Successful Landing Research Articles

Guidance Navigation and Control for Chang’E-5 Powered Descent

To achieve the goal of collecting lunar samples and return to the Earth for the Chang’E-5 spacecraft, the lander and ascender module (LAM) of the Chang’E-5 spacecraft successfully landed on the lunar surface on 1 Dec., 2020. The guidance, navigation, and control (GNC) system is one of the critical systems to perform this task. The GNC system of previous missions, Chang’E-3 and Chang’E-4, provides the baseline design for the Chang’E-5 LAM, and the new characteristics of the LAM, like larger mass and liquid sloshing, also bring new challenges for the GNC design. The GNC design for the descent and landing is presented in this paper. The guidance methods implemented in the powered descent are presented in detail for each phase. Propellant consumption and hazard avoidance should be particularly considered in the design. A reconfigurable attitude control is adopted which consists of the quaternion partition control, phase and gain stabilization filter, and dual observer. This controller could provide fast attitude maneuver and better system robustness. For the navigation, an intelligent heterogeneous sensor data fusion method is presented, and it is applied for the inertial measurement unit and velocimeter data. Finally, the flight results of the LAM are shown. Navigation sensors were able to provide valid measurement data during descent, and the thrusters and the main engine operated well as expected. Therefore, a successful soft lunar landing was achieved by the LAM.

Landing the Booster Using Parachute

This Paper involves designing, testing, construction and launching of rocket. The high cost of rocket technology has led to system reusability developments, particularly in the field of first stage rockets. With the motivation of decreasing production costs, successful vertical rocket landing attempts by Space X and Blue Origin have led the path for autonomous recovery and reusability of rocket engines. Landing an autonomous spacecraft or rocket is very challenging, and landing one with precision close to a prescribed target even more so. Precision landing has the potential to improve exploration of our solar system, and to enable rockets that can be refuelled and reused like an airplane. This paper aims to develop a vertical rocket landing simulation by parachute and reverse thrust methods. This paper will discuss the challenges of precision landing, recent advances that enabled precision landing on Earth for commercial reusable rockets, and what is required to extend this to landing on planet.

МАТЕРИАЛЫ КОЛЛЕКЦИИ ГЕРОЕВ СОВЕТСКОГО СОЮЗА В ЦГА МОСКВЫ: УЧАСТНИК ВЕЛИКОЙ ОТЕЧЕСТВЕННОЙ ВОЙНЫ Л.А. БУТКОВ

The work introduces into scientific circulation the documents (autobiography and memoirs) from the personal file of L.A. Butkov, the Soviet Union Hero; his dossier being deposited inside the collection of Soviet Union Heroes (the Central State Archives of Moscow, F. P-8682). If the autobiography is an extremely formalized text, the memoirs mentioning the author’s hatred towards the Nazi invaders are written in easy language, reflecting the impressions of those ordinary fighters who, to a large extent, won the Great Patriotic War. The title of the Soviet Union Hero was awarded to the company commander of the 164th Guards Rifle Regiment of the 55th Guards Rifle Division of the 56th Guards Army senior lieutenant L.A. Butkov on May 16, 1944, for his distinction in the Kerch-Eltigen military operation. The company was the first to land on the shore occupied by the enemy and managed to hold the bridgehead, ensuring the successful landing of the entire division. During the battle, the company commander personally destroyed the machine gun with the gunners and 11 more enemy soldiers. The documentary collection, which holds L.A. Butkov’s file, was collected after the war by the Institute of Party History of the MC and MGK VKP(b), headed by the director of the Institute G.D. Kostomarov

Astronomer-turned-filmmaker strives to ignite an interest in space

For scientists at NASA’s Jet Propulsion Laboratory in Pasadena, CA, the night of January 3, 2004 entailed six minutes of nerve-wracking terror. Around 8:30 PM Pacific Time, the Spirit rover began its plunge to the Martian surface, as an audience of engineers and others—temporarily unable to receive any communication from the craft—waited anxiously to get confirmation of its success. Aided by a heat shield, a giant parachute, airbags, and reverse-firing rockets, the rolling robotic laboratory had to decelerate from 12,000 miles per hour to zero miles per hour, with no input from its human designers, who were nervously drumming on their desks in Pasadena. Spirit’s successful landing was a defining moment in the human exploration of Mars. As part of projects he calls science-driven art, Jose Francisco Salgado created a mini-movie for each of the seven parts of Holst’s suite, which Holst had based on astrological characteristics of each world. Image credit: Jose Francisco Salgado (artist). But how might one capture the gravity of that moment, the tension among observers, the majesty of the feat, and its implications for researchers and the public? Astronomer-turned-filmmaker Jose Francisco Salgado had some ideas. A few years ago, he put together a film in which that landing event unfolds as a suspenseful, and ultimately heroic, scene. Audiences who attend presentations of the film—one of many in his “Science and Symphony” series—watch a reconstruction of Spirit’s journey on a giant screen while a live orchestra plays “Mars, The Bringer of War” from The Planets , Gustav Holst’s most famous contribution to classical music. In Salgado’s telling, the visuals and music line up exactly, so that the rover’s stressful fall occurs during a long and building crescendo in Holst’s piece (see https://vimeo.com/46390508). The treads of a rover sigh and settle into the alien soil at the …

Arresting-Cable System for Robust Terminal Landing of Reusable Rockets

Recent successful recovery techniques for rockets require that rockets maintain a vertical configuration with zero vertical and lateral velocities; otherwise, landings may fail. To relax this requirement, a new active-arresting system (inspired by the arresting gears used on aircraft carriers) is proposed herein to achieve a robust landing, even if the rocket deviates from the target position or has notable residual velocities and inclinations. The system consists of four deployable onboard hooks above the rocket’s center of mass, an on-ground apparatus containing four arresting cables forming a square capture frame, and four buffer devices to actively catch and passively decelerate the landing rocket. To catch the rocket, the capture frame was controlled by servo motors via a simple proportional–derivative controller. After catching, the buffer devices generate decelerating forces to stop its motion. A flexible multibody model of the proposed system was built to evaluate its robust performance under various combinations of multiple uncertainties, such as noise measurement, time delay in the motor, initial conditions, and wind excitation. Using a quasi-Monte Carlo method, hundreds of deviated landing cases were generated and simulated. The results confirmed the robustness of the proposed system for achieving successful terminal landings.

Litter and perch type matter already from the start: exploring preferences and perch balance in laying hen chicks

Early chick environment, such as provision of litter and perches, can be a predictor of laying hen welfare. Inadequate or nonpreferred litter and perch types could have similar negative effects as those seen when not providing these resources at an early stage, such as increased feather pecking and cannibalism in adult flocks. However, suitable litter and perch types for chicks are not well explored. In the present project, 6 different types of litter (crushed straw pellets, hemp shavings, peat, sand, straw, wood shavings) and 6 different types of perches (narrow or wide forms of rope, flat or round wood) were presented in a controlled way (3 at a time) to chicks in 6 pens. Usage was compared in 93 chicks of Lohmann Selected Leghorn Classic divided across the pens, during their first 3 wk after hatch. Different litter types were seen to be preferred for different behaviors. The majority of dustbathing bouts occurred in sand and peat. Chicks foraged more in wood shavings, hemp shavings, and sand than in peat and pellets (P < 0.05). Perch width and shape were found to affect both usage and perch balance, measured as the probability of successful or problematic landings. The wide rope was generally used more during the first week (P < 0.05) and was used more for sleeping or resting (P < 0.05) than the other wide perch types. Furthermore, birds were more likely to land on the wide rope or on flat perches successfully than they were to have a problematic landing (P < 0.05). That birds were more likely to be observed preening on flat perches than on the potentially shaky rope perches could further reflect a sense of security. Our results suggest that presenting several litter types could better fulfill chicks' behavioral needs and that flat perches or a wide rope (4.5-cm diameter) could be appropriate perch types for laying hen chicks and thereby promote early perch use and training.

Helicopter Shipboard Landing Simulation Including Wind, Deck Motion and Dynamic Ground Effect

A first principles physics-based simulation framework that accounts for wind-over-deck (WOD) and ground effects during approach and landing of a helicopter on a ship deck is developed. The WOD velocities are obtained from unsteady detached-eddy simulation of the flow over a simple frigate shape version 2 ship. The HeliUM2 flight dynamics code was modified to include WOD, static and dynamic ground effects, and landing gear models. A dynamic ground effect model that combines a finite-state wake model with a ground source distribution was also incorporated. Simulations are carried out to determine the combined effect of WOD and deck motion. Representative ship motion data are extracted from the Systematic Characterization of the Naval Environment database. A simple linear-quadratic-regulator-based flight control system is used to follow a prescribed trajectory during approach and landing. High-frequency oscillations are induced by the WOD. The entire helicopter has to be modeled to capture the complete WOD effect. In-ground-effect simulations show up to 10% reduction in rotor power consumption as well as good agreement with experimental data for a stationary deck. Deck heaving motion produces an additional change in rotor power consumption relative to the static ground effect, highlighting the importance of modeling the dynamic ground effect. The controller maintains the desired approach trajectory; and successful landing is demonstrated on level, inclined, and moving decks in the combined presence of WOD and ground effects.

Varroa destructor infestation impairs the improvement of landing performance in foraging honeybees.

The parasitic mite Varroa destructor is an important contributor to the high losses of western honeybees. Forager bees from Varroa-infested colonies show reduced homing and flight capacity; it is not known whether flight manoeuvrability and related learning capability are also affected. Here, we test how honeybees from Varroa-infested and control colonies fly in an environment that is unfamiliar at the beginning of each experimental day. Using stereoscopic high-speed videography, we analysed 555 landing manoeuvres recorded during 12 days of approximately 5 h in length. From this, we quantified landing success as percentage of successful landings, and assessed how this changed over time. We found that the forager workforce of Varroa-infested colonies did not improve their landing success over time, while for control bees landing success improved with approximately 10% each hour. Analysis of the landing trajectories showed that control bees improved landing success by increasing the ratio between in-flight aerodynamic braking and braking at impact on the landing platform; bees from Varroa-infested colonies did not increase this ratio over time. The Varroa-induced detriment to this landing skill-learning capability might limit forager bees from Varroa-infested colonies to adapt to new or challenging conditions; this might consequently contribute to Varroa-induced mortality of honeybee colonies.

Helicopter Pilots’ Tasks, Subjective Workload, and the Role of External Visual Cues During Shipboard Landing

Helicopter shipboard landing is a cognitively complex task that is challenging both for pilots and their crew. Effective communication, accurate reading of the flight instruments, as well as monitoring of the external environment are crucial for a successful landing. In particular, the final phases of landing are critical as they imply high workload situations in an unstable environment with restricted space. In the present qualitative study, we interviewed ten helicopter pilots from the Italian Navy using an applied cognitive task analysis approach. We aimed to obtain a detailed description of the landing procedure, and to identify relevant factors that affect pilots’ workload, performance, and safety. Based on the content analysis of the interviews, we have identified six distinct phases of approaching and landing on a ship deck and four categories of factors that may significantly affect pilots’ performance and safety of the landing procedure. Consistent with previous studies, our findings suggest that external visual cueing is vital for a successful landing, in particular during the last phases of landing. Therefore, based on the pilots’ statements, we provide suggestions for possible improvements of external visual cues that have the potential to reduce pilots’ workload and improve the overall safety of landing operations.

Research dynamic motion of a landing vehicle during the final landing stage

Landing systems for future space missions in Earth and Mars require trustable technologies capable of achieving its aim in the most accurate way possible. Using the software Universal Mechanism (developed by Bryansk State Technical University) and the classic mechanics theory on a model based on the geometry of the ExoMars vehicle, a series of different landing situations have been simulated varying the initial conditions, the approach to the surface and the surface itself. As a result, the values of the arising overloads and forces acting on the descent vehicle and its payload were calculated during the landing stage in Earth and Mars. The information collected would help understand to what extent it is crucial to know the characteristics of the landing zone (type of soil, slope, etc.) and to control the vehicle’s inclination (measured from the radial axis) to provide successful landings for future missions.

Stratigraphy of the Von Kármán Crater Based on Chang'E‐4 Lunar Penetrating Radar Data

AbstractThe Chang'E‐4 (CE‐4) achieved the first successful soft landing on the floor of the Von Kármán crater located in the northeast of the South Pole‐Aitken (SPA) basin on the Moon. Here, through analysis and processing of the dual‐channel lunar penetrating radar (LPR) data, the shallow regolith structure and deep geological strata below the landing site are exposed. The high‐frequency data (CH‐2, 500 MHz) show that the Von Kármán crater underwent remodeling because of ejecta from multiple craters within a thickness of 40 m. Under the surface fine‐grained regolith, superpositions among these crater materials and mare basalt units establish shallow regolith stratigraphic sequences. The low‐frequency data (CH‐1, 60 MHz) show a deep stratigraphic structure to the depth of 360 m that indicates the previous geological evolution history of the Von Kármán crater. The LPR results provide an important scientific basis for understanding the geological history of the far side of the Moon.

Real-Time Trajectory Generation and Reachability Determination in Autorotative Flare

Autorotation maneuvers inherently offer little margin for error in execution and induce high pilot workload, particularly as the aircraft nears the ground in an autorotative flare. Control augmentation systems may potentially reduce pilot workload while simultaneously improving the likelihood of a successful landing by offering the pilot appropriate cues. This paper presents an initial investigation of a real-time trajectory generation scheme for autorotative flare based on time-to-contact theory. The algorithm exhibits deterministic runtime performance and provides a speed trajectory that can be tracked by a pilot or inner-loop controller to bring the vehicle to a desired landing point at the time of touchdown. A low-order model of the helicopter dynamics in autorotation is used to evaluate dynamic feasibility of the generated trajectories. By generating and evaluating trajectories to an array of candidate landing points, the set of reachable landing points in front of the aircraft is determined. Simulation results are presented in which the trajectory generator is coupled with a previously derived autorotation controller. Example cases and trade studies are conducted in a six degree-of-freedom simulation environment to demonstrate overall performance as well as robustness of the algorithm to variations in target landing point, helicopter gross weight, and winds. The robustness of the reachability determination portion of the algorithm is likewise evaluated through trade studies examining off-nominal flare entry conditions and the effects of winds.

Divergence analysis of failed and successful unanticipated single-leg landings reveals the importance of the flight phase and upper body biomechanics

The purpose of this study was to describe neuromuscular and kinematic differences during failed and successful drop-vertical jumps in a pediatric population. Healthy young athletes (n = 32) completed single-leg drop vertical jump landings where the required landing leg was unanticipated. Trials were categorized as failed if the participant shifted their base of support during the landing. Joint kinematics and muscle activation amplitudes were time normalized over the flight and landing phases. Statistical parametric mapping (SPM) was used to compare landings and a moving average convergence divergence oscillator was then calculated to determine where failed and successful waveforms began to diverge prior to reaching statistical significance. SPM determined that participants performed the failed trials with reduced pelvic tilt towards the landing limb during 41–69% of the flight phase, greater trunk flexion angle during 31–100% of the landing phase and greater trunk tilt away from the landing limb during 3–13% and 21–90% of the landing phase. Greater rectus femoris activation during the failed trials was identified during 88–100% of the flight phase, as well as 1–4% and 71–97% of the landing phase. Greater gluteus medius and biceps femoris activation was also identified in the failed trials during 54–72% and 76–89% of the landing phase respectively. These findings indicate that the control of proximal joints has an important role in determining if a participant will fail a landing; and that how athletes prepare for a landing may be more relevant than the kinematics following ground contact.

Topographic and Geomorphological Mapping and Analysis of the Chang'E-4 Landing Site on the Far Side of the Moon

The Chinese lunar probe Chang'E-4 successfully landed in the Von Kármán crater on the far side of the Moon. This paper presents the topographic and geomorphological mapping and their joint analysis for selecting the Chang'E-4 landing site in the Von Kármán crater. A digital topographic model (&lt;small&gt;DTM&lt;/small&gt;) of the Von Kármán crater, with a spatial resolution of 30 m, was generated through the integrated processing of Chang'E-2 images (7 m/pixel) and Lunar Reconnaissance Orbiter (&lt;small&gt;LRO&lt;/small&gt;) Laser Altimeter (&lt;small&gt;LOLA&lt;/small&gt;) data. Slope maps were derived from the &lt;small&gt;DTM&lt;/small&gt;. Terrain occlusions to both the Sun and the relay satellite were studied. Craters with diameters ≥ 70 m were detected to generate a crater density map. Rocks with diameters ≥ 2 m were also extracted to generate a rock abundance map using an &lt;small&gt;LRO&lt;/small&gt; narrow angle camera (&lt;small&gt;NAC&lt;/small&gt;) image mosaic. The joint topographic and geomorphological analysis identified three subregions for landing. One of them, recommended as the highest-priority landing site, was the one in which Chang'E-4 eventually landed. After the successful landing of Chang'E-4, we immediately determined the precise location of the lander by the integrated processing of orbiter, descent and ground images. We also conducted a detailed analysis around the landing location. The results revealed that the Chang'E-4 lander has excellent visibility to the Sun and relay satellite; the lander is on a slope of about 4.5° towards the southwest, and the rock abundance around the landing location is almost 0. The developed methods and results can benefit future soft-landing missions to the Moon and other celestial bodies.

Training for success: Do simulated aerial landings replicate successful aerial landings performed in the ocean?

Physical preparation of competitive surfers includes substantial dry-land training. It is currently unknown, however, how closely these exercises replicate surfing manoeuvres performed in the ocean. This study compared the technique features displayed by surfers when landing simulated aerial manoeuvres on land to critical features previously established as necessary for surfers to successfully land aerials in the ocean during competition. Fourteen competitive surfers (age 20.6±5.7 years, height 178.1±9.50 cm, mass 70.6±10.8 kg) were recruited to perform two variations of a simulated aerial task, a Frontside Air (FA) and Frontside Air Reverse (FAR). Joint ranges of motion (ROM), centre of pressure and apparent gaze data were collected during the landing event. Paired t-tests or Wilcoxon Signed Rank tests were used to identify any significant differences in the outcome variables between the two aerial tasks. Participants displayed 100% and 60% of the critical features associated with successfully landing a FA and FAR, respectively. In both the simulated FA and FAR, participants landed in 1.0-3.7° of dorsiflexion, moving through significantly less ankle joint ROM in the lead limb during the FAR (p < 0.01). Participants also displayed significantly less knee and hip ROM (p = 0.002-0.048) while landing the FAR compared to the FA. The simulated FA and FAR tasks are appropriate training tools for surfers to replicate most of the critical features that a surfer should display to successfully land aerial manoeuvres in the ocean. These tasks therefore enable surfers to practice these complex movements in a controlled environment.

Go-Around Detection Using Crowd-Sourced ADS-B Position Data

The decision of a flight crew to undertake a go-around, aborting a landing attempt, is primarily to ensure the safe conduct of a flight. Although go-arounds are rare, they do cause air traffic disruption, especially in busy airspace, due to the need to accommodate an aircraft in an unusual position, and a go-around can also result in knock-on delays due to the time taken for the aircraft to re-position, fit into the landing sequence and execute a successful landing. Therefore, it is important to understand and alleviate the factors that can result in a go-around. In this paper, I present a new method for automatically detecting go-around events in aircraft position data, such as that sent via the ADS-B system, and apply the method to one year of approach data for Chhatrapati Shivaji Maharaj International Airport (VABB) in Mumbai, India. I show that the method is significantly more accurate than other methods, detecting go-arounds with very few false positives or negatives. Finally, I use the new method to reveal that while there is no one cause for go-arounds at this airport, the majority can be attributed to weather and/or an unstable approach. I also show that one runway (14/32) has a significantly higher proportion of go-arounds than the other (09/27).

Mawrth Vallis, Mars: A Fascinating Place for Future In Situ Exploration.

After the successful landing of the Mars Science Laboratory rover, both NASA and ESA initiated a selection process for potential landing sites for the Mars2020 and ExoMars missions, respectively. Two ellipses located in the Mawrth Vallis region were proposed and evaluated during a series of meetings (three for Mars2020 mission and five for ExoMars). We describe here the regional context of the two proposed ellipses as well as the framework of the objectives of these two missions. Key science targets of the ellipses and their astrobiological interests are reported. This work confirms that the proposed ellipses contain multiple past martian wet environments of a subaerial, subsurface, and/or subaqueous character, in which to probe the past climate of Mars; build a broad picture of possible past habitable environments; evaluate their exobiological potentials; and search for biosignatures in well-preserved rocks. A mission scenario covering several key investigations during the nominal mission of each rover is also presented, as well as descriptions of how the site fulfills the science requirements and expectations of in situ martian exploration. These serve as a basis for potential future exploration of the Mawrth Vallis region with new missions and describe opportunities for human exploration of Mars in terms of resources and science discoveries.

Development of an Automated Camera-Based Drone Landing System

Digital image processing serves as a multifunctional tool for measurement and positioning tasks in robotics. The present paper deals with the development of a camera-based positioning system for quadrocopters in order to automate their landing process. In this regard, a quadrocopter equipped with classical radio-control components is upgraded with applicable hardware, such as a Raspberry Pi 3B+ and a wide-angle camera. Hereupon, black-box system identifications are executed to attain the relevant plants of the attitude control performed by the flight controller. Thereby, a PID-controller for the altitude control including a back-calculation anti-windup as well as two PD-controllers for the horizontal plane are designed using a pole placement method. Effective tests of the controller gains are conducted by simulating the closed loops respectively. Since the camera functions as a position sensor, an image processing algorithm is then implemented to detect a distinctive landing symbol in real time while converting its image position into compliant feedback errors (pixel-to-physical distance-conversion). Ultimately, the developed system allows for the robust detection and successful landing on the landing spot by a position control operating at 20 hertz.

ADAPTATION OF DISPLAYED FLIGHT AND NAVIGATION DATA IN THE AIRCRAFT ELECTRONIC DISPLAY SYSTEM

The problem of flight safety continues to be of great importance in civil aviation, despite today aviation is the safest mode of transport. Particular attention is paid to the human factor, since it has a significant impact on safety. The article analyzes the impact of eye strain caused by displayed flight navigation data on a pilot during landing and discusses how to reduce it. It considers how the pilot interacts with aircraft equipment. The flight data, increasing eye strain, but having no affects on successful landing of the aircraft is specified. The article substantiates the necessity of adaptive display of flight data on the screen during landing. The proposed adaptive method for displaying flight navigation data is supposed to reduce the pilot’s eye strain, which contributes to improved quality of piloting and ensures flight safety.

Особливості проєктування споруд в умовах Марса

The article discusses the basic physical parameters and climatic features of Mars as a possible site for the construction of the first stationary research mission. They are the main factors of influence in the development of building structures for this planet. The analysis includes existing project proposals for buildings on Mars and effective means of protecting them against the negative impact of the environment, taking into account the experience of construction in complicated conditions on Earth. The detailed analysis of data allowed us to determine the parameters for the choice of location for building a colony. The parameters include soil composition, climatic indicators, terrain, level of cosmic radiation, methane fluctuations places, the equator zone, promising places for research, and successful landing places of the previous missions. Based on this, we justified the choice of the building complex location, which is the decisive factor for construction. An important aspect is also the determination of the planet colonization stages and the building requirements based on the needs of the colony. A project proposal has been developed for the second stage of planetary colonization. A colony is a quasi-closed system with its own “life cycle”, consuming only its own resources and available resources of the planet. The viability parameters of the project determine the full colony “life cycle”. We propose the hierarchical system of functions of the research mission complex. It includes five main functions: research, transport, residential, production, and recycling. The principle of hierarchy is used for the development of functional parameters of premises and the determination of links between them. In general, three blocks can be distinguished: residential, scientific, technical, and warehouse, which is organically interconnected. The system of functions is maximally optimized for human needs in Martian conditions and is designed to integrate artificial intelligence into the colony. However, the problems considered in the article are only a part of a wide range of technical, transport, financial, and other tasks that make up the range of issues of Mars development.