This is my interstellar spacecraft
There has been so much fanfare this week about the discovery of seven rocky planets around TRAPPIST-1, some 50 light years distant. That is further than I would care to venture with out some sort of warp drive. Fortunately, there is a nice and possibly earth-like planet orbiting our next door neighbor, Proxima Centauri: Proxima b is only 4.246 light years away!
I designed the spacecraft above using only available technology to carry a crew of twelve to Proxima b and back. The trip will take 25 years going, and nearly the same returning. They will spend one year there. They are very patient people. (They will carry twelve lifetime supplies of Celexa and probably grow cannabis as a staple crop.)
The Big Ball
The craft's most dominant feature is the large pressurized sphere. It is made entirely from separate water filled polymer 'pods'. They are microwave welded together and reinforced with kevlar strapping that wraps around the entire thing. It is insulated on the exterior and each pod has some provision for heating and water circulation through ports inside. The water stops cosmic rays and regulates temperature. There is also a superconducting coil wrapped in a ring all the way around the equator. The hope is that the magnetic field will deflect some of the cosmic rays over and into the polar regions, where they will pass through the center of the centrifulge, not the edge where the people live.
Suspended inside the sphere, rotating about the center truss is a large slowly turning centrifuge. This is the hamster wheel in which the crew will spend most of their time. It is built out to be a bright and stimulating place with a full 1-G of gravity. There will be ample space for everyone, green grass, and an artificial blue sky. There may even be a small golf green, though you'd be surprised how weirdly the ball will arc, given this decidedly non-Newtonian reference frame... The whole ordeal is attached to the center truss by a kind of rotating universal joint. This lets its axis of rotation float independently with respect to the truss. A must if you plan on being able to aim your spacecraft in different directions. There are plenty of carnival rides with more ambitious mechanisms at their core. Operated by guys in clown suits. Not the spacecraft, the carnival ride.
Sprouting off of the main truss is a rather extensive three-dimensional profusion of vegitation. Gardens held out in all directions and lighted with simulated day and night cycles, as much for the crew as for the plants. The plant life will be scaled to handle the bulk of the oxygen cycle for the crew, and will also produce nearly 100% of the food and waste-uptake services. All of the life support equipment, water circulation systems, and data centers are also located in the weightless portion of the craft inside the sphere and on the central truss. This makes it easy to service and protected from mechanical harm.
Space is vast. And cold. Distances are ridiculous. Scientific notation was invented to *help* but doesn't quite solve the problem. You as a human just can't actually understand how far away from everything you will be when you are between stars. The only power source that I would trust out there is a good old fashioned nuclear reactor. Actually six of them. They are out there on the end near the drive section. Don't worry about it. It's fine. Just relax in the knowledge that no force in the known universe can make the rocks in their hearts grow cold. The radiators that stick out are part of the whole deal, providing the cold side to the generator's heat cycle.
The electricity produced from the redundant set of reactors powers a highly redundant set of plasma engines. These things produce more thrust than classic ion engines, but also use more propellant. Each engine has a big fat spherical tank of liquid Argon. It'll be enough for there and back. (Again.. don't worry about it.. ;-> )
There will also be some navigational sorts of thrusters at the outer most edge. They will be used for orienting the space craft and also for performing the regular momentum-dumps needed to keep that centrifuge spinning and the rest of the craft not.
I put it way out on the outer most edge of the truss platform that holds the engines. It has to be able to look back at earth. Also it has to be out there so as to provide drama when Frank has to go out there to replace some part that the computer says is going to fail...
The very front of the craft has a pair of lander/return vehicles for completing that last 300 miles to the surface of the planet. Oh, and back up again. They land vertically and take off vertically. Basic SpaceX kind of stuff.
There is a zero-G laboratory and some provisioned modules in case we lose the big ball and the crew needs to survive inside these space-grade tin-cans. Which they can do. There's food and a toilet. Sorry. That's it.
The very front is a remarkable little observatory with a beautiful two meter reflecting telescope and an array of excellent digital optical equipment. Mostly stuff they made in Boulder, CO.
This is no small undertaking, and no picnic. Though there will surely be picnics aboard. This is final frontier kind of stuff. It is all the more daring because it will be done at sub-light speed by meticulous people who are in it for the long haul. It's a mini earth. These people have to know they very well might not come back. They may even choose not to come back, especially if Proxima b is actually a nice place.
You'd be hard pressed to find any place 1 / 100th as nice as earth, though.