled while flying over it. SPEX can provide synergy with instruments on rovers and landers, as it provides an overview of spatial and temporal variations of the Martian atmosphere.

This paper proposes a new parallel computing genetic algorithm framework for designing fuel-optimal trajectories for interplanetary spacecraft missions. The framework can capture the deep search-space of the problem with the use of a fixed chromosome structure and hidden-genes concept, can explore the diverse set of candidate solutions with the use of the Adaptive and Twin-Space Crowding techniques, can execute on any High-Performance Computing (HPC) platform with the adoption of the portable Message Passing Interface (MPI) standard. New procedures are developed for determining trajectories in legs of the flight from the launch planet, and deep-space maneuver legs of the flight from the launch and non-launch planets. The chromosome structure maintains the time of flight as a free parameter within certain boundaries. The fitness or the cost function of the algorithm uses only the mission ΔV, and does not include the time of flight. The proposed algorithm is proven superior to the classical genetic algorithm both in terms of convergence characteristics for the cost function and the depth of the search space explored.

SPEX (Spectropolarimeter for Planetary EXploration) is an innovative, compact remotesensing instrument for measuring and characterizing aerosols in the atmosphere. The shoebox size instrument is capable of accurate full linear spectropolarimetry without moving parts or liquid crystals. High precision polarimetry is performed through encoding the degree and angle of linear polarization of the incoming light in a sinusoidal modulation of the spectrum. Measuring this intensity spectrum thus provides the spectral dependence of the degree and angle of linear polarization. Polarimetry has proven to be an excellent tool to study microphysical properties of atmospheric particles. Such information is essential to better understand the weather and climate of a planet. Although SPEX can be used to study any planetary atmosphere, including the Earth's, the current design of SPEX is tailored to study Martian dust and clouds from an orbiting platform. SPEX’ 9 entrance pupils can simultaneously measure intensity spectra from 0.4 to 0.8 microns, in different directions along the flight direction (including two limb viewing directions). This way, the scattering phase functions of dust and cloud particles within a ground pixel are sampled while flying over it. SPEX can provide synergy with instruments on rovers and landers, as it provides an overview of spatial and temporal variations of the Martian atmosphere.

著者人数：14名, Accepted: 2007-10-17, 資料番号: SA1000248000

著者人数：12名, Accepted: 2007-05-10, 資料番号: SA1000247000

The navigation (Earth-based Orbit determination) technology have interest in examining the possibility of using one-way Doppler data alone to navigate interplanetary spacecraft. The one-way data can be formulated as the standard count Doppler or as phase measurements, and the observation data can be received at a single station or differentiated if obtained simultaneously at two stations. A covariance analysis, which analyzes the accuracy obtainable by combinations of one-way Doppler data, is performed and compared with similar results using two-way Doppler and range (Radiometric). The assumed interplanetary orbit used was that of the Venus mission (Planet-C)., 資料番号: AA0063354017

Li ion batteries for space applications possess high discharge voltage, high specific energy, and lightweight properties, their research and development being conducted rapidly in recent years not only in the U.S. and France but also in Japan. Because of its weight reduction, the asteroid sample return mission spacecraft, HAYABUSA (MUSES-C before launch), which was launched in May 2003 and will bring back samples of the asteroid subsequently named ITOKAWA, 1998SF36, to the earth in June 2010, carried a Li ion battery with a specific energy of more than 85 Wh/kg. The battery consists of 11 prismatic cells with a rated capacity of 13.2 Ah, which are connected in series to supply power required to loads at a bus voltage of about 50 V during a discharge period. We have already conducted the reset operation three times successfully in orbit after the launch. By the effect of the reset operation, the balance of SOC (State of Charge) of each cell was kept. In swing-by operation in May 2004, we navigated the spacecraft in earnest only with the Li ion battery. And then, evaluating the first capacity test of the onboard battery in July 2004, of the spare cells conducted on the ground at the same time. As a result, it has been confirmed that the capacity degradation of the onboard battery is as predicted according to the simulation model, and agreed with capacity degradation of the spare cells. HAYABUSA arrived at ITOKAWA in 2005 autumn. Battery was to be discharged in terminator observations to take images of the asteroid and touch down on it to collect its samples, but there was not the opportunity. The result of the assumption examination by the spare cells on the ground, we considered that the battery had achieved the load capacity which is required by these operations., 資料番号: AA0049121002

This paper describes the status of the next-generation xenon-ion-engine research at ISTA (The Institute of Space Technology and Aeronautics). A set of ion extraction grids which would be ready for producing 200-mN thrust with a shorter aging period than ever was manufactured. A problem that the heater of a graphite-orifice hollow cathode failed in repeated heating was figured out. Discharge can start in five minutes from the onset of heating the main cathode. The only subject left in the main cathode life is confirming the life of the impregnated cathode. Research and Development of graphite-orifice-hollow-cathode neutralizer started. The output filter of the laboratory-model discharge supply was modified to reduce ripples in discharge current. An ion target was modified to reduce the deposition rate at the ion thruster., 資料番号: AA0049054026, レポート番号: JAXA-SP-05-008

The Institute of Space and Astronautical Science (ISAS) of Japan Aerospace Exploration Agency (JAXA) is studying a new magnetic sail propulsion system, called MagSail since 2002. A MagSail travels interplanetary space by capturing the energy of the solar wind. A MagSail realizes analogous interactions between the solar wind and an artificial magnetic field produced around a spacecraft, to obtain a force in the direction of the solar wind. In order to demonstrate the momentum transfer process of the magnetic sail, we have started a preliminary experiment. In the experimental studies, some strong interactions between the high-density (10(exp 19)/cu m) and high velocity (17 km/s) plasma flow and an artificial magnetic field of about 1 T was observed. Now, we are designing and manufacturing an experimental simulator of the magnetic sail propulsion system. Especially, development of a solar wind simulator will be a key issue for the MagSail experiments. We selected an MPD arcjet device to be the solar wind simulator. And a new twelve L-C ladder Pulse Forming Network (PFN) is also now in manufacturing and testing. In this report, a development status of the MPD solar wind simulator for the MagSail experiment is described and some experimental results are reported., 資料番号: AA0049054024, レポート番号: JAXA-SP-05-008

BepiColombo計画は、JAXAが「水星磁気圏探査機・MMO(Mercury Magnetospheric Orbiter)」、ESAが「水星表面探査機・MPO(Mercury Planetary Orbiter)」を分担する初の本格的な日欧共同計画で、JAXAとESAの国際協力の中心を担う。本計画は、ESAではコーナーストーンミッションとして、JAXAでは太陽系科学探査の基幹として、いずれでも最重要ミッションの1つである。両探査機は、一体で「ソユーズ・フレガート2B」ロケットで打ち上げられ、水星到達後に分離、協力して観測活動を行う。「ベピ・コロンボ(BepiColombo)」計画は、ESAとJAXAの大型国際共同により、未知の惑星・水星の磁場・磁気圏・表層・内部を初めて多角的・総合的に観測しようとするプロジェクトである。本計画の科学的意義は、以下の2つである。(1)固有磁場と磁気圏を持つ地球型惑星は地球と水星だけである。水星の詳細探査は、「初の惑星磁場・磁気圏の詳細比較」の機会となる。「惑星の磁場・磁気圏の普遍性と特異性」の知見に大きな飛躍をもたらすことが期待される。(2)水星は、磁場の存在と関係すると見られる巨大な中心核など特異な構造と歴史を持つ。その内部・表層の全球観測は、太陽系形成、特に「地球型惑星の起源と進化」の解明に貢献することが期待される。本計画は、上記に最適化された2つの周回探査機、すなわち表面・内部の観測に最適化された水星表面探査機Mercury Planetary Orbiter[MPO:3軸制御、低高度極軌道]と、磁場・磁気圏の観測に最適化された水星磁気圏探査機Mercury Magnetospheric Orbiter[MMO:スピン制御、楕円極軌道]から構成される。JAXAは、日本の得意分野を主目標とするMMO探査機を担当する。ESAは「打ち上げ・惑星間空間の巡航・水星周回軌道への投入」およびMPO探査機を担当する。両探査機の観測装置は、日欧合同科学チームが開発・運用する。磁場や磁気圏の様子がよくわかっている惑星は地球だけである。唯一の「磁場を持つ地球以外の地球型惑星」である水星は、初めての地球との詳細比較機会を提供する。この両者の比較は、磁場/磁気圏を巡る惑星環境の更なる理解に貢献するとともに、広く宇宙に存在する様々な磁気圏の特殊性・普遍性を知る大きなステップとなる。JAXAの担当する水星磁気圏探査機Mercury Magnetospheric Orbiter[MMO]はこの解明に最適化されたもので、以下の特徴を持つ。(1)軌道:磁気圏全域をカバーするため、「夜側を包含しうる長楕円極軌道」をとる。(2)姿勢:ワイヤアンテナ展開、粒子全方位計測のため、「スピン制御」とする。(3)電磁干渉対策:精密な磁場・プラズマ計測のため、帯磁・帯電・電磁ノイズ低減を図る。磁場の存在は、半径の3/4を占める巨大な中心核を持つ水星の特異な構造に関係する。水星の特異な姿の原因は、原始太陽系星雲の最も内側で最後に固まったとされるこの天体の「初期」に遡ると考えられる。ESAの担当する水星表面探査機Mercury Planetary Orbiter[MPO]は、この解明に最適化されたもので、以下の特徴を持つ。(1)軌道:表層・内部・磁場を全球計測するため、「低高度極軌道」をとる。(2)姿勢:表層を高空間分解で計測するため、「3軸制御」とし、常時水星表面を指向する。, 資料番号: AA0063353059

In an attempt to overcome some of the deficiencies of existing meteoroid models, NASA’s Space Environments and Effects (SEE) Program sponsored a 3 year research effort at the University of Western Ontario. The resulting understanding of the sporadic meteoroid environment – particularly the nature and distribution of the sporadic sources – were then incorporated into a new Meteoroid Engineering Model (MEM) by members of the Space Environments Team at NASA’s Marshall Space Flight Center. This paper discusses some of the revolutionary aspects of MEM which include (a) identification of the sporadic radiants with real sources of meteoroids, such as comets, (b) a physics-based approach which yields accurate fluxes and directionality for interplanetary spacecraft anywhere from 0.2 to 2.0 astronomical units (AU), and (c) velocity distributions obtained from theory and validated against observation. Use of the model, which gives penetrating fluxes and average impact speeds on the surfaces of a cube-like structure, is also described along with its current limitations and plans for future improvements.