Magnetic cleanliness

Also known as Residual dipole, Solar panel back-wiring, Deperming

Controlling parasitic current loops, ferromagnetic fasteners and nickel-plated battery cases that otherwise dominate disturbance torques on 50 mm picosatellites.

Document: SQ-EN-007
Updated: 21 Oct 2026
Reading time: 1 min

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Why parasitic dipoles dominate 1P attitude dynamics#

In a $525 km$ polar orbit ( $B_{pole} \approx 47 μ T$ ), a parasitic magnetic dipole of just $m_{res} = 1 0^{- 3} A \cdot m^{2}$ ( $1 mA \cdot m^{2}$ ) produces a disturbance torque $T_{m} = m_{res} B \approx 47 nN \cdot m$ —more than a hundred times the gravity-gradient torque on a $1 P$ cube and comparable to the output of a PCB coil[1]. Worse, on a spacecraft with passive magnetic attitude control (), an uncompensated transverse dipole tilts the equilibrium axis by $Δ θ = arctan (m_{res, ⊥} / m_{PMAC})$ [2].

Worst-case 1P PocketQube disturbance torques vs. altitude (residual dipole 1.5×10⁻³ A·m², ΔI = 1.8×10⁻⁴ kg·m², CP–CM offset 4 mm)

Altitude (km)	Gravity gradient (N·m)	Aerodynamic (N·m)	Solar radiation (N·m)	Magnetic residual (N·m)	Dominant source
320	3.58 × 10⁻¹⁰	3.12 × 10⁻⁸	5.67 × 10⁻¹¹	7.93 × 10⁻⁸	Magnetic residual
400	3.46 × 10⁻¹⁰	7.76 × 10⁻⁹	5.67 × 10⁻¹¹	7.65 × 10⁻⁸	Magnetic residual
500	3.31 × 10⁻¹⁰	1.36 × 10⁻⁹	5.67 × 10⁻¹¹	7.32 × 10⁻⁸	Magnetic residual
525	3.27 × 10⁻¹⁰	8.83 × 10⁻¹⁰	5.67 × 10⁻¹¹	7.24 × 10⁻⁸	Magnetic residual
600	3.17 × 10⁻¹⁰	2.40 × 10⁻¹⁰	5.67 × 10⁻¹¹	7.01 × 10⁻⁸	Magnetic residual
700	3.03 × 10⁻¹⁰	4.22 × 10⁻¹¹	5.67 × 10⁻¹¹	6.72 × 10⁻⁸	Magnetic residual

References

[1]nadir lab. (2026). PocketQube picosatellites: A review of standards, mission trends and miniaturization constraints, with lessons learned from Grizu-263A, Türkiye’s first PocketQube [Preprint]. nadir lab.Read on nadir lab.
[2]nadir lab. (2026). Materials engineering for PocketQube picosatellites: A scaling-based review and design guide [Preprint]. nadir lab.Read on nadir lab.
[3]European Cooperation for Space Standardization. (2009). ECSS-Q-ST-70-36C: Space product assurance — Material selection for controlling stress-corrosion cracking. ESA-ESTEC.

Cite this SatWiki entry

@misc{nadirlab2026magnetic,
  author       = {{nadir lab.}},
  title        = {{Magnetic cleanliness}},
  year         = {2026},
  month        = oct,
  howpublished = {nadir lab. SatWiki SQ-EN-007 (Rev. 1)},
  url          = {https://nadirlab.space/en/wiki/magnetic-cleanliness/}
}

nadir lab. (2026). Magnetic cleanliness. nadir lab. SatWiki (SQ-EN-007, Rev. 1). https://nadirlab.space/en/wiki/magnetic-cleanliness/

TY  - ENCYC
AU  - {nadir lab.}
TI  - Magnetic cleanliness
T2  - nadir lab. SatWiki
PY  - 2026
ET  - Rev. 1
C1  - SQ-EN-007
UR  - https://nadirlab.space/en/wiki/magnetic-cleanliness/
ER  -