Method for identifying safety key items of manned spacecraft in long-term in-orbit operation

Abstract

The invention relates to a method for identifying safety key projects of a long-term in-orbit operation multi-cabin manned spacecraft, which comprises the following steps of: performing mission profile analysis, determining safety key programs in an in-orbit flight process of the manned spacecraft, and listing the safety key programs into a system-level safety key project list; performing function analysis on the system, determining safety key functions of the manned spacecraft, and listing the safety key functions into a system-level safety key item list; performing function analysis on the subsystems, determining safety key functions of the manned spacecraft, and listing the safety key functions into a subsystem-level safety key item list; carrying out danger analysis on the equipment, determining safety key equipment of the manned spacecraft, and listing the safety key equipment into an equipment-level safety key item list; and summarizing and comprehensively analyzing system-level, subsystem-level and equipment-level key item lists, determining equipment for realizing safety key programs and safety key functions as safety key equipment, removing repeated items, and finally forming a manned spacecraft key item list.

Description

Technical Field

[0001] The present invention relates to the technical field of overall design of manned spacecraft, specifically, to the technical field of safety design, and more specifically, to a method for identifying key safety items of a manned spacecraft. Background Art

[0002] The primary task of manned spacecraft in orbit is to ensure the safety of personnel. As manned spacecraft develop towards complexity and large-scale, there are more and more dangerous sources that can lead to serious consequences. Manned spacecraft accidents will cause casualties and major property losses, seriously hindering the development of space technology. Hazard identification and hazard analysis should be carried out during the design stage of the spacecraft. By controlling and eliminating the hazard sources, the safety of the spacecraft can be guaranteed to be at an acceptable level. Conducting hazard analysis of manned spacecraft is the premise and basis for ensuring safe and reliable operation.

[0003] Using the safety system engineering approach to conduct hazard analysis can comprehensively and systematically address the overall safety of spacecraft, preventing one-sidedness and putting the cart before the horse; through analysis, the weak links and risks of the system can be understood, and the possibility of accidents can be predicted, so that we can be prepared; through safety evaluation and optimization technology, we can find ways to achieve the best coordination among subsystems and obtain the best safety effect at a relatively small cost in system resources; we can promote the various technical standards and related data required for qualitative and quantitative safety analysis, and improve the ability to design and analyze the safety of manned spacecraft.

[0004] Since my country has no experience in large manned spacecraft in orbit for more than 10 years, although the safety design experience and hazard analysis methods of previous manned spacecraft can be used for reference, due to the huge differences in on-orbit flight time and mission types, simply applying the methods in the existing technology to long-term multi-cabin manned spacecraft assemblies may cause the following problems:

[0005] 1. Manned spacecraft that operate in orbit for a long time are generally assembled from multiple cabins, with a large number of equipment and types of hazardous sources, and it is impossible to accurately identify safety-critical equipment and effectively control hazardous sources;

[0006] 2. During the long-term on-orbit operation of spacecraft, a large number of on-orbit maintenance operations need to be carried out, and the hazards introduced by on-orbit maintenance need to be controlled;

[0007] 3. In view of the numerous hazardous sources, only safety control of key equipment cannot achieve the overall safety goals of manned spacecraft.

[0008] Therefore, the existing methods for identifying safety-critical items cannot be simply and directly applied. Summary of the invention

[0009] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and propose a method for identifying key safety items of manned spacecraft, which is used to determine the key safety items of manned spacecraft and perform hazard control during the long-term on-orbit operation of large manned spacecraft.

[0010] The solution to the technical problem of the present invention is: a method for identifying key safety items of a multi-compartment manned spacecraft in long-term orbit, the method comprising the following steps:

[0011] Conduct mission profile analysis to determine the safety-critical procedures of manned spacecraft during in-orbit flight and include them in the system-level safety-critical items list;

[0012] Conduct functional analysis on manned spacecraft systems, identify key safety functions of manned spacecraft, and include them in the system-level safety key project list;

[0013] Conduct functional analysis on subsystems, determine key safety functions for manned spacecraft, and include them in the subsystem-level safety key project list;

[0014] Conduct risk analysis on equipment, identify key equipment for manned spacecraft safety, and include it in the equipment-level safety key project list;

[0015] Summarize and comprehensively analyze the key project lists at the system level, subsystem level, and equipment level, identify the equipment that implements each safety-critical procedure and safety-critical function as safety-critical equipment, remove duplicate safety-critical functions, safety-critical procedures, and safety-critical equipment, and ultimately form a list of key items for manned spacecraft.

[0016] Preferably, a program with one of the following characteristics should be determined as a safety-critical program:

[0017] a) Procedures that can directly lead to total loss of the system or loss of life;

[0018] b) Programs that perform safety-critical functions and have constraints greater than or equal to 3.

[0019] Preferably, a function having one of the following characteristics is determined as a safety-critical function:

[0020] a) Functions that could cause catastrophic accidents if they fail;

[0021] b) Functions for safe control of serious accidents.

[0022] Preferably, the task profile analysis steps are as follows:

[0023] Analyze all flight events during the mission, identify the key events that have an impact on the safety of the entire manned spacecraft, take the key events as the top events, use the fault tree analysis method to sort out the relationships between the key events, and form a key event hierarchy diagram. The programs that realize the bottom events with the minimum cut set order of the key event hierarchy diagram less than the fault tolerance capability are identified as safety-critical programs.

[0024] Preferably, the steps of performing functional analysis on the manned spacecraft system and determining the key functions of the manned spacecraft safety are as follows:

[0025] Taking the user's overall mission requirements for the spacecraft as the top-level task, the top-level task is decomposed layer by layer into specific and implementable tasks, and the functions corresponding to completing the lowest-level tasks, namely the spacecraft subsystem-level functions, are determined, from which the key system-level safety functions are extracted.

[0026] Preferably, the steps for performing functional analysis on the subsystem are as follows:

[0027] Taking the spacecraft subsystem-level functions as the top-level functions, the method of establishing a function tree is used to decompose the top-level functions step by step to obtain the equipment-level functions, that is, the functions completed by the spacecraft equipment, from which the subsystem-level safety-critical functions are extracted.

[0028] Preferably, the risk analysis steps are as follows:

[0029] Identify the sources of danger, analyze their impact, and identify the equipment corresponding to the sources of danger that may cause disasters and serious dangers as safety-critical equipment.

[0030] Preferably, the risk analysis further comprises the following steps:

[0031] For spacecraft capable of on-orbit maintenance, a hazard analysis is conducted on the maintenance operation process, including potential hazards to equipment caused by maintenance operations, potential hazards to personnel, and potential hazards to system functions caused by faulty equipment. Equipment that causes catastrophic and severe hazards during the on-orbit maintenance process will be identified as safety-critical equipment.

[0032] The beneficial effects of the present invention compared with the prior art are:

[0033] (1) The present invention comprehensively considers the severity of the consequences caused by the possible danger sources during the on-orbit operation of large manned spacecraft, and integrates the results of mission profile analysis, function analysis and hazard analysis to identify the key functions, key procedures and key equipment that have an impact on the safety of manned spacecraft. Compared with the method in the prior art that only regards equipment as a key project, the coverage of key projects is expanded, and a better basis can be provided for the safety control during the development and production of manned spacecraft and on-orbit operation.

[0034] (2) The present invention conducts a risk analysis on the maintenance operation process of a repairable manned spacecraft, identifies the dangers that the on-orbit maintenance process may cause to people, equipment and spacecraft, and identifies related key items. Compared with the prior art method of identifying key items only based on the function or the function of the equipment, the present invention ensures that the key items cover all types of product states throughout the entire life cycle of the spacecraft while meeting the key item identification requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 The flowchart schematically shows the method for identifying safety-critical items of a multi-module manned spacecraft operating on-orbit for a long period of time according to the present invention. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with the embodiments.

[0038] The description of the embodiments of this specification should be combined with the corresponding drawings, which should be considered as part of the complete specification. In the drawings, the shape or thickness of the embodiments may be enlarged and indicated for simplification or convenience. Furthermore, the parts of each structure in the drawings will be described separately. It is worth noting that the elements not shown in the drawings or not described in words are in a form known to ordinary technicians in the relevant technical field.

[0039] The description of the embodiments herein and any reference to directions and orientations are only for the convenience of description and are not to be construed as any limitation on the scope of protection of the present invention. The following description of the preferred embodiments may involve combinations of features, which may exist independently or in combination, and the present invention is not particularly limited to the preferred embodiments. The scope of the present invention is defined by the claims.

[0040] The present invention provides a method for identifying key safety items of a multi-compartment manned spacecraft in long-term on-orbit operation, which performs hazard control on a large manned spacecraft during long-term on-orbit operation and reduces the occurrence of on-orbit hazardous events through control measures.

[0041] Safety-critical items include at least one of the following: safety-critical functions, safety-critical procedures, and safety-critical equipment that are capable of causing the final consequence state of concern.

[0042] like Figure 1As shown, the method comprises the following steps:

[0043] (1) Conduct mission profile analysis to determine the safety-critical procedures during the on-orbit flight of manned spacecraft and include them in the system-level safety-critical items list;

[0044] The present invention proposes a criterion for determining a safety-critical program, and a program having one of the following characteristics should be determined as a safety-critical program:

[0045] a) Procedures that can directly lead to total loss of the system or loss of life;

[0046] b) Programs that perform safety-critical functions and have constraints greater than or equal to 3.

[0047] A program may be a software program or an operating program.

[0048] The steps of mission profile analysis are as follows:

[0049] Analyze all flight events during the mission, identify the key events that have an impact on the safety of the entire manned spacecraft, take the key events as the top events, use the fault tree analysis method to sort out the relationships between the key events, and form a key event hierarchy diagram. The programs that realize the bottom events with the minimum cut set order of the key event hierarchy diagram less than the fault tolerance capability are identified as safety-critical programs.

[0050] (2) Conduct functional analysis on manned spacecraft systems, identify key safety functions of manned spacecraft, and include them in the system-level safety key item list;

[0051] The present invention proposes a criterion for determining safety-critical functions. A function having one of the following characteristics is determined as a safety-critical function:

[0052] a) Functions that could cause catastrophic accidents if they fail;

[0053] b) Functions for safe control of serious accidents.

[0054] Catastrophic accidents and serious accidents are defined in the accident level table.

[0055] Table 1 Spacecraft accident level table

[0056]

[0057]

[0058] The steps to conduct functional analysis on manned spacecraft systems and determine the key functions of manned spacecraft safety are as follows:

[0059] Taking the user's overall mission requirements for the spacecraft as the top-level task, the top-level task is decomposed layer by layer into specific and implementable tasks, and the functions corresponding to completing the lowest-level tasks, namely the spacecraft subsystem-level functions, are determined, from which the key system-level safety functions are extracted.

[0060] For example, if the user's overall mission requirement for the spacecraft is "to build a manned spacecraft that can operate safely and stably in orbit for a long time", after an overall mission analysis, it can be broken down into autonomous flight missions, rendezvous and docking missions, assembly and construction missions, and complex management and control missions.

[0061] (3) Conduct functional analysis on subsystems, determine key functions for manned spacecraft safety, and include them in the subsystem-level safety key item list;

[0062] The steps for functional analysis of subsystems are as follows:

[0063] Taking the spacecraft subsystem-level functions as the top-level functions, the method of establishing a function tree is used to decompose the top-level functions step by step to obtain the equipment-level functions, that is, the functions completed by the spacecraft equipment, from which the subsystem-level safety-critical functions are extracted.

[0064] For example, if the user's overall mission requirement for the spacecraft is "to build a manned spacecraft that can operate safely and stably in orbit for a long time", after an overall mission analysis, it will be decomposed into autonomous flight missions, rendezvous and docking missions, assembly and construction missions, and assembly management and control missions, and the rendezvous and docking mission will be used as a requirement for a certain subsystem. A certain subsystem takes the rendezvous and docking mission as the top-level function, decomposes it into the rendezvous function and the docking function, and then further decomposes it into the rendezvous measurement, rendezvous communication, active docking, and passive docking functions, and implements them at the device level. Among them, the rendezvous communication function is the key link in the transmission of information and control instructions during the rendezvous and docking process of the two aircraft. The failure of the information transmission function may cause the catastrophic consequence of the collision of the two aircraft, so it is identified as a safety-critical function.

[0065] (4) Conduct hazard analysis on equipment, identify equipment critical to the safety of manned spacecraft, and include it in the equipment-level safety critical item list;

[0066] Hazard sources are divided into general hazards and fault hazards.

[0067] The steps of risk analysis are as follows:

[0068] Identify the sources of danger, analyze their impact, and identify the equipment corresponding to the sources of danger that may cause disasters and serious dangers as safety-critical equipment.

[0069] For spacecraft capable of on-orbit maintenance, a hazard analysis is conducted on the maintenance operation process, including potential hazards to equipment caused by maintenance operations, potential hazards to personnel, and potential hazards to system functions caused by faulty equipment. Equipment that causes catastrophic and severe hazards during the on-orbit maintenance process will be identified as safety-critical equipment.

[0070] After the equipment is developed, on the basis of risk analysis, we can also consider failures or failures, human errors, accidents, etc., pay attention to the risk factors introduced by interfaces and interfaces when the equipment functions are combined, and refine and supplement the key safety equipment. Finally, according to technical changes, product status changes, etc., we can supplement and improve the risk analysis work, update the list of key safety items and risk control measures, and check the implementation of risk control measures.

[0071] (5) Summarize and comprehensively analyze the lists of key items at the system level, subsystem level, and equipment level, identify the equipment that implements each safety-critical procedure and safety-critical function as safety-critical equipment, remove duplicate safety-critical functions, safety-critical procedures, and safety-critical equipment, and ultimately form a list of key items for manned spacecraft.

[0072] Usually, the manned spacecraft as a whole identifies and determines the system-level critical safety items and compiles a list of system-level critical safety items. The manned spacecraft subsystem and single-machine research and development parties determine the equipment-level critical safety items based on the analysis results of the equipment's key characteristics and the functional-level critical safety items, compile a list of equipment-level critical safety items and report it to the overall team.

[0073] Example:

[0074] A manned spacecraft is assembled in orbit from spacecraft A and spacecraft B. Spacecraft A operates in orbit for a long time, and spacecraft B can operate in orbit after being assembled with spacecraft A in orbit, and can also perform round-trip transportation missions between the earth and the sky. Its safety goal is to ensure safe and stable operation in orbit for a long time.

[0075] The mission profile of spacecraft A includes the ascent phase, orbit entry phase and on-orbit operation phase, and the mission profile of spacecraft B includes the ascent phase, orbit entry phase, on-orbit operation phase and return phase. The key events of the ascent phase are guaranteed by the launch vehicle. The manned spacecraft in the orbit entry phase needs to unfold the solar wing to provide energy. The on-orbit operation phase requires the manned spacecraft to provide manned environmental control to ensure the stay of personnel. The return phase requires the manned spacecraft to provide personnel return control. The key event of solar wing unfolding is completed by the solar wing equipment and the solar wing unfolding program. The on-orbit stay of personnel is achieved by the manned environment control function of the manned spacecraft, and the return is achieved by the return control function. Therefore, the manned environment control function and the return control function are included in the system-level safety key project list, and the solar wing and the solar wing unfolding program are included in the equipment-level key project list.

[0076] Completing the mission of long-term on-orbit operation requires spacecraft A to operate in orbit for a long time and spacecraft B to perform round-trip transportation missions regularly. Therefore, from the system level, the top-level tasks are decomposed into autonomous flight tasks, rendezvous and docking tasks, assembly management tasks, etc. At the functional level, the above tasks can be further decomposed. The failure of communication equipment to deploy can cause catastrophic consequences such as loss of contact with manned spacecraft, and the propellant leakage control function is a safety control measure designed for possible propellant leakage accidents. Therefore, the communication equipment deployment function and the propellant leakage protection function are equipment-level safety-critical functions and need to be included in the equipment-level safety-critical project list.

[0077] High-pressure vessels are general hazard sources that can affect spacecraft and personnel; spacecraft control equipment is a fault hazard source, and failure can cause catastrophic consequences such as loss of control of the spacecraft. High-pressure vessels and control computers need to be identified as safety-critical equipment at the equipment level and included in the equipment-level safety-critical project list. In addition, manned spacecraft are in orbit for a long time and are staffed by personnel, so equipment can be repaired and replaced. During maintenance operations, some equipment may cause electric shock injuries to maintenance personnel due to residual voltage inside it. Such equipment should also be identified as safety-critical equipment and included in the equipment-level safety-critical project list.

[0078] Manned spacecraft usually design emergency evacuation procedures as an important measure to ensure personnel safety, which can isolate personnel from danger after a catastrophic accident. The emergency evacuation procedure is guaranteed by different functions of the manned spacecraft and ultimately executed by personnel, involving the coordination between different functions and equipment. Therefore, the emergency evacuation procedure is included in the list of system-level safety key items as a safety-critical procedure.

[0079] Based on the results of the above mission profile analysis, function analysis and hazard analysis, the safety critical project list determined in the early stage of the development phase includes key projects identified at the system level and equipment level, specifically: safety critical functions (manned environment control function, return control function, communication equipment deployment function, propellant leakage protection function), safety critical procedures (solar cell wing deployment procedure, emergency evacuation procedure), safety critical equipment (solar cell wing, high-pressure container, control computer, and repairable equipment with residual voltage after power failure). With the continuous deepening of manned spacecraft development and design optimization, the use of high-pressure containers may be cancelled through the improvement of design measures, and the safety critical project list can be adjusted to remove high-pressure containers from safety critical equipment.

[0080] Taking into account the severity of the consequences caused by possible hazards during the on-orbit operation of large manned spacecraft and based on the results of mission profile analysis, functional analysis and hazard analysis, the safety-critical items in the manned spacecraft are identified, including safety-critical functions, safety-critical procedures and safety-critical equipment, to ensure that the system resource cost of the safety control measures is minimized.

[0081] In summary, through the present invention, the severity of the consequences caused by the possible danger sources during the on-orbit operation of a large manned spacecraft is comprehensively considered and based on the results of mission profile analysis, function analysis and hazard analysis, the safety-critical items in the manned spacecraft are identified, including safety-critical functions, safety-critical programs and safety-critical equipment, to ensure that the system resource cost of the safety control measures is minimized and the maximum efficiency is achieved. In addition, the scheme of the present invention is simple, easy to implement, fast and convenient to operate, and can support data update and reanalysis processes during long-term operation.

[0082] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for identifying key safety items of multi-compartment manned spacecraft in long-term orbit, characterized in that The steps include: Conduct mission profile analysis to determine the safety-critical procedures of manned spacecraft during in-orbit flight and include them in the system-level safety-critical items list; Conduct functional analysis on manned spacecraft systems, identify key safety functions of manned spacecraft, and include them in the system-level safety key project list; Conduct functional analysis on subsystems, determine key functions for manned spacecraft safety, and include them in the subsystem-level safety key project list; Conduct risk analysis on equipment, identify key equipment for manned spacecraft safety, and include it in the equipment-level safety key project list; Summarize and comprehensively analyze the key project lists at the system level, subsystem level, and equipment level, identify the equipment that implements each safety-critical procedure and safety-critical function as safety-critical equipment, remove duplicate safety-critical functions, safety-critical procedures, and safety-critical equipment, and ultimately form a list of key items for manned spacecraft.

2. According to claim 1, a method for identifying key safety items of a multi-compartment manned spacecraft in long-term on-orbit operation is characterized in that Programs with any of the following characteristics should be identified as safety-critical programs: a) Procedures that can directly lead to total loss of the system or loss of life; b) Programs that perform safety-critical functions and have constraints greater than or equal to 3.

3. The method for identifying key safety items of a multi-compartment manned spacecraft in long-term on-orbit operation according to claim 2 is characterized in that Functions with any of the following characteristics are considered safety-critical functions: a) Functions that could cause catastrophic accidents if they fail; b) Functions for safe control of serious accidents.

4. The method for identifying key safety items of a multi-compartment manned spacecraft in long-term on-orbit operation according to claim 3 is characterized in that The steps of task profile analysis are as follows: Analyze all flight events during the mission, identify the key events that have an impact on the safety of the entire manned spacecraft, take the key events as the top events, use the fault tree analysis method to sort out the relationships between the key events, and form a key event hierarchy diagram. The programs that realize the bottom events with the minimum cut set order of the key event hierarchy diagram less than the fault tolerance capability are identified as safety-critical programs.

5. The method for identifying key safety items of a multi-compartment manned spacecraft in long-term on-orbit operation according to claim 4 is characterized in that: The steps to conduct functional analysis on manned spacecraft systems and determine the key functions of manned spacecraft safety are as follows: Taking the user's overall mission requirements for the spacecraft as the top-level task, the top-level task is decomposed layer by layer into specific and implementable tasks, and the functions corresponding to completing the lowest-level tasks, namely the spacecraft subsystem-level functions, are determined, from which the key system-level safety functions are extracted.

6. The method for identifying key safety items of a multi-compartment manned spacecraft in long-term on-orbit operation according to claim 4 is characterized in that The steps for functional analysis of subsystems are as follows: Taking the spacecraft subsystem-level functions as the top-level functions, the method of establishing a function tree is used to decompose the top-level functions step by step to obtain the equipment-level functions, that is, the functions completed by the spacecraft equipment, from which the subsystem-level safety-critical functions are extracted.

7. The method for identifying key safety items of a multi-compartment manned spacecraft in long-term on-orbit operation according to claim 1 is characterized in that The steps of risk analysis are as follows: Identify the sources of danger, analyze their impact, and identify the equipment corresponding to the sources of danger that may cause disasters and serious dangers as safety-critical equipment.

8. The method for identifying key safety items of a multi-compartment manned spacecraft in long-term on-orbit operation according to claim 7 is characterized in that The risk analysis also includes the following steps: For spacecraft capable of on-orbit maintenance, a hazard analysis is conducted on the maintenance operation process, including potential hazards to equipment caused by maintenance operations, potential hazards to personnel, and potential hazards to system functions caused by faulty equipment. Equipment that causes catastrophic and severe hazards during the on-orbit maintenance process will be identified as safety-critical equipment.

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