Planet round Alpha Centauri B found

[annodomini2]

http://www.bbc.co.uk/news/science-environment-1995...

I just remember hearing only a few years ago, someone saying that they'll never find planets there due to the relatively close proximity of the stars.

I see a plausible interstellar mission on the horizon.

[Eric Mc]

VERY interesting.

[Einion Yrth]

annodomini2 said:

I see a plausible interstellar mission on the horizon.

Plausible, when? 40,000 years with current technology - I'll be doing well if I manage another 40.

[Eric Mc]

Ion drive would get you there a lot faster - and we've already had a few small scale ion drive spacecraft.

So, the technology to get there in a lot less than 40,000 years is not that far away.

[Alex_6n2]

Pointless mission to go there anyway. The planet orbits its star every 3 days and burns at 1000s of degrees!

Unless they find any exo planets further out, which is still a possibility.

I find it astonishing that it took 4 YEARS of measurement to confirm the data. Mad

[hornet]

Eric Mc said:

Ion drive would get you there a lot faster - and we've already had a few small scale ion drive spacecraft.

So, the technology to get there in a lot less than 40,000 years is not that far away.

Would a solar sail be a viable option for that sort of trip?

[annodomini2]

Einion Yrth said:

annodomini2 said:

I see a plausible interstellar mission on the horizon.

Plausible, when? 40,000 years with current technology - I'll be doing well if I manage another 40.

http://news.cnet.com/8301-17938_105-57523867-1/sta...

[lazy_b]

Wow! here come the beademungen

[annodomini2]

Alex_6n2 said:

Pointless mission to go there anyway. The planet orbits its star every 3 days and burns at 1000s of degrees!

Unless they find any exo planets further out, which is still a possibility.

I find it astonishing that it took 4 YEARS of measurement to confirm the data. Mad

Basically from other measurements with other planet hosting stars, if there's one rocky planet, the odds of finding more are high.

The problem with the Alpha Centauri system(s) is the relative proximity of the stars, cause significant interactions on each other, as they were using the wobble method, they had to drone out the wobble induced by the other stars.

[scubadude]

Einion Yrth said:

Plausible, when? 40,000 years with current technology - I'll be doing well if I manage another 40.

I've seen that quote elsewhere and its total bilge. We've never built an interstellar probe so there is no "current technology", if they are relating it to the speeds obtained by probes sent out into our solar system they are forgetting that htose are intended to stop (orbit) and look at things so making them go as fast as possible isn't an issue.

The New Horizons mission to Pluto is going out fast, but it was a "cheapo" mission so no effort was made to go really fast.

If they found a need to send a probe to Alpha Centauri they would find a way to go faster- as has been suggested ION drive (probably nuclear powered) would be first choice

[annodomini2]

scubadude said:

Einion Yrth said:

Plausible, when? 40,000 years with current technology - I'll be doing well if I manage another 40.

I've seen that quote elsewhere and its total bilge. We've never built an interstellar probe so there is no "current technology", if they are relating it to the speeds obtained by probes sent out into our solar system they are forgetting that htose are intended to stop (orbit) and look at things so making them go as fast as possible isn't an issue.

The New Horizons mission to Pluto is going out fast, but it was a "cheapo" mission so no effort was made to go really fast.

If they found a need to send a probe to Alpha Centauri they would find a way to go faster- as has been suggested ION drive (probably nuclear powered) would be first choice

Fusion Bottle see my link above.

Ion Drive on steroids.

There's also VASIMR.

[Eric Mc]

scubadude said:

I've seen that quote elsewhere and its total bilge. We've never built an interstellar probe so there is no "current technology", if they are relating it to the speeds obtained by probes sent out into our solar system they are forgetting that htose are intended to stop (orbit) and look at things so making them go as fast as possible isn't an issue.

The New Horizons mission to Pluto is going out fast, but it was a "cheapo" mission so no effort was made to go really fast.

If they found a need to send a probe to Alpha Centauri they would find a way to go faster- as has been suggested ION drive (probably nuclear powered) would be first choice

Not quite true. Any probe going to the outer reaches of the solar system (whether they are fly bys of a planet or are intended to orbit the target planet) MUST, at the very least, reach the escape velocity of the sun or a speed just under it.

With a traditional chemical rocket system, that speed needs to be achieved in the early phase of the mission i.e. usually within hours of launch from earth. At the distance of the earth from the sun, that speed is in the order of 37,000 mph. Once the probe has been accelerated to that speed - usually by the upper stage of the launching rocket, the upper stage is jettisoned and the probe more or less free wheels at a fairly constant speed towards its destination.
It may get boosted along the way using "gravity assist" from other planets it encounters on its journey.

If the probe is intended to orbit its target planet, it then needs to slow down so that it can be captured by the target planet's garvity. This can be done by using braking rockets or aerobraking (if the planet has an atmosphere) or a combination of both.

The problem with chemical rockets is that all the velocity (gravity assist excepted) has to be given right at the start of the mission.

With something like ion drive, the acceleration can be more gradual and spread over a much longer period, - perhaps weeks, months or even years.

So, although the initial thrust may be low the speed builds up inexorably over time so that, after a few months of this constant push, the final velocity could four or five times (or even greater) that available from a chemical rocket.

Edited by Eric Mc on Thursday 18th October 14:16

[Einion Yrth]

Eric Mc said:

With something like ion drive, the acceleration can be more gradual and spread over a much longer period, - perhaps weeks, months or even years.

Even with the impressive Isp available from Ion drives, that's going to add up to a hell of a lot of Xenon.

Eric Mc said:

So, although the initial thrust may be low the speed builds up inexorably over time so that, after a few months of this constant push, the final velocity could four or five times (or even greater) that available from a chemical rocket.

Edited by Eric Mc on Thursday 18th October 14:16

So only 10,000 years - still not something I'm going to see.

Oh and scubadude, this IS rocket science and you have no clue.

[Eric Mc]

Still it's a start

We can see possible solutions even now. Which shows that the route to solving travel to the nearest stars is already visible.

If we could get the travel time to Alpha Centauri down to one human lifetime (say 80 years) I think then it should be attempted. Look at the Voyagers - still functioning after 35 years - so we are already capable of making space hardware that can last a generation.

I think the first starships are within our grasp already.

[annodomini2]

Einion Yrth said:

Eric Mc said:

With something like ion drive, the acceleration can be more gradual and spread over a much longer period, - perhaps weeks, months or even years.

Even with the impressive Isp available from Ion drives, that's going to add up to a hell of a lot of Xenon.

Eric Mc said:

So, although the initial thrust may be low the speed builds up inexorably over time so that, after a few months of this constant push, the final velocity could four or five times (or even greater) that available from a chemical rocket.

Edited by Eric Mc on Thursday 18th October 14:16

So only 10,000 years - still not something I'm going to see.

Oh and scubadude, this IS rocket science and you have no clue.

Ion engines, like Chemical engines have a maximum deltaV this is due to the ISP of the engine.

Basically you reach a point where the mass of the fuel added results in no additional acceleration and resultant velocity.

The resultant max deltaV is machine dependent.

[shouldbworking]

I wonder at what point we will deem the rate of technology change slow enough to make it worth sending a mission?

ie if we launched a ship today there would be no point as it'd doubtless be overtaken inside 20 years by the next ship sporting go-faster stripes. Technology would certainly have to be evolving a lot lot lot slower than it is today.

[Eric Mc]

The fastest spacecraft today are as fast as they were 40 years ago.

[shouldbworking]

Eric Mc said:

The fastest spacecraft today are as fast as they were 40 years ago.

Only because there is no significant impetus behind making anything faster at the moment. Even now, we know how to build faster craft. If we actually wanted to go to Alpha Centauri the current timeframes would make it a non starter, because we know our technology is immature and .. a bit crap. Suppose it would take 80 years, and there were no current equivalents to VASMIR etc in the pipeline. Do you launch, or do you wait? If you do launch, and then a new tech emerges, what do you write on the back of the new starship for the original one to read as it passes? Would a simple 'On a mission' sticker suffice?