Rocket Stages Research Articles

Vibration Control for Laminated Composite Spherical-Cylindrical-Combined Shells: Theory and Experiment

Considering the structural damage and instability due to extensive vibrations, the present investigation focuses on the dynamic characteristics analysis and vibration control for aerospace structures such as rocket stages and aircraft cowling, modeled as laminated composite spherical-cylindrical-combined shells (SCCSs). The theoretical model of the SCCSs is established by a series of artificial connection and boundary springs. The proposed method’s validity is confirmed through finite element analysis and experimental validation. Nickel-titanium-steel wire ropes (NiTi-STs) are then introduced as a passive vibration control method for the SCCSs. Both circumferential and axial NiTi-ST laying schemes demonstrate good vibration control capabilities on the SCCSs. For similar lengths of NiTi-STs, the vibration control effect of circumferential laying schemes is superior to that of the axial one. Furthermore, the vibration control effect of the circumferential schemes is found to be dependent on the number and positioning of NiTi-STs. The influence of the NiTi-ST structural parameters on the vibration control performance is also analyzed; adjusting the structural parameters appropriately is helpful to improve the vibration reduction effect.

The LCROSS Impact Crater as Seen by ShadowCam and Mini‐RF: Size, Context, and Excavation of Copernican Volatiles

AbstractThe Lunar CRater Observations and Sensing Satellite (LCROSS) impacted a Centaur rocket stage into a permanently shadowed region (PSR) in Cabeus crater, excavating water ice and other volatiles. We used the Miniature Radio Frequency (Mini‐RF) instrument on the Lunar Reconnaissance Orbiter and the ShadowCam instrument on the Korean Pathfinder Lunar Orbiter to detect the probable 22‐m diameter crater that resulted from the LCROSS impact. The crater formed superposed upon a dense small crater population along a crater ray from a larger pre‐existing crater. From its geologic context, the ice and regolith excavated by LCROSS were likely modified within the last 0.1–0.5 Gyr. An upper limit for the excavated volatiles is ~0.9 Gyr, as the location was not a PSR prior to that time. A young age for the LCROSS‐detected volatiles supports the idea that they were mostly emplaced by an exogenic mechanism, such as from comets or the solar wind.

A closed-form expression derived from virtual testing for structural optimization of L-flange bolted connections

L-flange bolted joints are extensively used in different industrial sectors, such as wind turbine towers, rocket stages, or pipelines. Typically, the design of these connections is based on analytical expressions derived from simplified beam models. However, the influence of specific factors such as curvature, adjacent bolts, or joint separation are not addressed within conventional approaches. Finite element models offer the advantage of comprehensively accounting for these effects and the interaction between different failure mechanisms. Nevertheless, their industrial implementation requires significant computational resources, in contrast to the use of analytical formulae. In this context, this paper proposes a new framework for designing optimized L-flange bolted connections, based on general closed-form expressions that rely on validated numerical results. Three expressions, each one related to a particular failure mechanism, are derived from parametric simulations varying the most influencing parameters in the structural behavior. The generated equations can be easily implemented to guide the design process towards an optimal configuration, taking advantage of beneficial effects not addressed within classical approaches. A closer prediction of the actual load capacity of the joint can be obtained, providing a tool that allows engineers to make more reliable and economical designs.

Assessment of the endurance limit of light structural metal components using the fatigue surface development method

The paper presents a numerical method developed by the authors. The method consists in obtaining a three-dimensional component fatigue surface model according to the results of tests corresponding to two to four values of the operational factor, making it possible to plot the fatigue limit – operational parameter curve. A description of the algorithm of the method is presented, its validity is confirmed. The results show good agreement with outside empirical data for other values of the operational parameters. A model of the fatigue surface is constructed. The model specifies the calculation of strength of aircraft elements operating in rarified atmosphere (e.g. engine compartments of space complexes and upper stages of carrier rockets). The model increases the endurance calculation accuracy and enables structural mass optimization.

Comprehensive Detection of Particle Radiation Effects on the Orbital Platform of the Upper Stage of the Chinese CZ-4C Carrier Rocket

Comprehensive Detection of Particle Radiation Effects on the Orbital Platform of the Upper Stage of the Chinese CZ-4C Carrier Rocket

Design optimization of a low-cost three-stage launch vehicle with modular hybrid rocket motors

This article investigates the impact of modular propulsion system design on the performance and cost of a three-stage hybrid rocket. Furthermore, it conducts a multi-objective optimization of unit payload cost, take-off mass, and payload mass ratio, considering factors such as the number of motors and layout considerations. The optimization design scheme for the three-stage hybrid rocket is divided into four cases. In the first case, each stage is equipped with a fixed single motor, and each stage is independently optimized without modular design. The second case considers the use of multiple motors in the first and second stages, still without modular design. The third case also involves multiple motors in the first and second stages, but all motors in each stage have identical parameters except for the nozzle expansion ratio, implementing a modular design. In the fourth case, the number and layout of the motor design method are the same as those in the third case, with independent optimization in the third stage using partial modular design. The results indicate that the unit payload cost of the multi-motor non-modular design case can be reduced by 13.12% compared to the single-motor non-modular design case. Within the modular case, the full modular design case is slightly inferior to the partial modular design case. Based on the above data, it can be concluded that the first and second stages of modular rockets offer the best performance and the lowest cost.

Probabilistic risk assessment: Hazard impact study of safety-critical space launch events onto world air traffic & creation of ADIONA software

Space and air traffic increase yearly, prompting concerns about their coexistence. Fallback and splashdown of rocket stages to earth into predefined areas is a usual scenario, explosions of rockets and fallback into unprecedented areas is a probable scenario. These events represent a threat to world air traffic. In the present study, a probabilistic risk assessment on the launcher's stages fallback onto world air traffic has been carried out. A novel method and software, ADIONA, were developed to assess risks of rocket explosions and debris impact on air traffic. This pioneering software, a venture of the Flight Safety Department of the French Space Agency (CNES), supervising European Space Agency (ESA) launches, calculates at every possible time instant, defined by the user, the estimated positions of airplanes with along their own trajectories, trajectories and positions of rockets and the corresponding areas where debris falls back on earth after an explosion or a deviation. It further assesses the risks of fall down of debris on air traffic in case of a launch mishap and the probability of fatality to an airplane regarding the risk boundaries set by the French Space Operations Act. The software has been implemented in a general way for broad future application in operations and continued studies and use. Real-world air traffic and rocket launch data were incorporated, particularly focusing on launches from the French Guiana Space Center (CSG) and air traffic over the North Atlantic Ocean. These real-world analyses represent realistic scenarios. The obtained results show a considerable high possible risk onto world air traffic in case of a rocket explosion after launch. It is concluded that the cohabitation of space and air traffic and the probabilistic risk assessment thereof is important to be monitored in order to eventually be diminished to reduce the risk. It is recommended to invest further resources into this observation type of analysis. Further investigations should take place on this probabilistic risk analysis, taking into account more details and fine-tuning in the risk calculation and assessment method. The study's findings and software lay the groundwork for future risk analysis and development, facilitating ongoing and future investigations.

Multibody modelling of tether and capture system for dynamic simulations of In-Air Capturing

The launcher recovery method known as ‘In-Air Capturing’ is an innovative approach where a winged rocket stage is captured mid-air by an aircraft and subsequently towed back to the launch site. To achieve this, a capturing device attached to a tether is released from the towing aircraft. This device autonomously connects the reusable launch vehicle to the aircraft, while the two vehicles are in proximity. The tether’s flexible dynamics have a strong influence on the maneuverability of the capturing device. Thus, it is critical to model the dynamics of the tether to get a realistic understanding and to evaluate feasibility of the concept. However, precise modelling and control of highly flexible systems with large deformations is both challenging and computationally intensive. For engineering applications which involve closed-loop simulations, finding a trade-off between accuracy and computational effort is crucial. In this paper, the tether is modelled as a discretized chain of rigid bodies connected by rotational springs at the joints. The tether along with the capture system is integrated in a simulation model and open loop tests are performed to analyse the system characteristics. The tether properties are studied to find a suited configuration for ‘In-Air Capturing’.

Simulation of In-Space Fragmentation Events

In the next years, the space debris population is expected to progressively grow due to in-space collisions and break-up events; in addition, anti-satellite tests can further affect the debris environment by generating large clouds of fragments. The simulation of these events allows identifying the main parameters affecting fragmentation and obtaining statistically accurate populations of generated debris, both above and below detection thresholds for ground-based observatories. Such information can be employed to improve current fragmentation models and to reproduce historical events to better understand their influence on the non-detectable space debris population. In addition, numerical simulation can also be used as input to identify the most critical objects to be removed to reduce the risk of irreversible orbit pollution. In this paper, the simulation of historical in-orbit fragmentation events is discussed and the generated debris populations are presented. The presented case-studies include the COSMOS-IRIDIUM collision, the COSMOS 1408 anti-satellite test, the 2022-151B CZ-6A in-orbit break-up, and a potential collision of ENVISAT with a spent rocket stage; for these events, results are presented in terms of cumulative fragments distributions and debris orbital distributions.

Worldwide detection of rocket launches for space missions using International Monitoring System infrasound arrays

The signals of rocket launches can be detected at infrasound arrays in thousands of kilometers distance. We use microbarometer arrays, which are part of the International Monitoring System (IMS) for the Comprehensive Nuclear-Test-Ban Treaty (CTBT), to identify and characterize rocket launches all over the world. We studied more than 1000 launch events for space missions and their infrasonic signatures. Even small-lift launch vehicles such as Electron rockets starting from New Zealand with payloads of only a few hundreds of kilograms, e.g., for small satellites, can regularly be detected by one or more remote infrasound stations. We present selected cases of interest, including the latest NASA Artemis 1 Space Launch System and SpaceX Starship launches as well as airborne rocket starts and small-lift launches by different companies. Furthermore, we present a systematic analysis of infrasound recorded from multiple and regularly launched vehicles like Ariane 5, Falcon 9, and various Soyuz and Long March rocket types. Our main focus is on the connection between the observed signatures and propagation-corrected acoustic amplitudes of rocket launches as well as rocket parameters like payload, size and thrust, rocket stage, and engine characteristics of different rocket types.

Developing an innovative and high-performance method for recovering reusable launcher stages: the in-air capturing method

In this paper, the research within the Horizon 2020-funded project FALCon on the innovative “In-Air Capturing” (IAC) method is presented. This recovery method for reusable rocket stages involves capture of a winged launcher stage with an aircraft in a gliding flight at subsonic velocity. Hence, the IAC procedure involves multiple vehicles interacting in a highly dynamic and complex environment, which requires detailed investigation before being used in a future full-scale setup. First, this paper gives an overview of the implications of using the IAC method on launcher system design. Second, the subscale flight testing with unmanned aerial systems (UASs) is explained. An analysis of all full-scale systems involved is also conducted, including the towing aircraft, an aerodynamically controlled capturing device that is connected via a rope to the aircraft, and the RLV stage. CFD simulations are conducted to understand the implications of the flow field around the vehicles and their impact on the IAC maneuver. Next, some full-scale trajectory simulations for different maneuvers involved in IAC are produced. The trajectory is also evaluated for subscale flight simulations, wherein the data acquired during flight tests is used. Finally, the progress and potential future outlook for this recovery method are described.

Full-scale simulations of ‘In-Air Capturing’ return mode for winged reusable launch vehicles

The recent success of reusable launchers has become a driving force for sustainable launch technologies. An innovative approach proposed by DLR, involves winged rocket stages captured mid air and towed back to the launch site by an aircraft. This recovery concept known as ‘In-Air Capturing (IAC)’, shows potential for substantial cost reduction, when compared to existing return modes. In the light of the Horizon 2020 project FALCon, full-scale simulations and sub-scale flight testing were carried out for further development of the technology. The paper summarizes the full-scale studies performed within FALCon. The full-scale test cases are introduced and the simulation framework for analysis of trajectories is presented. Then, the IAC maneuver is analyzed through trajectory simulations. Major external disturbances coming from the wake of the aircraft and flexibility of the rope connecting the rocket stage to the aircraft (after capture) are also addressed.

Application of additional inflatable aerodynamic device to ensure the required degradation of the disposal orbit of large-size space debris

The paper studies the effectiveness of joint application of active and passive space debris removal technologies in low-Earth orbits.An active spacecraft-collector (SC), equipped with several detachable thruster deorbiting kits (TDKs), ensures the capture of the rocket stage. The TDK of dry mass about 90 kg should be fixed in the stage nozzle. After undocking from the SC, the TDK executes a deorbiting velocity impulse in order to form an elliptical disposal orbit with a predicted lifetime of 25 years in compliance with ISO standard requirements. However, many experts have recently called for a significant enhancement of these requirements.One of the ways to reduce the lifetime of the resulting disposal orbit is to equip the TDK with an aerodynamic decelerator, which has a shape of a spherical balloon. After the deorbiting impulse is applied, the balloon is supercharged by the gas remaining in the pressurized-propellant feed system of the TDK. Rigidization of the balloon shell is carried out by supercharging it above the yield point. The most rational balloon diameters are chosen based on the analysis of its effect on the lifetime of the disposal orbit.If the detachable TDK is equipped with an inflatable balloon, one can consider the combined and hybrid braking schemes. According to the first scenario, the balloon of diameter 12–14 m (“Zenith-2” case) or 7–8 m (“Kosmos-3M” case) is inflated in the already formed 25-year disposal orbit reducing its lifetime to about 5 years, while the dry mass of each TDK increases by 28 kg and 10 kg, respectively. Within the second scenario, a noticeably smaller deorbiting impulse results in a hybrid disposal orbit, which exists for 25 years due to subsequent inflation of the balloon of almost the same size. An analysis shows that the combined braking scheme is more preferable: with an insignificant increase in the SC launch mass, it does not create additional risks of failure and quickly deorbits the object from the most populated altitudes.

Electric Rocket Launcher Aircraft—Drone-Launched Short Range Rocket System

This paper is concerned with the idea of a significant improvement of state-of-the-art short-range rockets by means of using rocket artillery systems. Such a system consists of a rocket launcher aircraft (RLA) and a drone-launched short range rocket (DLSRR). An RLA is a reusable first stage of a military rocket. A DLSRR is the expendable second stage, which flies to the target. RLA-DLSRR systems have not yet been built, but they have been described in previous works by the author. State-of-the-art rocket systems are completely expendable and, hence, extremely expensive. No rocket artillery system with a reusable first stage has been built so far. Civilian spaceships with reusable first stages have been successful since 2015. In an electrically pumped rocket engine, the fuel and oxidizer are pumped into a combustion chamber by an electric-motor-driven pump. The electric motor is powered by a battery bank. Electrically pumped rocket engines would further decrease the cost of RLA-DLSRR systems. These engines are less expensive and more reliable then conventional rocket engines. In the present paper, it is shown that commercially available lithium polymer battery banks, as well as high specific power electric motors, provide sufficient power for the rocket engines needed for RLA-DLSRR systems. In the example given, it is calculated that an ERLA–DLSRR system with a liftoff mass of 15 tons can deliver a 210 kg payload to a range of up to 567 km with an impact velocity of up to 2415 m/s.

Rocket Recovery Carbin Section Passive location based on whale optimization algorithm

The accurate location of the rocket recovery cabin section is one of the key technologies to realize the reliable recovery rockets. Based on the multi-station time difference of arrival (TDOA) passive location principle, a technical solution for the recovery and positioning of the rocket recovery cabin section is designed. Through the active radiation signal of the recovery cabin, the whale optimization algorithm (WOA) is used to locate the position of the rocket recovery cabin section. The recovery process trajectory of the rocket's stage 1 cabin was adopted to verify the feasibility of the designed recovery positioning technical scheme.

Full-scale simulation and analysis of formation flight during in-air-capturing of a winged reusable launch vehicle

In the past two decades, the renewed interest in sustainable space transportation has driven the development of many innovative reusable launch technologies. One such concept called ‘In-Air-Capturing (IAC)’ involves winged rocket stages captured mid-air and towed back to the launch site using an aircraft. The approach, patented by German Aerospace Centre (DLR), shows potential for substantial mass and cost reduction by eliminating the need for additional propulsion during the descent. A critical aspect of IAC requires the two involved vehicles to be in a parallel formation with similar velocities and altitudes separated by a safe distance. The preliminary requirement is to maintain the formation for a minimum of 60 s, despite any external disturbances.This paper presents the modelling and simulation of a full-scale reusable launch vehicle and a towing aircraft attempting the formation flight for IAC. First, a suitable aircraft configuration is selected based on the aerodynamic performance of the selected test rocket stage. Important subsystems are identified and modelled comprehensively. Then, trajectory simulations are performed to identify the best approach and conditions for the formation. The sensitivity of the formation flight to critical factors like the idle thrust and wake turbulence from the towing aircraft are also analysed. The simulation showed that the minimum duration of formation flight could be maintained in the presence of external disturbances. Lastly, potential improvements and future simulations are discussed.

Разработка микробиологического препарата для биоремедиации почв, загрязненных компонентами ракетных топлив

Heptyl rocket fuel and aviation kerosene are widely used in the propulsion systems of the Proton and Soyuz spacecraft. The propellant components (RFC) enter the environment, causing strong toxic effects, when the separating first stages of rockets fall away or in case of emergencies. The study was aimed to isolate strains of microorganisms-destructors of RFC, as well as to assess their safety for bioremediation of contaminated soils. Microorganisms capable of decomposing heptyl, formalin, and aviation kerosene were isolated from natural soils. An association of two strains of bacterial destructors Pseudomonas putida 5G and Rhodococcus erythropolis 62М/3 was obtained, and a method of their use in recultivation of soil contaminated with RFC was developed. The results of laboratory and field tests showed high efficiency of the microbial destruction of pollutants, the decrease in integral toxicity and phytotoxicity of the cleaned soil to safe levels, and an increase in the soil biological activity. Thus, dehydrogenase activity increased by 2.4 times, hydrolase activity by 2.1 times, and cellulase activity by 5.1 times. Microbial association can be recommended for recultivation of soil contaminated with RFC.

Experimental study of the boosters impact on the rocket aerodynamic characteristics

PurposeThe purpose of this study is to determine the impact of two parallel boosters fixed to the ILR 33 AMBER 2 K core rocket stage on its aerodynamic characteristics in the subsonic and transonic regimes and for M = 2.3.Design/methodology/approachWind tunnel tests of the rocket model were carried out in a trisonic wind tunnel using a six-component internal balance. Three rocket model configurations were investigated.FindingsThe results of the presented studies showed that the presence of boosters causes a significant increase in the total rocket drag, which depends on both the Mach number and the rocket flight phase. Experimental tests of the rocket model allowed to determine the difference in drag coefficient between active and passive flight versus Mach number. It was found that, in the case of a deviation from the rocket’s flight direction, the aerodynamic coefficients strongly depend on the location of the boosters in relation to the direction of the deviation.Practical implicationsStudies of the rocket model aerodynamic characteristics allow the assessment of the influence of parallel boosters on rocket performance, which is important when the decision of a rocket staging type is taken.Originality/valueThe presented wind tunnel test results of the rocket model equipped with the two parallel boosters are an original contribution to the rocket research results presented in the literature.

ON THE STABILITY OF THE STABILIZED MOTION OF A CARRIER ROCKET WITH A LIQUID-PROPELLANT JET ENGINE AND AN ONBOARD DIGITAL COMPUTER IN THE STABILIZATION LOOP

The problem of choosing the values of the variable parameters of the digital stabilizer of the cosmic stage of a carrier rocket with a liquid-propellant jet engine and an onboard digital computer in the stabilization loop, which ensures stable movement of the stage along the entire active section of the flight trajectory, is considered. The effect of the stabilizer quantization period on the stability region of a closed-loop stabilization system is considered. It is recommended to choose the intersection of stability regions corresponding to uniformly distributed moments of time along the active section of the stage flight trajectory as acceptable values for the variable parameters of the stabilizer of a non-stationary stabilization object.

Design of the landing guidance for the retro-propulsive vertical landing of a reusable rocket stage

Launcher reusability is the most effective way of reducing access to space costs, but remains a great technical challenge for the European aerospace industry. One of the challenges lies in the recovery GNC strategy and algorithms, in particular those of the powered-landing phase, which must enable a precise landing with low fuel margins and significant dispersions. While state-of-the-art solutions for Navigation and control problems can be applied, namely, hybrid Navigation techniques and robust control, for the powered descent guidance problem novel techniques are required to enable on-board optimization, that is necessary to achieve the landing accuracy required to recover the first stage of a launcher. This paper presents the GNC solution currently in development by DEIMOS Space for RETALT (Retro Propulsion Assisted Landing Technologies), an EU Horizon 2020 funded project for studying launch system re-usability technologies for different classes of vertical take-off vertical-landing vehicles. At first, the architecture of the GNC solution identified for the return mission of the launcher is presented. Then, the paper focuses on the landing phase guidance solution, whose performance is critical to enable the recovery and, therefore, the reusability of the launcher making use of retro-propulsion. The guidance strategy is based on direct optimal control methods via on-board optimization, which is necessary to satisfy the pinpoint landing requirement in a high uncertain dynamic system, such as a booster recovery mission. Online convex optimization and successive convexification are explored for the design of the guidance function. The proposed guidance solution was integrated and tested in a high-fidelity simulator and the performance was preliminary assessed. The guidance assessment allowed selecting the best algorithms to be further consolidated and integrated in an end-to-end GNC solution for the return mission.