# How large of a mirror would be needed to warm Titan up?

How large of a mirror would be needed to warm Titan up to ~290K?

Paul Birch in his paper "Terroforming Mars Quickly" calculated a mirror size of:

Support Mirror: 2.5 x 10^7m radius 3x 105m wide

Distance: between .91 x 10^8m perihelion and 1.09 x 10x10^14m2 aphelion.

4.6piR^2 ~ 1.7x10^ x 14m^2 with a mass of 5x10^10kg (55.12 short tons).

Lens 400km above the surface, 460km radius

Source: https://www.orionsarm.com/fm_store/TerraformingMarsQuickly.pdf (p. 4 -6 of PDF).

I understand that Titan has a thicker atmosphere + smaller land area and I don't know how to account for that.

Also, I understand you may only need small mirrors to warm smaller areas (i.e. not the whole planet). Is this viable given how thick Titan's clouds are?

• Well you can start by computing Titan's equilibrium temperature, then compare to the actual surface temperature. That will give you a handle on how important the greenhouse effect there is. Next you vary the surface area for the absorbed flux that goes into the equilibrium temp. That should give you your result. – AtmosphericPrisonEscape Apr 12 at 22:26