GB/T 34515-2026Thermal balance test method for spacecraft (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part

1.Structure and Drafting Rules of Standardization Documents". Drafting. This document replaces GB/T 34515-2017 "Test Methods for Thermal Balance of Spacecraft". Compared with GB/T 34515-2017, except for structural adjustment... Aside from integration and editorial changes, the main technical changes are as follows:

---Added a criterion for steady-state conditions to the temperature stability criterion in thermal equilibrium tests [see 7.3.2c). Please note that some content in this document may involve patents. The issuing organization of this document assumes no responsibility for identifying patents. This document was proposed and is under the jurisdiction of the National Technical Committee on Standardization of Aerospace Technology and Its Applications (SAC/TC425). This document was drafted by: Beijing Satellite Environmental Engineering Institute, Beijing Spacecraft Overall Design Department, and Shanghai Satellite Engineering Institute. Shanghai Satellite Equipment Research Institute, Aerospace Dongfanghong Satellite Co., Ltd., and China Aerospace Standardization Institute. The main drafters of this document are. Sun Yuwei, Wang Jing, Zhao Qiwei, Liu Xiaoning, Zhao Xiaoxiang, Tao Dongxing, Chen Li, Zhang Dong, Pei Yifei, and Gao Qinghua. Feng Yao, Qin Jiayong, Liu Bo, Ren Xiaoyu, Jin Yu, Fang Hongjun. This document was first published in.2017, and this is its first revision. Spacecraft thermal balance test methods

1.Scope This document specifies the purpose, requirements, thermal simulation methods, operating conditions, data measurement, equipment, and procedures for spacecraft thermal balance testing. Procedures, test interruptions and handling, test evaluation and data utilization. This document applies to thermal balance tests at the spacecraft system level, subsystem level, and module level.

4.Experimental Objective The objectives of the spacecraft thermal balance test are as follows:

a) Verify the correctness of the spacecraft's thermal design;

b) Verify the correctness of the spacecraft thermal analysis model and provide data for revising the thermal analysis model.

5 Test Requirements

5.1 Test Model Requirements The experimental model should meet the following requirements.

a) The external structure, materials, layout of instruments and equipment, cable network, various thermal control measures, and products meet the requirements of the research and development status;

b) The external dimensions, surface condition, installation and connection method, internal heat generation, and heat capacity of the instruments and equipment meet the requirements of the research and development status;

c) Considering the capabilities, safety, and special requirements of the testing equipment and instruments, individual instruments are permitted to use thermal performance parameters that meet the requirements. The requested substitute is a process part, a certification part, or a simulation part;

d) The thermal properties of the outer surface coating are the same as those in the manufacturing process;

e) External components such as large antennas and solar panels may be excluded from the test, but their impact on the test must be assessed, and hot-edge testing may be conducted as needed. Appropriate measures should be taken in boundary simulation;

f) For test models with sealed compartments, appropriate measures should be taken during the test to suppress the influence of natural gas convection within the sealed compartment;

g) For parts that exchange heat with the experimental model but do not participate in the experiment, alternative structures are used to participate in the experiment and simulate the thermal boundary;

h) Add protective gas to the propellant tank.

5.2 Volume requirements for space environment simulation chamber The volume of the space environment simulation chamber should meet the following requirements.

a) When using the incident heat flow method, the ratio of the characteristic dimensions (such as length, diameter, etc.) of the space environment simulation chamber to the test model shall not be less than 3;

b) When using the heat absorption method, the ratio of the characteristic dimensions (such as length, diameter, etc.) of the space environment simulation chamber to the test model shall not be less than 2.

5.3 Requirements for Installing the Test Model When installing the test model in a space environment simulation chamber, the following factors should be comprehensively analyzed.

a) Installation method and orientation;

7 Test Conditions

7.1 Types of Test Conditions Based on the internal heat source heating mode, simulated external heat flow, and other thermal boundary conditions, the following four test conditions can generally be combined.

a) Steady-state condition. The internal heat source, simulated external heat flow, and other thermal boundary conditions are all constant values. Both high-temperature and low-temperature conditions fall under this steady-state condition. Operating conditions.

b) Quasi-steady-state condition. The internal heat source operates according to a set periodic variation pattern, and the simulated external heat flow and other thermal boundary conditions are constant. A constant value.

c) Periodic transient condition. The internal heat source operates according to a set periodic variation pattern, simulating external heat flow and other thermal boundary conditions according to the orbit. It operates according to the cyclical change pattern.

d) Transient operating condition. Within a specified time, the internal heat source, simulated external heat flow, or other thermal boundary conditions operate in a non-periodic change mode. For periodic transient or quasi-steady-state operating conditions, tests are generally conducted according to the orbital period of the spacecraft. This can be based on one orbital cycle. The heat source working mode and simulated external heat flow were repeatedly tested for several cycles until the temperature of the test model reached a stable period. Alternatively, a number of orbital periods can be used as a test cycle, and this cyclical test can be repeated continuously for several test cycles until the test model is fully operational. The temperature reaches a stable period.

7.2 Principles for Determining Test Conditions The principles for determining test conditions are as follows:

a) The test conditions can obtain sufficient key parameters to support the validation of the thermal analysis model and the prediction of flight missions;

b) For tests that directly verify the thermal control design, at least high-temperature and low-temperature conditions must be included;

c) Tests that only verify the thermal analysis model generally include transient conditions;

d) When the changes in external heat flow or other thermal boundary conditions over time have a significant impact on the spacecraft temperature, periodic transient or transient dynamic methods should be used. Otherwise, steady-state or quasi-steady-state operating conditions are adopted.

9 Test Equipment

9.1 Space Environment Simulation Room The space environment simulation chamber must meet the following requirements.

a) The pressure in the space environment simulation chamber should not exceed 6.65 × 10^-3 Pa or other pressures required by the test (such as the pressure of the Martian surface environment);

b) The surface temperature of the heat sink should not exceed 100K or other temperatures required by the test;

c) The absorptivity alphaS of the heat sink-oriented surface of the test model for sunlight should not be less than 0.95, and the hemispherical emissivity epsilonH should not be less than [missing value]. 0.90;

d) Under no-load conditions, the background heat flux in the simulated space environment should not exceed 10 W/m^2;

e) The indoor space environment simulation room should have supports and suspension points for the test model to reduce heat leakage through the supports;

f) It can provide measurement, power supply, and signal (low-frequency, high-frequency) transmission channels that meet the test requirements, and reduce heat leakage through the cables;

g) After 24 hours of continuous no-load operation, the organic pollutant concentration in the simulated space environment should not exceed 1×10^-7 g/cm^2 (sampling point temperature). (The temperature should be -50°C, and the pressure should not exceed 6.65×10^-3 Pa).

10 Test Procedure

10.1 Inspection of the condition of the test equipment Before the test, each system and device (component) should be inspected according to the operating requirements of the test equipment to ensure the safety of the thermal balance test. It should be carried out on a trial basis. If necessary, a full system-wide commissioning or trial run should be conducted.

10.2 Test Model Status Check The test model status check should include.

a) Visual inspection;

b) Leakage rate checks for compartments and subsystems with leak rate requirements;

c) Mechanical and electrical function and performance checks;

d) Check the temperature measuring wire, heating wire, and various signal wires (continuity and insulation);

e) Inspection of external heat flow measurement and temperature measurement devices.

10.3 Check the integration status of the test model and the space environment simulation chamber The check on the integration status of the test model and the space environment simulation chamber should include.

a) The status of all cable connections, insulation, and continuity;

b) Verify that all grounding equipment is properly grounded and measure the grounding resistance;

c) When an infrared radiation heater is used to simulate external heat flow, check the correspondence between the infrared radiation heater and the external heat flow circuit and the relevant temperature measurement points. Whether the relationship is correct and whether there is mutual interference;

d) Check the electromagnetic interference between the test model and the test equipment.

10.4 Test Start The test initiation process should include.

a) Set the working status of the experimental model;