Scintillating Solar Sails

OK Humans,

Time to dream of distant shores,
Time to let our imagination soar,
Time to dream of worlds afar,
Time to reach out for the stars.

It’s time again to engage in the wonderous (and unique?) human capacity of imagining a better future, planning for and achieving it. Time again to dare challenge the unblinking Universe, to look steadily into the depths of space … and jump  🙂 

Above our heads now “flies” the new solar sail technology, testing for our future jump across our star system and beyond. Here is what it looks like up there, before its orbit slowly decays over the next few months.
And here is the latest image of the USA’s solar sail whizzing by above Finland. Wow! 🙂 Just a small, slowly moving light in the cold night sky, but … oh … what promise it holds.

Do you remember these similar jumps in human transport history? – first to sail around Africa, a Phoenician  trading round ship;  first Atlantic crossing steam ship; first flight round the world, first manned rocket ship and first interplanetary solar sail:


And here is Japan’s IKAROS solar sail being deployed in July 2010 in Earth-Venus interplanetary space.
Solar sail history is now about 100 years old. In 1964 Arthur C. Clarke, the famous science fiction writer (2001: A Space Odyssey) and first to propose putting satellites in geosynchronous orbit, wrote a novelette about a solar sail race to the Moon. I remember reading this story with starry eyes in the 1970s.


Since then many failed projects and attempts have passed … until now! Just like sail, steam, air and rocket travel.  And now we humans have finally succeeded … again!  🙂    

The basic physics of solar sails are quite simple. A light particle, a photon, because it has energy (and so mass, remember E=mc2) and hence a photon also has a certain amount of push or momentum, usually given the symbol P. The diagram below says all this quite well.

Here you can see how the Japanese IKAROS solar sail accelerates due to this light pressure on its sails. The first confirmation of solar sail physics in action.

Sooo … what next for solar sails? Well, let us dream and use our wonderous human capacity of imagination.


And why not further? … to touch the stars.

Human imagination and ingenuity has taken us to the ends of the Earth in the past and I will bet they’ll take us even further in the future. 

Historic Days Brady 🙂

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