what if we build a "mothership" or a huge space exploration spacecraft?

Interesting idea.

As far as your "deep space" plan, it could only explore our own solar system. To travel to the nearest star system to ours would require 50 to 150 thousand years - one way.

A trip to Mars would take a minimum of nine months one way. Needs for the crew would be constant food, water, pressure, oxygen, heat, medical care, recreation, exercise, cleaning etc. – plus equipment and supplies for each.

A vast ship would be needed just to carry supplies. If you add to this the equipment for running the ship and for the science then the amount of fuel would be far more than we could get off the Earth.

. .

About the size of the White House is likely optimum for a generation ship we can build in this century. We should build a bunch of them of various sizes and designs. They should all head out of our solar system in very close to the same direction = a steeple = a spike = a convoy. That way they can help each other at least rarely, and they will need help as centuries old systems become beyond repair. Probably all that leave in this century, will turn back toward Earth before they get even 1% of one light year, but we learn from doing, so long term a craft will reach a destination in our Oort cloud, or even farther. They can be propelled by ion engines or equivalent, powered by solar panels and a small nuclear reactor.They also have a laser (one megawatt?) which can send energy to a near by generation ship as sunlight is close to zero past Neptune's orbit.

There is no such thing as "deep space" exploration. Due to the amount of time it would take to even reach outside our own solar system, anyone who was onboard the ship would either be dead or be close to it. There is no such thing as "light speed" so theres no way to get places any faster.

Yes you could build a "mothership" that generations of families could live on, but it would need to be of considerable size to store oxygen, food, water etc.. for all those people. Since the ship would be huge it would need to be built in space since the amount of energy it would take to get it out of earths atmosphere would be unimaginable. So if it was built in space, it would take millions of trips with regular space shuttles to transit the material to build.

Even if such a thing was built, there are so many things to consider once it was in space...meteor showers, solar flares, asteroids, black holes...probably hundreds of things I cant even think of that could destroy it in an instant.

Humans will not get any further than our own solar system.

It would be similar to an O'Neill Cylinder, Bernal Sphere or Stanford Torus.

It would basically be a town or city with the surrounding countryside.

It would contain buildings within it's biosphere.

The power source would likely be Liquid Fluoride Thorium Reactors so it could be refueled easily. The propulsion would probably be ion-drives, plasma or hall effect.

Well it would probably be created in space because launching it all at once is just enormous. And it has an enormous chance of failure which would be catastrophic. So there would be like multiple launches and those space parts would then rendezvous in space. Propellant could be everything.

You mean like this:

http://en.wikipedia.org/wiki/Generation_ship

It would have levels.

Propulsion would probably be ion drive, solar sails close to the sun perhaps.

who.s gonna pay for it? it,s cheaper to unmanned send probes. those will be the 1st interstellar travelers from earth. if the energy requirements for the alcubierre "warp drive" ever get realized; this conversation becomes moot.

Impossible, simply not feasible in any way.