Space: News | Strange Ideas
6/20/2005 Space Science fiction may become fact: Cosmos 1 launches tomorrow
Watch the count down to the launch here.
"The sci-fi notion of a solar-light propelled spacecraft will take its first step towards turning into reality on Tuesday. A private group of space enthusiasts - the Planetary Society, will launch Cosmos 1, a spacecraft powered only by the light reflected off an array of mylar sails.
... Interestingly, the spacecraft's launch will be equally unique: it will ride a converted Volna intercontinental ballistic missile, a weapon of mass destruction of the kind used during the Soviet regime. The missile/spacecraft will be launched from a submerged Russian submarine in the Barent Sea (north Scandinavia). For instructions on observing the spacecraft you may log on to the site of the Planetary Society."
... Although photons have no mass, each carries a tiny amount of energy that would be transferred to the spacecraft; the collective energy of the photons would propel the craft forward in the friction-less environment of space." " - earthtimes
In the NASA photo above, "Les Johnson, of Marshall Space Flight Center, holds a rigid, lightweight carbon fiber material that may be used to build a giant space sail. ... In a recent experiment at NASA's Jet Propulsion Laboratory (JPL), sails were driven to liftoff using microwave beams, while laser beams were used to push the sail forward.
How, exactly do photons with zero mass propel something? An article in New Scientist in 2003 said solar sails break the laws of physics. Obviously light pressure works. But how? Answer:
"Light pressure does work. It is derived directly from Maxwell's equations of electromagnetism. It has been measured in laboratories since 1900 ... (one complaint) is that light can't have pressure because it is a scalar quantity [having only magnitude and no direction] while Newtonian momentum is a vector. Light pressure is a vector.
Maxwell's equations are vector equations. The velocity of a photon (an individual packet of light) is a vector equal to its direction multiplied by the speed of light. So, there is no conflict." - more
"... The propulsive force for a solar sail arises from the pressure of photons (light) from the Sun or from lasers. Sunlight at 1 Astronomical Unit (1 AU is Earth's distance from the sun = 150 million km or 93 million miles) exerts a force of 9 Newtons per square kilometer (0.78 pounds per square mile) on a solar sail." - howstuffworks
The "... advantage of a solar sail is that it accelerates CONSTANTLY. A rocket only burns for a few minutes, before releasing its payload and letting it cruise at a constant speed the rest of the way. A solar sail, in contrast, keeps on accelerating, and can ultimately reach speeds much greater than those of a rocket-launched craft. At an acceleration rate of 1 millimeter per second per second (20 times greater than the expected acceleration for Cosmos 1), a solar sail would increase its speed by approximately 310 kilometers per hour (195 mph) after one day, moving 7500 kilometers (4700 miles) in the process. After 12 days it will have increased its speed 3700 kilometers per hour (2300 mph). "
It works, but I still don't really get how. Light has a particle nature which is true and fundamental to quantum mechanics, but those particles of light have zero mass, so how do particles of pure energy propel mass by hitting it?
6/3/04 Space. (ufoevidence) This June 21st (a Monday) you can drive to Mojave ( 6 hours from Sacramento ) to see history being made when the first civilian craft, SpaceShipOne, reaches space and returns safely. The public is invited.
"If you weren't around for the first Moon landing (or can't remember it), here's another chance to see history ... The flight plan calls for SpaceShipOne to reach an altitude of 100 kilometers, the height specified by the X PRIZE ... It takes the pair of mated vehicles roughly one hour to reach 47,000 feet."
There may be some nice photo ops and sonic booms.
5/14/04 SpaceShipOne. (Yahoo | Space) Yesterday Mike Melvill, a 62-year-old test pilot moved his team one step closer to winning the $10-million Ansari X Prize for the first commercial space craft when SpaceShipOne, climbed to 211,400 feet, (40 miles) becoming the first privately funded vehicle to break through earth's atmosphere and reach the edge of space. More pics of the craft designed by Burt Rutan are available here.