Gravity and Planet Size?

Will there be varying gravity, depending on the size of the planet? If I stepped off onto a planet with low gravity, could I jump 6 feet into the air. If you landed on a planet 20% bigger than Earth, will it affect vehicle and walking speed? Also would the ships artificial gravity be able to be switched off?
Realistically, if you stepped onto an asteroid, you'd just float straight off it. I like the idea of having to maybe expand the radius of the ships gravity field to be able to walk on an object one it gets below a certain size, otherwise you'd just fly off into space.

Adding on about planet size, would size of planets and solar systems, and the distance between neighboring systems be reminiscent of Spore? Once walking on the planet things seem big enough. However, flying from planet to planet in systems seemed kind of small. Although that was with automated flying. Probably would feel bigger if you're actually piloting the ship.

Planets will have varying gravity and it will effect the way your ship flies and how high you can jump etc. Some planets will require allot more power to 'hover' than others so you have to find a nice balance for each.

You can walk on asteroid's, you can enter asteroid bases however, which have an artificial gravity generator of there own.

No, you will not be able to turn off ship gravity. At least not with the current setup anyway.

To the second question...Flying in space will feel large, what else can I say =D