Author Topic: Design a mission to Proxima b  (Read 16871 times)

Offline KelvinZero

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Re: Design a mission to Proxima b
« Reply #40 on: 08/26/2016 09:04 AM »
:P Please offer an alternate scheme that you think will be faster that might be possible in the next few decades..
Launching in the next few decades.. or arriving in the next few decades? VERY different question!  ;)

btw im not sure if it requires a new thread, but Im interested in imaging techniques specifically relevant to this planet that were not an option previously. Just the fact you have a single target to focus on makes a difference.

Example: I don't know if the gravitational focus is relevant to this, (can it image something that small, or is it better for larger objects at vast distance?) but one huge issue with missions to the gravitational focus is that you could only look at one precise direction, so you would have to have a very specific and worthwhile target, and you would not like to discover that there was a better choice when your probe is already on its way.

Of course the comparatively near range makes a difference also. Some technology that is irrelevant for all the other billions of stars in the sky, thus not worth considering, might be relevant for this one star and now worth considering.
« Last Edit: 08/26/2016 10:12 AM by KelvinZero »

Offline 93143

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Re: Design a mission to Proxima b
« Reply #41 on: 08/26/2016 11:17 AM »
:P Please offer an alternate scheme that you think will be faster that might be possible in the next few decades..

Fusion pulse with magsail braking.  Don't need fancy laser/Z-pinch/antimatter stuff; just use Teller-Ulam pulse units.  If we really wanted to, we could do it.

Pretty expensive for a first probe, though.  Hopefully we get some good news from those miniature laser-propelled probes, or a massive interferometer or some such, and the will materializes for a robust follow-up...

A major propulsion technology breakthrough is still possible, of course, and it could happen at any time; predictions of when to expect warp drive based on handwavy extrapolations of current progress in physics are probably worthless one way or the other and should not be listened to.  Probably the best approach is to not expect warp drive, but to keep half an eye out for it rather than dismissing it entirely.  (Unless you're in a position to help make it happen, in which case you should stop reading this forum and get some work done...)  Normally I'd consider warp drive off topic, but you did say "might be possible", not "is likely to be possible"...

Mass beam propulsion.

Unlike laser tech, it's scalable to crewed missions as well (without Singularity-level resources).

I must say don't like the idea of shooting relativistic bullets at a manned starship over light-year ranges (you can't use actual particle beams; they have to be immune to beam spreading and smart enough to maneuver).  Get one malfunctioning unit a little out of place, such that the ship can't compensate in time, and your mission is over.
« Last Edit: 08/26/2016 11:19 AM by 93143 »

Offline MAC74

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Re: Design a mission to Proxima b
« Reply #42 on: 08/26/2016 01:27 PM »
Wouldn't the James Webb Space Telescope be able to get a picture of this planet? The star is just a red dwarf.

Not even close.  Proxima b has a separation from it's star of about 20 milli-arcseconds.  The band limited Lyot coronagraphs in JWST's instruments have inner working angles varying from 400 mas to 800 mas.  So the coronagraphs would not be able to spatially resolve the planet or even come close to it.

In addition to that, there is the contrast problem.  A terrestrial planet in the habitable zone of a mid M dwarf has a contrast of about 1 X 10^-8 dimmer than its host star.  The coronagraphs on JWST are designed for about 1 X 10^-5 contract, since they are simple coronagrpahs without any wavefront control or diffraction suppression.

WFIRST would get closer but the inner working angle of the coronagraph would still be too large for this planet.

The best bet to study it in detail in the next few years would be if the planet transits its host star, which would allow JWST to use Transmission or Emission Spectroscopy on it.
Well what's been posted on Twitter tonight by the official JWST account would seem to disagree with you on completely precluding anything at this point in time.

https://mobile.twitter.com/NASAWebb/status/768923069805125632

I read that.  When they say Promixa b is a good target for JWST they mean for transits, not imaging.  I was responding to the original post about imaging.

Online Robotbeat

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Re: Design a mission to Proxima b
« Reply #43 on: 08/26/2016 01:41 PM »
...
Mass beam propulsion.

Unlike laser tech, it's scalable to crewed missions as well (without Singularity-level resources).

I must say don't like the idea of shooting relativistic bullets at a manned starship over light-year ranges (you can't use actual particle beams; they have to be immune to beam spreading and smart enough to maneuver).  Get one malfunctioning unit a little out of place, such that the ship can't compensate in time, and your mission is over.
Much, much smaller than bullets. More like grains of dust. Realize that a starship is going to be encountering dust particles of the same speed on its way to its destination, so this is a problem that will need to be solved either way.

Don't have to self-maneuver, by the way, although that is an option.

Also, your idea of pulse nuclear is just as crazy sounding! Sending thousands of h-bombs to explode right below your butt! :D

...but I support both ideas. I think interstellar travel probably works best by pursuing multiple approaches at once. Mass beam propulsion up to 4-6%c, then pulse nuclear another 4-6%c to 10%c, then coast until you decelerate with a magsail.

But maybe something like Zubrin's Nuclear Salt Water Rocket should be considered? It's more compact than Orion-style propulsion, so at very least could be used as the final stage before coast.

By splitting up the tech into stages, it makes it more viable. Perhaps cooling and ablation constraints limits the Isp of Orion-like or NSWR-like propulsion such that only 3-4% c is possible? And with beamed propulsion techniques, perhaps diffraction or aiming constraints also limit the speed? But if you use them together, you can get to 10%c.

EDIT: Also, the "bullets" don't actually /have/ to be relativistic (i.e. >10%c) when they reach the starship. The energy-optimal solution is to accelerate the bullets to twice the spaceship's velocity-at-intercept, so that the intercept velocity is the same as the current starship velocity, but that's not actually the only option. You can also accelerate the mass beam so that it impacts the starship at a fraction of the current speed, so the intercept velocity is as firmly sub-relativistic as you like, though the efficiency is lower (but that matters less because the power source need not be on the actual starship).
« Last Edit: 08/26/2016 02:19 PM by Robotbeat »
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Offline R7

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Re: Design a mission to Proxima b
« Reply #44 on: 08/26/2016 01:59 PM »
1. Raise a few trillion dollars.
2. ??
3. Proxima b!
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Online sevenperforce

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Re: Design a mission to Proxima b
« Reply #45 on: 08/27/2016 12:24 AM »
Three BFR launches, ~900 tonnes. A high-isp burn into a multiple-slingshot trajectory and everything else into a Project Orion burn at the solar periapse. How much dV can we squeeze out of 900 tonnes of Teller-Ulam devices, and how tightly can we make the solar swingby for maximum boost?

Online Robotbeat

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Re: Design a mission to Proxima b
« Reply #46 on: 08/27/2016 12:29 AM »
Three BFR launches, ~900 tonnes. A high-isp burn into a multiple-slingshot trajectory and everything else into a Project Orion burn at the solar periapse. How much dV can we squeeze out of 900 tonnes of Teller-Ulam devices, and how tightly can we make the solar swingby for maximum boost?
At least you're on the right track with pulse nuclear, here. But the solar swingby isn't very helpful. Skimming the surface, the escape velocity is 500km/s, which is all the help it could possibly give you (in practicality, the boost is going to be much less, maybe 100km/s).
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Offline Elmar Moelzer

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Re: Design a mission to Proxima b
« Reply #47 on: 08/27/2016 12:35 AM »
I still think that the directed energy system presented at NIAC makes the most sense. 10 minutes to 0.2c for a wafer size probe, 25 years to Proxima b and all that with technology that is conceivable today.

Offline Bob Shaw

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Re: Design a mission to Proxima b
« Reply #48 on: 08/27/2016 01:07 AM »
Tiny, laser propelled probes on fast flybys (perhaps with optical parachutes at target to increase encounter time) are entirely reasonable. We need, however, to industrialise the inner Solar System to make this work, and we also need to sort out major political issues on Earth.

Online Robotbeat

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Re: Design a mission to Proxima b
« Reply #49 on: 08/27/2016 02:15 AM »
I still think that the directed energy system presented at NIAC makes the most sense. 10 minutes to 0.2c for a wafer size probe, 25 years to Proxima b and all that with technology that is conceivable today.
There are lots of problems with it. First of all, flyby at 0.2c is such a short time that you'd actually be better off with a really good telescope at the gravitational focus. Also, the forces involved would tear the probe to shreds. And such intense laser light even if nearly perfectly reflected would vaporize the sail. Also, getting diffraction-limited optics over such a large area and through the atmosphere seems unlikely to say the least.

There are, in fact, several other concepts that also use technology conceivable today to achieve interstellar travel within decades.

Though perhaps it's useful, if those challenges are solved. At very least, it'd be nice to actually map the interstellar medium around us so that we could send large probes or crewed missions out and be able to reliably use a mag-sail to slow down.
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Offline Elmar Moelzer

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Re: Design a mission to Proxima b
« Reply #50 on: 08/27/2016 06:50 AM »
I still think that the directed energy system presented at NIAC makes the most sense. 10 minutes to 0.2c for a wafer size probe, 25 years to Proxima b and all that with technology that is conceivable today.
There are lots of problems with it. First of all, flyby at 0.2c is such a short time that you'd actually be better off with a really good telescope at the gravitational focus. Also, the forces involved would tear the probe to shreds. And such intense laser light even if nearly perfectly reflected would vaporize the sail. Also, getting diffraction-limited optics over such a large area and through the atmosphere seems unlikely to say the least.

There are, in fact, several other concepts that also use technology conceivable today to achieve interstellar travel within decades.

Though perhaps it's useful, if those challenges are solved. At very least, it'd be nice to actually map the interstellar medium around us so that we could send large probes or crewed missions out and be able to reliably use a mag-sail to slow down.
Did you watch the NIAC presentation? Agree on the forces and the speed issues during flyby.
« Last Edit: 08/27/2016 06:51 AM by Elmar Moelzer »

Offline indaco1

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Re: Design a mission to Proxima b
« Reply #51 on: 08/27/2016 08:55 AM »
..Just the fact you have a single target to focus on makes a difference.
..

The answer is economic: very expensive, but reusable, particle beam/laser/microwawe generator and cheap mass produced mostly passive probes.

As we know expensive and expendable is bad.  Expensive and reusable is slightly better.
 
Cheap probes allow multiple targets.

A less cheap probe whit passive magsail braking capabilities is for a next phase, further in the future.

Proxima B is interesting, but I think that the day we'll be able to arrive and stop there, we'll not need a planet anymore. Ie: Sirius will be much more interesting at that time because provides more raw material and solar energy.
Non-native English speaker and non-expert, be patient.

Online Robotbeat

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Re: Design a mission to Proxima b
« Reply #52 on: 08/27/2016 11:35 AM »
FYI reported on this very forum Dr Rodal reports after a lengthy peer review process Eagleworks latest paper on the EM drive has been accepted for publication in the American Institute of Aeronautics and Astronautics: AIAA Journal of Propulsion and Power.
And?
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Offline floss

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Re: Design a mission to Proxima b
« Reply #53 on: 08/27/2016 02:56 PM »
Build a massive 30,000 km Soletta in orbit of Venus Sun L 4  and use the solar power to make a large amount of Antimatter and open up the solar system up to commerce and use the left over antimatter to power interstellar space probes .

Pretty near term Technology just brute force economics.

Offline llanitedave

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Re: Design a mission to Proxima b
« Reply #54 on: 08/27/2016 03:30 PM »
I'm with those who say we should improve our imaging and remote sensing capabilities before we start planning an encounter mission with no information about what we would be encountering.  Let's concentrate on developing technology for Optical interferometry that can be applied to an array of good-sized telescope mirrors at a gravitationally stable location.

Probably not the Moon.
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Online Robotbeat

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Re: Design a mission to Proxima b
« Reply #55 on: 08/27/2016 08:12 PM »
Build a massive 30,000 km Soletta in orbit of Venus Sun L 4  and use the solar power to make a large amount of Antimatter and open up the solar system up to commerce and use the left over antimatter to power interstellar space probes .

Pretty near term Technology just brute force economics.
Not near term as antimatter production is insanely inefficient (such that you wouldn't have enough left to "brute force" anything) and there's no way to stably store vast amounts of antimatter in a mass-efficient way. The storage/containment problem is huge. You'd be better off with fission or fusion.
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Offline Bob Shaw

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Re: Design a mission to Proxima b
« Reply #56 on: 08/27/2016 08:22 PM »
Send an observatory directly away from Proxima Centaurus, and park it at the Sun's microlensing point (about half a light year from home). Use it to survey the whole Proxima system.

Pros: great science, testbed for starship technology

Cons: not much less difficult than building a starship

Online Robotbeat

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Re: Design a mission to Proxima b
« Reply #57 on: 08/27/2016 08:30 PM »
Send an observatory directly away from Proxima Centaurus, and park it at the Sun's microlensing point (about half a light year from home). Use it to survey the whole Proxima system.

Pros: great science, testbed for starship technology

Cons: not much less difficult than building a starship
MUCH less difficult than building a starship.

This would be the most straight-forward way to get it there:
http://xkcd.com/1244
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Offline hop

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Re: Design a mission to Proxima b
« Reply #58 on: 08/27/2016 10:55 PM »
Send an observatory directly away from Proxima Centaurus, and park it at the Sun's microlensing point (about half a light year from home). Use it to survey the whole Proxima system.
You only need to get a bit over 600 AU (~0.01 light year) to get to the suns gravitational focus, but it may not actually work better spending the same effort on a more traditional observatory (further discussion of the viability of the FOCAL concept should probably go in that thread)

Offline rdheld

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Re: Design a mission to Proxima b
« Reply #59 on: 08/27/2016 11:19 PM »
I read a paper that stated the solar focus is not sueful for sharp images.
no reason you cannot build bigger local imaging devices as you develop the infrastructor for making massive quantities of deuterium and antimatter

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