Japan to Launch Solar-Sail-Powered Craft Out Beyond Orbit for the First Time

I know you only have so much space for these articles, but you left out an important component of the IKAROS: it's photon propulsion engine. The article gives the impression of an un-manned skooner, drifting along. It's not just out there floating haplessly. It's more like a sailboat with a little propeller attached making it a sort of hybrid. I think that's an interesting addition the Japanese put on there.

several problems i might consider: micrometeroids will tear through the sail.

light has no mass so theoreticall and practically it cant push the craft, so i surmize its powered by solar wind: charged particls of electrons, protons, Hydrogen bonds and whatever has enough mass to make any difference in speed at all.

thats it i guess. although solar cells to power an electric propulsion system would work.

I liked project Orion better, if used correctly ( taking off in space rather than on earth :( )

@ extramechiton: It is true that photons of light have no mass, but they do carry momentum. When a photon bounces off an object, there is a momentum transfer that gives the object a nudge. Whenever a charged particle (like an electron) accelerates it emits photons, and conversely whenever a photon hits a particle, the particle gets an acceleration.

Energy E=hv (v is frequency, h is planck's constant)

Momentum P=h/y (y is wavelength, since I don't think I can insert a lambda in this text box)

I like that idea. Japan is great.

For a more effective and cost efficient way of space exploration by humans, I still prefer powerful means of propulsion such as aneutronic nuclear fusion.
www.youtube.com/watch?v=ng0NNRor_iQ
www.crossfirefusor.com/nuclear-fusion-reactor/overview.html

momentum= mass*velocity

im trying to picture this.... a teency weency ball of something... idk what a photon is since i think light is a wave... that has no mass but contains a velocity of 300 kilometers/second and theres an infinite amount of these lighty thingys collide with an object over 9x10^100000000000000000000000000000000000000000000000000000000000000000000 its mass (theoretically idk how heavy the craft is) and in space there is no weight due to 0 gravity... im losing myself.

> can just see the future ;won't just have america's cup yachting, there will be solar cup yacht race, 1st marker bouy the moon,2nd marker bouy venus,3rd marker bouy mercury,finish line earth;& not just windsurfing or landyachts; going to have solarsurfing(already they go skysurfing from thousands of feet) & solarkite surfing;
> or surfing the tail of comet as it goes around the sun, that would be xtreme sports.

The photons that bounce off the sail transfer momentum and in the process undergo a Doppler shift to a lower frequency. Now if we could only find a way back...tacking is going to take a while!

Robert M. Smith, MD, PhD

What about E=mc2? m=mass.

if light waves come from every where the craft will move in the opposite direction the most light waves are coming from.

if light waves come from every where the craft will move in the opposite direction the most light waves are coming from.