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The lunar surface is a complicated and unknown terrain, and hence, astronauts must be trained to travel on that surface by using a prototype vehicle on the Earth's terrain. However, the gravity of the Earth is six times that of the Moon; thus, the acceleration of a prototype vehicle on the Earth will differ from that of a manned lunar rover on the Moon, when the same acceleration handling input is provided. To obtain the same acceleration in the prototype vehicle on the Earth as that obtained on the Moon, an imitation handling ratio describing the relationship between the acceleration handling input and the wheel rolling speed is proposed in order to replicate the lunar gravitational conditions on the Earth. First, a whole-vehicle acceleration model was established based on the mechanical model of a deformable wheel with a mesh surface. Thereby an acceleration imitation algorithm was derived. A prototype vehicle for use on the Earth is proposed for the purpose of imitating the manned lunar rover under four different vehicle conditions. Fitted functions were used in order to obtain the imitation handling ratio. Finally, experiments were conducted to verify the imitation method; the results revealed that the prototype vehicle on the Earth could effectively approximate the same accelerations experienced by a manned lunar rover, when equivalent acceleration handling inputs were provided. [ABSTRACT FROM AUTHOR]

We tested science operations strategies developed for use in remote mobile spacecraft missions, to determine whether reconnoitering a site of potential habitability prior to in-depth study (a walkabout-first strategy) can be a more efficient use of time and resources than the linear approach commonly used by planetary rover missions. Two field teams studied a sedimentary sequence in Utah to assess habitability potential. At each site one team commanded a human “rover" to execute observations and conducted data analysis and made follow-on decisions based solely on those observations. Another team followed the same traverse using traditional terrestrial field methods, and the results of the two teams were compared. Test results indicate that for a mission with goals similar to our field case, the walkabout-first strategy may save time and other mission resources, while improving science return. The approach enabled more informed choices and higher team confidence in choosing where to spend time and other consumable resources. The walkabout strategy may prove most efficient when many close sites must be triaged to a smaller subset for detailed study or sampling. This situation would arise when mission goals include finding, identifying, characterizing or sampling a specific material, feature or type of environment within a certain area. [ABSTRACT FROM AUTHOR]

The requirements for the design of rovers and sample collecting devices for the Moon are driven by the harsh and diverse thermal lunar environment. Local lunar surface temperatures are governed by boulders and craters. The present work quantifies the changes in solar and infrared heat fluxes q ̇ Sol and q ̇ IR impinging on a rover or a sample collecting device, on the surface of the Moon, by combining lunar surface models, spacecraft and manipulator models, and transient thermal calculations. The interaction between a rover, boulders, and craters was simulated for three solar elevation angles ( θ = 2°, 10°, and 90°), resembling lunar surface temperatures of T reg = 170, 248, and 392 K, respectively. Infrared and solar heat fluxes for paths in the vicinity of a single boulder, a field of five boulders, and a single crater were compared to a path on an unobstructed surface. The same heat fluxes were applied to closed and open sample collecting devices to investigate the temperature development of the transported regolith sample. The results show how total received infrared heat on a rover may increase by up to 331%, over the course of a transit in front of sunlit boulders compared to the same transit over an unobstructed plane. Temporary this leads to a 12-fold increased infrared heat flux at closest distance to the obstacle. A transit through a small bowl shaped crater on the other hand may decrease total received solar heat by as much as 86%. Relative as well as absolute influence of surface features on received heat fluxes increases significantly towards smaller solar elevation angles. The temperature of pristine samples, transported in closed or open sample collecting devices, increase from 120 to 150 K within 1 to 1.3 h if exposed to direct solar illumination and infrared heat. Protection from solar illumination yields in 8-fold and 5-fold increased transport times for closed and open sample devices, respectively. Closed sample transporters dampen short exposure times to solar illumination but also lead to higher sample end temperatures in the same period. The degradation of absorptivity and emissivity, due to coverage with dust or scratches obtained during operation, will significantly alter the sample temperature in a negative manner. The results indicate that transient thermal analyses, that take into account the local lunar environment, are feasible and permit more detailed thermal envelopes for future rover missions to the surface of the Moon. [ABSTRACT FROM AUTHOR]

This article presents a comprehensive path-planning method for lunar and planetary exploration rovers. In this method, two new elements are introduced as evaluation indices for path planning: 1) determined by the rover design and 2) derived from a target environment. These are defined as the rover's internal and external elements, respectively. In this article, the rover's locomotion mechanism and insolation (i.e., shadow) conditions were considered to be the two elements that ensure the rover's safety and energy, and the influences of these elements on path planning were described. To examine the influence of the locomotion mechanism on path planning, experiments were performed using track and wheel mechanisms, and the motion behaviors were modeled. The planned paths of the tracked and wheeled rovers were then simulated based on their motion behaviors. The influence of the insolation condition was considered through path plan simulations conducted using various lunar latitudes and times. The simulation results showed that the internal element can be used as an evaluation index to plan a safe path that corresponds to the traveling performance of the rover's locomotion mechanism. The path derived for the tracked rover was found to be straighter than that derived for the wheeled rover. The simulation results also showed that path planning using the external element as an additional index enhances the power generated by solar panels under various insolation conditions. This path-planning method was found to have a large impact on the amount of power generated in the morning/evening and at high-latitude regions relative to in the daytime and at low-latitude regions on the moon. These simulation results suggest the effectiveness of the proposed pathplanning method. [ABSTRACT FROM AUTHOR]

Planetary rovers have played significant roles in exploring potential landing sites on Mars and the moon, and they will continue to work as one of the most effective tools for future planetary missions. Sample acquisition for on-site analysis and possible return to earth is one of the most challenging and promising missions for planetary exploration. The Kapvik microRover is a smart, reconfigurable all-terrain multimission microRover prototype that was developed to address the challenges of planetary exploration and sample acquisition. The Kapvik microRover consists of a mobile platform, an onboard robotic mast, and a number of scientific sensors. This article presents the development of the Kapvik robotic mast, which combines a robotic arm and microRover mast, delivering both of their functions. Namely, the innovative robotic mast can perform sample acquisition and transfer for storage as well as assist the microRover in navigation and inspection. To satisfy the stowage requirements and provide triangular support for the navigation cameras, a novel locking mechanism and associated control techniques are designed to enable self-locking and unlocking of the robotic mast. A prototype has been developed for the Canadian Space Agency, and extensive experiments have been conducted to validate the proposed design. [ABSTRACT FROM AUTHOR]

This paper discusses a landing response control system based on the momentum exchange principle for planetary exploration spacecraft. In the past, landing gear systems with cantilever designs that incorporate honeycomb materials to dissipate shock energy through plastic deformation have been used, but once tested before launch, the system cannot be used in a real mission. The sky crane system used for the Mars Science Laboratory by NASA can achieve a safe and precise landing, but it is highly complex. This paper introduces a momentum exchange impact damper (MEID) that absorbs the controlled object׳s momentum with extra masses called damper masses. The MEID is reusable, which makes it easy to ensure the landing gear׳s reliability. In this system, only passive elements such as springs are needed. A single-axis (SA) model has already been used to verify the effectiveness of MEIDs through simulations and experiments measuring the rebound height of the spacecraft. However, the SA model cannot address the rotational motion and tipping of the spacecraft. This paper presents a two-landing-gear-system (TLGS) model in which multiple MEIDs are equipped for two-dimensional analysis. Unlike in the authors׳ previous studies, in this study each MEID is launched when the corresponding landing gear lands and the MEIDs do not contain active actuators. This mechanism can be used to realize advanced control specifications, and it is simply compared with previous mechanisms including actuators, in which all of the MEIDs are launched simultaneously. If each MEID works when the corresponding gear lands, the rebound height of each gear can be minimized, and tipping can be prevented, as demonstrated by the results of our simulations. [ABSTRACT FROM AUTHOR]

The Japan Aerospace Exploration Agency (JAXA) views the lunar lander SELENE-2 as the successor to the SELENE mission. In this presentation, the mission objectives of SELENE-2 are shown together with the present design status of the spacecraft. JAXA launched the Kaguya (SELENE) lunar orbiter in September 2007, and the spacecraft observed the Moon and a couple of small satellites using 15 instruments. As the next step in lunar exploration, the lunar lander SELENE-2 is being considered. SELENE-2 will land on the lunar surface and perform in-situ scientific observations, environmental investigations, and research for future lunar utilization including human activity. At the same time, it will demonstrate key technologies for lunar and planetary exploration such as precise and safe landing, surface mobility, and overnight survival. The lander will carry laser altimeters, image sensors, and landing radars for precise and safe landing. Landing legs and a precisely controlled propulsion system will also be developed. A rover is being designed to be able to travel over a wide area and observe featured terrain using scientific instruments. Since some of the instruments require long-term observation on the lunar surface, technology for night survival over more than 2 weeks needs to be considered. The SELENE-2 technologies are expected to be one of the stepping stones towards future Japanese human activities on the moon and to expand the possibilities for deep space science. [ABSTRACT FROM AUTHOR]

Geomagnetic measurements are important in space weather and engineering applications of earth-orbiting satellites. This research presents an innovative algorithm that enables high-quality magnetic field measurements on spacecraft without booms. The algorithm estimates the background field using multiple magnetometers and current telemetry on board a spacecraft. Results of a hardware-in-the-loop simulation showed an order of magnitude reduction in the magnetic effects of spacecraft onboard time-varying currents—from 300 nT to an average residual of 15 nT. [ABSTRACT FROM AUTHOR]

The Mars Science Laboratory, also called Curiosity, is a rover mission that launched on 26 November 2011 and landed on Mars 6 August 2012 in Gale Crater. The main challenges for the interplanetary navigation of the mission were to deliver the spacecraft to the correct interface point above the atmosphere of Mars and to accurately tell the spacecraft where it was as it entered the atmosphere. The spacecraft used guidance during its descent to Mars before the deployment of the parachute in order to minimize landing dispersions, resulting in a smaller landing zone that was closer to terrain of high scientific interest. This required an accurate delivery of the spacecraft to the entry interface and an update of the spacecraft state at entry, which was used to initialize the descent guidance system. Orbit determination during cruise was very accurate, being able to predict the line-of-sight position of the spacecraft after one week to within a few meters during the final weeks of approach. The spacecraft hit the top of the Martian atmosphere just 200 m from where it had been predicted to enter more than six days earlier, when it was still 2.6 million km away from Mars. This excellent level of accuracy was achieved by a combination of factors, including spacecraft characteristics, tracking data processing, dynamical modeling choices, and navigation filter setup. The accurate interplanetary navigation contributed to the very precise landing performance and to the overall success of the mission. [ABSTRACT FROM AUTHOR]

Future planetary rovers are expected to probe across steep sandy slopes such as crater rims where wheel slippage can be a critical problem. One possible solution is to equip locomotion mechanisms with redundant actuators so that the rovers are able to actively reconfigure themselves to adapt to the target terrain. This study modeled a reconfigurable rover to analyze the effects of posture change on rover slippage over sandy slopes. The study also investigated control strategies for a reconfigurable rover to reduce slippage. The proposed mechanical model consists of two models: a complete rover model representing the relationship between the attitude of the rover and the forces acting on each wheel, and a wheel-soil contact force model expressed as a function of slip parameters. By combining these two models, the proposed joint model relates the configuration of the rover to its slippage. The reliability of the proposed model is discussed based on a comparison of slope-traversing experiments and numerical simulations. The results of the simulations show trends similar to those of the experiments and thus the validity of the proposed model. Following the results, a configuration control strategy for a reconfigurable rover was introduced accompanied by orientation control. These controls were implemented on a four-wheeled rover, and their effectiveness was tested on a natural sand dune. The results of the field experiments show the usefulness of the proposed control strategies. [ABSTRACT FROM AUTHOR]

A tumbleweed rover is a spherical wind-driven vehicle designed to negotiate harsh Martian terrain while searching for areas of scientific interest. This paper models Martian rock fields and analyzes the rover's dynamics on these terrains. Computational procedures are established for creating randomized Martian rock fields based on statistical models. Optimization techniques allow for terrain generation to coincide with the rover's motion, reducing the computational cost of exploring broad regions. Efficient collision detection routines reduce the number of tests of potential collisions that must be performed between the rover and the terrain while establishing new contact constraints. Simulations demonstrate that bouncing is the rover's dominant mode of travel through the rock fields, and Monte Carlo simulations illustrate how the rover's downrange position depends on the rover design and atmospheric conditions. The rover's capacity for long-distance travel over Martian rock fields is verified. [ABSTRACT FROM AUTHOR]

In this review, we discuss the current state of standoff Raman spectroscopy as it applies to remote planetary applications, including standoff instrumentation, the technique's ability to identify biologically and geologically important analytes, and the feasibility to make standoff Raman measurements under various planetary conditions. This is not intended to be an exhaustive review of standoff Raman and many excellent papers are not mentioned. Rather it is intended to give the reader a quick review of the types of standoff Raman systems that are being developed and that might be suitable for astrospectroscopy, a look at specific analytes that are of interest for planetary applications, planetary measurement opportunities and challenges that need to be solved, and a brief discussion of the feasibility of making surface and plume planetary Raman measurements from an orbiting spacecraft. [ABSTRACT FROM AUTHOR]

Measurements by instruments on spacecraft have significantly advanced cosmochemistry. Spacecraft missions impose serious limitations on instrument volume, mass, and power, so adaptation of laboratory instruments drives technology. We describe three examples of flight instruments that collected cosmochemical data. Element analyses by Alpha Particle X-ray Spectrometers on the Mars Exploration Rovers have revealed the nature of volcanic rocks and sedimentary deposits on Mars. The Gamma Ray Spectrometer on the Lunar Prospector orbiter provided a global database of element abundances that resulted in a new understanding of the Moon's crust. The Ion and Neutral Mass Spectrometer on Cassini has analyzed the chemical compositions of the atmosphere of Titan and active plumes on Enceladus. [ABSTRACT FROM AUTHOR]

Abstract: There is enormous potential for more mobile planetary surface science. This is especially true in the case of Mars because the ability to cross challenge terrain, access areas of higher elevation, visit diverse geological features and perform long traverses of up to 200km supports the search for past water and life. Vehicles capable of a ballistic ‘hop’ have been proposed on several occasions, but those proposals using in-situ acquired propellants are the most promising for significant planetary exploration. This paper considers a mission concept termed Mars Reconnaissance Lander using such a vehicle. We describe an approach where planetary science requirements that cannot be met by a conventional rover are used to derive vehicle and mission requirements. The performance of the hopper vehicle was assessed by adding estimates of gravity losses and mission mass constraints to recently developed methods. A baseline vehicle with a scientific payload of 16.5kg and conservatively estimated sub-system masses is predicted to achieve a flight range of 0.97km. Using a simple consideration of system reliability, the required cumulative range of 200km could be achieved with a probability of around 80%. Such a range is sufficient to explore geologically diverse terrains. We therefore plot an illustrative traverse in Hypanis Valles/Xanthe Terra, which encounters crater wall sections, periglacial terrain, aqueous sedimentary deposits and a traverse up an ancient fluvial channel. Such a diversity of sites could not be considered with a conventional rover. The Mars Reconnaissance Lander mission and vehicle presents some very significant engineering challenges, but would represent a valuable complement to rovers, static landers and orbital observations. [Copyright &y& Elsevier]

Abstract: In late 2006, NASA''s Constellation Program sponsored a study to examine the feasibility of sending a piloted Orion spacecraft to a near-Earth object. NEOs are asteroids or comets that have perihelion distances less than or equal to 1.3 astronomical units, and can have orbits that cross that of the Earth. Therefore, the most suitable targets for the Orion Crew Exploration Vehicle (CEV) are those NEOs in heliocentric orbits similar to Earth''s (i.e. low inclination and low eccentricity). One of the significant advantages of this type of mission is that it strengthens and validates the foundational infrastructure of the United States Space Exploration Policy and is highly complementary to NASA''s planned lunar sortie and outpost missions circa 2020. A human expedition to a NEO would not only underline the broad utility of the Orion CEV and Ares launch systems, but would also be the first human expedition to an interplanetary body beyond the Earth–Moon system. These deep space operations will present unique challenges not present in lunar missions for the onboard crew, spacecraft systems, and mission control team. Executing several piloted NEO missions will enable NASA to gain crucial deep space operational experience, which will be necessary prerequisites for the eventual human missions to Mars. Our NEO team will present and discuss the following: [•] new mission trajectories and concepts; [•] operational command and control considerations; [•] expected science, operational, resource utilization, and impact mitigation returns; and [•] continued exploration momentum and future Mars exploration benefits. [Copyright &y& Elsevier]

An electrodynamic bare-tether mission to Jupiter, following the capture of a spacecraft (SC) into an equatorial highly elliptical orbit with perijove at about 1.3 times the Jovian radius, is discussed. Repeated applications of the propellantless Lorentz drag on a spinning tether, at the perijove vicinity, can progressively lower the apojove at constant perijove, for a tour of Galilean moons. Electrical energy is generated and stored as the SC moves from an orbit at 1 : 1 resonance with a moon, down to resonance with the next moon; switching tether current off, stored power is then used as the SC makes a number of flybys of each moon. Radiation dose is calculated throughout the mission, during capture, flybys and moves between moons. The tour mission is limited by both power needs and accumulated dose. The three-stage apojove lowering down to Ganymede, Io, and Europa resonances would total less than 14 weeks, while 4 Ganymede, 20 Europa, and 16 Io flybys would add up to 18 weeks, with the entire mission taking just over seven months and the accumulated radiation dose keeping under 3 Mrad (Si) at 10-mm Al shield thickness. [ABSTRACT FROM AUTHOR]

Abstract: Traditionally, space systems have been built for fixed requirements and optimized for highest performance. Future systems for human exploration of Moon and Mars, however, require focus on new architectural strategies geared towards increased affordability and survivability in addition to performance. Reconfigurability is a new paradigm in system design that enhances these qualities. Reconfigurable systems can attain different states with new or modified capabilities, as required with changing needs, over time. Such systems can lower mission costs through mass savings by efficient use of a fixed set of hardware for multiple functions. Their survivability is improved through their ability to reconfigure into different states so that some level of over-all functionality is retained. This study, with a focus on planetary surface vehicles, presents a methodology for determining optimal designs of reconfigurable systems. It also proposes metrics for assessing the impact of reconfigurability. It is found that for the specific scenario considered, the mass utilization efficiency in a fleet of reconfigurable vehicles is increased by 27% while the survivability can be increased by a factor of 3. [Copyright &y& Elsevier]

A Mars Tumbleweed rover is a spherical, wind-driven, planetary rover. Compared with conventional rovers, a tumbleweed rover can travel farther faster and gain access to areas such as valleys and chasms that previously were inaccessible. This paper presents design, mathematical modeling, computer simulation, and testing of various tumbleweed rover concepts. In particular, we present wind-tunnel data indicating that a box-kite configuration represents a promising tumbleweed rover design, we show that a working box-kite-type tumbleweed can be constructed, and we show that center of mass variation shows promise as the basis of a tumbleweed rover navigation system. [ABSTRACT FROM AUTHOR]

The impending development of NASA's Orion crew exploration vehicle will require a new entry guidance algorithm that provides sufficient performance to meet all requirements. This study examined the effects on entry footprints of enhancing the skip trajectory entry guidance used in the Apollo program. The skip trajectory entry guidance was modified to include a numerical predictor-corrector phase during the atmospheric skip portion of the entry trajectory. A 4-degree-of-freedom simulation was used to determine the range capability of the entry vehicle for the baseline Apollo entry guidance and the predictor-corrector enhanced guidance with both high and low lofting at several lunar return entry conditions. The results show that the predictor-corrector guidance modification significantly improves the entry range capability of the crew exploration vehicle for the lunar return mission. The performance provided by the enhanced algorithm is likely to meet the entry range requirements for the crew exploration vehicle. [ABSTRACT FROM AUTHOR]

The VIRTIS (Visual IR Thermal Imaging Spectrometer) experiment has been one of the most successful experiments built in Europe for Planetary Exploration. VIRTIS, developed in cooperation among Italy, France and Germany, has been already selected as a key experiment for 3 planetary missions: the ESA-Rosetta and Venus Express and NASA-Dawn. VIRTIS on board Rosetta and Venus Express are already producing high quality data: as far as Rosetta is concerned, the Earth-Moon system has been successfully observed during the Earth Swing-By manouver (March 2005) and furthermore, VIRTIS will collect data when Rosetta flies by Mars in February 2007 at a distance of about 200 kilometres from the planet. Data from the Rosetta mission will result in a comparison – using the same combination of sophisticated experiments – of targets that are poorly differentiated and are representative of the composition of different environment of the primordial solar system. Comets and asteroids, in fact, are in close relationship with the planetesimals, which formed from the solar nebula 4.6 billion years ago. The Rosetta mission payload is designed to obtain this information combining in situ analysis of comet material, obtained by the small lander Philae, and by a long lasting and detailed remote sensing of the comet, obtained by instrument on board the orbiting Spacecraft. The combination of remote sensing and in situ measurements will increase the scientific return of the mission. In fact, the “ in situ” measurements will provide “ground-truth” for the remote sensing information, and, in turn, the locally collected data will be interpreted in the appropriate context provided by the remote sensing investigation. VIRTIS is part of the scientific payload of the Rosetta Orbiter and will detect and characterise the evolution of specific signatures – such as the typical spectral bands of minerals and molecules – arising from surface components and from materials dispersed in the coma. The identification of spectral features is a primary goal of the Rosetta mission as it will allow identification of the nature of the main constituent of the comets. Moreover, the surface thermal evolution during comet approach to sun will be also studied. [ABSTRACT FROM AUTHOR]

At the European Space Operations Centre in Darmstadt (Germany) the activities for ground segment development and mission operations preparation for Rosetta started in 1997. Many of the characteristics of this mission were new to ESOC and have therefore required an early effort in identifying all the necessary facilities and functions. The ground segment required entirely new elements to be developed, such as the large deep-space antenna built in New Norcia (Western Australia). The long duration of the journey to the comet, of about 10 years, required an effort in the operations concept definition to reduce the cost of routine monitoring and control. The new approaches adopted for the Rosetta mission include full transfer of on-board software maintenance responsibility to the operations team, and the installation of a fully functioning spacecraft engineering model at ESOC, in support of testing and troubleshooting activities in flight, but also for training of the operations staff. Special measures have also been taken to minimise the ground contact with the spacecraft during cruise, to reduce cost, down to a typical frequency of one contact per week. The problem of maintaining knowledge and expertise in the long flight to comet Churyumov–Gerasimenko is also a major challenge for the Rosetta operations team, which has been tackled early in the mission preparation phase and evolved with the first years of flight experience. [ABSTRACT FROM AUTHOR]

The article reports on the landing of the Tianwen-1 lander, a spacecraft from China, on Mars on May 15, 2021, and mentions that its six-wheel rover is expected to roll off the lander platform and operate for about 90 days to examine's the planet's geology, atmosphere, weather and magnetic field.

The article presents the discussion on the arrival of United Arab Emirates's (UAE) Hope mission examining martian atmosphere and climate including an orbiter, lander, and rover.

Features the interplanetary voyage of the Cassini spacecraft of the National Aeronautics and Space Administration of the U.S. Most exciting missions in planetary exploration history; Completion of plans for the observation of Cassini on the largest moon of Saturn; Moon in the solar system with a thick atmosphere.