Space Launch Site Research Articles

Research on the cooling mechanism of low-temperature liquid jet mixing in high-temperature and high-speed airflow

The multi-stage water spray cooling system of the space launch site involves a complex gas–liquid two-phase mixed cooling problem in the process of spraying water onto the rocket engine gas jet. To investigate the complex multiphase flow field of the interaction between the airflow and liquid water jet, the Mixture multiphase flow model is adopted, which is coupled with the vaporization equation and component transport model of liquid water. The computational fluid dynamics method is used to numerically analyze the mixing and cooling mechanism of low-temperature liquid jet in high-temperature and high-speed gas flow. The results show that mixing low-temperature liquid jets in high-temperature and high-speed airflow can cause the exchange of momentum and energy, resulting in pressure loss and temperature reduction in the gas phase flow field. Due to the acceleration of transverse airflow, the diffusion flow range of the jet is significantly increased, and violent vaporization occurs, which further consume a large amount of airflow energy. The mixing cooling effect of transverse airflow and liquid water jet is directly related to the mass flow rate ratio of the jet to airflow. In addition, directly designing liquid water jet orifices on the solid wall of the guiding device can achieve the effect of improving the gas flow field environment. This conclusion can provide theoretical reference for the thermal protection design of ground launch devices in space launch site.

A method for safety analysis of human-machine systems based on dynamic Bayesian simulation

Accidents in human-machine systems often lead to serious consequences, so safety analysis is very important for such systems. However, the existing approach to safety analysis of human-machine systems lacks clear delineation of the coupling relationships between human and machine, or provide quantitative analysis. To address these issues, this paper proposes a method for safety analysis of human-machine systems, utilizing dynamic Bayesian network (DBN) and dynamic fault tree (DFT). The core of this method is the identification of human-machine coupling relationships, proposing 10 types of logical relationships and presenting corresponding DFT logic. Then, a conversion method from DFT to DBN is designed to avoid combinatorial explosion in complex FTA calculations. Based on the DBN model, simulation is conducted using Gibbs sampling, which offers higher computational efficiency. Additionally, a method for importance analysis is devised to identify critical nodes that impact the system risk. At last, a case study of refueling mission at space launch site is given to illustrate how to apply the method. Through simulation analysis, the safety risks during the refueling mission are quantitatively assessed, while critical nodes are identified. The results indicate that the dynamic Bayesian simulation method is good in information utilization, dynamic representation, and time performance.

Selected results of the hypersonic flight experiment STORT

The three-stage rocket configuration of the hypersonic experiment STORT with several scientific payloads concerning hypersonic technologies was launched successfully from the Andøya Space launch site in northern Norway on June 26, 2022. The third stage performed a suppressed trajectory to increase integral heat load on the payload structures. The vehicle traveled at speeds above Mach 8 at altitudes between 30 km and 38 km for more than 60 s. The nose and forebody section of the payload was made of CMC structures. Three canards with a CMC thermal protection were equipped with thermal management experiments to verify the thermal efficiency of these methods. All engineering science experiments like aerothermal heating of the nose and forebody, CMC material response at temperatures above 2200 K, hypersonic thermal management, shock wave boundary layer interaction, CFRP module with cork coating for high temperature applications, high temperature fin leading edge and radiometer sensors provided unique flight data. A reduced in-flight 3 DoF trajectory simulation running on the flight computer determined the ignition time of the third stage which allowed improved experiment conditions in terms of Mach number and apogee altitude even in the presence of external perturbations.

Reliability modeling of modular k-out-of-n systems with functional dependency: A case study of radar transmitter systems

The k-out-of-n systems are among the most important redundancy structures in engineering practices, and their reliability assessment has been extensively studied in the past decades. However, components in a k-out-of-n structure are often subject to functional dependency (FDEP), in which component states are affected by other components’ states in the system. In this article, we study a new system structure, namely modular k-out-of-n system with FDEP. In such a system, the failure of some specific components will disable some components in the k-out-of-n structure. Bayesian network (BN) models are used to construct the structure function of modular k-out-of-n systems. The parameters encoded in the graphical structure of the modular k-out-of-n system are automatically generated by a customized algorithm. Furthermore, a dynamic BN (DBN) is developed to update the reliability of modular k-out-of-n system dynamically when observation data are collected from either component or system level. The Birnbaum importance measure of the different types of components in the modular k-out-of-n system is also evaluated by the DBN model via inserting evidence of the components’ states overtime. A real-world case of a radar transmitter system in the space launch site is studied to demonstrate the effectiveness of the proposed method.

Design and implementation of remote image processing system for space launch site

Telemetry image has the characteristics of intuitive image in the process of rocket flight. Through real-time acquisition of rocket flight video image, it can provide the working status of key nodes in the process of rocket flight, and provide intuitive decision-marking auxiliary information for commanders. This paper analyzes the design content of the image processing system of the space launch site from the aspects of image transmission mechanism, information flow, image data processing and image decoding, so as to provide technical basis for the image receiving, transmission and decoding process in the engineering practice of the image processing system.

Lightning electromagnetic transient characteristics of the space launch site

The direct lightning protection system of the space launch site can achieve effective protection against direct lightning. However, the lightning electromagnetic pulse cannot be ignored while the rocket waiting on the platform. The three-dimensional lightning transient electromagnetic model is established by method of moments, when the launch site is struck by direct lightning. In order to quantitatively evaluate lightning environment of the launch site, electromagnetic fields of launch area are calculated in this paper with a size of 40×40 m2 on the ground and at 40 m above ground. When the lightning current is 200 kA in the case of severe lightning, the simulation results of basic parameters show that magnetic field on the ground is much larger than 40 m above ground, and the maximum and minimum values of magnetic field on the ground are respectively 608 A/m (7.6Gs) and 95 A/m (1.2Gs). The electric field at 40 m above ground is much larger than the ground, and the maximum and minimum values of electric field at 40 m above ground are respectively 111 kV/m and 26 kV/m. Under six different factors, the three factors of number of shielded wires, distance between lightning towers and lightning current wave-front parameters have obvious effects on the electromagnetic field in the launch area. The highest and lowest reduction rates of electromagnetic fields are about 88% and 33% respectively. However, other factors reduce electromagnetic fields by no more than 13%. The critical magnetic field for permanent damage of electronic equipment is 2.4Gs, which is between the minimum and maximum magnetic fields of the launch area. It is recommended that electronic equipment is placed in area with smaller magnetic field, which is close to the center of the launch area. This paper provides a reference for the lightning protection indicators and suggestions for the space launch site.

Research on Fault Diagnosis Training System Based on Virtual Space Launch Site

Aiming at the problem that the ground equipment system of space launch range is complex and it is difficult to implement real fault diagnosis training, this paper analyses the requirements of fault diagnosis training, puts forward a design scheme of fault diagnosis system based on virtual range, and expounds the basic workflow of virtual fault diagnosis training system. The fault tree and expert system are combined to complete the fault diagnosis training process design. The real-time scheduling method of virtual scene based on multi-threaded entrance is used to load and render the virtual scene in real time according to the movement trend of the virtual avatar, which ensures the fluency of interoperability in terms of function and performance, so as to achieve the purpose of improving the training effect.

Safety Assessment System of Launching Tower Structure with Multi-information Fusion and Data-driven

In order to monitor and evaluate the impact of rocket launching shock, strain, vibration, typhoon, earthquake and other loads on the launch tower, an online monitoring and evaluation system was established based on multi-sensor information fusion technology in a space launch site. Firstly, the system integrates the information of vibration, pressure, deformation, wind load, temperature and other sensors to comprehensively analyze and evaluate the safety of tower structure, and realizes health diagnosis. Then use 3dmax to draw the 3D simulation model, and realize the real-time 3D display of various monitoring and analysis results based on the 3D visualization and data-driven technologies.

Implementation of FPGA-Based Controller in Automatic Control System Platform for Launch Site

To develop an FPGA-based controller, we proposed the architecture and implementation schemes for the controller and determined the technical indexes for the design. The schemes include the board layout and design of the logic daughter card for the architecture of the FPGA-based controller. To improve reliability, self-diagnosis and self-protection circuits are included in the controller design. The data communication design mainly consists of backplane serial data communication, a 422/485 serial data communication daughter card, and an I/O daughter card. We developed a prototype controller and established a propellant loading prototype control system for a space launch site. Experimental results show that the performance of the designed FPGA-based controller meets the major technical indexes. The controller is then compared with existing PLCs. The comparison shows that the FPGA-based controller has higher reliability, faster response time, and better performance.

Design for the Lift Platform Humanoid Climb Assisting Unit of the Space Launch Site

Humanoid climb assisting unit (HCAU) is a key mechanism for the lift platform to adjust its height-level of the space launch site. It is widely used for lift platforms of launch towers, service towers, vertical assembly test building for launch vehicles and that of silos for missiles. In this paper, its working principal is illustrated. The design requirements and terms, design steps and effecting factors are discussed. Three types of HCAU design methods and their calculating formulae are derived. Design examples are presented.

CREAM-Based Human Reliability Analysis for Space Launch Day

According to the characteristics of space launch day, the common performance conditions (CPC) were improved. After the CPC were weighted, the value of the performance influence index was presented. And based on the modified CREAM method, a human reliability assessment was given. Consequently, the outcomes of this work can provide the human error probability and data base for safety assessment of space launch site.

Laminar Flow Analysis of Low Temperature Propellant Flowing through Pipes of Filling System

With aiming at the problem of liquid hydrogen flowing through filling system in space launch site, the author set up a math model of laminar flow and coupled with the analysis of laminar flow condition of liquid hydrogen in tube. Based on the computational fluid dynamics, the flow field was studied according to the numerical simulation method. Then, the changes of flow parameters i.e. pressure and velocity at the tube were observed. Simulation results showed that, in the inlet-section, there existed boundary-layer, besides, the velocity and pressure which changed continually was not stable until the liquid hydrogen flowed through on-way. In addition, the velocity distributed in the form of rotary parabolic surface whose axis was the tube’s axis itself in water-carrying section of on-way. The velocity near the surface of the tube was about zero and the pressure turned to smaller with the increase of tube length. As a result of the pressure drop, there existed the loss of on-way. The above simulation results which provided the theoretical basis for liquid hydrogen study accorded with the actual condition.

Turbulence Flow Analysis of Low Temperature Propellant Flowing through Pipes of Filling System

With aiming at the problem of liquid hydrogen flowing through filling system in space launch site, the author set up a turbulence model and coupled with the analysis of turbulence condition of liquid hydrogen in tube. Based on the computational fluid dynamics, the flow field was studied according to the numerical simulation method. Then, the changes of flow parameters i.e. pressure and velocity at the tube were observed. Simulation results showed that, in the inlet-section, there existed boundary-layer, besides, the velocity and pressure which changed continually was not stable until the liquid hydrogen flowed through on-way. In addition, in water-carrying section of turbulence flow, the velocity distribution was even and there was no obvious delamination which explained that the mix was intense. The velocity near the surface of the tube was about zero and the pressure turned to smaller with the increase of tube length. As a result of the pressure drop, there existed the loss of on-way. The above simulation results which provided the theoretical basis for liquid hydrogen study accorded with the actual condition.

Synthesis of a system for monitoring oxygen concentration in working area air

Key stages of synthesis of a system for monitoring oxygen concentration in the working area air, which meets the requirements for reliability, precision, and speed of measurements, are examined. Based on the obtained data, the 13Sh34.01 system has been developed for monitoring volume fraction of oxygen in the working area air in filling station premises on the Baikonur space-launch site.

Beneath a Modern Sky: Space Technology and Its Place on the Ground

In delineating a trajectory of human history, anthropology and other social sciences have tended to describe traditional life in particular geographic terms while leaving modem experience universal in scope. Studies of science and technology, while helping to locate and describe centers of modern practice, have less frequently explored their edges. Using a case study of the location of the primary French/European space launch site in French Guiana, this article examines technologies associated with the development of space beyond the atmosphere by evaluating the impact of rockets and satellites on the construction of human space on the ground. Exploring the social significance of a modem sky and its transformation of one tropical margin into a technical center, the question of where things are becomes one of how they are defined. The modem appears less a placeless universal center and more a moving boundary, one dividing humans, nature, and technology into less stable domains.

European spaceflight at the crossroads

Plans for Europe's future participation in space development are still under active discussion. This article offers a contribution to the debate, considering how Europe can best fulfil its own objectives. Choice of launch vehicle and its payload, as well as of other tools such as space station, re-entry vehicle, and launch site equipment are analysed. The article also discusses the purposes of space research for Europe, and the costs of a useful programme. A far-reaching European space programme still needs to be drawn up if Europe is not to lose out.