Maraging Steel Thinsat Substrates

The current thinsat design presumes a pure aluminum substrate. However, maraging steel (68% iron, 18% nickel, 8% cobalt, 5% molybdenum, other elements ) offers interesting advantages.

Aluminum

Maraging Steel

goodness

density ρ kg/m³

2700

8100

rms. atomic number

13

27.2

2.09 :-)

avg. atomic weight

26

58.6

2.25 :-)

resistivity nΩ-m

28.2

181

0.156 :-(

thermal conductance W/m-K

237

24.8

0.105 :-(

thermal expansion μm/m-K

23.1e-6

10.3e-6

2.24 :-)

Youngs modulus E, GPa

70

210

3.0 :-)

Derived 5m²/kg

Thickness t μm

74.1

24.7

|| Bending Stiffness (1) E t || 5.2e6 || 5.2e6 ||

Bending Stiffness (2) E t³

28.4e-3

3.16e-4

0.111 :-(

Resistance mΩ/□

0.38

7.32

0.019 :-(

Thermal conduction mW/K

17.6

0.63

0.036 :-(

http://www.matweb.com/search/DataSheet.aspx?MatGUID=adaadfebfb20417db13ce8d3683dbccc&ckck=1

The main advantages are launch stack density, thermal expansion, belt particle scattering, and magnetic properties. The main disadvantages are lower lateral thermal conduction and thin shell bending stiffness - the resistivity is higher, but not that important.

Lateral thermal conduction helps cool chips, though they will be small and scattered and do not need to radiate over large areas.

Lower bending stiffness (2) makes area ripples in the curving surface slower and higher amplitude. However, slower is more easily corrected with the optical thrusters, and compensated by phasing of the emitters. Bending stiffness (1) is multiplied by thinsat shape factors, the same for both aluminum and maraging steel.

If the thinsats are magnetized on their north-south axis, then the earth's magnetic field will keep them aligned rotationally. Also, it will help the thinsats separate out of the launch stack. However, if a thinsat rotates 180 degrees in relation to a near neighbor, they may stick together inseparably. Shape tweaks to make them rotationally assymetric can reduce this effect.

Rutherford scattering is enhanced by higher nuclear weight and charge. Belt remediation will be faster, with less lattice displacement damage. Calculations should be scalable.

This requires more study.