Is it time to give interstellar travel a shot?

[DarkStar64]

What the title says!

Also would going 10th the speed of light be practical?

[SargeRho]

at .1c a ship would reach Alpha Centauri in aproximately half a century. Deffinitely worth it. The question is just how to achieve that. Solar Sails might be too inefficient to do that. We would need to build a fusion based rocket engine, and give the probe a magsail to brake in the target system.

[Ralathon]

We don't even have a moonbase or asteroid mining. We are as far from interstellar travel as Leonardo Da Vinci was from a moonlanding.

And yes, going at a 10th of c would be extremely practical. A probe to Alpha Centauri in 46 years sounds reasonable. Shame that we have no idea how to economically reach a 10th of c. As is we'd bankrupt half the world during the attempt.

For now we should focus on scientific probes, moon and asteroid bases and maybe a Mars landing. Interstellar travel is something we should look at when we actually know how to do it.

[guto8797]

I don't think so. Not only do we lack things like long duration life support, power and maintainance systems, but there are the obvious costs.

And even at a 10th of Light speed, the time the ship would reach a neighbouring star all astronauts would be dead (unless cryogenically preserved or a multi-generation ship)

Conclusion: I vote no. We don't have technology, and we have enough problems to sort on our home as it is, interstellar travel is very difficult and unlikelly to happen unless we develop some sort of alcumbierre drive, simply because with their travel time, any ship would arrive at the destination outdated, we just say "We'll wait about 10 more years for more technology), but we end up repeating that, because techonology develps fast, and these travels would take more than a century

[SargeRho]

Who says the ship needs to be manned? We should send unmanned ships, to prospect and if suitable, prepare the system first anyway.

[quasarrgames]

And in terms of practicality, it would really depend on the energy required. If it took only the power of a large nuclear reactor, then sure it would be practical. If it took the power of a black hole... maybe not.

If you're talking about interstellar travel by going 0.1c, it would be fine for colony missions and stuff, but for trade routes and passenger deliveries, i dont think so. sadly.

[SargeRho]

For trade routes, you'd perhaps need antimatter based engines, or have propellant-less propulsion methods, like magnetic sails. But there is already a thread about this *points to the slowboat thread*

[Skyler4856]

This is somewhat analogous to Colombus looking at rockets with enough d-v to achieve orbit

[Aghanim]

I think, not yet. Where do we want to go anyway if we already invented interstellar transport?

[Dispatcher]

Who says the ship needs to be manned? We should send unmanned ships, to prospect and if suitable, prepare the system first anyway.

Please elaborate on "prepare the system first anyway." I'm not sure what you mean by that, but it sounds like a huge undertaking just to do that.

[Camacha]

Who says the ship needs to be manned? We should send unmanned ships, to prospect and if suitable, prepare the system first anyway.

A big question would be how to build technology that reliably works for 500+ years. I do not see it happening easily. If you can not do that with a decent degree of certainty, the whole excercise becomes useless.

[DonLorenzo]

I say we make a big ball of spores and DNA, all kinds of the hardiest lifeforms we have here and send that on its way to where we think earthlike planets are. That way, if against the odds life here IS a fluke we at least did our duty and ensured (or at least... enlikened?) that the next galactic generation of life WILL grow up with conveniently nearby aliens.

[Rakaydos]

Orbit a Quantum thruster (1n per kilowatt, does not carry it's own propellant and so has infinite ISP) and a fission plant with a thousand year half life. Hook them together and point them at alpha centauri.

[NASAFanboy]

Orbit a Quantum thruster (1n per kilowatt, does not carry it's own propellant and so has infinite ISP) and a fission plant with a thousand year half life. Hook them together and point them at alpha centauri.

Not so simple.

An quantum thruster is still at theoretical stage, it will take decades before NASA even develops an actual one.

[Rakaydos]

Oh well. Too bad about the Buzzard Ramjet... that would have been the perfect interstellar drive. (fusion torch that doesnt bring it's own fuel)

[Albert VDS]

Why send out a craft that could be outrun by a newer craft maybe 25-50 years from now?

[FenrirWolf]

I think we should focus on the moon and Mars over trying to wander outside of the local system

[Nuke]

there are a few things i need to check off my list before i would be sufficiently satisfied with out ability to accomplish an interstellar mission.

1. we need lightweight fusion power reactors on the order of megawatts to gigawatts. we could do it with fission, but it would need to be some kind of breeder with online reprocessing, and with surplus nuclear fuel on board. whatever we end up with, it needs to last hudreds of years.

2. space infrastructure. any ship we build will need to be constructed and fueled in space.

and assuming this is going to be a manned mission:

3. improved life support technology. we need a totally closed loop system that can operate for hundreds of years. this can be a machine, or it can be an engineered small scale ecosystem.

if you have all that, then you are ready for an interstellar mission. note that propulsion is not on this list, we know how to do that, we just need to build it.

Edited March 12, 2014 by Nuke

[Vanamonde]

Too bad about the Buzzard Ramjet...

They'd have to flap pretty hard to get it up to interstellar speeds. Now the Bussard ramjet, on the other hand...

[Sillychris]

I'm not surprised nobody has mentioned the most often overlooked challenge of travelling at relativistic speeds.

Space isn't a perfect vacuum. There are particles everywhere. If you are going 0.1 c that means you are slamming into protons at 0.1c. (or approx 5MeV). You will also be slamming into neutrons at 5MeV. This is a nice energy level for nuclear reactions to occur. In particular, neutron bombardment. The front of your spacecraft will undergo gradual nuclear synthesis and inevitably, radioactive decay from the onslaught of MeV particles. I suppose a buttload of lead shielding would do the trick, but remember that it will break down over time.

[Ravenchant]

They'd have to flap pretty hard to get it up to interstellar speeds. Now the Bussard ramjet, on the other hand...

I'm now picturing an interstellar drive powered by a bunch of these:

And it is glorious.

Alas, AFAIK the ramjet would only achieve positive net force if it was already travelling at a significant portion of its maximum speed. Something to do with achieving fusion parameters in the reactor and all that.

[Camacha]

Why send out a craft that could be outrun by a newer craft maybe 25-50 years from now?

Because Voyager is yet to be outrun.

Edited March 12, 2014 by Camacha

[Streetwind]

We can build something that can outrun Voyager today... provided that we can give it the same gravity assists. Which is fairly difficult, because it needs the right planets to be in the right place, which happens only every few decades.

Other than that though, current electric propulsion should be able to pull off the trip to Centauri in roughly ten to fifteen thousand years, if we use a cubesat consisting mostly of fuel and power generation, and maybe a 1kg payload. I saw a paper running numbers on that sometime, currently trying to remember where.

In that kind of timeframe, it's absolutely guaranteed that we will overtake it with newer technology before it gets anywhere significant. As I said yesterday in a thread that is pretty much a carbon copy of this one, if your Isp isn't in the six digits, you don't even need to bother thinking about Centauri (much less any other star system). And to get that kind of propulsion up and running, we need sustained nuclear fusion. There's pretty much no way around it.

[78stonewobble]

I'd say that a more obvious first test at new drive technologies would be a probe dedicated to exploring the boundaries of the heliosphere or other outer solarsystem exploration.

But I'm still hoping new horizons will discover charon to be a mass relay.

[AngelLestat]

The first step in my opinion it will be a solar sail probe at 5% or 7% the speed of light using only the sun light (without laser).

TO achieve this we just need advance in the graphene production and be able to make holes of quarter wave or a reflective light coated.

If we have that, then we imprint most of the sensors in the same sail with a little payload in the (sail focus point "parachute") that would serve as comunication device.

In a close fly by over the sun at 0.008 Au, it would reach 5% to 7% of speed of light, then it can make the same manuver to brake on alpha centauri. Also it can manuver and go to any place in the centauri system.

Before that we need to launch a comunication probe to the sun focus point "700 AU" to serve as relay to amplify our comunication using the sun like parabolic.

Is the most realistic scenerario and the most easy to achieve.