An occultation atmosphere detection system based on the last-level cluster

Abstract

The present invention discloses an occultation atmospheric sounding system based on a final-stage cluster. By loading a GNSS occultation sounding payload on a final-stage cluster with an orbital retention platform, the final-stage cluster includes final-stage satellites in a number of sun-synchronous orbit missions and inclined orbit missions. These final-stage satellites adjust their attitudes through the orbital retention platform, and receive direct signals of GNSS navigation stars, rising occultation signals and falling occultation signals of GNSS occultations through the GNSS occultation sounding payload, and analyze parameter data including ionospheric electron density, atmospheric refractive index and temperature and humidity profiles to achieve atmospheric sounding. By making full use of the final-stage satellites in the high-density launch of the launch vehicle for adaptive modification, a giant hybrid detection network is formed with the existing GNSS occultation sounding satellite constellation, which can effectively improve the spatio-temporal resolution and detection accuracy of GNSS occultation atmospheric sounding.

Description

Technical Field

[0001] The present invention belongs to the technical field of atmospheric sounding, and particularly relates to an occultation atmospheric sounding system based on a cluster of upper stages. Background Art

[0002] The Earth's atmosphere provides a natural barrier for the reproduction of life on Earth and the development of humanity, and is one of the basic conditions for the survival of humanity and life on Earth. With the continuous exploration of the unknown world by humanity, the scope of human activities has gradually extended to the middle and upper atmosphere and space. The space atmospheric environment has become a new territory for human competition. Especially with the development of manned spaceflight technology, it is urgent for humanity to conduct in-depth research and analysis on the basic properties, movement and change laws, etc. of the atmosphere, and accurately forecast the space environment. Therefore, establishing a long-term stable, globally covered, high-precision, and high-resolution detection and analysis model for the Earth's atmosphere, and exploring its evolution law and influence scope is an important research field in current Earth science and space science. GNSS radio occultation atmospheric sounding, as a new field of application of navigation satellites in the 21st century, is one of the most economical and effective atmospheric sounding methods in the world.

[0003] GNSS occultation refers to the situation where GNSS satellites and low-orbit satellites are obscured by the Earth's atmosphere, that is, by measuring the delay of GNSS signals passing through the Earth's atmosphere, the refractive index of the atmosphere, ionospheric parameters, and other meteorological information such as air pressure, temperature, and water vapor can be obtained. The development of GNSS occultation sounding can make up for the deficiencies of traditional atmospheric sounding means such as water vapor radiometers, radiosondes, and meteorological satellites, and is a powerful supplement to traditional atmospheric sounding means. Its observation data has the advantages of all-weather, global coverage, self-calibration, real-time, high vertical resolution, high precision, and good stability. GNSS occultation atmospheric sounding provides a new method for meteorological data collection and has important application value in the fields of meteorology, climatology, ionosphere, and geodesy.

[0004] Since the GPS / MET experiment, GNSS occultation sounding has achieved vigorous development and gradually moved towards application. However, to exert its application effectiveness, it requires the support of a large-scale satellite constellation to provide a sufficient number of occultation events. The cycle and cost of satellite constellation construction cannot be underestimated. Currently, China's space launch missions are carried out continuously at a high density, resulting in an increasing number of upper stages left in orbit. If a GNSS occultation atmospheric sounding network is constructed based on the large-scale cluster of upper stages left in orbit naturally formed under high-density launches to carry out space weather forecasting, space ionosphere, and atmospheric environment detection, so that the system capabilities and application requirements are highly matched, it will become a beneficial supplementary method for China's GNSS occultation atmospheric sounding constellation and has great engineering application value. Summary of the Invention

[0005] The object of the present invention is to provide an occultation atmospheric sounding system based on a final-stage cluster, which can effectively solve the problems of long period and high cost of traditional GNSS occultation atmospheric sounding constellations, and can also form a giant hybrid sounding network with existing GNSS occultation sounding satellites, greatly improving the accuracy of occultation atmospheric sounding.

[0006] To solve the above problems, the technical solution of the present invention is as follows:

[0007] An occultation atmospheric sounding system based on a final-stage cluster, comprising: a final-stage cluster of a preset in-orbit platform and a GNSS occultation sounding payload, the GNSS occultation sounding payload being mounted on the final-stage in-orbit, and using the envelope space of the final-stage in-orbit, an array antenna is installed in the flight direction of the final-stage in-orbit.

[0008] The final-stage in-orbit cluster includes final-stage in-orbits on several sun-synchronous orbit missions and inclined orbit missions. The final-stage in-orbit adjusts its attitude through the in-orbit platform, and receives the direct signal of the GNSS navigation star, the ascending occultation signal and the descending occultation signal of the GNSS occultation through the GNSS occultation sounding payload, and analyzes parameter data including ionospheric electron density, atmospheric refractive index and temperature and humidity profiles to achieve atmospheric sounding.

[0009] According to an embodiment of the present invention, the final-stage in-orbit utilizes the remaining capacity of the launch vehicle attitude control system after the launch mission, gives play to the effectiveness of the remaining propellant, creates good attitude control initial conditions for the in-orbit platform, and adopts attitude control means such as zero momentum control and magnetic torquer control to realize stable control of the attitude of the large-inertia cabin of the final-stage, meeting the attitude requirements of the GNSS occultation sounding payload for the in-orbit platform.

[0010] According to an embodiment of the present invention, the electronics part of the GNSS occultation sounding payload on the final-stage in-orbit of the sun-synchronous orbit mission is installed in the support cabin of the final-stage in-orbit, meeting the thermal control requirements of the GNSS occultation sounding payload. The upward-looking antenna of the GNSS occultation sounding payload is installed on the II reference of the final-stage in-orbit, and the first side-looking antenna and the second side-looking antenna of the GNSS occultation sounding payload are respectively installed on the III reference and the I reference of the final-stage in-orbit;

[0011] The upward-looking antenna receives the direct signal of the GNSS navigation star, the first side-looking antenna receives the ascending occultation signal of the GNSS occultation, and the second side-looking antenna receives the descending occultation signal of the GNSS occultation.

[0012] According to an embodiment of the present invention, the electronics part of the GNSS occultation detection payload on the orbital retention sub-stage of the inclined orbit mission is installed in the orbital retention platform cabin to meet the thermal control requirements of the GNSS occultation detection payload. The upward-looking antenna of the GNSS occultation detection payload is installed on the top surface of the orbital retention platform, and the first side-looking antenna and the second side-looking antenna of the GNSS occultation detection payload antenna are respectively installed on the IV reference and II reference of the orbital retention sub-stage;

[0013] The upward-looking antenna receives the direct signal of the GNSS navigation star, the first side-looking antenna receives the ascending occultation signal of the GNSS occultation, and the second side-looking antenna receives the descending occultation signal of the GNSS occultation.

[0014] According to an embodiment of the present invention, the orbital retention platform includes an orbital retention control unit, a solar array, a TT&C antenna, and a cable network, which meet the mission requirements of the launch vehicle in terms of total weight, envelope, installation interface, test process, and environmental condition verification;

[0015] The orbital retention control unit is installed on the support cabin of the orbital retention sub-stage and has a shock absorption function;

[0016] The solar array is installed on the outer surface of the support cabin of the orbital retention sub-stage and has an equipotential and heat insulation function;

[0017] The TT&C antenna is installed on the surface of the transition section of the support cabin of the orbital retention sub-stage and has the function of mechanical and thermal simulation analysis in the active section of the launch vehicle, and is used for up and down communication of data information of the orbital retention control unit;

[0018] The orbital retention control unit is connected to the solar arrays installed at different positions on the support cabin through a cable network, and is used for supplying energy to the orbital retention platform and the GNSS occultation detection payload during the orbital retention process.

[0019] According to an embodiment of the present invention, the orbital retention control unit is an integrated electronic unit integrating energy management, TT&C communication, data management, attitude control, and thermal control, and the total weight is not greater than 4 kg.

[0020] According to an embodiment of the present invention, the orbital retention platform completes the flight state confirmation and setting through the test operation port reserved by the sub-stage before the launch vehicle launches, and does not separate from the orbital retention sub-stage in orbit.

[0021] Due to the adoption of the above technical solutions, the present invention has the following advantages and positive effects compared with the prior art:

[0022] In an embodiment of the present invention, a GNSS occultation atmospheric sounding system based on a final-stage cluster loads a GNSS occultation sounding payload on a final-stage cluster with an orbital retention platform. The final-stage cluster includes final-stage satellites on several sun-synchronous orbit missions and inclined orbit missions. These final-stage satellites adjust their attitudes through the orbital retention platform, and the GNSS occultation sounding payload receives the direct signal of GNSS navigation satellites, the ascending occultation signal and the descending occultation signal of GNSS occultation, and analyzes parameter data including ionospheric electron density, atmospheric refractive index and temperature and humidity profiles to achieve atmospheric sounding. By making full use of the final-stage satellites under high-density launches of launch vehicles for adaptive modification, a giant hybrid sounding network is formed with the existing GNSS occultation sounding satellite constellation. On the one hand, waste is reused, effectively reducing the cost of orbital missions and shortening the mission cycle. On the other hand, due to the large scale of the final-stage cluster, the spatio-temporal resolution and sounding accuracy of GNSS occultation atmospheric sounding can be effectively improved. Description of the Drawings

[0023] Figure 1 It is a block diagram of a GNSS occultation atmospheric sounding system based on a final-stage cluster in an embodiment of the present invention;

[0024] Figure 2 It is a schematic diagram of GNSS occultation atmospheric sounding in an embodiment of the present invention;

[0025] Figure 3 It is a structural diagram of a GNSS occultation sounding payload in an embodiment of the present invention;

[0026] Figure 4 It is an information flow diagram of a GNSS occultation sounding payload in an embodiment of the present invention;

[0027] Figure 5 It is a schematic diagram of GNSS occultation sounding of the final-stage satellite in a sun-synchronous orbit mission in an embodiment of the present invention;

[0028] Figure 6 It is a schematic diagram of GNSS occultation sounding of the final-stage satellite in an inclined orbit mission in an embodiment of the present invention.

[0029] Description of the Reference Numerals:

[0030] 1: Orbital retention control unit; 2: Solar array; 3: TT&C antenna; 4: Data transmission antenna; 5: Occultation sounding antenna; 6: Upward-looking antenna; 7: First side-looking antenna; 8: Second side-looking antenna; 9: Sunlight irradiation direction. Detailed Embodiment

[0031] The following further elaborates in detail on an occultation atmospheric sounding system based on a final-stage subcluster in combination with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer based on the following description and the claims.

[0032] The retained final stage is the largest space debris generated by launch vehicles, occupying valuable orbital resources for a long time. Currently, there is a certain amount of launch margin for each launch mission rocket. In this embodiment, a GNSS occultation atmospheric sounding payload is carried on the retained final stages of different launch missions. After entering the orbit with the main satellite, a GNSS occultation atmospheric sounding network with high spatio-temporal resolution is naturally formed, which can effectively solve problems such as the long construction period and high cost of the GNSS occultation sounding constellation, achieving "making the best use of things" and "turning waste into treasure" without generating new space debris.

[0033] Specifically, please refer to Figure 1 , the occultation atmospheric sounding system based on the final-stage subcluster in this embodiment includes a cluster of retained final stages of a preset retained platform and a GNSS occultation sounding payload, and the GNSS occultation sounding payload is installed on the retained final stage. Among them, the cluster of retained final stages includes retained final stages in several sun-synchronous orbit missions and inclined orbit missions. The retained final stage adjusts its attitude through the retained platform, and receives the direct signal of the GNSS navigation star, the ascending occultation signal and the descending occultation signal of the GNSS occultation through the occultation sounding antenna 5 of the GNSS occultation sounding payload, and analyzes parameter data including ionospheric electron density, atmospheric refractive index and temperature and humidity profiles to achieve atmospheric sounding.

[0034] Among them, the retained platform installed on the support cabin of the retained final stage includes a retained control unit 1, a solar array 2, a TT&C antenna 3 and a cable; the TT&C antenna 3 is installed on the surface of the retained control unit 1 and is used for the up-link and down-link communication of the data information of the retained control unit 1; the solar array 2 is installed on the outer surface of the support cabin of the retained final stage, and the solar array 2 is connected to the retained control unit 1 through a cable and is used for the energy supply of the retained platform during the retention process. In addition to supplying power to the retained platform, this solar array 2 is also electrically connected to the GNSS occultation sounding payload installed on the retained final stage to supply power to the GNSS occultation sounding payload.

[0035] The retained control unit in this embodiment is an integrated electronic device integrating energy management, TT&C communication, data management, attitude control and thermal control. This retained control unit is the core part of the retained platform, and can also be configured with a data transmission antenna 4, an attitude control component, etc. to achieve relevant data transmission and better control the attitude of the retained final stage.

[0036] Please refer to Figure 2, in this embodiment, GNSS occultation atmospheric sounding measures information such as the additional atmospheric phase delay of the occultation signal passing through the Earth's ionosphere and the atmospheric profile during the occurrence of the GNSS occultation event, and performs inversion of parameters such as ionospheric electron density, atmospheric refractive index, and temperature and humidity profiles. Generally, the point closest to the Earth's center on the propagation path of the radio wave is called the occultation tangent point. After the occultation condition is formed, as the last stage moves, when the radio wave completes a scan from top to bottom, the height of the occultation tangent point changes from high to low, that is, a complete descending occultation event is completed; correspondingly, as the last stage moves, when the radio wave completes a scan from bottom to top, the height of the occultation tangent point changes from low to high, that is, a complete ascending occultation event is completed. The direct signal of the GNSS navigation star is received by the upward-looking antenna installed on the support cabin of the retained last stage, and the ascending and descending occultation signals of the GNSS occultation are received by the side-looking antenna installed on the support cabin of the retained last stage.

[0037] Please refer to Figure 3 , the GNSS occultation sounding payload in this embodiment includes an antenna, a radio frequency preprocessing unit, a GNSS receiver, and an external interface; among them, the radio frequency preprocessing unit, the GNSS receiver, and the external interface are the electronics part of the GNSS occultation sounding payload and are installed in the support cabin of the retained last stage. There can be multiple GNSS receivers here, which can be divided into a GNSS receiving host and a GNSS receiving standby unit to achieve redundant setting of GNSS occultation sounding and improve the reliability of the GNSS occultation sounding payload.

[0038] Please refer to Figure 4 , the antenna transmits the direct signal of the GNSS navigation star, the ascending occultation signal and the descending occultation signal of the GNSS occultation received to the radio frequency preprocessing unit, and after amplification, filtering and down-conversion, outputs a digital intermediate frequency signal to the GNSS module (or GNSS receiver); the GNSS module performs correlation processing on the digital intermediate frequency signal, realizes signal acquisition, tracking and positioning, and outputs observation data (such as time, position, speed, pseudorange, carrier phase, etc.) to the retained platform through the external interface. This external interface can be any one of a CAN bus interface, an RS422 interface, and an RS485 interface. While sending the observation data to the retained platform, the GNSS occultation sounding payload sends a synchronous clock signal to the on-board computer of the retained platform and receives instructions from the on-board computer through the CAN bus.

[0039] Specifically, to ensure the reliability of on-orbit operation, the GNSS occultation sounding payload adopts a multi-antenna working mode to provide expandable multi-antenna input signals. The GNSS occultation sounding payload adopts a homogeneous cold backup mode and periodically sends observation application data, engineering data, etc. to the on-board computer of the retained platform.

[0040] The antennas of the GNSS occultation detection payload include an upward-looking antenna and a side-looking antenna. Taking advantage of the unique distributed load-bearing feature of the support module of the orbital transfer vehicle's upper stage, the upward-looking antenna and the side-looking antenna can be installed on the transition section of the support module to facilitate the acquisition of GNSS occultation data. Among them, the upward-looking antenna is used to receive the direct signal of the GNSS navigation satellite, and the side-looking antenna is used to receive the ascending occultation signal and the descending occultation signal of the GNSS occultation.

[0041] Please refer to Figure 5 , when performing GNSS occultation detection on the upper stage of the orbital transfer vehicle in a sun-synchronous orbit mission, after attitude control of the orbital transfer vehicle's upper stage through the orbital platform attitude control system, it is in a three-axis stabilized attitude towards the earth, which can meet the attitude requirements of the GNSS occultation atmosphere detection payload for the orbital platform. At the same time, the support module of the orbital transfer vehicle's upper stage has sufficient space to install one right-handed upward-looking antenna 6 (such as a POD antenna) and two right-handed side-looking antennas (the first side-looking antenna 7 and the second side-looking antenna 8) for receiving ionospheric and atmospheric parameters. Specifically, the upward-looking antenna 6 of the GNSS occultation detection payload is installed on the II reference of the orbital transfer vehicle's upper stage, and its first side-looking antenna 7 and second side-looking antenna 8 are installed on the III reference and I reference of the orbital transfer vehicle's upper stage respectively; among them, the II reference represents the sky-facing surface after the attitude of the upper stage is stabilized by the orbital control unit, the III reference represents the surface in the same direction as the flight direction of the upper stage, and the I reference represents the surface in the opposite direction to the flight direction of the upper stage.

[0042] The upward-looking antenna 6 receives the direct signal of the GNSS navigation satellite, the first side-looking antenna 7 receives the ascending occultation signal of the GNSS occultation, and the second side-looking antenna 8 receives the descending occultation signal of the GNSS occultation.

[0043] In the sun-synchronous orbit mission, the sunlight irradiation direction 9 always follows the Y direction of the orbital transfer vehicle's upper stage orbital platform, the X direction is the flight direction of the upper stage, and the Z direction is towards the earth. The solar array installed inside the orbital platform can receive sufficient sunlight to meet the energy requirements of the GNSS occultation atmosphere detection payload and the platform.

[0044] Please refer to Figure 6 , when performing GNSS occultation detection on the upper stage of the orbital transfer vehicle in an inclined orbit mission, the orbital platform and the GNSS occultation detection payload used in the GNSS occultation detection system of the upper stage of the orbital transfer vehicle in the sun-synchronous orbit mission are the same. However, since the sunlight irradiation direction along the Y direction of the orbital transfer vehicle's upper stage orbital platform changes with time in the inclined orbit mission, a solar array needs to be installed on the support module of the upper stage to meet the energy requirements of the orbital platform and the GNSS occultation detection payload.

[0045] Specifically, the upward-looking antenna 6 of the GNSS occultation detection payload is installed on the top surface of the in-orbit platform (i.e., the surface facing the sky after the attitude of the last stage is stabilized by the in-orbit control unit). Its first side-looking antenna 7 and second side-looking antenna 8 are respectively installed on the IV reference and II reference of the in-orbit last stage. Here, the IV reference represents the surface in the same direction as the flight direction of the last stage, and the II reference represents the surface in the opposite direction to the flight direction of the last stage.

[0046] The upward-looking antenna 6 receives the direct signal of the GNSS navigation star. The first side-looking antenna 7 receives the ascending occultation signal of the GNSS occultation, and the second side-looking antenna 8 receives the descending occultation signal of the GNSS occultation.

[0047] In this embodiment, the GNSS occultation detection payload has the advantages of low power consumption and light weight. Moreover, there is a certain payload margin in each launch mission of the launch vehicle. Therefore, the GNSS occultation receiver can be installed on the in-orbit last stages of launch vehicles with different configurations (second stage (including two-and-a-half stage), third stage (including three-and-a-half stage), fourth stage, payload fairing / payload support). Therefore, for the occultation atmosphere detection system based on the last stage cluster of the present invention, it can be simultaneously extended to the in-orbit last stages of other launch vehicles with different configurations (second stage (including two-and-a-half stage), fourth stage, payload fairing / payload support), so as to realize a GNSS occultation atmosphere detection network with a larger scale and higher spatio-temporal resolution based on the last stage.

[0048] In summary, the occultation atmosphere detection system based on the last stage cluster of the present invention can utilize a huge scale of in-orbit last stage clusters, which can effectively improve the spatio-temporal resolution of GNSS occultation atmosphere detection; it can form a giant hybrid detection network with the existing GNSS occultation detection satellite constellation, which can greatly improve the accuracy of occultation atmosphere detection; in addition, by making adaptive modifications to the in-orbit last stages under the high-density launch of the launch vehicle, waste can be reused, effectively reducing the cost of the detection mission and shortening the mission cycle.

[0049] The embodiments of the present invention have been described in detail above with reference to the drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, provided that these changes fall within the scope of the claims of the present invention and their equivalent technologies, they still fall within the protection scope of the present invention.

Claims

1. A occultation atmospheric detection system based on the last-stage sub-cluster, characterized in that, it includes: The last-stage sub-cluster of the preset on-orbit platform and the GNSS occultation detection payload. The GNSS occultation detection payload is installed on the last-stage sub-orbit. Using the envelope space of the last-stage sub-orbit, an array antenna is installed in the flight direction of the last-stage sub-orbit; The last-stage sub-cluster includes the last-stage sub-orbits of several sun-synchronous orbit missions and inclined orbit missions. The last-stage sub-orbit adjusts its attitude through the on-orbit platform, and receives the direct signal of the GNSS navigation star, the ascending occultation signal and the descending occultation signal of the GNSS occultation through the GNSS occultation detection payload, and analyzes the parameter data including ionospheric electron density, atmospheric refractive index and temperature and humidity profile to achieve atmospheric detection; Among them, the electronics part of the GNSS occultation detection payload on the last-stage sub-orbit of the sun-synchronous orbit mission is installed in the support cabin of the last-stage sub-orbit to meet the thermal control requirements of the GNSS occultation detection payload. The upward-looking antenna of the GNSS occultation detection payload is installed on the sky-facing surface after the last-stage sub-orbit stabilizes its attitude. The first side-looking antenna and the second side-looking antenna of the GNSS occultation detection payload are respectively installed on the surface in the same direction as the flight direction of the last-stage sub-orbit and the surface in the opposite direction to the flight direction of the last-stage sub-orbit; The upward-looking antenna receives the direct signal of the GNSS navigation star, the first side-looking antenna receives the ascending occultation signal of the GNSS occultation, and the second side-looking antenna receives the descending occultation signal of the GNSS occultation.

2. The occultation atmospheric detection system based on the last-stage sub-cluster according to claim 1, characterized in that, The last-stage sub-orbit utilizes the remaining capabilities of the carrier rocket attitude control system after the launch mission, gives play to the effectiveness of the remaining propellant, creates good initial attitude control conditions for the on-orbit platform, and adopts attitude control means such as zero-momentum control and magnetic torque control to realize the stable control of the attitude of the large-inertia cabin of the last-stage sub-orbit, and meets the attitude requirements of the GNSS occultation detection payload for the on-orbit platform.

3. The occultation atmospheric detection system based on the last-stage sub-cluster according to claim 1, characterized in that, The electronics part of the GNSS occultation detection payload on the last-stage sub-orbit of the inclined orbit mission is installed in the on-orbit platform cabin to meet the thermal control requirements of the GNSS occultation detection payload. The upward-looking antenna of the GNSS occultation detection payload is installed on the top surface of the on-orbit platform. The first side-looking antenna and the second side-looking antenna of the GNSS occultation detection payload antenna are respectively installed on the surface in the same direction as the flight direction of the last-stage sub-orbit and the surface in the opposite direction to the flight direction of the last-stage sub-orbit; The upward-looking antenna receives the direct signal of the GNSS navigation star, the first side-looking antenna receives the ascending occultation signal of the GNSS occultation, and the second side-looking antenna receives the descending occultation signal of the GNSS occultation.

4. The occultation atmospheric detection system based on the last-stage sub-cluster according to claim 1, characterized in that, The on-orbit platform includes an on-orbit control unit, a solar array, a TT&C antenna and a cable network, and meets the requirements of the carrier rocket mission in terms of total weight, envelope, installation interface, test process and environmental condition verification; The retention orbit control unit is installed on the support cabin of the last stage of the retention orbit, and has a shock absorption function; The solar array is installed on the outer surface of the support cabin of the last stage of the retention orbit, and has the functions of equipotential and heat insulation; The TT&C antenna is installed on the surface of the transition section of the support cabin of the last stage of the retention orbit, and meets the mechanical and thermal requirements of the active section of the launch vehicle, and is used for the up and down communication of the data information of the retention orbit control unit; The retention orbit control unit is connected to the solar arrays installed at different positions on the support cabin through a cable network, and is used for supplying energy to the retention orbit platform and the GNSS occultation sounding payload during the retention orbit process.

5. The occultation atmospheric sounding system based on the last stage cluster as claimed in claim 4, wherein, The retention orbit control unit is an integrated electronic unit integrating energy management, TT&C communication, data management, attitude control and thermal control, and the total weight is not more than 4 kg.

6. The occultation atmospheric sounding system based on the last stage cluster as claimed in claim 1, wherein, Before the launch of the launch vehicle, the retention orbit platform completes the flight state confirmation and setting through the test operation port reserved by the last stage, and does not separate from the last stage of the retention orbit in orbit.

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