Solar Sail Calculator

This page lets you play with values significant for a Solar Sail launch system to see what can be achieved:

This option allows you to preset all of the properties of the sail that depend only on the material. A short list is given of materials that either are available or have been proposed as producible in the near future with technology currently under development. Click the button to preset the yellow boxes to the values for the chosen material. After that, you can change the attributes to see how the properties affect the final outcome.

The green boxes are not constrained by the material. You can change them as you see fit to find out what size of sail you need for a given payload and so on. However, there is no guarantee that your selection will be feasible in the real world. 

For any real sail material, the reflectivity will be less than 100%. That part of the incident radiation which is not reflected must be absorbed by the sail, and that power must be balanced by radiation from the unlit side. If we assume the best possible emission characteristic, that of a black-body radiator, the radiated power depends only on the temperature. Maximum temperature at which the material retains adequate strength
Power radiated from the unlit side of the sail at maximum temperature
The reflectivity of the material together with the radiated power determines the maximum incident radiation that the sail can withstand. That in turn limits how close to the Sun the sail can be launched. Reflectivity
Maximum incident power
Minimum launch distance from the centre of the Sun
Of course we may choose to launch from further out. The Sun is a violently active object and various unpredictable phenomena may make it unsafe to approach to the theoretical limits of the material. In fact, with a sufficiently high temperature material such as Tungsten, the minimum launch distance may even be inside the Sun (695,500km ≡ 0.00465 AU).

Check this box to always use the minimum launch distance or uncheck the box and enter the desired launch location either in km or AU

Actual launch distance from the centre of the Sun
Incident power at launch
Sail temperature at launch
Radiation pressure at launch
The density of the material and the thickness of the sail determine the areal density (mass per unit area). This together with the radiation pressure will determine the acceleration of the sail  Material density
Sail thickness
Areal density (mass per unit area) of the sail
Initial acceleration without payload
The size of the sail can be increased to give an acceleration as close to the unloaded value as we like, but what size is needed for a given payload?
Diameter of the sail
Mass of the sail
The resulting performance of your launch system:

The fields should update automatically as you change the
entries, but if not just press this button.

Initial acceleration including payload
Final speed
Time to reach 95% of final speed
Time to reach Proxima Centauri

Go back to the Main Paper or look at a possible Low-mass Payload strategy.