Patent CN109573106B — Superconducting Magnetic Propulsion Device for Spacecraft (Nanjing University of Aeronautics)
Bibliographic Information
| Field | Details |
|---|---|
| Patent Number | CN109573106B |
| Title | Superconducting Magnetic Propulsion Device for Spacecraft |
| Inventors | Quan Ronghui (全荣辉), Dai Tianyi (戴天屹), Ma Jiaxing (马家兴), Fang Meihua (方美华), Lv Jinpeng (吕金鹏), Guo Yipan (郭义盼) |
| Assignee | Nanjing University of Aeronautics and Astronautics (南京航空航天大学) |
| Filing Date | October 30, 2018 |
| Publication Date | October 26, 2021 (grant) |
| Status | Active — anticipated expiration October 30, 2038 |
| Classification | B64G1/409 — Unconventional spacecraft propulsion systems |
| Jurisdiction | China (CN) |
Abstract
The invention discloses a magnetic propulsion device for a spacecraft, which relates to the technical field of spacecraft without working substance power. The superconducting coil unit can be placed inside an aerospace structure such as a space station to achieve a thrust of the order of 100 millinewtons, and can be extended to a thrust of the order of 1 Newton through the superposition of multiple partial shielding coils, avoiding the influence of the magnetic moment of the conventional magnetic propulsion device. It is suitable for planets with strong magnetic fields, such as Jupiter.
Claims (5 Total)
Claim 1: A superconducting magnetic propulsion device for spacecraft comprising: a magnetic field measurement module (102); an acceleration measurement module (103); a control module (104); a power supply module (105); a superconducting coil unit (106); and a liquid helium refrigeration system (108); wherein the superconducting coil unit is used for enlarging the Ampere force difference generated by planetary magnetic fields, and the control module controls the power supply module and superconducting coil unit to generate controlled thrust.
Claim 2: The device of claim 1, wherein the superconducting coil unit includes a storage tank with single-wall design, the storage tank housing the superconducting coil, superconducting pipe, inner aluminum bracket, outer aluminum bracket, and liquid helium inlet and outlet.
Claim 3: The device of claim 1, wherein the superconducting coil unit includes a storage tank with double-wall design, with liquid helium circulating between inner and outer walls, and sealing columns penetrating the walls for structural integrity.
Claim 4: The device of claims 2–3, wherein storage tank walls are made from non-magnetic stainless steel or titanium alloy, and support structures from 99%+ purity aluminum alloy.
Claim 5: The device of claim 2–3, wherein the superconducting pipe material is Bi₁.₈Pb₀.₂₆Sr₂Ca₂Cu₃O₁₀₊ₓ with minimum wall thickness of 0.5 mm.
Description / Specification
System Architecture
Six Core Modules:
| Module | Number | Function |
|---|---|---|
| Magnetic field measurement | 102 | Measures ambient planetary magnetic field B_ext |
| Acceleration measurement | 103 | Measures craft acceleration for control feedback |
| Control module | 104 | Computes required coil current to achieve commanded thrust |
| Power supply module | 105 | Provides electrical power to superconducting coil charging circuit |
| Superconducting coil unit | 106 | Generates magnetic dipole moment m interacting with B_ext |
| Liquid helium refrigeration | 108 | Two-stage Stirling refrigerator maintaining 20 K at 90 W input power |
Superconducting Coil Unit: Two Storage Tank Designs
Design 1 (Single-Wall): One outer wall housing all components. Superconducting coil, superconducting pipe, and supports immersed in liquid helium. Inlet/outlet ports for helium and superconducting wire connections.
Design 2 (Double-Wall): Liquid helium circulates between inner and outer walls. Internal components isolated from direct helium contact. Sealing columns penetrate walls for structural integrity.
Materials Specifications
| Component | Material |
|---|---|
| Storage tank walls | Non-magnetic stainless steel or titanium alloy |
| Support structures (inner/outer brackets) | Aluminum alloy, 99%+ purity |
| Superconducting pipe | Bi₁.₈Pb₀.₂₆Sr₂Ca₂Cu₃O₁₀₊ₓ (BSCCO-2223) |
| Minimum pipe wall thickness | 0.5 mm |
| Critical temperature of BSCCO-2223 | 108 K |
| Operating temperature | 20 K (at 1 MPa) |
Physics Mechanism: ∇(m · B_ext) Propulsion with Partial Shielding
The propulsion principle is the gradient force between the superconducting coil's magnetic dipole moment m and the gradient of an external planetary magnetic field:
F = ∇(m · B_ext)
For Earth's surface field (B_ext ≈ 50 μT) with vertical gradient:
∂B/∂z ≈ 20 nT/m
For a thrust of 100 mN, the required magnetic moment:
m = F / (∂B/∂z) ≈ 100×10⁻³ / (20×10⁻⁹) ≈ 5×10⁶ A·m²
This is achievable with a pancake-coil BSCCO-2223 superconductor of radius 1 m carrying approximately 1.6 MA — high but within range of high-temperature superconductors at 20 K. Per the patent's specific implementation:
- Coil current: ~6,000 A
- Single coil thrust: ~200 millinewtons
- Weight per unit: 65.3 kg (excluding power/control systems)
Partial Shielding Innovation
The key innovation is "partial shielding coils." A simple superconducting dipole interacts with the full external field including all gradient components, producing torques as well as forces — the torques are undesirable for spacecraft attitude control. Partial shielding coils (using the Meissner-effect shielding of the superconducting pipe) cancel specific multipole components of the external field interaction while leaving others:
The force difference between shielded and unshielded wire sections:
F = (B - B') × I × L × sin(θ)
where B represents external field strength and B' represents the shielded field intensity inside the superconducting pipe. The shielding reduces B' to far below B, creating an asymmetric force on the current-carrying conductor. Multiple partial shielding coils in Halbach-array-style configurations allow the thrust vector to be controlled independently of attitude.
Refrigeration System
The two-stage Stirling refrigerator achieves 20 K under input power consumption of 90 W, meeting aerospace heritage standards for compact cryogenic systems. This represents the state of the art for space-qualified Stirling cryocoolers as of 2018.
Jupiter Operation
For Jupiter, with an equatorial surface field of ~430 μT and much larger field gradients, the same superconducting coil produces proportionally larger forces:
F ≈ m × (∂B/∂z)|_Jupiter ≈ tens of Newtons
Sufficient for orbital maneuvering without propellant. The explicit mention of Jupiter in the abstract indicates this is a serious deep-space propulsion concept, not merely an Earth-orbital attitude control system. Jupiter's field is ~10× stronger than Earth's, and Ganymede (Jupiter's moon) has its own magnetosphere — both environments where this propulsion system operates at significantly enhanced performance.
Key Technical Advantages
- Compact — can be placed inside aerospace structure such as a space station
- Scalable — thrust scales with number of coil units superimposed
- Weak magnetic signature — partial shielding reduces external magnetic moment compared to conventional unshielded coils
- Propellant-free — no consumables required; energy input only
- Strong-field compatibility — specifically optimized for Jupiter-class environments
Technical Classifications
- B64G1/409 — Cosmonautic vehicles: unconventional spacecraft propulsion systems
Prior Art Cited
Six prior patents referenced, including:
- CN102862687A — earlier magnetic propulsion concept
- CN104554825A — another magnetic propulsion approach
- CN102136337A — superconducting magnet system
Family of Superconducting Propulsion Patents in This Archive
| Patent | Mechanism | Key Feature |
|---|---|---|
| RU2097274C1 (Track_17) | Meissner-effect levitation | EM shield sections, post-Soviet Russia |
| US6318666B1 (Track_25) | Meissner levitation + Ampere propulsion | Earth geomagnetic field, spherical |
| JP2936858B2 (Track_27) | Meissner asymmetric directional force | NEC Corp, multipole geometry |
| CN109573106B (this) | ∇(m·B_ext) with partial shielding | Jupiter-class deep space, BSCCO-2223 |
Citations
- Google Patents: CN109573106B
- BSCCO-2223 superconductor specifications (Bi₁.₈Pb₀.₂₆Sr₂Ca₂Cu₃O₁₀₊ₓ)
- Nanjing University of Aeronautics and Astronautics
- REBCO high-temperature superconductor specifications (comparative)
Patent text compiled from Google Patents. Machine-translated from Chinese; original Chinese text at the above URL.