.and that is precisely what rocket fuel is.When we walk, we throw the ground backwardsWhen we drive, the car tires throw the road backwardsWhen we swim, we throw water backwardsWhen boats drive,......
So in conclusion, solar power on a spacecraft is useful to keep the batteries charged, so that the batteries can operate lighting/computers/sensors/cameras/etcet… But it is not useful for propulsion through empty space. You gotta have something you can throw backwards if you want to go forwards...and that is precisely what rocket fuel is.
When we walk, we throw the ground backwards
When we drive, the car tires throw the road backwards
When we swim, we throw water backwards
When boats drive, the propellers throw the water backwards
When birds or aircraft fly, they throw air backwards
Spacecrafts though...they have to carry their own supply of stuff to throw backwards.
Except for rovers that have landed on the Moon or Mars. Those have wheels that can throw the surface of the planet or moon backwards.
Energy from the sun is not nearly powerful enough to lift a spacecraft off the planet and into orbit. It takes an astonishing amount energy to get the shuttle off the ground, and up to 17,500 mile per hour to maintain orbit. Only chemical rockets have sufficient power to do this today.
But to power the shuttle in orbit, you would need some very large solar panels which would add to the mass of the shuttle, which would take even more fuel to get off the ground and up to orbital speed.
Energy management is a delicate balance ... for example, something closer to home; if you take a jet plane across the country, for every 6 tons of fuel you put on the plane to make the trip, you need 1 ton of fuel just to move the fuel.
The sun isn't powerful enough to power a huge space shuttle. We might be able to power up small light bulbs with the sun down here in earth. But not a huge space shuttle, also, you tell me, what is going to happen when the space shuttle gets too distant away from the sun?
That's right, the space shuttle will not be solar powered anymore. This is why we can't make solar powered space shuttles.
Satellites do use solar power, but that's not enough to power all the systems aboard the space shuttle.
And it doesn't do you any good when you are on the night side of the earth, or far away from the sun in deep space.
But the Mars Rovers for instance used solar panels to charge up their batteries.
http://marsrover.nasa.gov/mission/spacec…
