Test platform and test method for thermal damage of space optical camera incident on sunlight

Abstract

The present invention specifically relates to a test platform and test method for thermal damage to a space optical camera incident on sunlight. The test platform includes a solar simulator, a heat-insulating shading device, an integrating sphere, a collimator, a multi-axis moving device, a space optical camera, a thermal imager, a test main control system, an infrared thermal imager, a temperature acquisition device, and a coaxiality detection device. This test platform can simulate and analyze the thermal damage to the space optical camera incident on sunlight on the ground, establish the relationship between the thermal damage to the space optical camera incident on sunlight and the sunlight incident angle and sunlight incident time, and provide a certain reference basis for the overall layout design of the space optical camera, the setting of the on-orbit flight attitude, the on-orbit mission mode and the business attitude, as well as the avoidance plan for sunlight incidence and the tracing of the cause of damage to the on-orbit camera after sunlight incidence during the development and on-orbit operation stages.

Description

Technical Field

[0001] The present invention relates to the technical field of space optical cameras, and in particular to a test platform and a test method for thermal damage to a space optical camera incident on sunlight. Background Art

[0002] With the growing demand for space remote sensing, space optical cameras, as a crucial component of space exploration payloads, face increasingly stringent performance and functionality requirements during their design and manufacturing process to effectively acquire observation target information. Furthermore, space optical cameras are difficult to repair and maintain after launch, which contributes to their high development costs. Therefore, improving the on-orbit lifespan of space optical cameras and ensuring their reliability and effectiveness during this lifespan has become a key research priority.

[0003] During the initial launch of a space optical camera into orbit, during certain special missions, or during attitude adjustments and orbit changes, the camera's optical axis can easily make a small angle with sunlight, allowing sunlight to enter the camera's interior. This can cause a sharp rise in local temperatures, thermally induced functional loss, or even irreversible damage to some components, seriously impacting the camera's image quality and on-orbit service life. In extreme cases, the camera can completely lose its detection capabilities. To prevent failure of space optical cameras due to thermal damage from incident sunlight on orbit, it is extremely important to conduct ground-equivalent thermal damage testing on the camera during development.

[0004] Currently, during the design, development, and testing of space optical cameras, there is limited research on on-orbit damage and failure. This research primarily focuses on damage to optical and mechanical structures caused by vibration and impact from the launch process and space debris, as well as high-energy particle radiation damage such as single-event effects from space radiation. Few studies have examined thermal damage to space optical cameras caused by sunlight, and even less has a relationship been established between the performance changes of space optical cameras in sunlight-incident scenarios and the angle between the camera's optical axis and the sun vector, as well as the duration of sunlight exposure. However, in actual on-orbit engineering applications of space optical cameras, it is difficult to completely avoid sunlight exposure. Consequently, there are no standards or literature available to guide the determination of boundary conditions for solar avoidance or the precise definition of the impact of sunlight exposure on space optical camera performance. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to address the defect that there is little research on the problem of thermal damage to space optical cameras incident on sunlight, thereby providing a test platform and test method for thermal damage to space optical cameras incident on sunlight.

[0006] A test platform for thermal damage to a space optical camera incident on sunlight, including a solar simulator, a heat-insulating shading device, an integrating sphere, a collimator, a multi-axis moving device, a space optical camera, a thermal imager, a test main control system, an infrared thermal imager, a temperature acquisition device, and a coaxiality detection device;

[0007] The axes of the solar simulator, integrating sphere, collimator and the optical axis of the space optical camera are in the same plane, and the normal of the plane is parallel to the Z axis, the axis of the solar simulator coincides with the Y axis, the axis of the collimator coincides with the X axis, the intersection of the axis of the solar simulator and the axis of the collimator is the origin, the axis of the integrating sphere forms an angle of 45° with the X axis, the intersection of the axis of the integrating sphere and the X axis is 700 mm away from the origin, the space optical camera is placed on a multi-axis mobile device, there are two thermal imager cameras, which are respectively installed on the heat insulation and shading device and the solar simulator, and the heat insulation and shading device is set at 10 mm away from the light outlet of the solar simulator;

[0008] The test control system is used to output commands and control equipment for the entire test platform. It has the functions of controlling other equipment and devices to perform corresponding operations after inputting parameters, monitoring the test status of the space optical camera and outputting a display, and automatically determining whether the test has been terminated. The test control system also has the function of determining whether the sensor has obvious performance impairment based on the real-time imaging data of the space optical camera;

[0009] The infrared thermal imager and temperature acquisition equipment are used to collect and record the temperature field distribution of the camera mirror and key mechanical components, monitor the temperature of the space optical camera in real time, and have the function of feeding back the temperature to the test main control system;

[0010] The coaxiality detection device is used to detect whether the physical optical axis of the solar simulator is concentric with the optical axis of the space optical camera.

[0011] Furthermore, the thermal insulation and shading device includes a bracket, a thermal insulation and shading plate, a linear motor and a light intensity sensor. The thermal insulation and shading plate, the linear motor and the light intensity sensor are all arranged on the bracket. The light intensity sensor is arranged on the side facing the solar simulator. The output end of the linear motor is connected to the thermal insulation and shading plate. The test main control system controls the linear motor according to the experimental conditions to realize that the thermal insulation and shading plate shields or releases the output radiation of the solar simulator.

[0012] Furthermore, the multi-axis moving device includes a two-dimensional moving platform and a lifting turntable, and the two-dimensional moving platform and the lifting turntable are cooperatively connected.

[0013] Furthermore, the thermal imaging camera is a 180-degree camera.

[0014] Furthermore, the space optical camera is a prototype of an optical camera used in a remote sensing satellite or other simulation components with optical imaging capabilities.

[0015] Furthermore, the diameter of the light exit port of the solar simulator is larger than the diameter of the light entrance port of the space optical camera, and the diameter of the light exit port of the integrating sphere is larger than the diameter of the light entrance port of the space optical camera.

[0016] Furthermore, the diameter of the light outlet of the solar simulator is 400 mm, the diameter of the light entrance of the space optical camera is 200 mm, and the diameter of the light outlet of the integrating sphere is 400 mm.

[0017] A test method for the sunlight incident thermal damage test platform for space optical cameras based on any one of the above-mentioned methods comprises the following steps:

[0018] S1: Build the test platform, set up the test environment, run the test main control system, and send instructions through the main control system to test the corresponding functions of other equipment and devices. Subsequent tests can be carried out only after no abnormalities are found;

[0019] S2: Set temperature measurement points at key locations of the space optical camera and collect temperature at each temperature measurement point in real time;

[0020] S3: Support the space optical camera at three points and fix it on the multi-axis moving device;

[0021] S4: adjusting the multi-axis moving device so that the optical axis of the space optical camera approximately coincides with the axis of the solar simulator;

[0022] S5: Using a coaxiality detection device, further accurately calibrate the optical axis of the space optical camera and the axis of the solar simulator. Adjust the three-point support at the bottom of the space optical camera so that the optical axis of the space optical camera and the axis of the solar simulator coincide with each other. At this time, the angle between the two axes is 0°. The position of the lifting turntable of the multi-axis mobile device at this time is set as the test position, marked as position A.

[0023] S6: Control the multi-axis moving device to move along the Y axis to adjust the distance between the light entrance of the space optical camera and the light exit of the solar simulator to an appropriate distance;

[0024] S7: Calculate the solar radiation intensity required to be output by the solar simulator based on the orbit of the space optical camera, taking into account the reduction of convective environmental conditions in the test site and the relative distance between the space optical camera and the solar simulator. After the solar simulator is shielded by the heat-insulating shading device, the solar simulator is started and operated, and the light intensity sensor on the heat-insulating shading device is used to determine whether the output radiation meets the requirements.

[0025] S8: Move the multi-axis motion device so that the intersection of the axis of the integrating sphere and the axis of the collimator falls on the focal plane of the space optical camera, and set the position of the lifting turntable of the multi-axis motion device at this time as the initial position, marked as position B, and rotate the lifting turntable so that the optical axis of the space optical camera is parallel to the axis of the integrating sphere and the axis of the collimator respectively. Test the space optical camera with the integrating sphere and the collimator respectively to record the DN value of the optical sensor and the transfer function of the camera before the test;

[0026] S9: Move the lifting turntable to position A, and rotate the lifting turntable so that the optical axis of the space optical camera and the axis of the solar simulator form an angle of 16°;

[0027] S10: Adjust the angle of the thermal imager according to the test position of the space optical camera and keep real-time tracking, thermally image the internal position of the space optical camera, and keep the interior of the space optical camera barrel and the mirror surface within the thermal imaging range during the test to obtain the temperature field distribution;

[0028] S11: Turn off the air conditioning in the test area to keep the test area in a weak wind environment to reduce the interference of air convection on the test. Turn off all indoor light sources and ask test participants to wear goggles for protection.

[0029] S12: After confirming that all systems are operating normally, the test main control system controls the space optical camera to power on, obtains the internal state of the imaging chip junction temperature, and removes the shielding of the heat insulation and shading device on the output radiation of the solar simulator (1);

[0030] S13: Control the space optical camera to perform real-time imaging for 300 seconds through the test main control system, monitor the imaging effect, the temperature of each temperature measurement point, and the junction temperature of the imaging chip in real time, and control the heat insulation and light shielding device to reset after the imaging is completed;

[0031] S14: Control the lifting turntable of the multi-axis mobile device to leave position A, and adopt fan convection-assisted heat dissipation and cooling measures for the space optical camera to accelerate its recovery to a normal temperature state;

[0032] S15: Control the lifting turntable of the multi-axis moving device to move to position B, rotate the lifting turntable to test and record the optical sensor DN value and camera transmission coefficient of the space optical camera after the test using an integrating sphere and a collimator;

[0033] S16: Control the lifting turntable of the multi-axis mobile device to move to position A, rotate the lifting turntable to reduce the angle between the optical axis of the space optical camera and the axis of the solar simulator by 2°-14°, and repeat steps S10-S15.

[0034] Furthermore, the key positions of the space optical camera include the mirror body, load-bearing truss, back plate, lens barrel and electrical box shell.

[0035] Furthermore, in step S6, the appropriate distance between the light entrance of the space optical camera and the light exit of the solar simulator is 50 mm.

[0036] Aiming at the current problem of thermal damage to space optical cameras caused by incident sunlight on orbit, the present invention provides a test platform and test method for thermal damage to space optical cameras caused by incident sunlight. The test and analysis of thermal damage to space optical cameras caused by incident sunlight can be simulated on the ground, and the relationship between thermal damage to space optical cameras caused by incident sunlight and the incident angle and incident time of sunlight can be established. During the development and on-orbit operation stages, a certain reference basis can be provided for the overall layout design of space optical cameras, the setting of on-orbit flight attitude, on-orbit mission mode and business attitude, as well as the avoidance plan for incident sunlight and the tracing of the cause of damage to on-orbit cameras after incident sunlight. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 This is a system diagram of a sunlight incident thermal damage test platform for a space optical camera provided by the present invention, showing a scene where a camera is subjected to a sunlight incident simulation test;

[0039] Figure 2 The scene shown is the camera performing DN value testing;

[0040] Figure 3 The scene shown is the camera performing a transmission test;

[0041] Figure 4 A flow chart of a method for testing thermal damage to a space optical camera incident on sunlight provided by the present invention;

[0042] Description of reference numerals:

[0043] 1- Solar simulator; 2- Heat insulation and shading device; 3- Integrating sphere;

[0044] 4-collimator; 5-multi-axis moving device; 6-space camera;

[0045] 7- Thermal imager camera. DETAILED DESCRIPTION

[0046] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0047] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0048] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0049] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] See also Figure 1 The test platform for thermal damage to a space optical camera incident on sunlight includes a solar simulator 1, a heat-insulating shading device 2, an integrating sphere 3, a collimator 4, a multi-axis moving device 5, a space optical camera 6, a thermal imager camera 7, a test main control system, an infrared thermal imager and temperature acquisition equipment, a coaxiality detection device, and goggles; the test main control system, the infrared thermal imager and temperature acquisition equipment, the coaxiality detection device, and the goggles are not shown in the figure;

[0051] The axes of the solar simulator 1, the integrating sphere 3, the collimator 4 and the optical axis of the space optical camera 6 are in the same plane, and the normal of the plane is parallel to the Z axis, the axis of the solar simulator 1 coincides with the Y axis, the axis of the collimator 4 coincides with the X axis, the intersection of the axis of the solar simulator 1 and the axis of the collimator 4 is the origin, the axis of the integrating sphere 3 forms an angle of 45° with the X axis, the intersection of the axis of the integrating sphere 3 and the X axis is 700 mm away from the origin, the space optical camera 6 is placed on the multi-axis moving device 5, and there are two thermal imager cameras 7, which are respectively installed on the heat insulation and shading device 2 and the solar simulator 1, and the heat insulation and shading device 2 is set at 10 mm away from the light outlet of the solar simulator 1;

[0052] The solar simulator 1 is used in the test platform to accurately simulate the spectral range and intensity of solar radiation, and the test main control system controls the output regulation of the solar simulator 1;

[0053] The test control system is used to output commands and control equipment for the entire test platform. It has the functions of controlling other equipment and devices to perform corresponding operations after inputting parameters, monitoring the test status of the space optical camera and outputting a display, and automatically determining whether the test has been terminated. The test control system also has the function of determining whether the sensor has obvious performance impairment based on the real-time imaging data of the space optical camera;

[0054] The infrared thermal imager and temperature acquisition equipment are used to collect and record the temperature field distribution of the camera mirror and key mechanical components, monitor the temperature of the space optical camera in real time, and have the function of feeding back the temperature to the test main control system;

[0055] The coaxiality detection device is used to detect whether the physical optical axis of the solar simulator is concentric with the optical axis of the space optical camera.

[0056] The goggles are used to protect the eyesight of test participants when they observe test phenomena, to prevent the strong light from the camera's reflected light from burning the naked eye.

[0057] The heat-insulating shading device 2 includes a bracket, a heat-insulating shading plate, a linear motor and a light intensity sensor. The heat-insulating shading plate, the linear motor and the light intensity sensor are all arranged on the bracket. The distance between the heat-insulating shading plate and the light outlet of the solar simulator 1 is 10 mm. The light intensity sensor is arranged on the side facing the solar simulator 1 and can monitor the light intensity output by the solar simulator 1. The output end of the linear motor is connected to the heat-insulating shading plate. The test main control system controls the linear motor according to the experimental situation to realize that the heat-insulating shading plate shields or releases the radiation output by the solar simulator 1. Figure 1 In the scenario shown, during the sunlight incident test, the heat-insulating shading device 2 releases the shielding of the solar simulator 1, and the space optical camera 6 is exposed to sunlight.

[0058] The integrating sphere 3 is controlled by the test main control system and is used to test the DN value of the optical sensor of the space optical camera 6 before and after the test to determine whether the optical sensor is damaged. Figure 2 As shown in the scene, the heat-insulating shading device 2 shields the solar simulator 1, and the space optical camera 6 faces the integrating sphere 3 to test the DN value of the camera optical sensor.

[0059] The collimator 4 is controlled by the test main control system and is used to test the transfer function of the space optical camera 6 and detect the imaging performance of the space optical camera to determine whether the entire optical system of the space optical camera 6 is damaged after the test. Figure 3 As shown in the scenario, the heat-insulating shading device 2 shields the solar simulator 1 , and the space optical camera 6 faces the collimator 4 to test the transfer function of the space optical camera 6 .

[0060] The multi-axis mobile device 5 includes a two-dimensional mobile platform and a lifting turntable. The two-dimensional mobile platform and the lifting turntable are connected in cooperation. After being combined, the whole can move along the X, Y, and Z axes and rotate around the Z axis. The above-mentioned space optical camera 6 and its supporting tooling are fixedly installed on the lifting turntable of the multi-axis mobile device 5. The movement of the multi-axis mobile device 5 is controlled by the test main control system, and the position of the space optical camera and the angle between the optical axis of the space optical camera and the axis of the solar simulator can be accurately adjusted as required.

[0061] The thermal imaging camera 7 is a 180-degree camera.

[0062] The space optical camera 6 is a prototype of an optical camera used in remote sensing satellites or a simulated device with optical imaging capabilities. A prototype can also be used if conditions permit (e.g., for mass production of optical cameras) or for further testing. In this embodiment, its light entrance diameter is 200 mm. During testing, the test control system issues control commands for the space optical camera 6, including power on and off, and imaging.

[0063] The light exit diameter of the solar simulator 1 is larger than the light entrance diameter of the space optical camera 6 , and the light exit diameter of the integrating sphere 3 is larger than the light entrance diameter of the space optical camera 6 .

[0064] In this embodiment, the diameter of the light outlet of the solar simulator 1 is 400 mm, the diameter of the light entrance of the space optical camera 6 is 200 mm, and the diameter of the light outlet of the integrating sphere 3 is 400 mm.

[0065] The present invention also includes a test method based on any one of the above-mentioned sunlight incident space optical camera thermal damage test platform, the process is as follows: Figure 4 As shown, the following steps are included:

[0066] S1: Build the test platform, set up the test environment, maintain the test site temperature at 20°C, run the test main control system, and send instructions through the main control system to test the corresponding functions of other equipment and devices. Subsequent tests can be carried out only after no abnormalities are found;

[0067] S2: Setting temperature measurement points at key positions of the space optical camera 6 and collecting the temperature of each temperature measurement point in real time;

[0068] S3: The space optical camera 6 is supported by three points and fixed on the multi-axis moving device 5;

[0069] S4: Adjust the multi-axis moving device 5 so that the optical axis of the space optical camera 6 approximately coincides with the axis of the solar simulator 1;

[0070] S5: The optical axis of the space optical camera 6 and the axis of the solar simulator 1 are further accurately calibrated using a coaxiality detection device. The three-point support at the bottom of the space optical camera 6 is adjusted so that the optical axis of the space optical camera 6 and the axis of the solar simulator 1 coincide with each other. At this time, the angle between the two axes is 0°. The position of the lifting turntable of the multi-axis mobile device 5 at this time is set as the test position, marked as position A.

[0071] S6: Control the multi-axis moving device 5 to move along the Y axis, and adjust the distance between the light entrance of the space optical camera 6 and the light exit of the solar simulator 1 to an appropriate distance, so as to prevent the output radiation of the solar simulator from being weakened too much by the air due to the distance being too large;

[0072] S7: Based on the operating trajectory of the space optical camera 6, taking into account the reduction of convective environmental conditions in the test site and the relative distance between the space optical camera 6 and the solar simulator 1, the solar radiation intensity required to be output by the solar simulator is calculated. In this embodiment, the output intensity of the solar simulator is set to 1.5 solar constants. After the heat-insulating shading device 2 shields the solar simulator 1, the solar simulator 1 is turned on and operated, and the light intensity sensor on the heat-insulating shading device 2 is used to determine whether the output radiation meets the requirements;

[0073] S8: Move the multi-axis motion device 5 so that the intersection of the axis of the integrating sphere 3 and the axis of the collimator 4 falls on the focal plane of the space optical camera 6. The position of the lifting turntable of the multi-axis motion device 5 at this time is set as the initial position, marked as position B. The lifting turntable is rotated so that the optical axis of the space optical camera 6 is parallel to the axis of the integrating sphere 3 and the axis of the collimator 4 respectively. The optical sensor DN value and the camera transfer function of the space optical camera 6 before the test are tested and recorded using the integrating sphere 3 and the collimator 4 respectively.

[0074] S9: Move the lifting turntable to position A and rotate the lifting turntable to a predetermined maximum angle under the radiation intensity. In this embodiment, the lifting turntable is rotated so that the optical axis of the space optical camera 6 and the axis of the solar simulator 1 form an angle of 16°;

[0075] S10: Adjust the angle of the thermal imaging camera 7 according to the test position of the space optical camera 6 and keep real-time tracking, thermally image the internal position of the space optical camera 6, and make the interior of the lens barrel and the mirror surface of the space optical camera 6 within the thermal imaging range during the test to obtain the temperature field distribution;

[0076] S11: Turn off the air conditioning in the test area to keep the test area in a weak wind environment to reduce the interference of air convection on the test. Turn off all indoor light sources and ask test participants to wear goggles for protection.

[0077] S12: After confirming that all systems are operating normally, the test main control system controls the space optical camera 6 to power on, obtains the internal state of the imaging chip junction temperature, and removes the shielding of the heat insulation and light shielding device 2 on the output radiation of the solar simulator 1;

[0078] S13: The test main control system controls the space optical camera 6 to perform real-time imaging for 300 seconds, and monitors the imaging effect, the temperature of each temperature measurement point, and the junction temperature of the imaging chip in real time. The space optical camera performs real-time imaging, and the test main control system determines whether the sensor has obvious physical damage by judging whether there are obvious abnormal image spots in the image. To prevent the optical-mechanical structure and electronic components from exceeding the upper temperature limit, when the temperature approaches the upper limit of each component and continues to rise, the test main control system should immediately reset the heat insulation and light shielding device; or when obvious abnormal image spots appear, the test main control system should immediately reset the heat insulation and light shielding device; or after the entire space optical camera is exposed to direct sunlight from the solar simulator for a period of time without abnormality, the test main control system resets the heat insulation and light shielding device;

[0079] S14: Control the lifting turntable of the multi-axis moving device 5 to leave position A, and adopt fan convection-assisted heat dissipation and cooling measures for the space optical camera 6 to accelerate its recovery to a normal temperature state;

[0080] S15: Control the lifting turntable of the multi-axis moving device 5 to move to position B, rotate the lifting turntable to test and record the optical sensor DN value and camera transfer function of the space optical camera 6 after the test through the integrating sphere 3 and the collimator 4, and determine whether the test has any impact on the optical sensor DN value and transfer function of the space optical camera;

[0081] S16: Control the lifting turntable of the multi-axis moving device 5 to move to position A, move the multi-axis moving device 5 to rotate the space optical camera 6 to a smaller angle under the radiation intensity, and repeat steps S10-S15. In this embodiment, the lifting turntable is rotated to reduce the angle between the optical axis of the space optical camera 6 and the axis of the solar simulator 1 by 2°-14°.

[0082] Specifically, when the embodiment of the present invention reached 4° imaging angle for 230 seconds, the junction temperature of the sensor imaging chip reached 86°C and continued to rise. The test was stopped, and the camera transmission coefficient and DN value were tested. Compared with the pre-test, the camera transmission coefficient was found to have decreased to 0.092 (0.097 before the test, a decrease of approximately 5%), and the DN value was found to have decreased to 3195 (3260 before the test, a decrease of approximately 2%). In addition, the electronic chip exceeded the operating temperature range, and if this continues for a long time, there is a risk of damage. Therefore, it is not recommended that the camera of this embodiment be used in orbit with sunlight incident at an angle less than 4° for more than 230 seconds.

[0083] The test requires reducing the angle between the optical axis of the space optical camera 6 and the physical axis of the solar simulator 1 multiple times until the optical sensor shows obvious abnormal spots, or the DN value of the optical sensor changes significantly, or the transfer function of the optical system decreases significantly.

[0084] After the test is completed as a whole, the temperature rise during the test at various angles, the imaging conditions of the optical sensor, the changes in the DN value of the optical sensor before and after the test, and the changes in the camera transmission function are analyzed to analyze the safety threshold of the sunlight incident angle-duration of the space optical camera and the impact of sunlight incident at various angles and different durations on the performance of the space optical camera.

[0085] The key positions of the space optical camera 6 include the mirror body, load-bearing truss, back plate, lens barrel and electrical box shell.

[0086] In step S6 , the appropriate distance between the light entrance of the space optical camera 6 and the light exit of the solar simulator 1 is 50 mm.

[0087] The above-mentioned test platform and test method for thermal damage to space optical cameras incident on sunlight can simulate the test of thermal damage to space optical cameras incident on sunlight on the ground. The thermal damage to space optical cameras incident on sunlight is mainly detected based on the imaging effect, transmission function, DN value, temperature rise, etc. of the space camera, and the space camera's ability to tolerate sunlight incident on orbit is evaluated.

[0088] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A test platform for thermal damage to space optical cameras incident on sunlight, characterized by: It includes a solar simulator (1), a heat-insulating shading device (2), an integrating sphere (3), a collimator (4), a multi-axis moving device (5), a space optical camera (6), a thermal imager camera (7), a test main control system, an infrared thermal imager, a temperature acquisition device, and a coaxiality detection device; The integrating sphere (3) is used to test the DN value of the optical sensor of the space optical camera (6) before and after the test to determine whether the optical sensor is damaged; the collimator (4) is used to test the transfer function of the space optical camera (6) and detect the imaging performance of the space optical camera to determine whether the entire optical system of the space optical camera (6) is damaged after the test; wherein the axes of the solar simulator (1), the integrating sphere (3), the collimator (4) and the optical axis of the space optical camera (6) are in the same plane, and the normal of the plane is parallel to the Z axis, and the axis of the solar simulator (1) is parallel to the Y axis. The axis of the collimator (4) coincides with the X-axis, the intersection of the axis of the solar simulator (1) and the axis of the collimator (4) is the origin, the axis of the integrating sphere (3) forms an angle of 45° with the X-axis, the intersection of the axis of the integrating sphere (3) and the X-axis is 700 mm away from the origin, the space optical camera (6) is placed on the multi-axis moving device (5), and there are two thermal imager cameras (7), which are respectively installed on the heat insulation and light shielding device (2) and the solar simulator (1), and the heat insulation and light shielding device (2) is set at 10 mm away from the light outlet of the solar simulator (1); The test control system is used to output commands and control equipment for the entire test platform. It has the functions of controlling other equipment and devices to perform corresponding operations after inputting parameters, monitoring the test status of the space optical camera and outputting a display, and automatically determining whether the test has been terminated. The test control system also has the function of determining whether the sensor has obvious performance impairment based on the real-time imaging data of the space optical camera; The infrared thermal imager and temperature acquisition equipment are used to collect and record the temperature field distribution of the camera mirror and key mechanical components, monitor the temperature of the space optical camera in real time, and have the function of feeding back the temperature to the test main control system; The coaxiality detection device is used to detect whether the physical optical axis of the solar simulator is concentric with the optical axis of the space optical camera.

2. The test platform according to claim 1, characterized in that: The heat-insulating shading device (2) comprises a bracket, a heat-insulating shading plate, a linear motor and a light intensity sensor. The heat-insulating shading plate, the linear motor and the light intensity sensor are all arranged on the bracket. The light intensity sensor is arranged on a side facing the solar simulator (1). The output end of the linear motor is connected to the heat-insulating shading plate. The test main control system controls the linear motor according to the experimental situation to enable the heat-insulating shading plate to shield or release the output radiation of the solar simulator (1).

3. The test platform according to claim 1, characterized in that: The multi-axis moving device (5) comprises a two-dimensional moving platform and a lifting turntable, and the two-dimensional moving platform and the lifting turntable are cooperatively connected.

4. The test platform according to claim 1, characterized in that: The thermal imaging camera (7) is a 180-degree camera.

5. The test platform according to claim 1, characterized in that: The space optical camera (6) is a prototype of an optical camera used in a remote sensing satellite or other simulation components having an optical imaging function.

6. The test platform according to claim 1, characterized in that: The diameter of the light exit port of the solar simulator (1) is larger than the diameter of the light entrance port of the space optical camera (6), and the diameter of the light exit port of the integrating sphere (3) is larger than the diameter of the light entrance port of the space optical camera (6).

7. The test platform according to claim 6, characterized in that: The diameter of the light outlet of the solar simulator (1) is 400 mm, the diameter of the light entrance of the space optical camera (6) is 200 mm, and the diameter of the light outlet of the integrating sphere (3) is 400 mm.

8. A test method based on the sunlight incident space optical camera thermal damage test platform according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: Build the test platform, set up the test environment, run the test main control system, and send instructions through the main control system to test the corresponding functions of other equipment and devices. Subsequent tests can be carried out only after no abnormalities are found; S2: Setting temperature measurement points at key positions of the space optical camera (6) and collecting the temperature of each temperature measurement point in real time; S3: Support the space optical camera (6) at three points and fix it on the multi-axis moving device (5); S4: adjusting the multi-axis moving device (5) so that the optical axis of the space optical camera (6) and the axis of the solar simulator (1) approximately coincide with each other; S5: further accurately calibrate the optical axis of the space optical camera (6) and the axis of the solar simulator (1) through the coaxiality detection equipment, adjust the three-point support at the bottom of the space optical camera (6), so that the optical axis of the space optical camera (6) and the axis of the solar simulator (1) coincide with each other, and at this time, the angle between the two axes is 0°, and set the position of the lifting turntable of the multi-axis moving device (5) at this time as the test position, marked as position A; S6: Control the multi-axis moving device (5) to move along the Y axis, and adjust the distance between the light entrance of the space optical camera (6) and the light exit of the solar simulator (1) to an appropriate distance; S7: Based on the running track of the space optical camera (6), taking into account the reduction of the convective environmental conditions of the test site and the relative distance between the space optical camera (6) and the solar simulator (1), the solar radiation intensity required to be output by the solar simulator is calculated. After the heat-insulating shading device (2) shields the solar simulator (1), the solar simulator (1) is started and operated, and the light intensity sensor on the heat-insulating shading device (2) is used to determine whether the output radiation meets the requirements; S8: Move the multi-axis moving device (5) so that the intersection of the axis of the integrating sphere (3) and the axis of the collimator (4) falls on the focal plane of the space optical camera (6), and set the position of the lifting turntable of the multi-axis moving device (5) at this time as the initial position, marked as position B, rotate the lifting turntable so that the optical axis of the space optical camera (6) is parallel to the axis of the integrating sphere (3) and the axis of the collimator (4) respectively, and record the optical sensor DN value and the transfer function of the space optical camera (6) before the test through the integrating sphere (3) and the collimator (4); S9: moving the lifting turntable to position A, and rotating the lifting turntable so that the optical axis of the space optical camera (6) and the axis of the solar simulator (1) form an angle of 16°; S10: adjusting the angle of the thermal imaging camera (7) according to the test position of the space optical camera (6) and keeping real-time tracking, thermal imaging the internal position of the space optical camera (6), and making the interior of the lens barrel and the mirror surface of the space optical camera (6) within the thermal imaging range during the test to obtain the temperature field distribution; S11: Turn off the air conditioning in the test area to keep the test area in a weak wind environment to reduce the interference of air convection on the test. Turn off all indoor light sources and ask test participants to wear goggles for protection. S12: After confirming that all systems are operating normally, the test main control system controls the space optical camera (6) to power on, obtains the internal state of the imaging chip junction temperature, and simultaneously releases the shielding of the heat insulation and light shielding device (2) on the output radiation of the solar simulator (1); S13: Control the space optical camera (6) to perform real-time imaging for 300 seconds through the test main control system, monitor the imaging effect, the temperature of each temperature measurement point and the junction temperature of the imaging chip in real time, and control the heat insulation and light shielding device (2) to reset after the imaging is completed; S14: controlling the lifting turntable of the multi-axis moving device (5) to leave position A, and taking fan-assisted convection cooling measures for the space optical camera (6) to accelerate its recovery to a normal temperature state; S15: Control the lifting turntable of the multi-axis moving device (5) to move to position B, rotate the lifting turntable to test and record the optical sensor DN value and camera transmission function of the space optical camera (6) after the test through the integrating sphere (3) and the collimator (4); S16: Control the lifting turntable of the multi-axis moving device (5) to move to position A, rotate the lifting turntable to reduce the angle between the optical axis of the space optical camera (6) and the axis of the solar simulator (1) by 2°-14°, and repeat steps S10-S15.

9. The method according to claim 8, characterized in that The key positions of the space optical camera (6) include the mirror body, the load-bearing truss, the back plate, the lens barrel and the electrical box housing.

10. The method according to claim 8, characterized in that In step S6, the appropriate distance between the light entrance of the space optical camera (6) and the light exit of the solar simulator (1) is 50 mm.

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