China Patent CN109573106B: Superconducting Magnetic Propulsion Device for Spacecraft (Nanjing University of Aeronautics)

Patent Number: CN109573106B Title: Superconducting Magnetic Propulsion Device for Spacecraft Inventors: 全荣辉, 戴天屹, 马家兴, 方美华, 吕金鹏, 郭义盼 (Quan Ronghui, Dai Tianyi, Ma Jiaxing, Fang Meihua, Lv Jinpeng, Guo Yipan) Assignee: Nanjing University of Aeronautics and Astronautics Filed: October 30, 2018; Granted October 26, 2021 Status: Active — anticipated expiration 2038-10-30 Jurisdiction: China (foreign) Track Directory (Physics_Math): Track_3/ — partial-shielding superconducting coil for ∇(m·B_ext) propulsion; Meissner-effect flux management for deep-space maneuvering; directly relevant to Attempt 3 gravitomagnetic track

Image files:

• patents_intl/tweets/raw_download/2043357725984199127_1.jpg

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."

System Architecture

The system includes:

• Magnetic field measurement module (101)
• Acceleration measurement module (102)
• Control module (103)
• Power supply module (104)
• Superconducting coil unit (105/106)
• Liquid helium refrigeration system (109)
• Energy storage (110)

The superconducting shielding cross-section diagrams show the coil winding with Type II superconductor sheathing that partially expels magnetic flux — the "partial shielding" arrangement is key.

Physics Mechanism: ∇(m · B_ext) Propulsion with Partial Shielding

The propulsion principle is the interaction 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), a superconducting coil with persistent current I and area A producing moment m = IA faces a gradient:

∂B/∂z ≈ 20 nT/m (vertical gradient over Earth)

For a thrust of 100 mN, the required magnetic moment is:

m = F/(∂B/∂z) ≈ 100×10⁻³/(20×10⁻⁹) ≈ 5×10⁶ A·m²

This is achievable with a pancake-coil superconductor of radius 1 m carrying 1.6 MA — high but within the range of REBCO high-temperature superconductors.

Partial Shielding Innovation

The "partial shielding" innovation addresses the main practical problem with magnetic propulsion: a simple superconducting dipole interacts with the full external field including all gradients, producing torques as well as forces. Partial shielding coils (Halbach-array-style configurations of superconducting shields) can cancel specific multipole components of the external field while leaving others, allowing the thrust vector to be controlled independently of attitude. This is the key engineering contribution of the Nanjing patent.

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. A spacecraft with m ≈ 5×10⁶ A·m² in Jupiter's field would experience:

F ≈ m × (∂B/∂z)|_Jupiter ≈ tens of Newtons

— sufficient for orbital maneuvering without propellant. The explicit mention of Jupiter indicates this is a serious deep-space propulsion concept, not merely an Earth-orbital attitude control system.

Relationship to Other Superconducting Propulsion Patents

This patent is one of a family of superconducting magnetic propulsion concepts documented in the archive:

Patent	Mechanism	Key Feature
RU2097274C1 (Track_17)	Meissner-effect levitation	Electromagnetic shield sections
US6318666B1 (Track_25)	Meissner levitation + Ampere propulsion	Geomagnetic field interaction
JP2936858B2 (Track_27)	Meissner asymmetric directional force	NEC Corp, asymmetric field geometry
CN109573106B (this)	∇(m·B_ext) with partial shielding	Jupiter-class deep space operation

Sources

• CN109573106B on Google Patents
• REBCO high-temperature superconductor specifications
• Nanjing University of Aeronautics and Astronautics

This information was compiled from Break_thrus.mdx staging file.