No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Modular Mechatronics Infrastructure for robotic planetary exploration assets in a field operation scenario
Abstract
https://www.sciencedirect.com/science/article/abs/pii/S0094576523003909
In 2021 the Modular Mechatronics Infrastructure (MMI) was introduced as a solution to reduce weight, costs, and development time in robotic planetary missions. With standardized interfaces and multi-functional elements, this modular approach is planned to be used more often in sustainable exploration activities on the Moon and Mars. The German multi-robot research project "Autonomous Robotic Networks to Help Modern Societies (ARCHES)" has explored this concept with the use of various collaborative robotic assets which have their capabilities extended by the MMI. Different scientific payloads, engineering infrastructure modules, and specific purpose tools can be integrated to and manipulated by a robotic arm and a standardized electromechanical docking-interface. Throughout the MMI's design and implementation phase the performed preliminary tests confirmed that the different systems of the robotic cooperative team such as the Docking Interface System (DIS), the Power Management System (PMS), and the Data Communication System (DCS) functioned successfully. During the summer of 2022 a Demonstration Mission on Mount Etna (Sicily, Italy) was carried out as part of the ARCHES Project. This field scenario allowed the validation of the robotics systems in an analogue harsh environment and the confirmation of enhanced operations with the application of this modular method. Among the numerous activities performed in this volcanic terrain there are the efficient assembling of the Low Frequency Array (LOFAR) network, the energy-saving and reduced complexity of a detached Laser Induced Breakdown Spectroscopy (LIBS) module, and the uninterrupted powered operation between modules when switching between different power sources. The field data collected during this analogue campaign provided important outcomes for the modular robotics application. Modular and autonomous robots certainly benefit from their versatility, re-usability, less complex systems, reduced requirements for space qualification, and lower risks for the mission. These characteristics will ensure that long duration and complex robotic planetary endeavours are not as challenging as they used to be in the past.
... Furthermore, [51] uses the V-model methodology to carry out a modular mechatronic infrastructure, particularly for robotic planetary exploration among a field operation scenario; which, under the Autonomous Robotic Networks to Help Modern Societies (ARCHES) project, validated the importance of the verification and validation process as a critical asset to ensure that requirements are aligned to the target's application in robotic applications. In a similar way, [50] shows how, from the perspective of a robotic platform designed for sanitizing purposes, the V-model enhances the way robotic platforms can be developed in a systematic path to reduce performance uncertainty in the final product. ...
... Summarizing the concepts from the robotics development process from [47]- [51], Fig.4 shows the V-model structure adapted to the RaccoonBot's development process, where the input of the development process are the required robot's solar-tracking, wire-traversing, and energy-aware features, and the expected output is the RaccoonBot itself. This V-model adaptation, also drags inspiration from the described Vmodel for electrical systems addressed by SIEMENS in [52] for industrial applications. ...
The growing demand for renewable energy and automation technologies has led to increased interest in solar-powered robotic systems. This work focuses on the design of a solar-powered wire-traversing robot for environmental monitoring in remote areas, where solar power harvesting ensures continuous operation without frequent external charging. This paper presents an integrated power electronics design, emphasizing system-level considerations for efficient energy management and enhanced battery life, extending operational time and reliability. Experimental results showed the RaccoonBot could dynamically locate maximum solar exposure with 0.134[mm] resolution, maintain up to 7.5[W] of charging power, and consume just 0.025[A] in standby. These features, combined with the bio-inspired solar-tracking features and fail-safe design, enable over a week of autonomous operation, extending runtime from 5 hours to weeks. The findings validate the V-model’s effectiveness in creating efficient, reliable systems, demonstrated by the RaccoonBot for environmental monitoring.
... In the framework of the Helmholtz Future Project ARCHES ("Autonomous Robotic Networks to Help Modern Societies"), a heterogeneous team of robots was prepared to cooperate and autonomously deploy tools and sensors for the exploration of an unknown terrain [19,[27][28][29][30]. In addition to performing scientific measurements, the mission scenario also includes the collection of samples. ...
... The execution of the LIBS measurement task followed the modular approach presented in [30]. With several hardware and software modular components integrated into both the LRU and the payload module, this strategy provided versatility and robustness to the ARCHES scientific mission. ...
In the framework of the Helmholtz ARCHES project, a multitude of robots, including rovers and drones, were prepared for the autonomous exploration of a test site at the foothills of Mt. Etna, Sicily—a terrain resembling extraterrestrial locations such as the Moon. To expand the suite of tools and sensors available for the exploration and investigation of the test site, we developed a laser-induced breakdown spectroscopy (LIBS) instrument for the geochemical analysis of local geological samples. In alignment with the mission scenario, this instrument is housed in a modular payload box that can be attached to the robotic arm of the Lightweight Rover Unit 2 (LRU2), allowing the rover to use the instrument autonomously in the field. A compact Nd:YAG laser is utilized for material ablation, generating a micro-plasma that is subsequently analyzed with a small fiber-coupled spectrometer. A single-board computer controls the LIBS hardware components for data acquisition. In this study, we provide details of the ARCHES LIBS instrument implementation, report on preceding laboratory tests where the LRU2 operated the LIBS module for the first time, and showcase the results obtained during the successful ARCHES space analogue demonstration mission campaign in summer 2022 in Sicily.
... Contemporary equipment and systems dedicated to research, manufacturing, visualization, and free space communication rely on high-precision mechatronic motion and manipulation devices and their components. These systems control the position and orientation of optical devices by focusing, pointing, and intensely modulating devices associated with laser beams [1][2][3]. Therefore, mechatronic systems must provide high-resolution motion, good repeatability, and optimal performance. Furthermore, in response to contemporary demands, these systems and devices must meet weight, physical footprint, and versatility criteria in both operation and installation. ...
In this paper, we present research on a novel low-profile piezoelectric rotary motor with a triangle-shaped stator. The stator of the motor comprises three interconnected piezoelectric bimorph plates forming an equilateral triangle. Bimorph plates consist of a passive layer fabricated from stainless steel and four piezo ceramic plates glued to the upper and lower surfaces. Furthermore, spherical contacts are positioned on each bimorph plate at an offset from the plate’s center. Vibrations from the stator are induced by a single sawtooth-type electric signal while the frequency of the excitation signal is close to the resonant frequency of the second out-of-plane bending mode of the bimorph plate. The offset of the spherical contacts allows for a half-elliptical motion trajectory. By contrast, the forward and backward motion velocities of the contacts differ due to the asymmetrical excitation signal. The inertial principle of the motor and the angular motion of the rotor were obtained. Numerical and experimental investigations showed that the motor operates at a frequency of 21.18 kHz and achieves a maximum angular speed of 118 RPM at a voltage of 200 Vp-p. Additionally, an output torque of 18.3 mN·mm was obtained under the same voltage. The ratio between motor torque and weight is 36 mN·mm/g, while the ratio of angular speed and weight is 28.09 RPM/g.
Traditionally, the robotic systems which aim to explore other celestial bodies include all instruments and tools necessary for the mission. This makes them unique developments. Usually, they are heavy, complex, costly and do not provide any interchangeable parts that could be replaced in the event of permanent failure. However, for future missions, agencies, institutes and commercial companies are developing robotics systems based on the concept of modular robotics. This new strategy becomes critical for planetary exploration because it is able to reduce load, costs and development time. In the German multi robot research project, ‘’Autonomous Robotic Networks to Help Modern Societies (ARCHES)”, led by the German Aerospace Center (DLR), this modern design methodology is followed. Cooperation among robots and modularity are the core of its structure. These characteristics are present in the collaboration between the rovers and the uncrewed aerial vehicle (UAV) during navigation tasks, or when the Lightweight Rover Unit (LRU) interacts with changeable manipulator tools and payload boxes through its robotic arm and its standardized electromechanical interface. Examples of these modules include scientific packages, power supply systems, communication and data acquisition architectures, soil sample storage units, and specific purpose end-effectors. The focus of this work is in the design and implementation of a mechatronics infrastructure (MI) which encompasses the docking interface, the payload modules, and the power and data management electronics board inside each box. These three elements are essential for the extension of the capabilities of the rover and the enhancement of the robotics systems according to the tasks to be performed. This will ensure that robots can cooperate with each other either in scientific missions or in the construction and maintenance of large structures. The MI’s hardware and software developed in this project will be tested and validated in the ARCHES demonstration mission on Mount Etna, Sicily, in Italy between 13th June and 9th July 2022. Finally, it is important to highlight that modularity and standardization were considered at all levels of the infrastructure. From the robotics systems to the internal architecture of each payload module, these concepts can provide versatility and reliability to the cooperative robotic network. This will improve the problem-solving capabilities of robots performing complex tasks in future planetary exploration missions.
This paper was initially intended to report on the outcome of the twice postponed demonstration mission of the ARCHES project. Due to the global COVID pandemic, it has been postponed from 2020, then 2021, to 2022. Nevertheless, the development of our concepts and integration has progressed rapidly, and some of the preliminary results are worthwhile to share with the community to drive the dialog on robotics planetary exploration strategies. This paper includes an overview of the planned 4-week campaign, as well as the vision and relevance of the missiontowards the planned official space missions. Furthermore, the cooperative aspect of the robotic teams, the scientific motivation, the sub task achievements are summarised.
The Earth's moon is currently an object of interest of many space agencies for unmanned robotic missions within this decade. Besides future prospects for building lunar gateways as support to human space flight, the Moon is an attractive location for scientific purposes. Not only will its study give insight on the foundations of the Solar System but also its location, uncontaminated by the Earth's ionosphere, represents a vantage point for the observation of the Sun and planetary bodies outside the Solar System. Lunar exploration has been traditionally conducted by means of single-agent robotic assets, which is a limiting factor for the return of scientific missions. The German Aerospace Center (DLR) is developing fundamental technologies towards increased autonomy of robotic explorers to fulfil more complex mission tasks through cooperation. This paper presents an overview of past, present and future activities of DLR towards highly autonomous systems for scientific missions targeting the Moon and other planetary bodies. The heritage from the Mobile Asteroid Scout (MASCOT), developed jointly by DLR and CNES and deployed on asteroid Ryugu on 3 October 2018 from JAXA's Hayabusa2 spacecraft, inspired the development of novel core technologies towards higher efficiency in planetary exploration. Together with the lessons learnt from the ROBEX project (2012–2017), where a mobile robot autonomously deployed seismic sensors at a Moon analogue site, this experience is shaping the future steps towards more complex space missions. They include the development of a mobile rover for JAXA's Martian Moons eXploration (MMX) in 2024 as well as demonstrations of novel multi-robot technologies at a Moon analogue site on the volcano Mt Etna in the ARCHES project. Within ARCHES, a demonstration mission is planned from the 14 June to 10 July 2021,1 during which heterogeneous teams of robots will autonomously conduct geological and mineralogical analysis experiments and deploy an array of low-frequency antennas to measure Jovian and solar bursts. This article is part of a discussion meeting issue ‘Astronomy from the Moon: the next decades'.
This session will focus on cooperative and robotic systems as they apply to the space domain. This emerging topic includes concepts such as constellations, multi-satellite architectures, and on-orbit servicing of space systems and technologies. Hosted payloads, where their objectives may be unrelated to the principal mission, are also addressed. Additional areas of interest include collaborative robotic systems, such as space robotic systems and manipulators, robotic/human interactions and distributed multi-agent technologies. Papers in this session will look at current missions and future opportunities, while addressing both benefits and challenges as the world-wide space community moves into these exciting areas.
Teams of mobile robots will play a crucial role in future missions to explore the surfaces of extraterrestrial bodies. Setting up infrastructure and taking scientific samples are expensive tasks when operating in distant, challenging, and unknown environments. In contrast to current single-robot space missions, future heterogeneous robotic teams will increase efficiency via enhanced autonomy and parallelization, improve robustness via functional redundancy, as well as benefit from complementary capabilities of the individual robots. In this article, we present our heterogeneous robotic team, consisting of flying and driving robots that we plan to deploy on scientific sampling demonstration missions at a Moon-analogue site on Mt. Etna, Sicily, Italy in 2021 as part of the ARCHES project. We describe the robots' individual capabilities and their roles in two mission scenarios. We then present components and experiments on important tasks therein: automated task planning, high-level mission control, spectral rock analysis, radio-based localization, collaborative multi-robot 6D SLAM in Moon-analogue and Mars-like scenarios, and demonstrations of an autonomous sample-return mission.
The here presented flying system uses two pairs of wide-angle stereo cameras and maps a large area of interest in a short amount of time. We present a multicopter system equipped with two pairs of wide-angle stereo cameras and an inertial measurement unit (IMU) for robust visual-inertial navigation and time-efficient omni-directional 3D mapping. The four cameras cover a 240 degree stereo field of view (FOV) vertically, which makes the system also suitable for cramped and confined environments like caves. In our approach, we synthesize eight virtual pinhole cameras from four wide-angle cameras. Each of the resulting four synthesized pinhole stereo systems provides input to an independent visual odometry (VO). Subsequently, the four individual motion estimates are fused with data from an IMU, based on their consistency with the state estimation. We describe the configuration and image processing of the vision system as well as the sensor fusion and mapping pipeline on board the MAV. We demonstrate the robustness of our multi-VO approach for visual-inertial navigation and present results of a 3D-mapping experiment.
Reports on the international standards development in the robotics and automation indusry.
This paper presents first results of the analog mission campaign which was performed between the 12th of June and the 10th of July 2017 on Mount Etna in Europe, Italy. The aim of the ROBEX demonstration mission is to test and validate a complex robotic mission. This includes highly autonomous tasks with supervision from scientists to guarantee measurement of real and scientifically relevant data. The main scientific objective of the ROBEX mission, the detailed analysis of the lunar crust layers, that is replaced by the analysis of Etna lava layers in the demo mission, has been guiding the developments of the last four years. As key missions, a seismic network has been deployed and a seismic profile measurement has been conducted using only robots on the landing site. Additional experiments consisted of long term autonomous navigation, multi-robot mapping and exploration of craters as well as experiments with the aim of geological analyses and probe selection. During the one month analog campaign, a realistic mission scenario has been built up, including a control station approximately 30 km from the remote site.
Planetary exploration poses many challenges for a robot system: From weight and size constraints to extraterrestrial environment conditions, which constrain the suitable sensors and actuators. As the distance to other planets introduces a significant communication delay, the efficient operation of a robot system requires a high level of autonomy. In this work, we present our Lightweight Rover Unit (LRU), a small and agile rover prototype that we designed for the challenges of planetary exploration. Its locomotion system with individually steered wheels allows for high maneuverability in rough terrain and stereo cameras as its main sensors ensure the applicability to space missions. We implemented software components for self-localization in GPS-denied environments, autonomous exploration and mapping as well as computer vision, planning and control modules for the autonomous localization, pickup and assembly of objects with its manipulator. Additional high-level mission control components facilitate both autonomous behavior and remote monitoring of the system state over a delayed communication link. We successfully demonstrated the autonomous capabilities of our LRU at the SpaceBotCamp challenge, a national robotics contest with focus on autonomous planetary exploration. A robot had to autonomously explore an unknown Moon-like rough terrain, locate and collect two objects and assemble them after transport to a third object – which the LRU did on its first try, in half of the time and fully autonomously. The next milestone for our ongoing LRU development is an upcoming planetary exploration analogue mission to perform scientific experiments at a Moon analogue site located on a volcano.
Autonomous robotic systems are key to planetary exploration. A facility
including virtual/physical environments for validation and verification
is described.
Scarab is a prospecting rover for lunar missions to survey resources, particularly water ice, in polar craters. It is designed for the deployment of a deep coring drill and for transport of soil analysis instruments. Its chassis can transform to stabilize the drill in contact with the ground and can also adjust to ascend and descent steep slopes of unconsolidated soil. Additional features include a compact body for better thermal regulation, laser scanners for dark navigation, and power system designed for a persistent, low-capacity source. Scarab was prototyped at the Robotics Institute, has undergone mobility testing in soils laboratories and field sites leading up to an integrated system test including the RESOLVE drill and instrument suite at the PISCES lunar analogue site on Mauna Kea in Hawaii.
The authors propose an optimal structure decision method which can
determine cell type, arrangement, degree of freedom, and link length. It
can be used for fixed-base and mobile-base manipulators, so that
universal/modular manipulators can be made. Simulation results show the
differences in evaluation for different candidates and tasks and also
demonstrate that the structure decision method works efficiently. With
respect to the software structure, optimal knowledge allocation is one
of the most important issues for CEBOT. The authors propose a method of
optimal knowledge allocation based on the amount of communication among
cells. Communication among cells for the control proposed is described
The goal of the mission is to enter a martian or lunar skylight in order to check for cave continuations and placement of a sensor suite. A camera will also be used in order to deliver visible light images for context. With a combination of the navigation suite and communication modules, the cave passages will also be surveyed in order to produce a map, as is tradition in terrestrial speleology.From a technical point of view, themission is planned to be as simple as possible. Thus,it is planned to discard rope access systems and tofocus on sufficient robustness of the rover system. This allows for dropping into smaller skylights (10-20m depth) or larger ones, partially filled with regolith.Figure 1illustrates an overview of the mission sequencewhich is designed to be“one way”, i.e. the rover is going into the cave but never out again. Itallows to take a higher risk of going beyond obstaclesthat are not reversible and to omit the need for a recharging system for the rover once it is in the cave. Thus,the mission inside the cave will last as long as the battery runtime. As the scout rover is a small, lightweight system, several such roversmay be part of one mission to increase the exploration impact and science return.In order to access an entrance of a lava tube there are several options to be considered: having a bigger main rover that is delivering one or more Scoutsfrom the landing moduleto the entrance, or havingthe Scout equipped with solar panels to make the approach on its own. The first option isfavorable as system complexity of the Scout is reduced, while the second option ispreferred for rough terrain during the approach.
Robotic systems map unknown terrain and collect scientific relevant data of foreign planets. Currently, pilots from Earth steer these rovers on Moon and Mars surfaces via teleoperation. However, remote control suffers from a high delay of the long distance communication which leads to a reduction of the time the rover can spent gathering scientific data. We propose a system architecture for an autonomous rover for planetary exploration. The architecture is centered around a flexible, scalable world model to record and represent the environment of the robot. An autonomous task control framework and a versatile constraint motion planner use the live information from the world model to steer the rover through complex manipulation tasks. Furthermore, we present the enhancement of our Light Weight Rover Unit (LRU) with an innovative docking interface for arbitrary tool handling. We showcase the effectiveness of our approach at the moon-analogue demonstration mission of the ROBEX project on Mt. Etna, Sicily. We show in two experiments that the robot is capable of autonomously deploying scientific instruments and collecting soil samples from the volcano's surface.
Mechatronics - the synergetic integration of different engineering domains such as mechanics, electronics and information technology can create new products and stimulate innovative solutions. In order to yield this potential, experts from the involved domains need a cross-domain methodology for the systematic design of mechatronic systems. Inspite of the wide spectrum of research activities and industrial developments in the mechatronic field it seems to be difficult for the design engineer in practice - in particular for the still unexperienced one - to select the suitable procedures, methods and tools for his design task. Therefore a committee of the German Association of Engineers (VDI) is working out a new VDI-guideline. The VDI 2206 guideline „Design methodology for mechatronic systems” intends to structure the variety of findings and to make them accessible to the practician in a concise and understandable way. This contribution presents the draft of the VDI 2206 guideline.
The paper presents the latest work on modularity carried out by the EC funded CLAWAR project partners during the second year of the project. This work has focused on specifying the design tools needed to support the overall open modular concepts being proposed to encourage the creation of a component based research and development community for robotics.
On 6 August 2012, the Curiosity rover successfully touched down on the Martian surface setting off the most ambitious surface exploration of this planetary body. Preceding this significant step were years of design, development, and testing of the Curiosity Entry, Descent, and Landing system to prepare for the most complex landing endeavor ever attempted at Mars. To address the numerous challenges, the approach and implementation of the overall Entry, Descent, and Landing verification and validation program relied on its decomposition into three distinct domains: flight dynamics, flight system and subsystem verification and validation. The test and analysis scope, the venues, and the processes utilized were tailored to each of these domains, and are discussed in greater detail. The overall lessons learned and conclusions described herein can serve as a pathfinder for the Entry, Descent, and Landing system testing approach and implementation of future Mars landed missions.
This paper presents the multirobot team RIMRES (Reconfigurable Integrated Multirobot Exploration System), which is comprised of a wheeled rover, a legged scout, and several immobile payload items. The heterogeneous systems are employed to demonstrate the feasibility of reconfigurable and modular systems for lunar polar crater exploration missions. All systems have been designed with a common electromechanical interface, allowing to tightly interconnect all these systems to a single system and also to form new electromechanical units. With the different strengths of the respective subsystems, a robust and flexible overall multirobot system is built up to tackle the, to some extent, contradictory requirements for an exploration mission in a crater environment. In RIMRES, the capability for reconfiguration is explicitly taken into account in the design phase of the system, leading to a high degree of flexibility for restructuring the overall multirobot system. To enable the systems' capabilities, the same distributed control software architecture is applied to rover, scout, and payload items, allowing for semiautonomous cooperative actions as well as full manual control by a mission operator. For validation purposes, the authors present the results of two critical parts of the aspired mission, the deployment of a payload and the autonomous docking procedure between the legged scout robot and the wheeled rover. This allows us to illustrate the feasibility of complex, cooperative, and autonomous reconfiguration maneuvers with the developed reconfigurable team of robots.
In this paper, the recent results of the space project IMPERA are presented. The goal of IMPERA is the development of a multirobot planning and plan execution architecture with a focus on a lunar sample collection scenario in an unknown environment. We describe the implementation and verification of different modules that are integrated into a distributed system architecture. The modules include a mission planning approach for a multirobot system and modules for task and skill execution within a lunar use-case scenario. The skills needed for the test scenario include cooperative exploration and mapping strategies for an unknown environment, the localization and classification of sample containers using a novel approach of semantic perception, and the skill of transporting sample containers to a collection point using a mobile manipulation robot. Additionally, we present our approach of a reliable communication framework that can deal with communication loss during the mission. Several modules are tested within several experiments in the domain of planning and plan execution, communication, coordinated exploration, perception, and object transportation. An overall system integration is tested on a mission scenario experiment using three robots.
A robotic vehicle called ATHLETE—the All-Terrain Hex-Limbed, Extra-Terrestrial Explorer—is described, along with initial results of field tests of two prototype vehicles. This vehicle concept is capable of efficient rolling mobility on moderate terrain and walk-ing mobility on extreme terrain. Each limb has a quick-disconnect tool adapter so that it can perform general-purpose handling, assembly, maintenance, and servicing tasks using any or all of the limbs. © 2007 Wiley Periodicals, Inc.
A comprehensive modular assembly system model has been proposed that extends the art from modular hardware, to include in-space assembly, servicing and repair and it's critical components of infrastructure, agents and assembly operations. Benefits of modular assembly have been identified and a set of metrics defined that extends the art beyond the traditional measures of performance, with emphasis on criteria that allow life-cycle mission costs to be used as a figure of merit (and include all substantive terms that have an impact on the evaluation). The modular assembly approach was used as a basis for developing a Solar Electric Transfer Vehicle (SETV) concept and three modular assembly scenarios were developed. The modular assembly approach also allows the SETV to be entered into service much earlier than competing conventional configurations and results in a great deal of versatility in accommodating different launch vehicle payload capabilities, allowing for modules to be pre-assembled before launch or assembled on orbit, without changing the space vehicle design.
The LUNARES (Lunar Crater Exploration Scenario) project emulates the retrieval of a scientific sample from within a permanently
shadowed lunar crater by means of a heterogeneous robotic system. For the accomplished earth demonstration scenario, the Shakelton
crater at the lunar south pole is taken as reference. In the areas of permanent darkness within this crater, samples of scientific
interest are expected. For accomplishment of such kind of mission, an approach of a heterogeneous robotic team consisting
of a wheeled rover, a legged scout as well as a robotic arm mounted on the landing unit was chosen. All robots act as a team
to reach the mission goal. To prove the feasibility of the chosen approach, an artificial lunar crater environment has been
established to test and demonstrate the capabilities of the robotic systems. Figure 1 depicts the systems in the artificial
crater environment. For LUNARES, preexisting robots were used and modified were needed in order to integrate all subsystems
into a common system control. A ground control station has been developed considering conditions of a real mission, requiring
information of autonomous task execution and remote controlled operations to be displayed for human operators. The project
successfully finished at the end of 2009. This paper reviews the achievements and lessons learned during the project.
KeywordsLunar crater exploration–Cooperative robotic team–Autonomous robots–Space robotics–Legged locomotion–Wheeled locomotion
From single autonomous robots toward cooperative robotic interactions for future planetary exploration missions
- Wedler
CLAWAR modularity for robotic systems
- Virk
Modularity: The degree to which a system components may be separated and combined
- Norman
Verification and validation of the Mars Science Laboratory/Curiosity rover entry, descent, and landing system
- Wedler
The gateway as a building block for space exploration and development
- Lehnhardt