Rocket Body Research Articles

ASSESSMENT OF THE POSSIBILITY OF USING POLYMERS IN THE BODIES OF PROMISING LAUNCH VEHICLES BASED ON THE HEAT RESISTANCE FACTOR

One of the possible ways to solve the problem of quick and low-cost payloads to low Earth orbits is the creation of ultralight rockets that use new construction materials, in particular, synthetic polymers. A promising approach to creating a launch vehicle of this type is the concept of a burnt rocket, the body of which is made of thermoplastic polymer materials. At the same time, the practical implementa- tion of such a launch vehicle requires additional research, in particular, the possible process of premature destruction of the structure due to aerodynamic heating. In this work, the heat resistance of polymer bodies of a new type of ultralight launch vehicles during flight in the atmospheric part of the trajectory was evaluated. For mathematical modeling of heating processes, we used the results of experimental studies of the thermodynamics of polyethylene and polypropylene during heating. These results allowed us to propose a mathematical model for calculating the process of heating polymer shells. The dynamics of the temperature fields during movement along the given trajectory of the launch vehicle in the atmospheric stage have been determined. It was established that under the given trajectories, both considered materials satisfy the conditions of heat resistance. The influence of temperature on the reduction of the strength characteristics of polymer bodies is shown, and the necessary thicknesses of the walls of the body shells, which should prevent deformation of the structure during aerodynamic heating, are determined. So, for the first time, the possibility of making rocket bodies from thermoplastic polymer materials has been theoretically substantiated.

Orbit Determination of Chinese Rocket Bodies from the Picosecond Full-Rate Laser Measurements

Abstract In this paper, the results of the orbit determination of two Chinese rocket bodies from low earth orbit (LEO) regime based on the picosecond laser measurements provided by one laser sensor are presented. A new approach was implemented that involved using a set of single laser measurements known as full-rate measurements instead of normal points. The computation strategy was applied using three different scenarios, and several key parameters such as root mean square (RMS), RMS of position (RMSPOS), RMS of velocity (RMSVEL), and alert time were determined. The results obtained indicate that the most optimal solution is to use short orbital arcs that are 24 h long. In this case, the average RMSPOS is approximately 345–530 m, the average RMSVEL is approximately 1 m/s, and the average arc RMS is approximately 3.7–7.0 cm. The determined alert time parameter, which refers to the time during which the laser observation of a given object should be repeated, is on average approximately 19.5 h. If longer orbital arcs, such as 2 days or more, are used, RMSPOS and RMSVEL actually reach the level of single centimeters and single millimeters per second, respectively. However, the arc RMS increases significantly to at least decimeters and even above 1 m in some cases. This suggests that the long arc approach is not a favorable solution. In addition, an interesting discovery has been presented that some Chinese launchers are equipped likely with the laser retroreflectors that can easily reflect the laser beam.

Physical Characterization of Moon Impactor WE0913A

On 2022 March 4, the object known as WE0913A crashed into the Moon after several close flybys of the Earth and the Moon in the previous three months. Leading up to impact, the identity of the lunar impactor was up for debate, with two possibilities: the Falcon 9 from the DSCOVR mission or the Long March 3C from the Chang’e 5-T1 mission. In this paper, we present a trajectory and spectroscopic analysis using ground-based telescope observations to show conclusively that WE0913A is the Long March 3C rocket body (R/B) from the Chang’e 5-T1 mission. Analysis of photometric light curves collected before impact give a spin period of 185.221 ± 6.540 s before the first close Earth flyby on 2022 January 20 and a period of 177.754 ± 0.779 s, both at a 1σ confidence level, before the second close Earth flyby on 2022 February 8. Using Markov Chain Monte Carlo sampling and a predictive light curve simulation based on an anisotropic Phong reflection model, we estimate both physical and dynamical properties of the Chang’e 5-T1 R/B at the start of an observation epoch. The results from the Bayesian analysis imply that there may have been additional mass on the front of the rocket body. Using our predicted impact location, the Lunar Reconnaissance Orbiter was able to image the crater site approximately 7.5 km from the prediction. Comparing the pre- and post-impact images of the location shows two distinct craters that were made, supporting the hypothesis that there was additional mass on the rocket body.

Bending of sheets and profiles on a four-roll machine for rocket bodies, tubular and frame products. Part 12

The theory of stamping is developed taking into account the anisotropy and hardening of the workpiece. The calculation of the parameters of the deformed-stressed state of the workpiece is carried out using the example of bending of a thin strip onto an edge on a roller machine or in a stamp. Deformations, stresses and forces from the action of rolls or die tools on the workpiece are studied by CAD/CAE modeling. The criteria for crack formation, low accuracy and excessive springback of the part after processing are determined, recommendations for their elimination are given. Keywords: stamping, anisotropy, workpiece, bending, roll machine, die, CAD/CAE modeling. dr_zharkov_v_a@mail.ru

Attitude Estimation of H2A Rocket Body from Light Curve Measurements

Attitude Estimation of H2A Rocket Body from Light Curve Measurements

On a general apogee formula for the disposal of satellites and rocket bodies below the geosynchronous protected region

The geosynchronous orbital region (GEO) is heavily used by satellites. To avoid the proliferation of space debris in this unique orbital environment, space debris mitigation guidelines define a protected region around the orbit and recommend disposal strategies that avoid long-term interference. For satellites operating in the GEO-protected region, a well-known formula was established that defines a minimum-perigee altitude, for a given eccentricity, that avoids drifting back into this regime after the end of the mission. This formula, found in the IADC space debris mitigation guidelines, suggests disposal in near-circular, long-term ‘stable’ orbits above the GEO-protected region, whereby the altitude of perigee is beyond 235 km plus a factor accounting for the solar radiation pressure perturbations. Recently, an extension of this formula that also accounts for the inclination has been suggested. With the advent of direct launch into GEO, whereby either a rocket body or satellite is left in an orbit below the protected region, the natural question arises whether a similar formula can be found for the apogee of disposal orbits below the protected region. The presented work investigates the dynamics of the sub-GEO region and establishes and validates an upper-apogee-difference limit for a time span of at least 100 years. Moreover, the practical implication of such a strategy on the delta-V budget of a mission is assessed.

Metals from spacecraft reentry in stratospheric aerosol particles

Large increases in the number of low earth orbit satellites are projected in the coming decades [L. Schulz, K.-H. Glassmeier, Adv. Space Res. 67, 1002-1025 (2021)] with perhaps 50,000 additional satellites in orbit by 2030 [GAO, Large constellations of satellites: Mitigating environmental and other effects (2022)]. When spent rocket bodies and defunct satellites reenter the atmosphere, they produce metal vapors that condense into aerosol particles that descend into the stratosphere. So far, models of spacecraft reentry have focused on understanding the hazard presented by objects that survive to the surface rather than on the fate of the metals that vaporize. Here, we show that metals that vaporized during spacecraft reentries can be clearly measured in stratospheric sulfuric acid particles. Over 20 elements from reentry were detected and were present in ratios consistent with alloys used in spacecraft. The mass of lithium, aluminum, copper, and lead from the reentry of spacecraft was found to exceed the cosmic dust influx of those metals. About 10% of stratospheric sulfuric acid particles larger than 120 nm in diameter contain aluminum and other elements from spacecraft reentry. Planned increases in the number of low earth orbit satellites within the next few decades could cause up to half of stratospheric sulfuric acid particles to contain metals from reentry. The influence of this level of metallic content on the properties of stratospheric aerosol is unknown.

Radial envelope forming mechanism and process design method for cylindrical rings with thin wall and high web ribs

Cylindrical rings with thin wall and high web ribs (CRTWHWR) are widely used as the key load bearing structures such as rocket body and space station cabin in aerospace field. However, it is still difficult to efficiently manufacture CRTWHWR with high performance because of their extreme geometry with thin-walled skins, high web ribs and large size. In this paper, a novel radial envelope forming process is put forward to efficiently achieve the plastic forming of CRTWHWR with high performance. Firstly, the principle of radial envelope forming process is clarified. Then, an efficient design method for the tool motion and geometry is proposed based on the reverse envelope principle, i.e., CRTWHWR is adopted to reversely envelope the tool and thus the tool which does not interfere with CRTWHWR can be efficiently obtained in a single operation. Finally, a reasonable 3D FE model of the radial envelope forming process of CRTWHWR is established and the radial envelope forming mechanism of CRTWHWR is comprehensively revealed. Through the FE simulation and experiments with material of plastic mud, a typical CRTWHWR with diameter of 300 mm, axial height of 192 mm, the maximum rib height of 25 mm, the minimum rib thickness of 3 mm and skin thickness of 5 mm is radial envelope formed, i.e., the ratio of the maximum rib height to the minimum rib thickness reaches 8.33, the ratio of the maximum rib height to skin thickness reaches 5 and the ratio of diameter to the minimum rib thickness reaches 100. The above results verify that the proposed radial envelope forming process has great potentials in efficiently manufacturing CRTWHWR with extreme geometry.

Characterization of deorbiting satellites and space debris with radar

During deorbiting, be it natural orbital decay or otherwise (e.g. self-disposal or active debris removal), precise knowledge of the condition of the target is of critical importance. The Tracking and Imaging Radar (TIRA) is an instrument that possesses the ability to accurately determine satellite and space debris orbits while also generating detailed radar images of them.We present recent results from the characterization of deorbiting satellites and space debris employing TIRA. Drawing examples from orbital decay events (Tiangong-1, Soyuz 2.1v R/B), deorbiting (Tiangong-2) and self-disposal operations (Carbonite-1, MicroSCOPE), we demonstrate the potential of TIRA. Furthermore, we focus on the emerging field of active debris removal (ADR), where reliable information of the on-orbit status and attitude motion of potential targets can “make or break” an ADR mission. In this context, the on-orbit status of a JAXA R/B (43682) and a VESPA adapter (39162) are investigated.We employ inverse synthetic aperture radar (ISAR) imaging and 3D modelling of ISAR images, obtained with TIRA, to characterize the status and attitude motion of satellites and space debris. When certain conditions render direct imaging unsuitable, the more powerful L-band tracking radar of TIRA is used to obtain and analyze the temporal evolution of their radar cross-section (RCS). In this work, we employ for the first time, a wavelet time–frequency analysis of such RCS signatures, specifically of NABEO-1 (43692) in LEO and an Ariane 5 rocket body (28904) in geostationary transfer orbit (GTO), to characterize their on-orbit status. The wavelet analysis delivers results in good agreement with more traditional tools, with added information on time localization of periodicities. We are thus able to confirm the tumbling motion of NABEO-1 and constrain the rotational velocity of Ariane 5 upper stage (28904).

Can the Orbital Debris Disease Be Cured Using Lasers?

Ground-based high-power lasers are, in principle, able to de-orbit any kind of space debris object from the low Earth orbit (LEO) by remotely inducing laser-ablative momentum. However, the assessment of efficiency and operational safety depends on many factors, like atmospheric constraints or the risk of debris disintegration during irradiation. We analyze laser momentum for a great variety of target geometries and sizes and—for the first time in a large-scale simulation—include thermal constraints in the laser irradiation configuration. Using a coherently coupled 100 kJ laser system at 1030 nm wavelength and a 5 ns pulse duration in an optimized pointing elevation angle range, the pulse frequency should amount to less than 10 Hz to prevent fragment meltdown. For mechanically intact payloads or rocket bodies, repetition rates should be even lower. Small debris fragments sized between 10 and 40 cm can be de-orbited by employing around 100 to 400 station passes with head-on irradiation, while objects exceeding 2 m typically require far more than 1000 irradiations for de-orbit. Hence, laser-based debris removal cannot be considered a prime space sustainability measure to tackle the highest-risk large debris, yet it can provide the remediation of a multitude of small-sized debris using small networks of globally distributed laser sites.

Research on verticality adjustment scheme of launch vehicle

This paper introduces the current situation of verticality adjustment of launch vehicles at home and abroad, and analyses the problems and risks existing in verticality adjustment of launch vehicles at home and abroad. A new scheme for vertical adjustment of a launch vehicle is proposed in this paper. The paper compares the new and the old schemes with the actual application of a certain type of launch vehicle. The new scheme cancels the level measuring instrument on the rocket, simplifies the operation of rocket verticality adjustment at the launching site, reduces the design requirements for the launching station system, avoids the risk of structural damage and tower interference caused by the data distortion of the horizontal measuring instrument and the verticality adjustment operation of the rocket body.

Dynamics model and numerical simulation of single stage water rocket

The initial launch parameters of a water rocket have a significant impact on its speed, altitude and other flight performance. The dynamic model describing the mass, velocity, nozzle velocity and internal pressure of water rocket was established by the force analysis of its ascending stage. Numerical simulation was carried out on the movement process of the water rocket. The changes of the internal pressure and thrust of the rocket body, and the speed and height law of the rocket in the flight process under the conditions of the same initial internal pressure and different initial loading propellant liquid were studied respectively. The results show that, under the designed conditions, the change law of the thrust force is similar to the variation of the internal air pressure in the ascending stage, and the internal air pressure decreases to 45%~57% of the initial value at last. Setting the volume of the initial loaded liquid to 0.43 helps to increase the boost duration and improve the utilization of the initial pressure, in which case, the maximum velocity of the launch rocket is not affected, but will lead to a decrease in thrust size.The above results provide important technical support for the optimal design of single-stage or multistage water rocket, and have strong guiding significance for carrying out water rocket flight test.

Bending of sheets and profiles on a four-roll machine for rocket bodies, tubular and frame products. Part 11

dr_zharkov_v_a@mail.ru The theory of stamping is developed taking into account the anisotropy and hardening of the workpiece. The calculation of the parameters of the deformed-stressed state of the workpiece is carried out using the example of bending on a roller machine or in a die. Deformations, stresses and forces acting on the workpiece from rolls or die tools are studied by CAD/CAE modeling. The criteria for crack formation, low accuracy and excessive springback of the part after processing are determined, recommendations for their elimination are given. Keywords: stamping, anisotropy, workpiece, bending, roll machine, die, CAD/CAE modeling

Modelling and analysis of metal flowing behaviors in constraining ring rolling of tapered ring with thin wall and three high ribs

Tapered ring with thin wall and three high ribs (TRTWTHR), showing complicated geometry (wall thickness is less than 4 mm and rib height exceeds 20 mm), is extensively utilized to fabricate the critical structural parts of aerospace equipment such as spacecraft cabin, rocket body and fuel tank because of light weight and high carrying capacity. How to fabricate TRTWTHR with high performance is a critical problem that aerospace area needs to solve. In this work, constraining ring rolling (CRR) technique is first adopted to form TRTWTHR. However, unreasonable metal streamlines (UMS) and uncoordinated growth of three ribs easily occur in CRR of TRTWTHR, which makes the forming quality of TRTWTHR difficult to be controlled. Faced with this difficulty, an analytical model that can predict UMS and the height of three ribs in CRR of TRTWTHR is established so as to guide the process design of CRR. Subsequently, the reliability of the established analytical model and the feasibility of CRR of TRTWTHR are confirmed by FE simulation and experiment. Then, using the established analytical model, the window of UMS occurring relevant to the tapered angle of TRTWTHR and the location of the rib of middle end is developed. Finally, three uncoordinated growth modes among three ribs are found when the width of three ribs is identical and UMS do not occur, and the mechanisms of three uncoordinated growth modes are revealed.

A Load-Carrying Capacity Evaluation Method for the Welded Joints of Rocket Engine Frame

The load-carrying capacities of welded joints need to be paid attention to in the design of the frame, which transfers the thrust generated by the rocket engine to the rocket body. A load-carrying capacity evaluation method of welded joints based on the structural stress method is proposed in this study. Both the ultimate load-carrying capacity and fracture section angle are precisely obtained by the evaluation method. At the same time, a definition of weld-failure stress is given based on the evaluation method and tests. The load-carrying capacity of welded joints in the rocket engine frame is analyzed through the finite element model, including the overall structure and local weld details. The weld-failure stress of welded joints is obtained based on the analysis of three types of welded structures—standard shear specimen, U-shaped fillet welded specimen and pipe-plate fillet welded specimen. The safety factors of the transverse rod and longitudinal bearing rod welded joints of the frame are 8.6 and 13.4, respectively.

Space Debris Laser Ranging with range-gate-free Superconducting Nanowire Single-Photon Detector

Space Debris Laser Ranging (DLR) is a technique to measure range to defunct satellites, rocket bodies or other space targets in orbits around Earth. The analysis shows that one of the reasons for the low success probability of DLR is the inaccurate orbital prediction of targets. Then it is proposed to use the Superconducting Nanowire Single-Photon Detector (SNSPD) running in automatic-recoverable range-gate-free mode, in which case, the effect of the accuracy of the target’s orbital prediction on the success probability of DLR is greatly reduced. In this way, 249 space debris were successfully detected and 532 passes of data were obtained. The smallest target detected was the space-debris (902) with an orbital altitude of about 1000 km and a Radar Cross Section (RCS) of 0.0446 m2. The farthest target detected was the space-debris (12,445) with a large elliptical orbit and an RCS of 18.2505 m2, of which the range of the normal point (NPT) of the measured arc-segment on January 27, 2019 was 6260.805 km.

Bending of sheets and profiles on a four-roll machine for rocket bodies, tubular and frame products. Part 10

The theory of stamping is developed taking into account the anisotropy and hardening of the workpiece. The calculation of the parameters of the deformed-stressed state of the billet is carried out using the example of bending on a roller machine or in a die. Deformations, stresses and forces acting on the billet from rolls or die tools are studied by CAD/CAE modeling. The criteria for crack formation, low accuracy and excessive springback of the part after processing are determined, recommendations for their elimination are given. Keywords: stamping, anisotropy, billet, bending, roll machine, die, CAD/CAE modeling. dr_zharkov_v_a@mail.ru

Attitude Stabilization of Rocket Elastic Vibration Based on Robust Observer

This paper proposes an approach to suppressing the elastic vibration and propellant sloshing in attitude control of a high slenderness ratio rocket. The main method is to combine a variable-gain robust observer with a variable structure controller for the purpose of attitude stability and elastic vibration suppression. A variable-gain robust observer is designed to reconstruct the attitude variable and complex multi-order elastic state. In this way, each order elastic vibration can be transformed into an additional attitude with the attitude characteristics of the rocket, which is easy to control. The reconstructed rocket body with an additional attitude is treated as the input of the designed variable structure controller to output the control signal. Under the simultaneous action between the variable-gain robust observer and variable structure controller, attitude stability is achieved for the rocket considering multi-order elastic vibration, and the propellant sloshing in the launch vehicle storage tank can be suppressed simultaneously. According to the simulation results, the proposed method produces a satisfactory stabilization outcome on each order of elastic vibration (especially low-order elastic vibration) and is better than a single variable structure controller.

Study on bottom thermal environment of launch vehicle during high altitude flight

Aiming at the problem of the thermal environment at the bottom of the launch vehicle in the high-altitude flight stage, taking the launch vehicle with core stage four-way machine as the model, the coupled convection / radiation heat transfer problem at the high-altitude of the launch vehicle is deeply studied through the numerical simulation method, the gas jet flow model of the launch vehicle in the high-altitude flight stage is established, and the flow field information of the rocket under different working conditions and the heat flow at the bottom of the rocket are obtained. The numerical results are compared with the experimental data to verify the effectiveness of the selected model and calculation method. The research shows that the external flow field of the rocket body will have a great impact on the thermal environment at the bottom. With the continuous increase of flight altitude, the convective heat flow at the bottom of the rocket body first rises and then decreases. In the high-altitude stage, the total heat flow at the bottom of the rocket body is dominated by radiant heat flow, the convective heat flow outside the main nozzle is dominant, and the radiant heat flow outside the traveling jet nozzle is dominant.

Key Technology and Application of Production Scheduling for Heating Forming of Forgings: A Review

Forgings represented by rocket body rings, engine casings, vehicle drive shafts, etc., are key components of important equipment in the fields of aerospace, automobiles and high-speed rail. In recent years, with the rapid development of the manufacturing industry, it is also facing an increasingly fierce international competition environment. In order to adapt to the new production mode and quickly respond to the changing market demand, forging enterprises urgently need a reasonable and efficient forging production scheduling method, and based on the excellent production organization, in order to further build an intelligent production line, develop a forging production intelligent management and control integration architecture. This paper analyzes the production scheduling problem of forging thermoforming from two aspects: forging production line scheduling and forging production workshop scheduling. The research progress of optimization objectives and optimization algorithms of production scheduling is systematically reviewed. The subsystems serving the production and processing process and the intelligent management and control architecture based on system integration are summarized. It is of great significance to effectively reduce production costs, improve product quality, realize energy saving and emission reduction in the production process and promote further intelligent upgrading of the forging industry through production scheduling and intelligent management and control of the heating and forming process of forgings.