Your ideal Interstellar vehicle/system (no FTL)

[fredinno]

On March 16, 2014 at 8:21 AM, palioxis1248 said:

Proton decay rockets, if they're at all possible. Closest thing to a mass-converter we'll ever have.

Proton decay is too slow for that to be viable.

[Bill Phil]

Bussard Ramjet, even with the drag. Although we could, theoretically, surpass the drag....

But we're in a relatively low density area anyways. At least for hydrogen.

Beyond that, and if we can't solve the drag problem, I'd go with a fusion rocket, or a laser sail. Maybe a combination of both..,

[Aladran]

I'd like to think that we would be using some kind of black hole starship with stasis chambers for the long trip.

https://en.wikipedia.org/wiki/Black_hole_starship

Quote

Although beyond current technological capabilities, a black hole starship offers some advantages compared to other possible methods. For example, in nuclear fusion or fission, only a small proportion of the mass is converted into energy, so enormous quantities of material would be needed. Thus, a nuclear starship would greatly deplete Earth of fissile and fusile material. One possibility is antimatter, but the manufacturing of antimatter is hugely energy-inefficient, and antimatter is difficult to contain. The Crane and Westmoreland paper continues

Quote

On the other hand, the process of generating a BH from collapse is naturally efficient, so it would require millions of times less energy than a comparable amount of antimatter or at least tens of thousands of times given some optimistic future antimatter generator. As to confinement, a BH confines itself. We would need to avoid colliding with it or losing it, but it won't explode. Matter striking a BH would fall into it and add to its mass. So making a BH is extremely difficult, but it would not be as dangerous or hard to handle as a massive quantity of antimatter. Although the process of generating a BH is extremely massive, it does not require any new Physics. Also, if a BH, once created, absorbs new matter, it will radiate it, thus acting as a new energy source; while antimatter can only act as a storage mechanism for energy which has been collected elsewhere and converted at extremely low efficiency. (None of the other ideas suggested for interstellar flight seems viable either. The proposal for an interstellar ramjet turns out to produce more drag than thrust, while the idea of propelling a ship with a laser beam runs into the problem that the beam spreads too fast.)

If our civilization survives her industrial era I think it's reasonable to think we should harness the technology do use such a drive at some point.

 

Edited February 12, 2016 by Aladran

[Chewy62]

The Venture Star from Avatar is probably one of the most realistic interstellar ships ive ever seen, film or otherwise.

Laser power out, antimatter to slow down at the destination. Antimatter back out, lasers to slow down at home.

Having said that, the rest of that movie made no damn sense.

[Bill Phil]

4 minutes ago, Chewy62 said:

The Venture Star from Avatar is probably one of the most realistic interstellar ships ive ever seen, film or otherwise.

Laser power out, antimatter to slow down at the destination. Antimatter back out, lasers to slow down at home.

Having said that, the rest of that movie made no damn sense.

I'm sure they could have set up lasers at the target system, as well. Then you could probably have a lot more cargo.

[kunok]

4 minutes ago, Chewy62 said:

The Venture Star from Avatar is probably one of the most realistic interstellar ships ive ever seen, film or otherwise.

Laser power out, antimatter to slow down at the destination. Antimatter back out, lasers to slow down at home.

Having said that, the rest of that movie made no damn sense.

Well I think all the human technology in the film except the avatars are pretty realistic.

[Wjolcz]

First lasers to propel the craft, then switching to big scoops scooping interstellar hydrogen, fusing it and shooting it backwards in order to propel the vessel. I don't know if interstellar space contains enough hydrogen for something like this to work, but it sounds cool and I'd go exploring and having adventures with something like that.

[PB666]

Tritium Deuterium-breeder fusion reactor with helium reaction mass for acceleration, mounted inside of a hollowed out asteroid capable of 1000s of years of travel. 

Venture star is unrealistic, if does not factor enough time between worlds, which is more or less 20 to 100 ly and it also allows to much dV.

 

[K^2]

For traveling between stars without FTL? It's black hole drive or bust. So it's probably bust.

[Shpaget]

How do you attach a ship to the black hole?

Let's say you manage to make a suitable black hole and place parabolic mirror in the correct position, with the rest of the ship attached to the mirror. The BH radiates and the mirror focuses radiation to provide thrust. The ship moves and the black hole is no longer in the focal point.

[PB666]

6 hours ago, K^2 said:

For traveling between stars without FTL? It's black hole drive or bust. So it's probably bust.

black hole drive? hmmph.

How exactly do you accelerate something that absorbs all matter it touches, and how do you decelerate it?

Edited February 13, 2016 by PB666

[K^2]

14 minutes ago, PB666 said:

How exactly do you accelerate something that absorbs all matter it touches, and how do you decelerate it?

Simple, you charge it. Black hole can hold a charge that's almost arbitrarily large. So you are limited by how much electric field can the structure of your ship withstand. And it just so happens that the force such a field will apply is roughly the same magnitude as structural strength limits on materials. Works out that way because electrostatic forces are responsible for maintaining matter bonds. In a way, this is exactly the same thing, only with much greater charge with a much larger gap between things it holds together.

[PB666]

9 minutes ago, K^2 said:

Simple, you charge it. Black hole can hold a charge that's almost arbitrarily large. So you are limited by how much electric field can the structure of your ship withstand. And it just so happens that the force such a field will apply is roughly the same magnitude as structural strength limits on materials. Works out that way because electrostatic forces are responsible for maintaining matter bonds. In a way, this is exactly the same thing, only with much greater charge with a much larger gap between things it holds together.

And if your isolation field has a power outage, whoopsie. poof. The other issue is the reflection of hawking radiation is basically going to be N/300 MW which is rather horrible efficiency for acceleration and deceleration, unless you are planning on converting the energy to electricity and using a cannae drive, ROFL.

 

[magnemoe]

6 hours ago, K^2 said:

For traveling between stars without FTL? It's black hole drive or bust. So it's probably bust.

Read about the black hole drive, looks good but hard to make. First problem is to make the hole, this would require far more energy than you get out of it. And you need lots of energy at once. 
Its also in the range of antimatter in efficiency. 

[K^2]

Power efficiency is irrelevant. Black hole is free mass to power converter. So only mass efficiency matters, and black hole drive matches that of an antimatter drive. Except your fuel is ordinary matter.

Yes, power failure of any kind would be bad. "Abandon ship" bad at best. But that is not unique to this design. Build with redundancies.

 

And yeah, hard to make, no kidding. That is why I do not have too much hope for it. And with all that in mind, it is still our best bet if we do not figure out something like warp drive.

Edited February 13, 2016 by K^2

[sgt_flyer]

1 hour ago, PB666 said:

black hole drive? hmmph.

How exactly do you accelerate something that absorbs all matter it touches, and how do you decelerate it?

 

39 minutes ago, K^2 said:

Simple, you charge it. Black hole can hold a charge that's almost arbitrarily large. So you are limited by how much electric field can the structure of your ship withstand. And it just so happens that the force such a field will apply is roughly the same magnitude as structural strength limits on materials. Works out that way because electrostatic forces are responsible for maintaining matter bonds. In a way, this is exactly the same thing, only with much greater charge with a much larger gap between things it holds together.

could the gravitation come into play too, or those involved masses would still be too small to have an effect? theoritical blackhole ships are supposed to have the same mass as the blackhole they hold - if the blackhole 'pushes' the starship away, their gravitation should tend to attract each other - so the ship would be towing the blackhole. (problem is - how do you prevent thrust ? ^^ - you can't stop the blackhole ^^ - unless you place the blackhole at the ship's exact center of mass, and change your mirror configuration to send the radiation to opposite sides of the starship instead only out of the back)

Edited February 13, 2016 by sgt_flyer

[magnemoe]

14 hours ago, Bill Phil said:

I'm sure they could have set up lasers at the target system, as well. Then you could probably have a lot more cargo.

Would require an serious infrastructure as in an an Kardashev type one civilization, as I understand they carried antimatter for slowing down and accelerating again and just topped up with reaction mass. 
Ship would also have issues performing as well as described but overall design is very good. 
The Kardashev type one civilization also applies to Earth too, more so as they have to make the antimatter too. Makes the backstory fall apart as they did not have energy problems outside of too much waste heat. 

14 hours ago, kunok said:

Well I think all the human technology in the film except the avatars are pretty realistic.

Yes an bit low tech I think, makes sense as most is made locally. The avatars make no sense on many levels, first is bandwidth, second is that the idea would probably scare the natives rather than improve them, first reaction is that they are possessed. 
But the movie had catgirls in fur bikinis so it all forgiven
 

[SargeRho]

2 hours ago, sgt_flyer said:

 

could the gravitation come into play too, or those involved masses would still be too small to have an effect? theoritical blackhole ships are supposed to have the same mass as the blackhole they hold - if the blackhole 'pushes' the starship away, their gravitation should tend to attract each other - so the ship would be towing the blackhole. (problem is - how do you prevent thrust ? ^^ - you can't stop the blackhole ^^ - unless you place the blackhole at the ship's exact center of mass, and change your mirror configuration to send the radiation to opposite sides of the starship instead only out of the back)

The black hole wouldn't actually be all that large. I think 660000 tons was the optimal mass, that's comparable to a fully loaded supertanker. The gravity of that is negligible.

Edited February 13, 2016 by SargeRho

[fredinno]

4 hours ago, PB666 said:

And if your isolation field has a power outage, whoopsie. poof. The other issue is the reflection of hawking radiation is basically going to be N/300 MW which is rather horrible efficiency for acceleration and deceleration, unless you are planning on converting the energy to electricity and using a cannae drive, ROFL.

 

Yeah, and fusion-electric and antimatter drives still have you screwed if you lose power- because the stuff inside will no longer be contained by magnets.

A bigger problem is stopping the thrust from a black hole- just letting it die will release so much hawking radiation it would destroy the spacecraft.

[Bill Phil]

5 hours ago, magnemoe said:

Would require an serious infrastructure as in an an Kardashev type one civilization, as I understand they carried antimatter for slowing down and accelerating again and just topped up with reaction mass. 
Ship would also have issues performing as well as described but overall design is very good. 
The Kardashev type one civilization also applies to Earth too, more so as they have to make the antimatter too. Makes the backstory fall apart as they did not have energy problems outside of too much waste heat. 

Yes an bit low tech I think, makes sense as most is made locally. The avatars make no sense on many levels, first is bandwidth, second is that the idea would probably scare the natives rather than improve them, first reaction is that they are possessed. 
But the movie had catgirls in fur bikinis so it all forgiven
 

I mean that they could have used the starships to send lasers there. Saving energy. Even if it's less power it'll just take longer to slow down.

[AngelLestat]

the problem with subatomic black holes is how do you feed them...   Or how you made them in the first place.
Not sure what of those 2 is harder.
For the feed to be practical we should use matter, to not waste more energy that the one you will get back.

Then to make the black hole; you need to concentrate a ""huge"" power of gamma rays in a same instant over a super tiny point.

The last problem but maybe no so big as the first two..  is how you focus that power to get thrust.
Is harder to focus those emissions than a antimatter annihilation.

 

Edited February 13, 2016 by AngelLestat

[SurrealShock]

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Edited April 25, 2024 by SurrealShock

[magnemoe]

1 hour ago, Bill Phil said:

I mean that they could have used the starships to send lasers there. Saving energy. Even if it's less power it'll just take longer to slow down.

Problem is that the system has be be gigantic. You need serious space infrastructure think solar collectors of some hundred million km^2. 
Yes if you have regular traffic and an civilization at both ends it makes lots of sense. 

[Bill Phil]

8 minutes ago, magnemoe said:

Problem is that the system has be be gigantic. You need serious space infrastructure think solar collectors of some hundred million km^2. 
Yes if you have regular traffic and an civilization at both ends it makes lots of sense. 

It seems like traffic is pretty regular...

Also, antimatter has even worse requirements. And they have to store it for nearly 6 years.

[sgt_flyer]

2 hours ago, fredinno said:

Yeah, and fusion-electric and antimatter drives still have you screwed if you lose power- because the stuff inside will no longer be contained by magnets.

A bigger problem is stopping the thrust from a black hole- just letting it die will release so much hawking radiation it would destroy the spacecraft.

only way you could 'stop' the thrust without 'turning off' the black hole  would be to be able to adjust the mirrrors so your hawking radiation is evenly expelled on opposing sides of the spacecraft. (so both thrust vectors would cancel each other)

Edited February 13, 2016 by sgt_flyer