Science

Concepts

Photon Acceleration

Light produces a certain amount of pressure per unit of intensity when it is reflected directly back towards the source, and about half as much when it is absorbed and radiated in all directions. This is the effect harnessed by a solar sail. However, extremely lightweight materials are needed to overcome the Sun’s gravity substantially this way.

Both gravity and the intensity of sunlight diminish with distance at the same rate because they are distributed over an equally larger spherical region at a given distance. This relationship is the area of a sphere, a square law, meaning that going to 10% of the distance would imply 100 times the gravity and light intensity.

The ions in the solar wind are too small to absorb and radiate most of the sunlight (x-rays and gamma rays excepted). A perfect state with the same influence of gravity and light pressure would hover at any distance. However, aerographite shells can be 1/1000th as massive per unit of area while being thick enough (1 micron) to absorb and radiate sunlight.

The resulting acceleration is high as the result of aerographite’s amazing lightness and high photon absorbtion. It begins at 400 gees, which results in it reaching 1% of c in 14 minutes. It can reach 2% of c after another 20 days.

Aerographite

Aerographite is sometimes called aerographene. It’s a hollow nanoframework, which is slightly different from an aerogel. It is produced by beginning with a zinc oxide tetrapod dust, which is treated with a hydrocarbon at high temperatures in a vacuum. The carbon atoms form sp2 hybridized structures (hexagonal units) on the surface, with the arms being somewhat analogous to carbon nanotubes.

Once these have formed a layer one atom thick around each tetrapod, the oxygen is removed from the zinc by exposure to hydrogen, and the zinc is evaporated at high temperatures. So this form of carbon consists of nanoscale hollow structures shaped like zinc tetrapods. This makes it incredibly lightweight.

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