Editing Solar sail (section)

===Constraints===
In Earth orbit, solar pressure and drag pressure are typically equal at an altitude of about 800&nbsp;km, which means that a sail craft would have to operate above that altitude. Sail craft must operate in orbits where their turn rates are compatible with the orbits, which is generally a concern only for spinning disk configurations.

Sail operating temperatures are a function of solar distance, sail angle, reflectivity, and front and back emissivities. A sail can be used only where its temperature is kept within its material limits. Generally, a sail can be used rather close to the Sun, around 0.25&nbsp;AU, or even closer if carefully designed for those conditions.<ref name="Wright " />