Spaceship Design

[Jay-qu]

sounds cool - but funny looking :eek2:

 

In trips to the outer planets at least, a short stop at the asteroid belt to collect some reaction mass might save a lot of time.

most likely deccelerating to stop and get fuel and then accelerating back to your previous speed would end up using more fuel than you can collect..

[TheBigDog]

My ship would work on the concept of never needing to refuel. It would use nuclear propulsion with the capability of running its engine for 100 years non stopped. The drive section would be a long cylinder that would store the nuclear fuel and direct the energy out the tail. Around the drive section at a radius of some distance would be the crew ring. While the engine is firing the ship would maintain a near 1G accelleration until it reaches its desired speed. During this accelleration the ring would not be rotating. Instead the sections of the ring would rotate to that the ceiling is where you are going and the floor is where you have been. As the decelleration stops the ship would begin rotation with the sections of the ring shifting so that the ceiling is toward the center and the floor is at the outside of the ring. For the passengers there would be some orientation change during thiss time, but they would always live in a 1G envioronment. The ship would have only limited ability to send shuttles or unmanned probes down to the surface of planets. The long term surface exploration shuttles would only be used on planets where resources for gathering return fuel had been detected. Such a shuttle could remain on the surface of a planet with a crew for extended periods of time (up to a year?) without resupply from the mother ship. Any number of probes could be put into orbit of planets to gather information and then be collected for reuse again at another planet.

 

The mother ship itself would be capable of remaining completely self sustained with a standard crew size of, say... 200-300 almost indefinately. This could be used for both exploration of our own solar system, and exploration of anything in space that a crew of people brave enough to commit their lives and their children's lives and their children's children's lives to taking.

 

Bill

[TheFaithfulStone]

Ladies and Gentlenerds...

 

I give you - the TFS Arthur C. Clarke (AMC-1)

 

 

The Clarke is a 100m+ Antimatter clipper. It's primary means of long distance propulsion is a Reinforced Aerogel Sheet coated with Salt Water Ice on the front, and on the back with Uranium-235. From the Antimatter storage tank located fore of the main body of the craft, nanoflakes of antihydrogen are eject, where they collide with the U-235. Besides the annihilation energy, the U-235 will undergo a low-intensity fusion reaction, producing thrust. Speeds of 116kps in about four months. Standard thrusters just aft of antimatter storage on a rotating ring provide steering.

 

The ship itself is a hollow tube with a habitat ring about 3m thick roating within the stationary outer shell. The spinning of the habitat ring provides microgravity. Long-term low gravity effects are not prevented, but unfortunate mishaps with zero-gee toilets are lessened. The central, zero gee section of the tube is the hydroponic farms / oxygen regenerating plants, yeast and fungal farms, which provide much of the food, and biological waste reclamation.

 

At the fore of this section is a pebble bed reactor, which provides electrical energy for ship systems. Communication is a high bandwidth microwave transmission. Surrounding the Midships are Fuel, Air, and Water supplies, which also provide additional radiation sheilding. The rotating inner ring is actually broken into two section here, making it possible to put additional working space along the outside of this section. The bridge is also located on the dorsal side of midships. (inasmuch as space has an "up")

 

In the aft section are landing modules and solar panels which provide additional energy. The solar panels are adjustable and deployable, so they need only be used when the ship is in orbit or coasting. There are two VASIMR engines at the back of the ship for high thrust manuevers (like orbit insertion or escape.) Also, there are several small, "Apollo-style" landing craft - which parachute to the ground. They may have control thrusters, but they don't have lift off thrusters, although they could be equipped.

 

Rotating behind the spaceship are sensor pods and "fling tethers" The sensor pods have small thrusters so they can be moved around, but mostly they "orbit" the center of the ship on the end of long tethers. The tethers are of variable length, but can be retracted. In any case, the landing vessells or cargo pods are attached to the ends of the tethers, and then release strategically so that they land where the crew wants.

 

Also back there is the science section - a large flat section with variable gravity. At the center, it's zero gee - and gravity increases as you move outward.

 

It has ~22,000 m^3 of space, not counting the internal space which is an additional 33,000 m^3 (minus space for the reactor, bay, etc._

 

And that's my spaceship.

 

TFS

[Tormod]

but the solar wind doesnt flow around behind the sail like air does, you would be unable to create a lower pressure on the sun side of the sail.. oh wait you where joking, turtle you old dog you :phones:

 

Hm...just aim at the Sun, pull down the sails, and ride into the sunset? Then unfurl it when it's time to break down.

[Jay-qu]

yeah gravity will help in that - I am yet to do the calculations but my guess is that you aint going to get pulled towards the sun very fast, even at the distance of earth, which is relatively close..

 

Calculations: a = (Mass of sun*G)/(earths distance from sun^2)

= (1.98892×10^30 * 6.67300×10^-11)/[(1.496x10^11)^2]

= 0.00593m/s/s

so it would take half an hour to reach just 10m/s.. guess we will just have to be patient it is free towing :phones:

 

I like your ideas TFS, but I have one major hitch in your plan that also goes with pyrotex's design - Where do you get all the antimatter from? and then how is it stored?

[TheFaithfulStone]

Well, I'm not sure it possible to build an interplanetary cruiser like we're discussing with only exsisting technology.

 

The antimatter would be stored in a very large Penning-Ioffe trap - but there wouldn't be a whole lot of it - the antimatter is really a catalyst in my design. 30 milligrams gets you to the Kuiper belt. If we had a gram we could cruise around the solar system for YEARS.

 

TFS

[Kayra]

My ship would work on the concept of never needing to refuel. It would use nuclear propulsion with the capability of running its engine for 100 years non stopped. The drive section would be a long cylinder that would store the nuclear fuel and direct the energy out the tail. Around the drive section at a radius of some distance would be the crew ring. While the engine is firing the ship would maintain a near 1G accelleration until it reaches its desired speed. During this accelleration the ring would not be rotating. Instead the sections of the ring would rotate to that the ceiling is where you are going and the floor is where you have been. As the decelleration stops the ship would begin rotation with the sections of the ring shifting so that the ceiling is toward the center and the floor is at the outside of the ring. For the passengers there would be some orientation change during thiss time, but they would always live in a 1G envioronment. The ship would have only limited ability to send shuttles or unmanned probes down to the surface of planets. The long term surface exploration shuttles would only be used on planets where resources for gathering return fuel had been detected. Such a shuttle could remain on the surface of a planet with a crew for extended periods of time (up to a year?) without resupply from the mother ship. Any number of probes could be put into orbit of planets to gather information and then be collected for reuse again at another planet.

 

The mother ship itself would be capable of remaining completely self sustained with a standard crew size of, say... 200-300 almost indefinately. This could be used for both exploration of our own solar system, and exploration of anything in space that a crew of people brave enough to commit their lives and their children's lives and their children's children's lives to taking.

 

Bill

 

Admirable goals. How do we accomplish them?

[Kayra]

sounds cool - but funny looking :hyper:

 

 

most likely deccelerating to stop and get fuel and then accelerating back to your previous speed would end up using more fuel than you can collect..

 

Good point.

All reaction mass would have to be carried with the ship for each leg of the journey. Since any material can be used as reaction mass in this system, as long as the destination has something, it would work.

 

Given a tremendous amount of radiant heat energy, what propulsion system would yield the greatest amount of thrust? Keep in mind that the design would also allow the generation of a minimum of 400 MW hrs of electricity, a large portion of which could be used for propulsion.

[Jay-qu]

Well, I'm not sure it possible to build an interplanetary cruiser like we're discussing with only exsisting technology.

 

The antimatter would be stored in a very large Penning-Ioffe trap - but there wouldn't be a whole lot of it - the antimatter is really a catalyst in my design. 30 milligrams gets you to the Kuiper belt. If we had a gram we could cruise around the solar system for YEARS.

 

TFS

Ok since these are theoretical designs - what theorectical methods do you have to create your antimatter?

 

also would you care to elaborate on the function of a Penning-Ioffe trap.

[TheFaithfulStone]

A Penning-Ioffe trap is a modified version of a Penning Trap.

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

 

As for the anti-matter production - I'm no particle physicist, so I couldn't tell you HOW it was made. But there is conflicting information on how much it costs. Everywhere from 20 million per gram (not to bad if ten or fifteen grams would get you Alpha Centauri) to a million jillion quadrillion per gram. I doubt if either of those facts is true. HOWEVER - we do KNOW how to make antimatter, and we can produce it in nano-gram quantities. I would say that learning to make in quantity is less a matter of theoretical processes and more a matter of economy. If you built three dozen CERN laboratories, you could make nearly a miligram of antimatter a year easily, which could be used for pretty much constant lunar traffic, and even the occasional Mars trip.

 

On the other hand, from a strictly practical point of view, their is only one existing technology that can be used for human space flight with no further technological or theoretical developments - one that is ready for prime time right now and that's chemical rockets. Any ion engine has too low thrust, and MPD requires too much power. Something like VASIMR or Orion will work, but it requires a LOT of R&D to get it ready for primetime.

 

So, if we want to limit ourselves to technology that we could deploy TODAY, or within the next ten years, we have chemical rockets... or nothing.

 

TFS

[Jay-qu]

No i dont want to put that limit on us, pretend that money and basic resources are not an issue and anything that is you need just needs to be developed and perfected. :note:

[TheFaithfulStone]

Well then... antimatter. :note:

 

TFS

[Kayra]

If that is the case, anti-matter will win out every time. There is simply no greater density energy storage system.

 

CraigD has made several plausible posts about how this could be accomplished. http://hypography.com/forums/space/5550-colonizing-solar-system-2.html is but one example.

 

Remember that Anti-matter in the end provides our spaceship with practically unlimited thermal energy. We would still require reaction mass for it to heat and expel. Limitations on material able to withstand heat would likely leave us using a tantalum or hafnium carbide material(capable of withstanding 2800K). Hydrogen heated to 2,800K would give us a specific impulse of .. 900-1,200 (I think). MUCH higher the the Space shuttle engine, and without the mass of the engine itself.

 

Personally, I would be a fan of beamed power sent to a solar pumped laser to drive a thermal rocket (http://en.wikipedia.org/wiki/Solar_thermal_rocket) on the ship until Anti-matter is at least proven to be feasible.

 

A propulsion system like the one above could provide both high specific impulse as well as high thrust. Since it is powered by the beamed solar energy (basically limited to the size of the solar collector near the sun) it is capable of generating exactly the same thrust as an Anti-Matter system, without the problems of creating, containing, and manipulating the material.

 

It is also something we can build today.

 

To bad it is not as sexy as Anti-matter :note:

[TheFaithfulStone]

I don't want to spend the whole thread arguing over which propulsion system to use. Especially when they are all equally difficult. Putting a power beamer in a polar orbit around the sun is probably not that much less difficult that producing 30 milligrams of Anti-matter and a sheet of U235 125M in diamater.

 

Jay, can you add a poll to the thread? Like "what propulsions should we use?"

 

The options I count so far are.

 

Chemical Rocket

Ion Engine / Advanced

Solar Thermal Rocket with Beamed Energy

Antimatter Sail

Solar Sail

Nuclear Propulsion (I'm assuming either Nuclear Electric Rocket or Nuclear Pulse)

A combination of these.

 

Does anybody else have any to add? And then we can move on to a different system...

 

TFS

[Kayra]

I thought the discussion was going quite well :shrug:

 

I guess you could even forgo choosing a propulsion method, and just concentrate on your craft.

[TheFaithfulStone]

Well, I did too, but between the options that we're all looking at here, there's no clear winner, and I doubt that there will be. Each method has it's problems, and I think we could stand (or sit) here and quote them back and forth at each other until we're blue in the face.

 

I just don't think it's terribly interesting to argue over whether a Solar Thermal Rocket or an Anti-matter catalyzed fusion reactor is the best option for interplanetary propulsion. I think an argument over whether something is possible is good to have, but arguing the theoretical benefits of theoretical systems on a theoretical ship... just not as much fun as dreaming them up.

 

The Solar Thermal Rocket is just as good as idea as the antimatter sail. That's why I suggested the poll.

 

TFS

[Pyrotex]

...As for the anti-matter production - I'm no particle physicist, so I couldn't tell you HOW it was made. But there is conflicting information on how much it costs. ...

My information comes from a published analysis by Robert Forward, a physicist in California. He prepared the report for Air Force and NASA. Basically, it said that it WAS possible to make anti-H rapidly enough to be practical as a propulsion source for large ships. A factory on the Moon would need about 100 sq miles of solar arrays and a dozen linear accelerators, to make about 1 gram per year. Approx 100 milligrams could be stored in a 10 ton magnetic bottle. It could be bled out slowly, using lasers, at a rate sufficient to turn a ton of water per second into 10,000 degree plasma.

 

About 10 bottles (100 tons) would get a 10,000 ton spaceship with a crew of 100, around the Solar System, to Pluto and back, in perhaps 10 years.

 

I am thinking larger scale. What in SF is called a "generation ship". With a crew of 3,000 or more, and spare sperm and ova in deep freeze (to insure genetic diversity), you get a new trained crew every 30 years or so. Plus there's the recreation factor. :)

 

The "Turtle" ship I suggested, with the life support system built within a MagLev train, has room for 3,000, with lots of elbow room.

 

Water is free for the taking at comets and many moonlets. The ship (a kilometer in diameter, remember) has room to store a "mini-factory" that can be assembled on an airless moon close to the star and create anti-H.

 

A ship that big (a million tons? ten million tons??) Would require perhaps 2-5 grams of anti-H to get it half way around a new solar system and in orbit at its target planet. Let's assume the mini-factory can produce 5 gm/year. Advanced technology, you know.