Interplanetary Spacecraft Research Articles

Analysis of Single Event Effects Created by Space Ionizing Radiation in the Microcircuits of the Interplanetary Spacecraft Radio Electronic Equipment

Analysis of Single Event Effects Created by Space Ionizing Radiation in the Microcircuits of the Interplanetary Spacecraft Radio Electronic Equipment

First measurements of periodicities and anisotropies of cosmic ray flux observed with a water-Cherenkov detector at the Marambio Antarctic base

A new water-Cherenkov radiation detector, located at the Argentine Marambio Antarctic Base (64.24S-56.62 W), has been monitoring the variability of galactic cosmic ray (GCR) flux since 2019. One of the main aims is to provide experimental data necessary to study interplanetary transport of GCRs during transient events at different space/time scales. In this paper we present the detector and analyze observations made during one full year. After the analysis and correction of the GCR flux variability due to the atmospheric conditions (pressure and temperature), a study of the periodicities is performed in order to analyze modulations due to heliospheric phenomena. We can observe two periods: (a) 1 day, associated with the Earth’s rotation combined with the spatial anisotropy of the GCR flux; and (b) ∼ 30 days due to solar impact of stable solar structures combined with the rotation of the Sun. From a superposed epoch analysis, and considering the geomagnetic effects, the mean diurnal amplitude is ∼ 0.08% and the maximum flux is observed in ∼ 15 h local time (LT) direction in the interplanetary space. In such a way, we determine the capability of Neurus to observe anisotropies and other interplanetary modulations on the GCR flux arriving at the Earth.

Optimal Earth Gravity-Assist Maneuvers with an Electric Solar Wind Sail

Propellantless propulsive systems such as Electric Solar Wind Sails are capable of accelerating a deep-space probe, only requiring a small amount of propellant for attitude and spin-rate control. However, the generated thrust magnitude is usually small when compared with the local Sun’s gravitational attraction. Therefore, the total velocity change necessary for the mission is often obtained at the expense of long flight times. A possible strategy to overcome this issue is offered by an Earth gravity-assist maneuver, in which a spacecraft departs from the Earth’s sphere of influence, moves in the interplanetary space, and then re-encounters the Earth with an increased hyperbolic excess velocity with respect to the starting planet. An Electric Solar Wind Sail could effectively drive the spacecraft in the interplanetary space to perform such a particular maneuver, taking advantage of an augmented thrust magnitude in the vicinity of the Sun due to the increased solar wind ion density. This work analyzes Earth gravity-assist maneuvers performed with an Electric Solar Wind Sail based probe within an optimal framework, in which the final hyperbolic excess velocity with respect to the Earth is maximized for a given interplanetary flight time. Numerical simulations highlight the effectiveness of this maneuver in obtaining a final heliocentric orbit with high energy.

Head-Mounted Dynamic Visual Acuity for G-Transition Effects During Interplanetary Spaceflight: Technology Development and Results from an Early Validation Study.

INTRODUCTION: Dynamic visual acuity (DVA) refers to the ability of the eye to discern detail in a moving object and plays an important role whenever rapid physical responses to environmental changes are required, such as while performing tasks onboard a space shuttle. A significant decrease in DVA has previously been noted after astronauts returned from long-duration spaceflight (0.75 eye chart lines, 24 h after returning from space). As part of a NASA-funded, head-mounted multimodal visual assessment system for monitoring vision changes in spaceflight, we elaborate upon the technical development and engineering of dynamic visual acuity assessments with virtual reality (VR) technology as the first step in assessing astronaut performance when undergoing G-transitional effects. We also report results from an early validation study comparing VR DVA assessment with traditional computer based DVA assessment.METHODS: Various VR/AR headsets have been utilized to implement DVA tests. These headsets include HTC Vive Pro Eye system. Epic's game engine UnrealEngine 4 Version 4.24 was used to build the framework and SteamVR was used to experience virtual reality content. Eye tracking technology was used to maintain fixation of the participant. An early validation study with five participants was conducted comparing this technology versus traditional DVA with a laptop.RESULTS: The head-mounted technology developed for assessing DVA changes during G-transitions is fully functional. The results from the early validation study demonstrated that the two DVA tests (laptop-based and VR) indicated a strong association between both methods (Pearson correlation coefficient of 0.91). A Bland-Altman plot was employed to assess levels of agreement, with all data points falling within the limits of agreement.DISCUSSION: The results from this early validation study indicate that head-mounted DVA assessment performs similarly to traditional laptop-based methods and is a promising method for assessing DVA during spaceflight, particularly in G-transitions. Future studies are required for further assessment of validation and reliability of this technology. With its ease of use, accessibility, and portable design, VR DVA has the potential in the near-future to replace conventional methods of assessing DVA. The technology will likely be an important aspect to help monitor functionality and safety during interplanetary missions where astronauts are exposed to G-transitions.Waisberg E, Ong J, Zaman N, Kamran Sa, Lee AG, Tavakkoli A. Head-mounted dynamic visual acuity for G-transition effects during interplanetary spaceflight: technology development and results from an early validation study. Aerosp Med Hum Perform. 2022; 93(11):800-805.

Dry heat sterilization modelling for spacecraft applications.

Inactivation processes using heat are widely used for disinfection and sterilization. Dry heat sterilization of spacecraft equipment has been the preferred microbial inactivation method as part of interplanetary travel protection strategies. An antimicrobial model, based on temperature and exposure time based on experimental data, was developed to provide reliable sterilization processes to be used for interplanetary applications. Bacillus atrophaeus spores, traditionally used to challenge dry heat sterilization processes, were tested over a range of temperatures in comparison with spores of Bacillus canaveralius that have been shown to have a higher heat resistance profile. D-value and Z-values were determined and used to develop a mathematical model for parametric sterilization applications. The impact of the presence of a contaminating soil, representative of Mars dust, was also tested to verify the practical application of the model to reduce the risk of microbial contamination in such environments. The sterilization model developed can be used as an intrinsic part of risk reduction strategies for interplanetary protection. Forward and backward planetary protection strategies to reduce the risks of microbial contamination during interplanetary exploration and research is an important consideration. The development of a modern sterilization model, with consideration of microorganisms identified with higher levels of heat resistance than traditionally deployed in terrestrial applications, allows for the consideration of optimal inactivation processes to define minimum criteria for engineering design. The ability to inactivate living microorganisms, as well as to degrade biomolecules, provides a reliable method to reduce the risk of known and potentially unknown contaminants in future applications.

Active shape control for flexible space structures using an optimal gyricity distribution

An active shape control approach for a circular flexible space structure is studied. The shape of these flexible structures may need active shape control due to some particular mission objectives. For example, antenna reflectors may have requirements for their shape accuracy to guarantee communication performance; and some solar sails may change their shape to realize different commissions during interplanetary flight. This paper investigates an active shape control process executed by the gyricity (stored angular momentum) distribution existing in the circular flexible space structure. The shape of the circular flexible space structure is expected to be reformed from a plane plate to a paraboloidal plate. An optimal gyricity distribution is derived based on the optimal control theory for systems described by partial differential equations. Distributed forces can be generated by the optimal gyricity distribution in a rotating field to implement the active shape control. The dynamic model of the circular flexible space structure is established for the active shape control through the finite element method. Numerical simulation validates the functionality of the shape control method, and illustrates the shape-adjusting process of the circular flexible space structure.

Sequential Processing of Inter-Satellite Doppler Tracking for a Dual-Spacecraft Configuration

The navigation of future interplanetary spacecraft will require an increasing degree of autonomy to enhance space system performance. A real-time trajectory determination is of paramount importance to reduce the risks of operations devoted to the exploration of celestial bodies in the solar system and to reduce the dependence and the loading on the ground systems. We present a technique for a sequential estimation of spacecraft orbits through the processing of line-of-sight relative velocity measurements that are acquired by the novel inter-satellite tracking system. This estimation scheme is based on the extended Kalman filter and is tested and validated in a realistic Mars mission scenario. Our numerical simulations suggest that the proposed navigation system can provide accuracies of a few meters in position and a few millimeters per second in velocity.

A spacecraft-compatible combined artificial gravity and exercise (CAGE) system to sustain astronaut health in the next generation of long-term spaceflight

Human spaceflight exposes astronauts to prolonged periods of microgravity and high doses of radiation, leading to life-threatening cardiovascular, musculoskeletal and neurological damage. One of the most dangerous effects of microgravity is the accumulation of cerebrospinal fluid in the intracranial space. The cephalad-fluid shift and muscular atrophy triggered and worsened by microgravity, largely contribute to physiological deconditioning, making medical care for astronauts challenging in many cases. Artificial Gravity (AG) produced by centrifugation may provide an efficient countermeasure against spaceflight physiological deconditioning. The acceleration forces in a centrifuge follow an increasing pattern in the general direction of the upper to lower body, resulting in the creation of AG. Centrifuge-produced AG results in a downward shift of fluid towards the lower body. This downward motion restores fluid balance in the body, lowering the pressure inside the intracranial space and the upper body. Our team at Simon Fraser University's Aerospace Physiology Laboratory has proposed a design for a Combined Artificial Gravity and Exercise (CAGE) device, that would be compatible with the next generation of the commercial spacecrafts and space stations, as well as Lunar bases. CAGE features a customized squat module built at the circumference of the centrifuge apparatus. Squatting activates a full-body workout that allows for an efficient shift of fluid towards the lower body while preventing muscle and bone density loss. Squatting motion will also partially power the rotation of the device, providing a sustainable power source for the apparatus during long-term missions. It is expected that incorporating our proposed CAGE on board of upcoming spacecraft could reduce the current exercise time by approximately half by eliminating the need to transition between devices and maximizing multi-system workouts. The significance of this reduction in scheduled exercise time, besides reducing medical care complications, is the effective time that can be added to running scientific experiments and operational tasks. Along with the maintenance of skeletal, muscle, and cardiovascular systems, active maintenance of fluid balance in the body will enable astronauts to perform long-term space missions with a significantly lower risk of medical complications associated with microgravity. The use of AG combined with exercise in future space missions will be an essential element for interplanetary travel, medical care, and life establishment on other planetary surfaces.

Decentralized X-ray pulsar-based navigation system for space-borne gravitational wave detector

In this paper, the inter-satellite link (ISL) aided X-ray pulsar-based navigation (XPNAV) system is studied to improve the survivability of space-borne gravitational wave detector. An unscented transform (UT) based distributed Kalman estimator is proposed for state estimation within less computational and communication costs. Three different navigation scenarios are designed based on a typical large-scale distributed heliocentric orbital space-borne gravitational wave detector, Laser Interferometer Space Antenna (LISA). Simulation results show that the positioning root-mean-square error (RMSE) reduces ̃28% after introducing the ISL to XPNAV. Moreover, the proposed distributed Kalman estimator and the classical Kalman estimator shows similar performance in XPNAV/ISL integrated navigation system with the positioning RMSE of ̃528m and ̃520m, respectively. Compared with the classical method, both analytical and simulating analyses demonstrate that the proposed algorithm efficiently reduces the computational costs to 1/N2 for a team with N agents and avoids additional communication needs simultaneously. The efficient distributed Kalman estimator-based XPNAV/ISL integrated navigation provides a high-performance autonomous navigation solution for interplanetary spacecraft formation flying missions.

The Second Stage of BTN Neutron Space Experiment onboard the Russian Section of the International Space Station: the BTN-M2 Instrument

As recent studies onboard various spacecraft have shown, one unresolved technical problem of manned interplanetary flights at the moment is the high radiation background of interplanetary space, which, as in the case of a manned mission to Mars, can be critically dangerous for the crew. Work on this topic is being carried out by all space agencies. One such space experiment is represented by the BTN-Neutron experiment onboard the Russian section of the International Space Station (ISS). The main result of the work was the construction of the BTN-M2 instrument for creating effective radiation protection onboard prospective manned spacecraft, creating an engineering model of the radiation background both inside and outside the ISS, and for registration of γ rays and neutrons during solar flares and cosmic γ-ray bursts.

О надежности функционирования механизмов раскрытия десантных модулей

The development of mechanisms for deploying, fixing nodes and systems of interplanetary automatic spacecraft landing modules is the most difficult engineering task, errors in its solution lead to critical or fatal failures. The fact that interplanetary missions are rare and the implementation of each of them is very expensive leads to the need for practically trouble-free operation of deploying mechanisms, which in turn requires improving the efficiency of design techniques and computational and experimental reliability assurance in the face of limited statistical data and incomplete knowledge of the conditions and effects of planets on interplanetary spacecraft. In contrast to foreign experience, in domestic practice insufficient attention is payed to the methodology for designing highly reliable opening and fixation mechanisms. The article considers approaches to the computational and experimental reliability assurance of the functioning the mechanisms for deploying landing modules. The factors having a decisive effect on the reliability of the deploying and fixation mechanisms are analyzed. It is shown that the reliability of the functioning the deploying and fixation mechanisms largely determines the reserves of driving moments (forces) of the deploying drives, taking into account design and technological factors, and for the landing module mechanisms, they should be calculated based on the conditions and effects of the destination planets (climatic, atmospheric and gravitational)

Hydrogen ice within lunar polar craters

We might have overlooked the widespread presence of methanol on the Moon and hydrogen ice within lunar polar craters. Here we show that (1) US Moon Mineralogy Mapper (M3) cannot distinguish between hydroxyl radicals from lunar water and hydroxyl groups from lunar methanol because the absorption strengths of the two are all 2.9 μm, and there are no established methods to distinguish them using the 2.9 μm band. Water ice within lunar polar craters is worthy of renewed investigation. (2) The ‘surficial water’ illogically appears at the lunar equator based on M3 spectral detection, seriously shaking the credibility of M3 spectral data analysis. (3) Methanol and water brought about by the interstellar methanol ice react in lunar carbon-rich regolith using Ce/Cu/Zn–Al catalysts to produce massive molecular hydrogen. This molecular hydrogen escapes into the lunar exosphere and is transported to lunar cold traps, forming brown-black solid molecular hydrogen (hydrogen ice) that appears in snowflake patterns at the lowest temperature within lunar polar craters. (4) The author concludes with a model of the physico-chemical process chains on the lunar surface, which systematically elucidates the mechanism of lunar hydrogen ice formation. (5) Hydrogen ice within lunar polar craters can become a fuel base for interplanetary flight.

Feasibility studies for a dust observatory between earth and the asteroid belt

Cosmic dust transports information about the composition and evolution of distant realms over space and time. Dust sources may be in our local neighbourhood, such as the surfaces of moons and small bodies, or further away, in the galactic environment. The interior of moons like Io or Enceladus are well known dust sources in our solar system. Dust grains are therefore like probes, giving us the opportunity to investigate these objects at a distance. Thus, a new field of activity has been born: Dust Astronomy. The ultimate tool for Dust Astronomy is a dust observatory which was never been flown so far. Until today, all our knowledge is based on smaller individual dust detectors flown on various interplanetary spacecraft. Recently, a new generation of dust telescopes, which can be combined to a full dust observatory, became available. The scientific goal of such an observatory is to characterise our micrometeoroid environment with high precision and sensitivity and to record an inventory of various dust populations from asteroidal, cometary and interstellar dust sources.Two competitive studies on a Dust Astronomy mission were performed as part of a master’s course, including mission analysis and spacecraft design. The goal was to demonstrate the feasibility of an observatory reaching the main asteroid belt with a minimum spacecraft mass using electric propulsion. Additional secondary payloads supporting the primary objective were selected as well. The results prove that small probes with less than 700kg mass are capable of placing an array of dust telescopes deep in the asteroid belt, leading to a huge leap in Dust Astronomy and our knowledge about the local dust environment.

Comparison of the particle flux measured by Liulin-MO dosimeter in ExoMars TGO science orbit with those calculated by models

The knowledge of the space radiation environment in spacecraft transition and in Mars vicinity is of importance for the preparation of the human exploration of Mars. ExoMars Trace Gas Orbiter (TGO) was launched on March 14, 2016 and was inserted into circular Mars science orbit (MSO) with a 400 km altitude in March 2018. The Liulin-MO dosimeter is a module of the Fine Resolution Epithermal Neutron Detector (FREND) aboard ExoMars TGO and has been measuring the radiation environment during the TGO interplanetary travel to Mars and continues to do so in the TGO MSO. One of the scientific objectives of the Liulin-MO investigations is to provide data for verification and benchmarking of the Mars radiation environment models. In this work we present results of comparisons of the flux measured by the Liulin-MO in TGO Mars orbit with calculated estimations. Described is the methodology for estimation the particle flux in Liulin-MO detectors in MSO, which includes modeling the albedo spectra and procedure for calculation the fluxes, recorded by Liulin-MO on the basis of the detectors shielding model. The galactic cosmic rays (GCR) and Mars albedo radiation contribution to the detectors count rate was taken into account. The GCR particle flux was calculated using the Badhwar O'Neil 2014 model for December 1, 2018. Detailed calculations of the albedo spectra of protons, helium ions, neutrons and gamma rays at 70 km height, performed with Atmospheric Radiation Interaction Simulator (AtRIS), were used for deriving the albedo radiation fluxes at the TGO altitude. In particular, the sensitivity of the Liulin-MO semiconductor detectors to neutron and gamma radiation has been considered in order to calculate the contribution of the neutral particles to the detected flux. The results from the calculations suggest that the contribution of albedo radiation can be about 5% of the measured total flux from GCR and albedo at the TGO altitude. The critical effect of TGO orientation, causing different shading of the GCR flux by Mars, is also analysed in detail. The comparison between the measurements and estimations shows that the measured fluxes exceed the calculated values by at least 20% and that the effect of TGO orientation change is approximately the same for the calculated and measured fluxes. Accounting for the ACR contribution, secondary radiation and the gradient of GCR spectrum from 1 AU to 1.5 AU, the calculated flux may increase to match the measurement results. The results can serve for the benchmarking of GCRs models at Martian orbit.

MINERVA: A CubeSat for demonstrating DNA damage mitigation against space radiation in C. elegans by using genetic modification

The ideas of deep-space human exploration, interplanetary travel, and space civilizations are becoming a reality. However, numerous hindrances remain standing in the way of accomplishing these feats, one of which is space ionizing radiation. Space ionizing radiation has become the most hazardous health risk for long-term human space exploration, as it can induce chromosomal damage and epigenetic changes. The Minerva mission aims to demonstrate cutting-edge technology to inhibit DNA damage against deep-space radiation exposure by using genetic modification. The concept of the experiment is to transform a creature with radiation intolerance into a transgenic organism that is radiation-tolerant. In this mission, Caenorhabditis elegans (C. elegans) will be genetically engineered with a protein-coding gene associated with DNA damage protection called damage suppressor (Dsup). Dsup is a nucleosome-binding protein from the tardigrade Ramazzottius varieornatus that has a unique ability to prevent DNA damage. This paper describes the feasibility of Minerva CubeSat, which will venture out to cis-lunar orbit with a biosensor payload capable of sustaining and culturing C. elegans under space environment conditions for 4 months. The mission will set in motion a paradigm shift corresponding to future space medicines and how they will be developed in the future, introducing a platform suitable for future experiments in the fields of space biology. Ultimately, the paramount objective of Minerva will be to test the limits of genetic engineering and incorporate it into the arduous journey of human perseverance to overcome the boundaries of space exploration—a vital step in making Mars colonization safe.

Effect of Exercise on Energy Expenditure and Body Composition in Astronauts Onboard the International Space Station: Considerations for Interplanetary Travel.

Body mass (BM) loss and body composition (BC) changes threaten astronauts' health and mission success. However, the energetic contribution of the exercise countermeasure to these changes has never been investigated during long-term missions. We studied energy balance and BC in astronauts during 6-month missions onboard the International Space Station. Before and after at least 3months in space, BM, BC, total and activity energy expenditure (TEE and AEE) were measured using the doubly labeled water method in 11 astronauts (2011-2017). Physical activity (PA) was assessed by the SensewearPro® activity-device. Three-month spaceflight decreased BM (-1.20kg [SE 0.5]; P = 0.04), mainly due to non-significant fat-free mass loss (FFM; -0.94kg [0.59]). The decrease in walking time (-63.2min/day [11.5]; P < 0.001) from preflight was compensated by increases in non-ambulatory activities (+ 64.8min/day [18.8]; P < 0.01). Average TEE was unaffected but a large interindividual variability was noted. Astronauts were stratified into those who maintained (stable_TEE; n = 6) and those who decreased (decreased_TEE; n = 5) TEE and AEE compared to preflight data. Although both groups lost similar BM, FFM was maintained and FM reduced in stable_TEE astronauts, while FFM decreased and FM increased in decreased_TEE astronauts (estimated between-group-difference (EGD) in ΔFFMindex [FFMI] 0.87kg/m2, 95% CI + 0.32 to + 1.41; P = 0.01, ΔFMindex [FMI] -1.09kg/m2, 95% CI -2.06 to -0.11kg/m2; P = 0.03). The stable_TEE group had higher baseline FFMI, and greater baseline and inflight vigorous PA than the decreased_TEE group (P < 0.05 for all). ΔFMI and ΔFFMI were respectively negatively and positively associated with both ΔTEE and ΔAEE. Both ground fitness and inflight overall PA are associated with spaceflight-induced TEE and BC changes and thus energy requirements. New instruments are needed to measure real-time individual changes in inflight energy balance components.

A new method to determine solar energetic particle anisotropies and their associated uncertainties demonstrated for STEREO/SEPT

Context. The shape of the pitch-angle distribution (PAD) of solar energetic particles (SEPs) can be used to infer information about their source and interplanetary transport. In modeling and observational studies of SEP events, these PADs are frequently applied to determine the anisotropy which is a proxy for the strength of the pitch-angle scattering during transport. For the determination of the PAD, derivation of the pitch angle of SEPs takes on a crucial role. For most instrument-sampled PADs, the particle’s pitch angle cannot be resolved directly but is usually approximated by considering the time-averaged in situ magnetic field direction, and the center viewing direction of the telescope. However, variations of the magnetic field, and the extent of the physical opening of the instrument lead to uncertainty on the determination of the pitch angle and therefore to uncertainty on the anisotropy and its interpretation. Aims. In this work, we present a new method to determine a distribution of anisotropy values which allows us to estimate the corresponding uncertainty ranges. We apply our method to electron measurements by the Solar Electron and Proton Telescope on board each STEREO spacecraft. Methods. We determined a distribution of anisotropy values by solving an inversion problem that takes into account the directional response of the instrument, the variation of the in situ magnetic field, and the stochastic nature of particle detection. Using 95% confidence intervals, we estimate the uncertainty on the anisotropy. Results. The application of our method to a solar electron event observed by STEREO B on 14 August 2010 yields a maximum anisotropy of 1.9 with an uncertainty on the order of ±0.1. During the background period, the anisotropy shows strong fluctuations, and absolute uncertainties on the order of ±0.5 that are attributable to low counting statistics.

Surgery in deep space travel

The article is devoted to the problems that the crew of a spacecraft may face during long flights in open space during interplanetary travel. The most probable diseases that can develop in crew members under conditions of medical selection of candidates on earth are shown. The issues of instrumental diagnostics of acute diseases and injuries of the thoracic and abdominal cavities are considered. The main attention in the article is paid to the issues of the operational manual in the conditions of microgravity of the spacecraft. Possible surgical accesses for the treatment of acute surgical diseases and possible injuries of crew members are being considered. It also describes possible problems on the part of both the surgical technique itself with virtually no gravity, and the reason not allowing the use of robotic remote surgical techniques.

Robust Low-Thrust Trajectory Optimization Using Convex Programming and a Homotopic Approach

A robust algorithm to solve the low-thrust fuel-optimal trajectory optimization problem for interplanetary spacecraft is developed in this article. The original nonlinear optimal control problem is convexified and transformed into a parameter optimization problem using an arbitrary-order Gauss–Lobatto discretization scheme with nonlinear control interpolation. A homotopic approach that considers the energy-to-fuel smoothing path is combined with an adaptive second-order trust-region mechanism to increase performance. The overall robustness is assessed in several fuel-optimal transfers with poor initial guesses. The results show a superior performance in terms of convergence and computational time compared to standard convex programming approaches in the literature.

The Transmission of ULF Waves From the Solar Wind to the Magnetosphere: An Analysis of Some Critical Aspects

Several critical aspects may influence the analysis of the relationship between the solar wind (SW) and magnetospheric fluctuations, for example, the characteristics and frequency of SW fluctuations that are expected to impinge the magnetosphere may not be the same when they are observed by spacecraft located at different places in front of the magnetosphere; similarly, the choice of analytical methods adopted for the spectral analysis might influence the frequency estimate (as well as the wave identification itself) both in the SW and magnetosphere. Focusing our attention on these aspects, we present an analysis of SW compressional fluctuations (f ≈ 1–5 mHz), following two interplanetary shocks observed by two interplanetary spacecraft, regarded as two different situations in terms of spacecraft separation and distance from the magnetosphere. Our results show that some differences in the characteristics of SW fluctuations emerge when the same stream is observed at different places and confirm the critical role of analytical methods in determining fluctuation characteristics. We compared aspects of SW fluctuations with those of magnetospheric fluctuations following the sudden impulses due to the impact of interplanetary shocks. For this scope, we examined observations by two satellites at geostationary orbit and at several ground-based stations. We found that the magnetospheric fluctuations were related to compressional SW fluctuations approximately at the same frequencies, with no evidence for wave activity of internal origin or directly driven by the shock impact.