A power generation and controllable space electromagnetic pulse radiation time division multiplexing system based on conductive tether

Abstract

This invention discloses a time-division multiplexing system for power generation and controllable space electromagnetic pulse radiation based on a conductive tether, belonging to the field of aerospace electric tether technology. The invention uses a single retractable conductive tether as the core carrier and adopts a time-division multiplexing topology. A fully integrated radiation-resistant solid-state switch array within the cabin achieves physical-level electrical isolation and nanosecond-level disconnect-before-make switching between power generation and pulse radiation modes. The controllable space electromagnetic pulse radiation is actively excited high-energy pulse radiation, with high-energy nanosecond-level electromagnetic pulses actively injected through a pulse emission module, significantly increasing radiation power and possessing practical value for electromagnetic passivation of space debris. In power generation mode, the tether and space plasma form a closed loop to cut the geomagnetic field and generate electricity. In pulse radiation mode, the tether acts as an end-fed directional long-line antenna radiating electromagnetic pulses. Active sheath control stabilizes the sheath potential and suppresses losses. Radio frequency isolation achieves electrical decoupling between the cabin section and the radiation section, and the mode switching timing does not depend on the plasma's millisecond-level relaxation response, avoiding the risks of mutual exclusion and self-interference. This invention resolves the fundamental conflict between single-strand conductive tether power generation and pulsed radiation. It exhibits strong dynamic stability and meets electromagnetic compatibility standards. The core components are based on on-orbit verification technologies such as TSS-1R, PMG, and T-Rex, making it highly feasible for engineering applications. It can be applied to aerospace scenarios such as satellite on-orbit operation and maintenance and space debris management.

Description

Technical Field

[0001] This invention relates to the field of aerospace electric tether technology, specifically to a system that realizes time-division multiplexing of space on-orbit power generation and controllable space electromagnetic pulse radiation based on a single conductive tether. Background Technology

[0002] Electric tether technology is considered an important technological direction for low-Earth orbit satellite on-orbit servicing due to its advantages such as not requiring propellant and having a long theoretical lifespan. Currently, relevant on-orbit verification missions at home and abroad (such as TSS-1R, PMG, T-Rex, etc.) have mainly verified single functions of tethers, such as power generation, thrust, or passive electromagnetic radiation. They have not yet achieved full-process verification of the fusion and multiplexing of power generation and pulse radiation on a single tether, and related technologies are still mainly based on ground tests.

[0003] The power generation function requires the tether to form a closed loop with the space plasma to create a low-impedance current path that cuts through the geomagnetic field to generate electricity. The pulse radiation function requires the tether to act as an open-circuit resonant antenna to efficiently radiate nanosecond-level broadband electromagnetic pulses. The two modes have fundamentally different requirements for the electrical topology: the closed loop requires low-impedance conduction, while the open-circuit antenna requires high-impedance open circuitry and broadband matching. Currently, there is a lack of a single conductive tether multiplexing scheme that can simultaneously accommodate both functions. Existing representative technical approaches have the following limitations: (1) Low power function tether (LWT) thrust / generation mode: It operates in a quasi-steady state with a current build-up time scale of milliseconds, which cannot support the rapid switching and open-circuit conditions required for nanosecond-level transient pulse radiation.

[0004] (2) Bare tethered power generation mode: It requires a low impedance closed path to be formed through a hollow cathode contactor, and there is a lack of compatible switching device between it and the open antenna topology required for pulse radiation.

[0005] (3) Dynamic modeling of electrodynamic tethers: mostly based on the quasi-static current assumption, without covering the distributed capacitance-inductance effect of the tether during nanosecond pulse transmission and the nonlinear response of the plasma sheath.

[0006] In summary, existing technologies have not established a unified fusion and reuse scheme, making it impossible to simultaneously achieve both power generation and controllable high-power pulse radiation on a single conductive tether. This invention proposes a time-division multiplexing topology architecture, which resolves topology conflicts through physical-level electrical isolation, avoids the risk of mode coexistence through nanosecond-level break-before-reconnect timing, and achieves controllable plasma-antenna coupling design through active sheath control and broadband impedance matching. Summary of the Invention

[0007] The purpose of this invention is to provide a time-division multiplexing system for power generation and controllable space electromagnetic pulse radiation based on conductive tethers, so as to solve the problem of mutual exclusion of the principle that a single conductive tether cannot simultaneously realize power generation (closed loop) and controllable space electromagnetic pulse radiation (open-circuit antenna), while taking into account dynamic stability and electromagnetic compatibility.

[0008] This invention is achieved using the following technical solution: A time-division multiplexing system for power generation and controllable space electromagnetic pulse radiation based on a conductive tether includes a single retractable conductive tether (2), a high-voltage solid-state switching unit (6), an energy regulation module (7), a pulse emission module (8), a hollow cathode plasma contactor (5), a cold cathode electron emission terminal (4), a timing control unit (9), an active sheath control unit (10), and a radio frequency isolation device (11) located at the outlet of the tether release mechanism (3). Wherein: The near end of the single retractable conductive tether (2) is fixed to the tether release mechanism (3) inside the satellite cabin, and the far end is fixedly connected to the cold cathode electron emitter (4). The tether tensile strength is ≥2GPa, and the release length is continuously adjustable within the range of 100m to 2km.

[0009] The high-voltage solid-state switching unit (6) is integrated within the satellite cabin and comprises two independent single-pole double-throw solid-state switch arrays: a mode-switching main switch (6-1) and an active sheath control switch (6-2). The normally closed contact of the mode-switching main switch (6-1) is electrically connected to the energy regulation module (7), and the normally open contact is electrically connected to the pulse emission module (8). The normally closed contact of the active sheath control switch (6-2) is electrically connected to the hollow cathode plasma contactor (5), and the normally open contact is electrically connected to the active sheath control unit (10). Both switch arrays adopt a multi-stage series SiC MOSFET architecture, follow aerospace-grade derating design principles, and are equipped with active voltage equalization circuits and redundant fault-tolerant circuits. The mode-switching main switch (6-1) has 12 or more series stages to meet the rated isolation withstand voltage requirement of ≥20kV; the active sheath control switch (6-2) has 2 to 4 series stages. The output terminal of the active sheath control switch (6-2) is connected to the cold cathode electron emitter (4) via an independent electrical path.

[0010] The timing control unit (9) is electrically connected to the control terminals of the mode switching main switch (6-1), the active sheath control switch (6-2), the pulse emission module (8), and the active sheath control unit (10), respectively, and is used to control the two sets of switches to perform a first-off-then-close timing sequence: when switching modes, all switch contacts corresponding to the current mode are completely disconnected first, and after waiting for a safety window of ≥200ns without simultaneous closure, the switch contacts corresponding to the target mode are closed. This timing sequence only controls the electrical on / off state and does not depend on the plasma millisecond-level relaxation response.

[0011] The input terminal of the radio frequency isolation device (11) is electrically connected to the common terminal of the mode switching main switch (6-1), and the output terminal is electrically connected to the proximal end of a single retractable conductive tether (2). In pulsed radiation mode, the device exhibits a high impedance of ≥1kΩ, electrically isolating the unreleased coiled tether segment from the released extended tether segment inside the satellite cabin; in power generation mode, it exhibits a low impedance at the milliohm level, allowing the power generation current to pass through, with insertion loss ≤0.5dB within the pulsed operating frequency band.

[0012] The system has a power generation mode and a pulse radiation mode. In the power generation mode, the tether and the space plasma form a closed loop to cut the geomagnetic field and generate electricity; in the pulse radiation mode, the tether acts as an end-fed directional long-line antenna to radiate electromagnetic pulses, which, in conjunction with active sheath control, stabilize the sheath potential and suppress losses. The two modes operate in a time-division manner, and physical-level electrical isolation and nanosecond-level disconnect-then-connect switching are achieved through a high-voltage solid-state switching unit (6).

[0013] Furthermore, the pulse emission module (8) is equipped with a tunable broadband impedance matching network and a feeding balun. The matching network can adjust the matching parameters in real time according to the release length of the tether rope from 100m to 2km, so as to control the standing wave ratio within 1.1 and the reflection loss ≤3%; the feeding balun achieves back radiation suppression ≥30dB.

[0014] Furthermore, in pulsed radiation mode, the active sheath control unit (10) applies a DC bias voltage of -10V to +20V to the cold cathode electron emitter (4) through an aerospace-grade isolated high-voltage DC-DC module, dynamically matching the plasma floating potential around the satellite, controlling the radiation impedance fluctuation within ±5%, and suppressing sheath loss.

[0015] Furthermore, the energy regulation module (7) includes a graded hybrid energy storage unit containing a conventional energy storage group and a pulse-specific energy storage group. The two groups are unidirectionally isolated by a high-voltage diode and can replenish the pulse emission energy consumption within 50ms.

[0016] Furthermore, the system is equipped with dynamic stability and electromagnetic compatibility protection mechanisms: the mode switching frequency is ≤1Hz, which is lower than the natural vibration frequency of the tether, thus avoiding the risk of resonance; during pulse transmission, the Lorentz force is along the tether axis, with no lateral excitation; the power generation circuit and the pulse circuit adopt a ground separation design, which, together with the shielding structure, achieves electromagnetic compatibility of the system.

[0017] The beneficial effects achieved by this invention are: This invention uses a single retractable conductive tether as the core carrier and adopts a time-division multiplexing topology. It achieves physical-level electrical isolation and nanosecond-level disconnect-before-make switching between power generation and pulse radiation modes through a fully integrated radiation-resistant solid-state switch array inside the cabin, thus solving the problem of mutual exclusion between power generation and pulse radiation from a single conductive tether.

[0018] The controllable space electromagnetic pulse radiation described in this invention is an actively excited high-energy pulse radiation. By actively injecting high-energy nanosecond-level electromagnetic pulses through a pulse emission module, the radiation power is significantly improved, and it has practical value for electromagnetic passivation of space debris.

[0019] This invention achieves electrical decoupling between the cabin section and the radiation section through a radio frequency isolation device, and the mode switching timing does not depend on the plasma millisecond-level relaxation response, thus avoiding the risks of mutual exclusion and self-interference. It stabilizes the sheath potential and suppresses losses through active sheath control, and ensures system stability and reliability through dynamic and electromagnetic compatibility design.

[0020] The core components of this invention are based on on-orbit verification technologies such as TSS-1R, PMG, and T-Rex, and have high engineering feasibility. They can be applied to aerospace scenarios such as satellite on-orbit operation and maintenance and space debris management. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure and electrical topology of the conductive tether power generation and electromagnetic pulse radiation time-division multiplexing system described in an embodiment of the present invention; Figure 2 The schematic diagram of the time-division multiplexing control circuit described in this embodiment of the invention is shown below. In this circuit, V3 is the main power DC source, V1 and V2 are the switch drive pulse sources output by the timing control unit, S1 corresponds to the mode switching main switch 6-1, S2 corresponds to the active sheath control switch 6-2, and R1 and R2 are the equivalent loads of the switches. The two drive pulse sources drive the corresponding switches to perform a graded first-break-then-make timing sequence, thereby realizing a non-overlapping and safe switching between the power generation mode and the pulse radiation mode. Figure 3 The waveform diagram for the mode switching timing simulation of the time-division multiplexing system according to an embodiment of the present invention is shown below. In the waveform diagram, V1 is the drive signal of the mode switching main switch S1, and S1 is its power output waveform; V2 is the drive signal of the active sheath control switch S2, and S2 is its power output waveform. The waveform shows that the sheath switch is turned on in advance and turned off with a lag. An electrical isolation safety window of ≥200ns is formed between the main switch and the sheath switch, which verifies the timing control logic of the present invention of disconnecting before closing and matching before transmitting. Figure 4 This is a flowchart illustrating the core workflow of the time-division multiplexing system described in this embodiment of the invention.

[0022] Explanation of reference numerals in the attached figures: 1—Satellite platform; 2—Single retractable conductive tether; 3—Tether release mechanism; 4—Cold cathode electron emitter; 5—Hollow cathode plasma contactor; 6—High-voltage solid-state switching unit; 6-1—Mode switching main switch; 6-2—Active sheath control switch; 7—Energy regulation module; 8—Pulse emission module; 9—Timing control unit; 10—Active sheath control unit; 11—RF isolation device; V3—Main power DC source; V1, V2—Switch drive pulse source; S1, S2—Power switching device; R1, R2—Load resistor. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Example

[0024] The first aspect of this embodiment provides a time-division multiplexing system for power generation and controllable space electromagnetic pulse radiation based on conductive tethers, suitable for on-orbit power generation and electromagnetic passivation of space debris on low-Earth orbit small satellite platforms. Please refer to... Figures 1 to 4 The system includes a satellite platform (1), a single retractable conductive tether (2), a tether release mechanism (3), a cold cathode electron emitter (4), a hollow cathode plasma contactor (5), a high-voltage solid-state switching unit (6), an energy regulation module (7), a pulse emission module (8), a timing control unit (9), an active sheath control unit (10), and a radio frequency isolation device (11), which are implemented as follows:

[0025] I. Overall System Structure and In-cabin Integration Implementation The system adopts an integrated architecture within the entire cabin, with a single retractable conductive tether (2) as the core reuse carrier. The high-voltage solid-state switching unit (6), energy regulation module (7), pulse emission module (8), timing control unit (9), and active sheath control unit (10) are all integrated inside the aerospace-grade electromagnetic shielding enclosure. The modules are interconnected by shielding cavities and low parasitic shielding cables to meet the electromagnetic compatibility and radiation resistance design requirements of low-orbit space.

[0026] The near end of a single retractable conductive tether (2) is fixed to the tether release mechanism (3) inside the cabin, and the far end is rigidly connected to the cold cathode electron emitter (4). The tether adopts an aerospace-grade multi-layer composite flexible conductive structure with a tensile strength ≥2GPa. The on-orbit release length can be continuously adjusted within the range of 100m to 2km. Under pulse radiation conditions, the Lorentz force is unidirectionally loaded along the tether axis without lateral vibration excitation, ensuring on-orbit dynamic stability.

[0027] A radio frequency isolation device (11) is connected in series at the outlet of the tether release mechanism (3). Its input end is electrically interconnected with the common end of the mode switching main switch (6-1), and its output end is directly connected to the near end of the conductive tether (2). The device exhibits a high resistance characteristic of ≥1kΩ in pulse radiation mode, realizing the electrical decoupling between the tether coiled inside the cabin and the tether extended outside the cabin. In the power generation mode, it exhibits a low resistance conduction characteristic of milliohm level, and the insertion loss is ≤0.5dB in the pulse working frequency band, taking into account the electrical performance requirements of dual modes.

[0028] The high-voltage solid-state switching unit (6) integrates two independent single-pole double-throw SiC MOSFET solid-state switch arrays, namely the mode switching main switch (6-1) and the active sheath control switch (6-2); the normally closed contact of the mode switching main switch (6-1) is connected to the energy regulation module (7), and the normally open contact is connected to the pulse emission module (8); the normally closed contact of the active sheath control switch (6-2) is connected to the hollow cathode plasma contactor (5), and the normally open contact is connected to the active sheath control unit (10); the two sets of switches are uniformly executed by the timing control unit (9) to perform nanosecond-level hierarchical break-before-make timing control; the output terminal of the active sheath control switch (6-2) is directly connected to the cold cathode electron emission terminal (4) through an independent shielded path to realize independent regulation of sheath potential.

[0029] II. Implementation of High-Voltage Solid-State Switching Unit and Timing Control The high-voltage solid-state switching unit (6) adopts a multi-stage series SiC MOSFET topology, follows the aerospace-grade first-level derating design principle, and is equipped with an active voltage equalization circuit and a redundant fault-tolerant protection circuit; the mode switching main switch (6-1) is configured with 12 series stages, with a rated isolation withstand voltage ≥20kV, which is suitable for nanosecond pulse high-voltage isolation requirements; the active sheath control switch (6-2) is configured with 2 to 4 series stages, which is suitable for low-voltage sheath bias regulation withstand voltage requirements.

[0030] Figure 2 This is a schematic diagram of the time-division multiplexing control circuit of the present invention. Figure 3 The waveform diagram is shown in the simulation of the mode switching timing. The core timing control logic of this invention is a graded disconnect-then-make electrical isolation window with no simultaneous closing of ≥200ns, and the entire process does not depend on the millisecond-level relaxation response of space plasma. During the mode switching phase, the timing control unit (9) first disconnects the corresponding contacts of the current mode of the two sets of switches synchronously, and cuts off the electrical connection between the power generation circuit and the pulse circuit; waits for a safety window of ≥200ns without simultaneous closing, to ensure that the two power switches are completely turned off and there is no conduction overlap; after the safety window ends, the active sheath control switch (6-2) is closed first to complete the antenna impedance matching, and the mode switching main switch (6-1) is closed after a delay to feed in nanosecond pulse power, and complete the dual-mode interference-free safe switching.

[0031] The ≥200ns simultaneous closure safety window is determined based on the turn-off physical mechanism of SiC MOSFET devices, the cumulative delay effect of multi-stage series topology, and aerospace-grade engineering margin. Regarding the turn-off physical mechanism, SiC MOSFETs, as unipolar voltage-controlled devices, exhibit no minority carrier storage effect and no tail current during turn-off, with a single-transistor turn-off time of only 5–20ns, far superior to the 100–500ns tail turn-off characteristic of IGBTs. Regarding the cumulative delay of multi-stage series topology, the mode-switching main switch of this invention adopts a 12-stage SiC MOSFET series architecture. There are nanosecond-level propagation delay differences between each stage of the drive circuit; the propagation delay can reach approximately 145ns under aerospace high-temperature environments. The 12-stage series architecture needs to consider delay superposition and worst-case margin. In terms of engineering margin, taking into account the differences in device consistency, temperature drift and derating design criteria for space radiation environment, the 200ns safety window can cover the entire link delay from the issuance of the shutdown command to the complete shutdown of all series switches, ensuring that there is no conduction overlap interval during the nanosecond-level mode switching of the two power switches, and completely avoiding the risk of high voltage crosstalk and short circuit from the timing level. Figure 3 The simulation waveforms further verified that there was no conduction overlap between the two switches throughout the entire process under this safety window.

[0032] Figure 2 The schematic diagram of the time-division multiplexing control circuit shows that V3 is the main power DC source, V1 and V2 are isolated drive pulse sources output by the timing control unit, V1 drives the main switch S1 (6-1) for mode switching, V2 drives the active sheath control switch S2 (6-2), and R1 and R2 are the equivalent load resistors of the switches. This topology realizes that the drive signal and the power switch respond synchronously and in phase. The hardware interlocking mechanism prevents the two switches from being turned on at the same time, thus avoiding the risk of high voltage short circuit and crosstalk from the hardware level.

[0033] Figure 3 The simulation waveforms for the mode switching timing are shown below, from top to bottom: V1 drive signal, S1 power output waveform, V2 drive signal, and S2 power output waveform. The simulation results verify that the active sheath control switch S2 turns on early and turns off late, the mode switching main switch S1 turns on late and turns off early, there is no conduction overlap between the two switches, the electrical isolation window is ≥200ns, and the timing design requirements of the hierarchical break-before-make and match-before-transmit are fully met.

[0034] III. System Workflow and Modality Switching Implementation like Figure 4 As shown, the entire system workflow is uniformly scheduled by the timing control unit (9), and the specific steps are as follows: (1) On-orbit deployment: The tether release mechanism (3) releases the conductive tether according to the mission length (2), the system is powered on and initialized, and the graded hybrid energy storage unit completes pre-charging and voltage equalization; (2) Power generation mode: The mode switching main switch (6-1) and the active sheath control switch (6-2) are both closed to the normally closed contact. The conductive tether (2), the energy regulation module (7), the hollow cathode plasma contactor (5), the cold cathode electron emitter (4) and the space plasma form a closed power generation circuit. The tether cuts the geomagnetic induction to generate electricity. The electrical energy is rectified and regulated and then stored in the hybrid energy storage unit. This stage continues until the pulse launch mission command is received. (3) Switching preparation: After receiving the pulse transmission command, the pulse-dedicated energy storage group is quickly charged to the rated pulse voltage; (4) Switch mode switching: The timing control unit (9) executes the hierarchical first-break-then-close timing sequence, simultaneously disconnects the normally closed contacts of the two sets of switches, waits for a safety window of ≥200ns, and then closes the normally open contacts of the sheath switch first, and then closes the normally open contacts of the main switch later. (5) Pulse radiation: Activate the active sheath control unit (10) and apply an adjustable DC bias voltage of -10V to +20V to the cold cathode electron emitter (4) to dynamically match the space plasma suspension potential; the pulse emission module (8) feeds high-energy nanosecond electromagnetic pulses into the conductive tether (2) through the main switch, and the external tether serves as an end-feed directional long-line antenna to radiate directional controllable space electromagnetic pulses; the radiation impedance fluctuation is controlled within ±5%; if an abnormal state occurs during this process, it will enter the fault classification and disposal process and be reported to the satellite service system simultaneously; (6) Mode Reset: After a single pulse transmission is completed, the active sheath control unit (10) is turned off; the timing control unit (9) first disconnects the main power switch and then disconnects the sheath control switch, the high voltage solid-state switching unit is reset, and the system seamlessly switches back to the power generation mode to continue working.

[0035] IV. Implementation of Control Circuit and Timing Simulation Verification based on Figure 2 The circuit topology shown was used to build an LTspice simulation verification platform to complete the full-condition verification of nanosecond-level timing and electrical characteristics. The obtained simulation waveforms are as follows. Figure 3 As shown, the specific results are as follows: The V1 drive signal responds synchronously and in phase with the mode switching main switch S1. A high level drives the switch to turn on, and a low level drives the switch to turn off. The power output waveform of S1 follows the drive command, exhibiting the characteristics of delayed turn-on and early turn-off, and undertakes the function of high voltage pulse power feeding. The V2 drive signal turns on before S1 and turns off after S1, driving the active sheath control switch S2 to continuously conduct through the full pulse window; the S2 power output waveform covers the entire pulse radiation range, achieving antenna impedance matching and stable control of sheath potential.

[0036] The full-condition simulation results show that: there is no conduction overlap between the two power switches, the electrical isolation window for mode switching is ≥200ns, the circuit response time is ≤50ns, the timing control accuracy meets the nanosecond-level switching requirements, there is no high voltage crosstalk and no mode conflict, which fully verifies the engineering feasibility and on-orbit safety of the topology and timing logic of this invention.

[0037] V. System Performance Indicators and Engineering Adaptation Implementation Based on typical operating conditions of a 500km low-Earth orbit, a geomagnetic field strength of 0.3Gs, and a tether length of 1km, the core performance of the system is quantified as follows: Power generation performance: The theoretical power generation capacity covers 10-50W, which can meet the continuous power supply requirements of low-power payloads on the satellite; Pulse performance: The energy consumption of a single pulse radiation is about 0.05J, the peak power is 500kW, the pulse width is 100ns, and the graded hybrid energy storage unit can complete the pulse energy consumption replenishment within 50ms; Compatibility: The core components are all based on TSS-1R, PMG, and T-Rex on-orbit verification technologies, and the entire architecture is compatible with 10kg-class low-Earth orbit small satellite platforms. The dynamics and electromagnetic compatibility indicators meet the aerospace on-orbit standards.

[0038] By integrating switches throughout the cabin, implementing radio frequency isolation and decoupling, and employing a hierarchical timing interlock design, the risk of pulse energy entering the power generation circuit and sensitive onboard payloads is completely avoided at the hardware level, while also ensuring dual-mode function reuse and high on-orbit reliability.

[0039] The second aspect of this embodiment provides a time-division multiplexing control method based on the above system, including the following steps: (a) In the power generation mode, the timing control unit (9) controls the mode switching main switch (6-1) to close to the normally closed contact and the active sheath control switch (6-2) to close to the normally closed contact, so that the single retractable conductive tether (2) forms a closed power generation circuit with the energy regulation module (7), the hollow cathode plasma contactor (5), the cold cathode electron emission terminal (4) and the space plasma; (b) When a pulse transmission mission command is received, the timing control unit (9) executes a break-before-close timing sequence: first, the normally closed contacts of the mode switching main switch (6-1) and the active sheath control switch (6-2) are simultaneously disconnected, and after waiting for a safety window of ≥200ns without simultaneous closure, the normally open contact of the active sheath control switch (6-2) is closed first to complete impedance matching, and the normally open contact of the mode switching main switch (6-1) is closed later to feed in pulse power; (c) In pulse radiation mode, the pulse emission module (8) feeds power to the single retractable conductive tether (2) through the normally open contact of the mode switching main switch (6-1), and the active sheath control unit (10) applies a DC bias voltage that dynamically matches the plasma suspension potential to the cold cathode electron emission end (4) through the normally open contact of the active sheath control switch (6-2), so that the released tether extension section becomes an end-fed directional long-line antenna that radiates directional controllable spatial electromagnetic pulses; (d) After the pulse transmission is completed, the timing control unit (9) first disconnects the mode switching main switch (6-1), then disconnects the active sheath control switch (6-2) with a lag, and finally resets to the normally closed contact corresponding to the power generation mode, and the system resumes the power generation mode.

[0040] In summary, the system provided in this embodiment represents a significant engineering advancement compared to existing electric tether technologies: it resolves the mutual exclusion problem between single-tether power generation and pulsed radiation principles, achieving physical-level electrical isolation and nanosecond-level seamless switching; it overcomes the passive radiation power bottleneck, enabling active high-energy pulsed radiation, thus possessing practical value for space debris mitigation; its timing control is independent of plasma response, and its dynamics and electromagnetic compatibility performance meet standards; and its core technologies are based on an on-orbit verification scheme, exhibiting strong engineering adaptability and wide applicability to aerospace scenarios such as low-Earth orbit satellite on-orbit operation and maintenance, and space environment management.

[0041] It should be noted that the circuit topology, component selection, and space environment adaptation design not elaborated in the above scheme are all existing mature technologies in the aerospace field and are not within the scope of improvement of this invention, so they will not be described in detail. The above embodiments are only preferred solutions of this invention and do not limit the scope of protection of this invention; equivalent substitutions, structural optimizations, and parameter adaptations made by those skilled in the art within the substantial scope of this invention should all fall within the patent protection scope of this invention.

Claims

1. A time-division multiplexed system for power generation and controllable space electromagnetic pulse radiation based on electrically conductive tether, characterized in that, include: A single retractable conductive tether (2) has its near end fixed to the tether release mechanism (3) inside the satellite cabin, and its far end fixedly connected to the cold cathode electron emitter (4). The high-voltage solid-state switching unit (6) is integrated into the satellite cabin and includes two independent single-pole double-throw solid-state switch arrays, namely the mode switching main switch (6-1) and the active sheath control switch (6-2). The energy regulation module (7) is electrically connected to the normally closed contact of the mode switching main switch (6-1); The pulse emission module (8) is electrically connected to the normally open contact of the mode switching main switch (6-1) and is used to output high-energy nanosecond electromagnetic pulses for active excitation. The hollow cathode plasma contactor (5) is electrically connected to the normally closed contact of the active sheath control switch (6-2); The active sheath control unit (10) is electrically connected to the normally open contact of the active sheath control switch (6-2); The timing control unit (9) is electrically connected to the control terminals of the mode switching main switch (6-1), the active sheath control switch (6-2), the pulse emission module (8), and the active sheath control unit (10), respectively. The system also includes a radio frequency isolation device (11), which is located at the outlet of the tether release mechanism (3). Its input end is electrically connected to the common end of the mode switching main switch (6-1), and its output end is electrically connected to the proximal end of the single retractable conductive tether (2). The system has a power generation mode and a pulse radiation mode. The timing control unit (9) controls two sets of switches to perform a first-close-then-close timing sequence: when switching modes, all switch contacts corresponding to the current mode are completely disconnected first, and after waiting for a ≥200ns safety window without simultaneous closing, the switch contacts corresponding to the target mode are closed to achieve safe switching between the two modes.

2. The system of claim 1, wherein, The radio frequency isolation device (11) presents a high impedance of ≥1kΩ in pulse radiation mode, which electrically isolates the unreleased coiled tether section from the released extended tether section inside the satellite cabin. It exhibits milliohm-level low impedance in power generation mode, allowing power generation current to pass through, and the insertion loss is ≤0.5dB in the pulse operating frequency band.

3. The system of claim 1, wherein, The two sets of switch arrays of the high-voltage solid-state switching unit (6) adopt a multi-level series SiC MOSFET architecture, follow the aerospace-grade derating design principle, and are equipped with active voltage equalization circuit and redundant fault-tolerant circuit; the series number of the mode switching main switch (6-1) is 12 levels or more, meeting the rated isolation withstand voltage requirement of ≥20kV, and the series number of the active sheath control switch (6-2) is 2 to 4 levels.

4. The system of claim 1, wherein, The pulse emission module (8) is equipped with a tunable broadband impedance matching network and a feeding balun. The matching network can adjust the matching parameters in real time according to the release length of the tether rope from 100m to 2km, so as to control the standing wave ratio within 1.1 and the reflection loss ≤3%. The feeding balun achieves back radiation suppression ≥30dB.

5. The system of claim 1, wherein, In pulsed radiation mode, the active sheath control unit (10) applies a DC bias voltage of -10V to +20V to the cold cathode electron emitter (4) through an aerospace-grade isolated high-voltage DC-DC module, dynamically matching the plasma suspension potential, controlling the radiation impedance fluctuation within ±5%, and suppressing sheath loss.

6. The system of claim 1, wherein, The energy regulation module (7) includes a graded hybrid energy storage unit, which contains a conventional energy storage group and a pulse-specific energy storage group. The two groups are unidirectionally isolated by a high-voltage diode and can replenish the pulse emission energy consumption within 50ms.

7. The system of claim 1, wherein, The single stretchable conductive tether (2) has a tensile strength ≥2GPa, and the release length can be continuously adjusted within the range of 100m to 2km. During pulse emission, the Lorentz force is along the tether axis and there is no lateral excitation.

8. The system of claim 1, wherein, The system is also equipped with dynamic stability and electromagnetic compatibility protection mechanisms: the mode switching frequency is ≤1Hz, which is lower than the natural vibration frequency of the tether, thus avoiding the risk of resonance; the power generation circuit and the pulse circuit adopt a ground separation design, which, together with the shielding structure, achieves electromagnetic compatibility of the system.

9. A time division multiplexing control method based on the system of any one of claims 1 to 8, characterized by, Includes the following steps: (a) In the power generation mode, the timing control unit (9) controls the mode switching main switch (6-1) to close to the normally closed contact and the active sheath control switch (6-2) to close to the normally closed contact, so that the single retractable conductive tether (2) forms a closed power generation circuit with the energy regulation module (7), the hollow cathode plasma contactor (5), the cold cathode electron emission terminal (4) and the space plasma; (b) When a pulse transmission mission command is received, the timing control unit (9) executes a break-before-close timing sequence: first, the normally closed contacts of the mode switching main switch (6-1) and the active sheath control switch (6-2) are simultaneously disconnected, and after waiting for a safety window of ≥200ns without simultaneous closure, the normally open contact of the active sheath control switch (6-2) is closed first to complete impedance matching, and the normally open contact of the mode switching main switch (6-1) is closed later to feed in pulse power; (c) In pulse radiation mode, the pulse emission module (8) feeds power to the single retractable conductive tether (2) through the normally open contact of the mode switching main switch (6-1), and the active sheath control unit (10) applies a DC bias voltage that dynamically matches the plasma suspension potential to the cold cathode electron emission end (4) through the normally open contact of the active sheath control switch (6-2), so that the released tether extension section becomes an end-fed directional long-line antenna that radiates directional controllable spatial electromagnetic pulses; (d) After the pulse transmission is completed, the timing control unit (9) first disconnects the mode switching main switch (6-1), then disconnects the active sheath control switch (6-2) with a lag, and finally resets to the normally closed contact corresponding to the power generation mode, and the system resumes the power generation mode.

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