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Solar Sail Will Work, says Planetary Society
degauss writes "In response to Cornell Physicist Thomas Gold's paper declaring the theroy behind solar sails flawed (previously mentioned in this Slashdot article), Louis Freedman, executive director of the Planetary Society (the organization behind the COSMOS project), has written a brief rebuttal to the claims in Dr. Gold's paper regarding the feasibility of solar sails for use as a method of transportation in space. He does not go in to detail with equations and such, but does give an overview of the reasons he believes Gold's hypothesis is incorrect."
The interesting thing is that the Mercury orbiter that NASA launched (one of the pioneer series) used the pressure of sunlight on its solar panels, just like a solar sail would on the sail material, to give it a spin. That, IMO, gives the theory supporting solar sails working a whole lot more credibility.
Do you know why the road less traveled by is littered with the bones of the unwary?
a presigious US astronomer, wrote a paper in 1902 in which he concluded:
p 16 7y1977-78.pdf
"Flight by machines heavier than air," Simon Newcomb declared one day in 1902, "is unpractical and insignificant, if not utterly impossible."
His arguments were quite reasonable on the surface - Imagine a bird as a model. If you increase the size of the bird, the mass increases proportionally to the third power of its wingspan. But the surface area of the wings only increases proportionally to the square of its wingspan. Thus something much larger than a bird would never be able to fly, and all attempts to build heavier than air flying machines capable of carrying a human would prove futile.
Fortunately, the Wright brothers never read his paper, or at least never took him seriously.
About 40 years later it was argued by learned men that manned supersonic flight would never be achievable.
http://www.garfield.library.upenn.edu/essays/v3
Marconi wasn't formally educated, and he was laughed at for spending vast sums of money to send a radio signal across the Atlantic ocean. Any fool knows that radio waves couldn't penetrate the earth, and was limited to line of sight communication! Yet despite all logic, the damned fool contraption eventually worked. It was only later that they discovered the ionosphere could reflect certain frequencies back to earth.
Even great men of science make mistakes sometimes.
My rights don't need management.
in more speed then any conventional propelled rocket that you send in space.
The main practical difficulty I see is stopping. You can't slap propelled rockets on the ship to do the job; if you did, I would want to know you didn't propell you ship with that to begin with.
Maybe some fancy gravity trickery... deaccelerate as a star's gravity starts to whip you around. Other than that, I don't see how you could do it. I still don't see a use for these other than minute corrections in satellite trajectories. They're not directional, and the methods by which, say, sailboats can sail against the wind won't work here. Only way to slow yourself down is to stop sailing and let gravity do it's thing... a big problem when you're somewhere in space in which gravity isn't acting against you. Moreover, we wouldn't get very far away, because the force provided by sunlight diminishes exponentially as you move further away. And going towards another star wouldn't help, because you can't sail against the "wind" in this case (ship sails can because of how the wind will curve and press on the sail in a different direction than what it was originally travelling, which won't happen with light).
We're getting to the point where it will just take too long to go where we want to go, and eventually it's going to make us ask if we really can go there. I mean, hundreds of years later, who's going to care that a probe, unable to communicate with us, is careening somewhere past Neptune? As for people, don't hold your breath on this transporting us; it just takes too long. I don't know about you, but going to another planet wouldn't be worth most of my life, if not the whole thing and part of my children's. And I don't even want to hear this whole "Once we figure out how to go faster than light" garbage. You've all been taking Star Trek too seriously. Granted, people didn't believe we could fly, or the earth was round, blah blah blah. As we progress we do realize that things were wrong, but some things become more compellingly right as well. The speed of light, the fact that we can't exceed it and its correlation with time are what defines our reality. Sending something faster than light, AND slowing it back down without the obvious logical and physical laws getting in the way is impossible. Sending something as complicated and sensetive as an organism is absurd. Sending an organism as intricate as a person should be grounds for insanity.
Sorry, that just bothers me when geeks worldwide sit back after watching something on the Sci-Fi channel and think "Man, once we learn to warp... that'll be good times my friend", to which his friend replies "Affirmative" and starts taking readings on his platic light-up box... er, tricorder.
It's always the turtle that wins...
Unless there's a dog running after you. I got 5 bucks on the hare.