Author Topic: Flagship mission to Proxima Centauri or Epsilon Eridani?  (Read 15832 times)

Offline Khadgars

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Catching up on Voyager missions got me thinking about a flagship mission to one of our closest neighbors for anyone that's interested.

What are the chances of a flagship mission in the 2030's to either Proxima Centauri which is the closest to us at 4.2 LY or Epsilon Eridani at 10.5 LY but is the closest system to be know to harbor a planet?  Which one do you think makes the most sense?

What kind of propulsion do you guys think would be available by 2030 for interstellar space travel?

Offline hop

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #1 on: 11/23/2011 09:43 PM »
What kind of propulsion do you guys think would be available by 2030 for interstellar space travel?
Powerpoint and wishful thinking.

If you want some serious discussion of this kind of mission, google "Project Daedalus", "Project Longshot" and "Project Icarus".

Offline apace

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #2 on: 11/23/2011 09:44 PM »
What kind of propulsion do you guys think would be available by 2030 for interstellar space travel?

As all money from Nasa is using to the mid 2020 for the SLS there will be no new advances propulsion technology available in 2030.

Offline neilh

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #3 on: 11/23/2011 09:46 PM »
A related fun thought experiment: At what ppoint (in terms of technology, speed, and/or year) might one launch such a probe and have > 50% confidence that a later mission with more advanced technology and greater average speed wouldn't get there first?
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Offline hop

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #4 on: 11/23/2011 09:47 PM »
As all money from Nasa is using to the mid 2020 for the SLS there will be no new advances propulsion technology available in 2030.
Do we really need *another* thread flogging this particular horse ?

Regardless of SLS, there's no realistic chance of an interstellar mission in this time frame. Look at the costs estimates for the studies I mentioned. SLS wouldn't even be in the noise.

Offline spectre9

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #5 on: 11/24/2011 09:29 AM »
Some kind of electric thrusting nuclear powered probe might get there in a century.

Not worth it when you consider we could just build space telescopes to have a look and then choose those systems with earthlike planets to launch the flagship mission probes at.

Offline kkattula

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #6 on: 11/24/2011 03:50 PM »
What kind of propulsion do you guys think would be available by 2030 for interstellar space travel?

As all money from Nasa is using to the mid 2020 for the SLS there will be no new advances propulsion technology available in 2030.

Right... the budget just passed allocates 27% for Science and only 10% for SLS. But let's not let facts get in the way of a good diatribe.


On topic: The only near term propulsion options I can think of are nuclear pulse and laser-boosted solar sail. Anything else requires breakthrough science, not just clever (and massive) engineering.

Offline Cog_in_the_machine

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #7 on: 11/24/2011 06:25 PM »
Right... the budget just passed allocates 27% for Science and only 10% for SLS. But let's not let facts get in the way of a good diatribe.

I like how you lump science and advanced propulsion together, like they invariably go hand and hand.

Anyway, Khadgars, from what I understand sending anything to another star is likely to remain a herculean task for quite some time. Don't count on any nation/s undertaking it while you (or your grand children) are alive. I'm aware of a few interstellar studies under NASA's banner:

Solar sail propelled - http://interstellar.jpl.nasa.gov/interstellar/probe/introduction/intro.html

Ion engine propelled - http://interstellarexplorer.jhuapl.edu/index.php

Admitedly I found out about these from wikipedia. It also mentions a NIAC study called "Realistic Interstellar Explorer", which supposedly:

Quote
... suggested a 5 megawatt fission reactor utilizing 16 metric tonnes of H2 propellant. Targeting a launch in the mid-21st century, it would accelerate to 200 AU/year over 4200 AU and reach the star Epsilon Eridani after 3400 years of travel in the year 5500 AD.
However, this was a 2nd generation vision for a probe and the study acknowledged that even 20 AU/year might not be possible with then current (2002) technology.

It cites this as it's source - http://www.niac.usra.edu/files/library/meetings/misc/trieste_may02_mtg/McNutt_Ralph.pdf

My computer hasn't been able to load that pdf file though. Perhaps you'll have more luck with it. If the wikipedia synopsis is accurate though, it doesn't sound promising at all. The first two interstellar missions (the ones that actually don't aim to go to other stars) are likely the most that can be expected within reason. You can browse the links and see their scientific merit, engineering requirements, spacecraft specs etc.
^^ Warning! Contains opinions. ^^ 

Offline aquanaut99

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #8 on: 11/24/2011 06:39 PM »
It's exceedingly unlikely that any kind of interstellar unmanned mission will be carried out this century. The obstacles to it are gargantuan.

First of all, there is no current or forseeable propulsion system capable of propelling such a craft to destination in any sort of useful time-frame (with the possible exception of a Project Orion-type nuclear pulse drive, which is out of the question since it is a political no-go as it is a breach of the Outer Space Treaty and contrary to the spirit of nuclear disarmement. Plus, the drive's NEMP would also wreck havoc on our communication satellites and electronics grid on Earth if were lit up anywhere near our planet).

Then, even if such a drive were available, the mission would still last many decades before arriving at destination. With no remote-operation possible from Earth (years of light-lag); the probe would require some sort of artificial intelligence capable of making the kind of complex decisions a live human crew would be capable of, as well as being equipped with self-repair and reprogramming abilities. This is also far beyond anything we are currently capable of.

Finally, it is total idiocy to launch a mission requiring what is probably a multi-trillion dollar investment with such an unclear objective. Before we could even contemplate beginning such a pharaonic task, we would have to remotely scout out the possible target star systems (with telescopes and the like) and be darn sure there is actually something WORTH exploring there. And by "worth" I mean unique and interesting enough to warrant a pharaonic, multi-decade, multi-trillion dollar effort. (Nobody is going to build an interstellar probe just to look at the Proxima Centauri version of asteroids).

Right now, about the only thing I can think of that would potentially justify such a an effort is if we found conclusive evidence that intelligent extra-terrestrial life was present in the target star system...
« Last Edit: 11/24/2011 06:47 PM by aquanaut99 »

Offline savuporo

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #9 on: 11/24/2011 07:48 PM »
(with the possible exception of a Project Orion-type nuclear pulse drive, which is out of the question since it is a political no-go as it is a breach of the Outer Space Treaty and contrary to the spirit of nuclear disarmement. Plus, the drive's NEMP would also wreck havoc on our communication satellites and electronics grid on Earth if were lit up anywhere near our planet).
You do not need to light it this side of jupiter, do you ? Neither would you need to launch reactor and the fuel in the same container. We are talking a century lasting mission anyway, so there really would not be much rush for the mission staging.
Orion - the first and only manned not-too-deep-space craft

Offline aquanaut99

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #10 on: 11/24/2011 08:25 PM »
You do not need to light it this side of jupiter, do you ? Neither would you need to launch reactor and the fuel in the same container. We are talking a century lasting mission anyway, so there really would not be much rush for the mission staging.

It would still violate the 1963 Partial Test Ban Treaty, which outlaws any nuclear detonation that is not carried out underground. And yes, it specifically includes Outer Space, even beyond Jupiter.

In fact, the signing of this treaty is what ended Project Orion in the first place.

Offline Watchdog

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #11 on: 11/24/2011 10:07 PM »
What are the chances of a flagship mission in the 2030's to either Proxima Centauri which is the closest to us at 4.2 LY or Epsilon Eridani at 10.5 LY but is the closest system to be know to harbor a planet?  Which one do you think makes the most sense?

What kind of propulsion do you guys think would be available by 2030 for interstellar space travel?

The chances are very slim. But supposed the sort of financial crises we observe today can be overcome and the economic development of the technologically leading countries of the world will not be interrupted by regional or global war there is a possibility to send a small probe between 2030 and 2040 to Proxima Centauri.

I estimate that the 25 most developed countries have to spend about 2 percent of their annual national budget over 10 years in order to built up the necessary infrastructure. This infrastructure will not only allow the interested nations to accelerate a high tech nanoprobe (about 10 kg science payload) to about 5 to 10 percent of the speed of light, but also use the same infrastructur to explore the Kuiper belt, the Oort cloud and the outer planets and their moons.

In analogy to the earth bound navigation and communication systems (e.g. Iridium, Gobalstar, GPS, Glonass, Compass) a network of solar and nuclear power stations are required to provide the external propulsion for the various probes to be send to the target bodies within and without the solar system. This international system of stations will be coordinated and used like modern telescopes where every party gets its share in terms of observation time, here "propulsion time/power".

In the inner solar system the solar powered stations will generate a beam of particles over the time the target probe can be sustained to be reflected by its mirror (passive propulsion). In the outer solar system nuclear powered stations will take over the accelaration of outgoing and the deceleration of incoming (e.g. sample return) probes.

Why is the system so expensive and will take decades to develop and to deploy? First, solar sails are at the beginning of their development. Even the feasibility of this technology has not yet been demonstrated succesfully in space, although a Japanese sail has tested the unfolding mechanism while flying behind the Venus probe Akatsuki.

Super light materials coated with suitable reflective layers to obtain a huge reflective area will be needed just to reflect solar radiation. Since the specific impulse of photons may not be sufficient to propel a probe to highest speeds heavier particles need to be applied. All the electronic and other components of the spacecraft need to be tolerant to highest speeds as well as side effects of the acceleration process.

Nevertheless, 95 percent of the costs of interstellar travel will be consumed by the development, construction and transportation to their various solar orbits of the beaming stations. I envision up to 200 of such stations distributed over the solar system in the final version. Their mass may vary between 20 and 100 metric tons. Space tugs need to haul them to their final orbits and even manned space ships will be required to repair and maintain them. In order to ensure a continuous accelaration of the probes one station has to give over the job to the next as soon as orbital parameters and the intensity and focus of the beam require this.

I donīt know if the feasibility of the technology could be tested by just flying a smaller beaming station behind the probe or even a cascade of beaming stations accelerating each other and finally providing sufficient thrust to the main probe. But the installation of a permanent network of stations just in the right distance from the sun to allow an orchestrated teamwork seems to be the most sustainable solution.

An initial version of the network comprising an affordable number of stations may be combined with gravity assist and solar sail propulsion to gain the neccesary velocity, but on the costs of a decade of time at least. Since most electronic and mechanical components need to function for about 50 to 100 years and redundancy will be limited due to mass restrictions the time the probe will spend to gain speed will be an issue. However, you need to send 10 probes of different design anyway to have a good chance of one of them surviving the trip.

I am sorry for the missing calculations or even estimated numbers. But without money these ideas are just a short summary of what most engineers already know: Interstellar travel is just expensive, because you simply cannot take your engine with you.
« Last Edit: 11/24/2011 10:37 PM by Watchdog »

Online douglas100

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #12 on: 11/24/2011 11:04 PM »
One of the best sites for this subject: http://www.centauri-dreams.org/
It has extensive coverage of all aspects of interstellar flight. Recommend you have a read (if you haven't already done so) before you go posting on this thread.
« Last Edit: 11/24/2011 11:06 PM by douglas100 »
Douglas Clark

Offline Watchdog

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #13 on: 11/24/2011 11:47 PM »
One of the best sites for this subject: http://www.centauri-dreams.org/
It has extensive coverage of all aspects of interstellar flight. Recommend you have a read (if you haven't already done so) before you go posting on this thread.

Thank you very much for the link. I did not know the site, but appreciate the overwhelming information over there. Need more time to read...

Offline hop

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #14 on: 11/25/2011 12:13 AM »
One of the best sites for this subject: http://www.centauri-dreams.org/
It has extensive coverage of all aspects of interstellar flight. Recommend you have a read (if you haven't already done so) before you go posting on this thread.

Thank you very much for the link. I did not know the site, but appreciate the overwhelming information over there. Need more time to read...
I also recommend http://www.icarusinterstellar.org/blog/

Offline gospacex

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #15 on: 11/25/2011 11:16 PM »
Catching up on Voyager missions got me thinking about a flagship mission to one of our closest neighbors for anyone that's interested.

What are the chances of a flagship mission in the 2030's to either Proxima Centauri which is the closest to us at 4.2 LY or Epsilon Eridani at 10.5 LY but is the closest system to be know to harbor a planet?  Which one do you think makes the most sense?

For that we'd better to focus on mastering IR and visible light interferometers.

We can create a million mile-base interferometers on much shorter timeframes and image planets and moons in those star systems than we can actually reach them with a (necessarily very weight-limited) probe.

On another angle, we'd better focus on exploring much closer objects such as outer planets, their satellites, and trans-Neptunian objects. For one, they are MUCH easier to reach. Secondly, they are more useful: we will definitely need to colonize them before we fly to other stars.

Offline hop

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #16 on: 11/25/2011 11:39 PM »
We can create a million mile-base interferometers on much shorter timeframes and image planets and moons in those star systems than we can actually reach them with a (necessarily very weight-limited) probe.
er stars.
Or a telescope using the sun as a gravitational lens http://www.centauri-dreams.org/?p=785 ... while the requirements of this are pretty mind boggling, it's still a lot easier than an interstellar mission. Also useful for data return if you do an interstellar mission.

Offline manboy

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #17 on: 11/26/2011 12:16 AM »
Catching up on Voyager missions got me thinking about a flagship mission to one of our closest neighbors for anyone that's interested.

What are the chances of a flagship mission in the 2030's to either Proxima Centauri which is the closest to us at 4.2 LY or Epsilon Eridani at 10.5 LY but is the closest system to be know to harbor a planet?  Which one do you think makes the most sense?

What kind of propulsion do you guys think would be available by 2030 for interstellar space travel?
Its not going to happen by 2030. Project Longshot required a mass of 400 mt to be launched. The science budget couldn't even pay for the launch costs of a mission like that.

First of all, there is no current or forseeable propulsion system capable of propelling such a craft to destination in any sort of useful time-frame
How long is a useful time-frame?
« Last Edit: 11/26/2011 12:22 AM by manboy »
"Cheese has been sent into space before. But the same cheese has never been sent into space twice." - StephenB

Offline the_roche_lobe

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #18 on: 11/26/2011 02:35 AM »
Quote
Catching up on Voyager missions got me thinking about a flagship mission to one of our closest neighbors for anyone that's interested.

What are the chances of a flagship mission in the 2030's to either Proxima Centauri which is the closest to us at 4.2 LY or Epsilon Eridani at 10.5 LY but is the closest system to be know to harbor a planet?  Which one do you think makes the most sense?

How about we wait and let the teams that are currently planet hunting more fully characterise local systems? Its takes a long time to pull RV data out of the noise, even if you are HARPS, which seem to do this better than anyone. There may well be a planet in the a Cen system, we just haven't found it (them) yet. Heck, there may well still be a closer brown dwarf or rouge planet, the remaining WISE dataset will help with that. Lastly GAIA is going to hopefully revolutionise astrometric planetfinding. Perhaps in ten years we'll know where we *should* be sending hardware (not that I think its likely in this environment). If I was Czar for the day I'd fund the TPF, but I don't think that's going to happen either  :(

P

Offline JosephB

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #19 on: 11/26/2011 03:11 AM »
Were TPF & SIM victims of JWST or was the technology not quite there or what?
What a cool area of astronomy to have the plug pulled.

Offline as58

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #20 on: 11/26/2011 09:03 AM »
Were TPF & SIM victims of JWST or was the technology not quite there or what?
What a cool area of astronomy to have the plug pulled.

One could probably say that JWST costs contributed to the cancellation of the SIM. On the other hand TPF concepts (especially the interferometer) were quite ambitious and I'm not sure if the technology was ready. In any case the TPF missions would have been very expensive.

Offline spaceStalker

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #21 on: 11/26/2011 09:55 AM »
If you go to nearest star with convenient speed, let say you are covering the distance in 2 years. How do you actually communicate with that ship?
To moon you have few seconds delay, to Mars what.. 20 min to and from?
On the span of 4,2LY how do you actually communicate with the ship,its crew, daddy call home?


Offline pierre

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #22 on: 11/26/2011 11:07 AM »
If you go to nearest star with convenient speed, let say you are covering the distance in 2 years.

The nearest star is enormously much farther away than you imagine.

2 years is impossible, at a distance of 4.2 light-years even the light takes 4.2 years and we are very, very far from even being able to reach 1/1000 of the speed of light.

So if you want a ballpark number to reason about, start with 2,000 years, not 2.

On the span of 4,2LY how do you actually communicate with the ship,its crew, daddy call home?

You don't.

There will be no ship and no crew.

The only vaguely realistic way to get there with near-future tech is to have a payload of only a few kilograms. I.e. science sensors, computer and communication instruments.

Any civilization able to send probes to nearby stars will likely have decent artificial intelligence anyway, so there would be no 2-way communication (the probe zips through the target star system so quickly that there's no time for that; remember: the probe cannot decelerate at destination or enter any kind of orbit), just a download over several decades of the data collected.

Please see the links posted by others, they're very informative.

The short version is that if we want information about nearby systems our best shot in this century (and possibly for much longer) is using huge swarms of telescopes, not sending stuff there.

Offline JohnFornaro

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #23 on: 11/26/2011 02:43 PM »
Quote
What are the chances of a flagship mission in the 2030's to either Proxima Centauri ...

Between slim and fat.
Sometimes I just flat out don't get it.

Offline majormajor42

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #24 on: 11/26/2011 04:27 PM »
considering the pace of remote sensing developments, why would we spend money on sending something that would take generations to reach its target? Just looking at the pace of exo-planet discoveries makes me extremely optimistic about new discoveries. 15-20 years ago we discovered the first one and now we know of hundreds. Now that we are or very close to finding or confirming the first Goldilocks planets, in another 15-20 years I think we will know of many of them as well. By that point, perhaps the 2030 date that was mentioned, we may be learning all sorts of new exciting things about these planets. I would really rather spend money on gaining these sorts of results, that can be analyzed by today's scientists.

Even if we gained the propulsion technology to do an interstellar mission that would take generations, I agree with others here who have said that those latter generations may leap-frog our technology.

We can look forward to lower launch costs hopefully leading to more advances of and applications for faster spacecraft that will further explore our solar system. There will be fascinating missions to Kuiper belt objects (in addition to New Horizon's possibilities). The desire to minimize radiation exposure on humans flying to Mars (and beyond) may also drive propulsion technologies.

« Last Edit: 11/26/2011 04:29 PM by majormajor42 »
...water is life and it is out there, where we intend to go. I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man or machine on a body such as the Moon and harvest a cup of water for a human to drink or process into fuel for their craft.

Offline savuporo

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #25 on: 11/26/2011 04:50 PM »
Just looking at the pace of exo-planet discoveries makes me extremely optimistic about new discoveries. 15-20 years ago we discovered the first one and now we know of hundreds. Now that we are or very close to finding or confirming the first Goldilocks planets, in another 15-20 years I think we will know of many of them as well.
Note that technology does not just advance on its own as time goes by, it actually needs further investments and developments. I don't see a lot of reason to be very sanguine about future discoveries, looking at currently planned observatories.
Orion - the first and only manned not-too-deep-space craft

Offline majormajor42

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #26 on: 11/26/2011 06:22 PM »
1. Note that technology does not just advance on its own as time goes by, it actually needs further investments and developments.

2. I don't see a lot of reason to be very sanguine about future discoveries, looking at currently planned observatories.

1. duh

2. I am hopeful about lower launch costs in the future. I am thrilled about what Kepler has/will accomplish for $.5 billion. But any current plan of observatories is effected by JWST and the fact that low cost launch is not here yet. Hopefully a temporary condition.
...water is life and it is out there, where we intend to go. I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man or machine on a body such as the Moon and harvest a cup of water for a human to drink or process into fuel for their craft.

Offline K-P

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #27 on: 11/26/2011 06:55 PM »
If you go to nearest star with convenient speed, let say you are covering the distance in 2 years.

Yes. 2 years to Sun is reasonable.

Otherwise, LOL.  :D

btw. where is "convenient speed" in this scale?
http://www.urbandictionary.com/define.php?term=ridiculous%20speed
« Last Edit: 11/26/2011 07:04 PM by K-P »

Offline drbobguy

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #28 on: 11/26/2011 07:20 PM »
Although keep in mind 2 years from the perspective of the ship/probe is doable for a distance of 4.2 LY.  That is from the perspective of the ship/probe you can go faster than the speed of light (as viewed from Earth – since it looks like your time slows down).  That doesn't violate any physical laws.

Indeed at 1g constant acceleration/deceleration you can go basically anywhere in the Milky Way galaxy within a human lifetime.

But as others have said this is so pie-in-the-sky that there's basically no chance of any of this happening.

Maybe, maybe if you expended trillions of dollars over decades we MIGHT be able to design a probe that could get up to 0.05c or 0.1c or something, and so a 40-50 year mission flyby of proxima centauri with a very small probe could be conceivable.  But as others have said, why? The money could get you more information by putting it into remote sensing.
« Last Edit: 11/26/2011 07:21 PM by drbobguy »

Offline K-P

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #29 on: 11/26/2011 07:33 PM »
Maybe, maybe if you expended trillions of dollars over decades we MIGHT be able to design a probe that could get up to 0.05c or 0.1c or something, and so a 40-50 year mission flyby of proxima centauri with a very small probe could be conceivable.

My 2 cents, on the other hand, are in the possibility that we learn to manipulate time or space or dimensions themselves in an exotic way unknown to us yet, so that we can really travel distances between stars in the far future. (call that the Star Trek way or Babylon 5 way or CERN way whatever...)

In my opinion, the current "tin-can" architecture of space travel has its limits, around Kuiper Belt, I would guess. So, spending time & effort on dreaming interstellar travel with either chemical or nuclear propulsion is similar to dreaming of moon flights with zeppelins.

Just my thoughts...

Offline Khadgars

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #30 on: 11/26/2011 07:59 PM »
I agree there are better ways of searching for planets with telescopes, I was thinking more on the lines of a Voyager 2.0 idea that specifically designed for interplanetary travel with more conventional propulsion that wouldn't break the bank.


Offline drbobguy

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #31 on: 11/26/2011 08:11 PM »
My 2 cents, on the other hand, are in the possibility that we learn to manipulate time or space or dimensions themselves in an exotic way unknown to us yet, so that we can really travel distances between stars in the far future. (call that the Star Trek way or Babylon 5 way or CERN way whatever...)

Yeah, but I think we should always be reminded that modern notions of "technological progress" are laden with a disturbing amount of hubris.  It might be that the basic laws of physics don't allow bending of space and time (except with massive energy/mass wells like black holes) and so we're just SOL in terms of interstellar travel.  There's nothing that says interstellar travel is inevitable or doable.

I personally believe we've gone from an Aristotelian version of the universe where stars are fundamentally unknowable structures created by God on crystalline spheres rotating about the center of the universe (Earth) to a more modern scientific notion over the last half-millenia of what is out there, to wild expectations of where we are going (Star Trek), and finally I believe we are heading back towards the first vision, where maybe we can get some knowledge about the stars but they are fundamentally unknowable and untouchable by human kind for the rest of time.

And while you can point to examples of "we made this work, we made that work" most of the basics of these ideas are very old.  Electromagnetism was worked out 150 years ago, chemical propulsion by rockets a century ago, hell rocket engines themselves haven't substantially improved since the early 1960s (or 1970s at the lastest).  There are no corresponding theories of how FTL travel might actually work that seem plausible in any kind of real way, as for instance, a chemical rocket might have seemed possible to those that understood fireworks and ballistics in the 19th century.

Wild optimism about the future of computers and biology while maybe not completely warranted is at least understandable given current events.  Wild optimism about space travel is not.
« Last Edit: 11/26/2011 08:15 PM by drbobguy »

Offline Patchouli

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #32 on: 11/26/2011 08:28 PM »
My 2 cents, on the other hand, are in the possibility that we learn to manipulate time or space or dimensions themselves in an exotic way unknown to us yet, so that we can really travel distances between stars in the far future. (call that the Star Trek way or Babylon 5 way or CERN way whatever...)

Yeah, but I think we should always be reminded that modern notions of "technological progress" are laden with a disturbing amount of hubris.  It might be that the basic laws of physics don't allow bending of space and time (except with massive energy/mass wells like black holes) and so we're just SOL in terms of interstellar travel.  There's nothing that says interstellar travel is inevitable or doable.

I personally believe we've gone from an Aristotelian version of the universe where stars are fundamentally unknowable structures created by God on crystalline spheres rotating about the center of the universe (Earth) to a more modern scientific notion over the last half-millenia of what is out there, to wild expectations of where we are going (Star Trek), and finally I believe we are heading back towards the first vision, where maybe we can get some knowledge about the stars but they are fundamentally unknowable and untouchable by human kind for the rest of time.

And while you can point to examples of "we made this work, we made that work" most of the basics of these ideas are very old.  Electromagnetism was worked out 150 years ago, chemical propulsion by rockets a century ago, hell rocket engines themselves haven't substantially improved since the early 1960s (or 1970s at the lastest).  There are no corresponding theories of how FTL travel might actually work that seem plausible in any kind of real way, as for instance, a chemical rocket might have seemed possible to those that understood fireworks and ballistics in the 19th century.

Wild optimism about the future of computers and biology while maybe not completely warranted is at least understandable given current events.  Wild optimism about space travel is not.

Actually ion rockets are ten times as efficient as chemical rockets and VASIMR can be ten times again.

As for the ground to LEO part chemical propulsion may be the primary means for the near future but propellant is a tiny tiny fraction of the cost.
If we get the flight rates up and develop reusable launch vehicles the cost will come down.

If we absolutely had to travel to the nearest star we can do it with today's technology.
Pulsed fusion can achieve 10% light speed.
BTW this is without staging.
For the cost of the wars in the last 20 years we could build an orion starship.
http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29

A low cost unmanned interstellar probe could be the starwisp here the expensive part remains inside the solar system and can be reused for other missions or double as an SPS sat.
http://en.wikipedia.org/wiki/Starwisp
I don't think we can even totally discount FTL travel esp with the findings coming out of CERN.

It's not technology or physics holding us back it's politics.

The worst thing we can do is go back to an Aristotelian vision of the universe that will only lead to extinction.
« Last Edit: 11/26/2011 08:38 PM by Patchouli »

Offline savuporo

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #33 on: 11/26/2011 10:47 PM »
I am hopeful about lower launch costs in the future. I am thrilled about what Kepler has/will accomplish for $.5 billion. But any current plan of observatories is effected by JWST and the fact that low cost launch is not here yet. Hopefully a temporary condition.
I'm not sure how lower launch costs would bring about better observatories. In case of JWST the launch costs are absolutely dwarfed by the total project budget.
There has not exactly been a rush of telescope proposals for F9H either, that is supposed bring about the true era of cheap launch, or something.
Orion - the first and only manned not-too-deep-space craft

Offline spaceStalker

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #34 on: 11/27/2011 05:46 AM »
I was more interested in how would one communicate with far object like nearest star ( not our Sun ). And more over without delay, or at least acceptable - like 10 mins.
Is there any effort to do high bandwidth, low delay, very deep space communication technology?
Nasa deep space network is primary for communication with it's probes?
What would it take? (no politicians, sls, jwst or health care spelling)


Offline david1971

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #35 on: 11/27/2011 06:08 AM »
I was more interested in how would one communicate with far object like nearest star ( not our Sun ). And more over without delay, or at least acceptable - like 10 mins.
Is there any effort to do high bandwidth, low delay, very deep space communication technology?
Nasa deep space network is primary for communication with it's probes?
What would it take? (no politicians, sls, jwst or health care spelling)

It would take a re-writing of the laws of physics.  If you are 4.2 light years away, it will take 4.2 years for signals to come back.  You can't send information faster than the speed of light.

Offline Sparky

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #36 on: 11/27/2011 06:39 AM »
I was more interested in how would one communicate with far object like nearest star ( not our Sun ). And more over without delay, or at least acceptable - like 10 mins.
Is there any effort to do high bandwidth, low delay, very deep space communication technology?
Nasa deep space network is primary for communication with it's probes?
What would it take? (no politicians, sls, jwst or health care spelling)

It would take a re-writing of the laws of physics.  If you are 4.2 light years away, it will take 4.2 years for signals to come back.  You can't send information faster than the speed of light.

Unless you find a way of communicating via entangled particles.

Offline strangequark

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #37 on: 11/27/2011 07:33 AM »
Unless you find a way of communicating via entangled particles.

Entanglement doesn't allow FTL communication. It makes for good SciFi, but the actual theory has been done to death.

Offline Sparky

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #38 on: 11/27/2011 07:35 AM »
Agreed. I should have added that that still qualifies as re-writing physics.

Offline majormajor42

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #39 on: 11/27/2011 01:36 PM »
I am hopeful about lower launch costs in the future. I am thrilled about what Kepler has/will accomplish for $.5 billion. But any current plan of observatories is effected by JWST and the fact that low cost launch is not here yet. Hopefully a temporary condition.
I'm not sure how lower launch costs would bring about better observatories. In case of JWST the launch costs are absolutely dwarfed by the total project budget.
There has not exactly been a rush of telescope proposals for F9H either, that is supposed bring about the true era of cheap launch, or something.

Define "better" observatories? Clearly I'm a big fan of Kepler. It has been fruitful and relatively inexpensive. Hopefully JWST will produce some mind blowing results as well. But hopefully the lessons of what happened that made JWST cost so much more money will be applied. In the future, perhaps the ratio of Discovery to Flagship missions will change.

There has not been a rush of telescope proposals for FH, nor has there been a rush of any FH proposals for that matter. Still too soon. It hasn't even flown yet nor has the fairing diameter been nailed down from what I was reading in other threads.  And I don't think you'll see much of a rush until JWST is closer to launch and they know exactly how much it will cost. Perhaps by that time, in a few years, we'll also have a better idea about the cost, specifications, and reliability of lower cost rockets.

...water is life and it is out there, where we intend to go. I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man or machine on a body such as the Moon and harvest a cup of water for a human to drink or process into fuel for their craft.

Online douglas100

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #40 on: 11/27/2011 02:37 PM »
I was more interested in how would one communicate with far object like nearest star ( not our Sun ). And more over without delay, or at least acceptable - like 10 mins.
Is there any effort to do high bandwidth, low delay, very deep space communication technology?
Nasa deep space network is primary for communication with it's probes?
What would it take? (no politicians, sls, jwst or health care spelling)



What would it take? A change in the laws of physics.
Douglas Clark

Offline spaceStalker

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #41 on: 11/27/2011 03:18 PM »
How about space-time inception?
Physic law within a physic law within a physic law?
It's unstable but it may just work!

Offline quanthasaquality

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #42 on: 11/28/2011 05:18 AM »
We could built a cluster of giant telescopes in outer space, with a total area in square miles. That single cluster would be able to give a mediocre survey of all the hundreds of stars within 50 light years of earth. The cluster could also be used for general astronomy.

Giant telescope clusters will beat an interstellar probe on cost effectiveness. I think it will be a very very long time before a high speed interstellar probe gets built.

Offline spaceStalker

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #43 on: 11/28/2011 06:49 AM »
As with delayed communications the light is delayed too  - you see something that happened 50 years ago or 4000. While telescope idea is great (this is pushing technology) you have to know what is happening there in real time. If you are searching for ET then "ET was there 50 years ago" is not exactly what you want. On the other side, if ET is there then situation like in the latest Star Trek where you are leaving warp speed to go right into the scrap 5+ BIG destroyed ships + Evil ET in front of you. 

So having real time communication is giving you Situation Awareness. And exploration is exactly that.
Or is it?

Offline Sparky

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #44 on: 11/28/2011 07:27 AM »
So having real time communication is giving you Situation Awareness. And exploration is exactly that.
Or is it?


Not necessarily. Such a mission would likely include an advanced AI that would observe its surroundings and make decisions accordingly. There would likely be little to no input from Earth at all.

Offline spaceStalker

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #45 on: 11/28/2011 07:42 AM »
Your probe evade evil et but wont notify you because there is no way to do so. But then again if that probe successfully evade et it have to phone home "I haz ET", ET will very likely hear that call too.
But you send probe to find that very ET, why little or at all control/comm with Earth?
When you know "U haz ET" ? How?

Offline kkattula

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #46 on: 11/28/2011 07:43 AM »
Right... the budget just passed allocates 27% for Science and only 10% for SLS. But let's not let facts get in the way of a good diatribe.

I like how you lump science and advanced propulsion together, like they invariably go hand and hand.
...

No, I was pointing out how SLS is only a small part of the NASA budget, not consuming the whole thing as claimed by the earlier post. Obviously very little is spent on advanced propulsion as this time, partly because CxP and science like JWST have sucked up all the funds.

Offline kkattula

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #47 on: 11/28/2011 07:51 AM »
Another possibility is that controlled fusion is developed in the near future.

A direct fusion products drive with an Isp around 1,000,000, could approach 0.1c with a (staged) mass ratio of 20. That would allow a fly-by of Alpha Centauri in less than 50 years.

A probe that that decelerated and stayed in the system would take closer to 100 years. It would take some seriously good engineering for the guidance, communication, instrument, fuel and propulsion systems to still be operational after that length of time.

Offline spaceStalker

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #48 on: 11/28/2011 08:04 AM »
What will happen if you travel with speed of light and stop in an instant?
Like car in 3 meter thick concrete, without the concrete wall in front the ship.

What will happen with the ship, crew, surrounding area?

Online douglas100

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #49 on: 11/28/2011 08:16 AM »
Another possibility is that controlled fusion is developed in the near future.

A direct fusion products drive with an Isp around 1,000,000, could approach 0.1c with a (staged) mass ratio of 20. That would allow a fly-by of Alpha Centauri in less than 50 years.

A probe that that decelerated and stayed in the system would take closer to 100 years. It would take some seriously good engineering for the guidance, communication, instrument, fuel and propulsion systems to still be operational after that length of time.

Yes, there have been studies of just that. See hop's link: http://forum.nasaspaceflight.com/index.php?topic=27361.msg832854#msg832854
Douglas Clark

Online douglas100

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #50 on: 11/28/2011 08:25 AM »
What will happen if you travel with speed of light and stop in an instant?
Like car in 3 meter thick concrete, without the concrete wall in front the ship.

What will happen with the ship, crew, surrounding area?

The question is meaningless. Nothing will happen since you can't make a material object travel at the speed of light in the first place. Nor can you transmit information faster than the speed of light. Instant reports from probes light years away are impossible. This is the way the real universe works. We don't live in a Star Trek universe.



Douglas Clark

Offline colbourne

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #51 on: 11/28/2011 01:08 PM »
What will happen if you travel with speed of light and stop in an instant?
Like car in 3 meter thick concrete, without the concrete wall in front the ship.

What will happen with the ship, crew, surrounding area?

The question is meaningless. Nothing will happen since you can't make a material object travel at the speed of light in the first place. Nor can you transmit information faster than the speed of light. Instant reports from probes light years away are impossible. This is the way the real universe works. We don't live in a Star Trek universe.

I believe there are big gaps in our understanding of physics so I would not totally believe that ftl communication and travel is impossible. Recent experiments seem to infer that neutrons can achieve ftl speeds (probably by tunneling).
Anti matter might also offer some chance in this area as well.
I think we might get the answers in the near future so I would not be launching an inter-stellar mission for a few years, as you will probably be over-taken by a more advanced space craft launched many years later.
There is also  a good chance that it will become possible to take short cuts through other dimensions at some point.

Offline JohnFornaro

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #52 on: 11/28/2011 01:39 PM »
I think we should always be reminded that modern notions of "technological progress" are laden with a disturbing amount of (1) hubris.  It might be that the basic laws of physics don't allow bending of space and time ... and so we're just SOL in terms of interstellar travel.  (2) There's nothing that says interstellar travel is inevitable or doable.

I personally believe we've gone from an Aristotelian version of the universe where stars are fundamentally unknowable structures created by God ... to a more modern scientific notion ... and finally I believe we are heading back (3) towards the first vision, where maybe we can get some knowledge about the stars but they are fundamentally unknowable and untouchable by human kind for the rest of time.

And while you can point to examples of (4) "we made this work, we made that work" most of the basics of these ideas are very old ...  There are no corresponding theories of how FTL travel might actually work that seem plausible ... as for instance, a chemical rocket might have seemed possible ... in the 19th century.

(5) Wild optimism about the future of computers and biology ... is at least understandable given current events.  Wild optimism about space travel is not.

(5) Bingo.

(4) Too many people extrapolate without reason, and by using the wrong metrics.  For example, say it costs $1B to get to the Moon, 240K miles away.  Then, would it be accurate to think that Mars would cost about the same per mile?  Of course not.  Dollars per mile is an inappropriate metric.  Moore's Suggestion is just that; it is not a "Law" at all, but merely his observation about calculating power, now being used as a target for creating new chips.  But what exactly are we getting with these new chips?  More lame emails, spam, whatnot?  Human nature is simply not going to evolve as fast as the artifacts that humans create.  A stone tipped spear will kill more or less as effectively as a steel one; technology will not change mankind's underlying violent nature.  Vacuum tubed computers, it could be argued, are more effective than solid state ones in getting to the Moon.

"We made this work, we made that work", is an excellent summary of how technology fails humanity, when humans erroneously believe that technology is some sort of god which serves humanity.

(3, 2, 1)  To me, the hubris is perfectly understandable; the technocrats merely want to make money, and the hubris is basically an out of control marketing meme.  Further, it is yet another "means of control", in the "Matrix" sense.  The next software release will "always" fix the problems with the previous releases.  As long as the sheople believe this falsehood, they can be counted upon to provide profit, and may never notice that their lives are hollow and that they are being controlled; thus the "system" maintains itself.

This thread is an excellent example of belief in technology outstripping rational thought about the possible and practical uses of technology.  If colonizing the Moon is a fantasy, or even repairing Phobos-Grunt is a fantasy, then the idea of suggesting interstellar probes and FTL travel, is merely a substitution of fantasies.

The best part of Dr. Bob's paragraph tho, is his observation that the Aristotelian view may be experiencing a comeback.  My addition to this observation would be that we may be devolving, as a culture, into a re-belief in magic, because there is so much that is "unknowable".  For how is it that cell phones work?  Or computers?  Or the Internets?  Or air conditioning?  Or cars?  Or anything in our technical society, for that matter.  One pays a priesthood to tend to these things, with the condolence that one is letting an "expert" do some sort of "dirty" technical work.

Knock your all selves out.
Sometimes I just flat out don't get it.

Offline JohnFornaro

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #53 on: 11/28/2011 01:50 PM »
Quote
I think we might get the answers in the near future so I would not be launching an inter-stellar mission for a few years, as you will probably be over-taken by a more advanced space craft launched many years later.

BTDT:

Quote
What CAN'T we do with a 50 mt to LEO laucnher in the next decade?

Easy.  We couldn't go to Alpha Centauri.  Or Barnard's star.

of course we could use a 50 mt launcher to sent a probe to Alpha Centauri or Barnard's Star ...

There's one in every crowd.

Actually depends very much on the propulsion system.  ...

Ok, two in this crowd.
Sometimes I just flat out don't get it.

Offline aquanaut99

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #54 on: 11/28/2011 02:06 PM »

The best part of Dr. Bob's paragraph tho, is his observation that the Aristotelian view may be experiencing a comeback.  My addition to this observation would be that we may be devolving, as a culture, into a re-belief in magic, because there is so much that is "unknowable".  For how is it that cell phones work?  Or computers?  Or the Internets?  Or air conditioning?  Or cars?  Or anything in our technical society, for that matter.  One pays a priesthood to tend to these things, with the condolence that one is letting an "expert" do some sort of "dirty" technical work.

Bingo! Sums up my feelings exactly.

I have also made the observation that for more and more Westerners, science, technology, optimism and belief in progress is being replaced by obscurantism, faith, esoteric wierdness and general pessismism. It is most accute in Europe, but America is not immune.

Maybe the future will be a lot like the past. Witches, plagues and perhaps a knight in shiny armor (or two).
« Last Edit: 11/28/2011 02:08 PM by aquanaut99 »

Offline gospacex

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #55 on: 11/28/2011 02:30 PM »
(3, 2, 1)  To me, the hubris is perfectly understandable; the technocrats merely want to make money, and the hubris is basically an out of control marketing meme.  Further, it is yet another "means of control", in the "Matrix" sense.  The next software release will "always" fix the problems with the previous releases.  As long as the sheople believe this falsehood,

WTF?

Software releases indeed do fix bugs. Sometimes they introduce new ones. And quite often they introduce *new features*. You don't like it? Would you like to have software which does NOT evolve? Are you ok with using solely batch processing on time-shared computers a-la 1960 and with perforated punch cards as data medium? I doubt it. So why are you unhappy?

Quote
they can be counted upon to provide profit, and may never notice that their lives are hollow and that they are being controlled; thus the "system" maintains itself.

Ha ha ha. "System". Phlease. Society is a system. You have a choice to participate in changing the society you live in, because you live in a *free* society and can become a journalist, politician or activist and try to make a difference; or you can emigrate to a different society which you consider to be better. Socialist paradises of Cuba and North Korea, etc. (Just don't blame anyone if you don't like them after you saw them up close).

Quote
This thread is an excellent example of belief in technology outstripping rational thought about the possible and practical uses of technology.  If colonizing the Moon is a fantasy, or even repairing Phobos-Grunt is a fantasy, then the idea of suggesting interstellar probes and FTL travel, is merely a substitution of fantasies.

"Belief" in technology? Well, if someone would say "FTL *will be* invented", that would be at irrational belief. But no one seems to be saying it here. I see that people say "our current understanding of physics is not yet complete, maybe FTL is physically possible, and maybe this possibility can be used for FTL travel". Sounds rational to me.

Offline Joris

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #56 on: 11/28/2011 02:45 PM »
I was more interested in how would one communicate with far object like nearest star ( not our Sun ). And more over without delay, or at least acceptable - like 10 mins.
Is there any effort to do high bandwidth, low delay, very deep space communication technology?
Nasa deep space network is primary for communication with it's probes?
What would it take? (no politicians, sls, jwst or health care spelling)

No there is currently no way that we are able to transmit information over a distance faster than c.
But in the near future it might be possible to transmit information using entangled particles.

On a related note, does anyone know when this project will report results/conclusions:
http://www.nasa.gov/offices/oct/early_stage_innovation/niac/kwiat_entanglement_assisted.html
Or any of the other NIAC-studies?
JIMO would have been the first proper spaceship.

Offline Robotbeat

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #57 on: 11/28/2011 03:54 PM »
If we're talking about a mission to Proxima Centauri, FTL travel is NOT required (with good reason... it may well be impossible, especially for stuff made of hadrons like you and me), and it's counter-productive to talk about it when discussing such a mission. Mission lengths measured in decades is actually not far-fetched and is in our current experience (Voyager 1 & 2 launched over 30 years ago, at least one of them will probably get to 40 years maybe even 50+ if we're lucky... the probes' primary missions lasted only 3 years, so they've already lasted ten times longer than necessary... I am pretty confident that if we were TRYING, we could make a probe which could last the better part of a century). And fission- or fusion-fragment rocket design is capable of reaching a few percent of the speed of light.

But no way in heck will our first mission to the Centauri system launch in the 2030s. (And I think that braking in the interstellar medium is probably a requirement because a flyby would happen so quickly otherwise that it wouldn't be worth it.)
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Offline Cog_in_the_machine

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #58 on: 11/28/2011 04:37 PM »
No, I was pointing out how SLS is only a small part of the NASA budget,

Describing something that has an anual budget profile worthy of a flagship mission as a "small part" is amusing. But whatever, even then you could have just mentioned the percentage it takes up and made your point, but you didn't. You just had to bring up how much "science" was getting, as if it had any bearing on the item in question - advanced propulsion.

Quote
not consuming the whole thing as claimed by the earlier post. Obviously very little is spent on advanced propulsion as this time,

Which was the point, badly worded as it was.

Quote
partly because CxP and science like JWST have sucked up all the funds.

Umm, no. Partly because a lot of money, which could have gone to R&D after decades of neglect in favor of operations and pure science missions, was redirected elsewhere. But that isn't really a reason either, any more than what you claim is. It's just an event that points to the actual cause - it's not a priority either for engineers or politicians. There's very little a politician would gain from fighting for advanced propulsion and there's probably more to be lost by doing so. On the engineering side it's a similar situation - it's unclear if the technical benefits would justify the investment of time and finances.

In short: the reason advanced propulsion is going nowhere isn't simply programs becoming money pits. The cause is what the people relevant to aerospace have in their heads. Right or wrong they act on that and it all ads up to one general decision (regarding advanced propulsion right now the consensus being that investing heavily in it is not worth it).
^^ Warning! Contains opinions. ^^ 

Offline Patchouli

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #59 on: 11/28/2011 05:15 PM »
Unless you find a way of communicating via entangled particles.

Entanglement doesn't allow FTL communication. It makes for good SciFi, but the actual theory has been done to death.

Actually it has not been tested much we can barely do entanglement at this stage let along test if it can be used for FTL coms.
It has not been tested in the lab much and until you test it in a lab a theory is just that a theory that more likely then not could be completely wrong.
As for new physics unless you been living under a rock the past few months the latest finding at CERN say we do need new theories.

Probably the worst part of relativity is assuming causality breaks if c is broken.

If we're talking about a mission to Proxima Centauri, FTL travel is NOT required (with good reason... it may well be impossible, especially for stuff made of hadrons like you and me), and it's counter-productive to talk about it when discussing such a mission. Mission lengths measured in decades is actually not far-fetched and is in our current experience (Voyager 1 & 2 launched over 30 years ago, at least one of them will probably get to 40 years maybe even 50+ if we're lucky... the probes' primary missions lasted only 3 years, so they've already lasted ten times longer than necessary... I am pretty confident that if we were TRYING, we could make a probe which could last the better part of a century). And fission- or fusion-fragment rocket design is capable of reaching a few percent of the speed of light.

But no way in heck will our first mission to the Centauri system launch in the 2030s. (And I think that braking in the interstellar medium is probably a requirement because a flyby would happen so quickly otherwise that it wouldn't be worth it.)

If FTL is found possible today it could be decades maybe even a centuries before someone builds a hyperdrive.
Leonardo described a helicopter in the 15th century it took another 450 years for someone to actually build one that flew.

It may take harnessing the power of a star or maybe it'll be much easier to the point our descendants would call traveling at just under c a wasteful way to travel we simply don't know at this point.
Probably we should be happy this solar system has at least 100 worlds for us to explore as otherwise we'd be in big trouble unless some advanced aliens were kind enough to help us.

As for making a long lived sub light probe using physics and technology we already know I wonder if it might be good to go back to large scale integration components so it can survive.
I'm talking 1970s tech here and maybe even a modern version of core memory.

Standard Plutonium RTGs would not the mission duration AM241 RTGs might or a very long lived fission reactor.
Moving parts in the power generation system probably should be avoided.

One reason I kinda like the starwisp if it can be produced in theory it could be cheap enough you just send a lot of them.
« Last Edit: 11/28/2011 05:34 PM by Patchouli »

Online douglas100

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #60 on: 11/28/2011 09:10 PM »

The question is meaningless. Nothing will happen since you can't make a material object travel at the speed of light in the first place. Nor can you transmit information faster than the speed of light. Instant reports from probes light years away are impossible. This is the way the real universe works. We don't live in a Star Trek universe.

I believe there are big gaps in our understanding of physics so I would not totally believe that ftl communication and travel is impossible. Recent experiments seem to infer that neutrons can achieve ftl speeds (probably by tunneling).
Anti matter might also offer some chance in this area as well.
I think we might get the answers in the near future so I would not be launching an inter-stellar mission for a few years, as you will probably be over-taken by a more advanced space craft launched many years later.
There is also  a good chance that it will become possible to take short cuts through other dimensions at some point.

I must admit I made this reply dogmatically to see what sort of response it might provoke.  :) However, it is what I basically believe at the current time.

You say you believe there are big gaps in our understanding of physics. Well, of course our understanding is incomplete. How big the "gaps" may be is, by definition, unknown. But that doesn't mean that the basic principles of relativity are wrong. Physicists know that relativity is incomplete, that it fails to describe the very small. But it describes the large very accurately indeed.

The main reason I don't believe in ftl communication or travel is that it would involve a violation of causality and the distinction between the past and the future would be lost.

The recent experiments with neutrinos (not neutrons) at CERN and OMEGA are intriguing and if they hold up I might change my mind. (I'm not totally dogmatic.  :))

Finally, interstellar flight is not a project for a few decades: it is something that has to be sustained over centuries and millennia.



Douglas Clark

Offline Patchouli

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #61 on: 11/28/2011 10:39 PM »

You say you believe there are big gaps in our understanding of physics. Well, of course our understanding is incomplete. How big the "gaps" may be is, by definition, unknown. But that doesn't mean that the basic principles of relativity are wrong. Physicists know that relativity is incomplete, that it fails to describe the very small. But it describes the large very accurately indeed.


Actually Relativity describes things on the scale of a star system very well indeed but it strains with things big as a galaxy and breaks on a galactic cluster.
We had to invent dark matter and dark energy just to describe what we see.
It also breaks horribly when trying to describe a black hole.
Infinities start cropping up so we called the thing at the center a signularity.
To quote Michio Kaku   Singularity means, “We don't know”

As for FTL coms breaking past and future relations this does not necessarily need to occur anytime c is exceeded over distance you need looped back space time for that.
FTL is a bit of a misnomer what is often called FTL such as the Alcubierre drive is really taking a short cut through space time c is never exceeded locally.

M theory which has many worlds and possible timelines seems to be a likely good model for the universe and it can deal with time travel.

Now on Interstellar flight we can't really say when we can do it.
But I think we might be able to send simple probes to the very nearest stars in the next 50 years.

As for human interstellar flight that may not happen for centuries.
Even without FTL it will eventually happen probably within the next 300 years if we do not wipe ourselves out first.

Our present stage of development being technologically advanced but only living on one planet is probably one the most precarious stages a civilization can be at.

If we make it past this stage we'll almost certainly make it to the stars.
« Last Edit: 11/28/2011 10:55 PM by Patchouli »

Offline kkattula

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #62 on: 11/29/2011 12:46 AM »
Reiterating the point: you don't need FTL for inter-stellar travel.

Using currently understood technology, it's going to be pretty slow, but it's possible.

Moving off into highly speculative territory, what is really needed is control over gravity. AIUI, no-one really understands gravity yet, but if one day it could be manipulated (huge if), then perhaps one could impart arbitarily high accelerations to spacecraft. Without squishing the crew. That would allow high fractional c travel. Still take more than a year to travel each light year, but time dilation kicks in, so subjective time could be only weeks.

Offline Patchouli

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #63 on: 11/29/2011 01:08 AM »
Reiterating the point: you don't need FTL for inter-stellar travel.

Using currently understood technology, it's going to be pretty slow, but it's possible.

Moving off into highly speculative territory, what is really needed is control over gravity. AIUI, no-one really understands gravity yet, but if one day it could be manipulated (huge if), then perhaps one could impart arbitarily high accelerations to spacecraft. Without squishing the crew. That would allow high fractional c travel. Still take more than a year to travel each light year, but time dilation kicks in, so subjective time could be only weeks.

You would not really need gravity control.
A spacecraft could nearly attain light speed if it accelerated at 1g for 354 days.

An advanced sub light interstellar mission in theory could even be designed to keep the vehicle under acceleration or deceleration for much of the duration of the trip with the decks organized along the line of thrust.
« Last Edit: 11/29/2011 01:13 AM by Patchouli »

Offline Robotbeat

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #64 on: 11/29/2011 01:18 AM »
Reiterating the point: you don't need FTL for inter-stellar travel.

Using currently understood technology, it's going to be pretty slow, but it's possible.

Moving off into highly speculative territory, what is really needed is control over gravity. AIUI, no-one really understands gravity yet, but if one day it could be manipulated (huge if), then perhaps one could impart arbitarily high accelerations to spacecraft. Without squishing the crew. That would allow high fractional c travel. Still take more than a year to travel each light year, but time dilation kicks in, so subjective time could be only weeks.

You would not really need gravity control.
A spacecraft could nearly attain light speed if it accelerated at 1g for 354 days.

An advanced sub light interstellar mission in theory could even be designed to keep the vehicle under acceleration or deceleration for much of the duration of the trip with the decks organized along the line of thrust.
The need for artificial gravity is such a small, relatively easy thing to engineer that it's not even worth mentioning. Might as well talk about how the Enterprise has replicators.
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Offline JohnFornaro

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #65 on: 11/29/2011 01:27 AM »
Quote from: GoSpaceX
WTF? ... Sounds rational to me.

Since you put it that way, Win The Future and all, I find that I now believe.  This is a brave new world, with such marvelous creatures in it
« Last Edit: 11/29/2011 12:37 PM by JohnFornaro »
Sometimes I just flat out don't get it.

Online scienceguy

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #66 on: 11/29/2011 01:35 AM »
I agree that we don't need FTL for interstellar travel. If we could travel at say 0.9c that would be plenty.

http://en.wikipedia.org/wiki/Negative_mass
e^(pi*i) = -1

Offline alexterrell

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #67 on: 11/29/2011 09:31 AM »
Just as a thought, regarding 2030/2040s technology.

A potential drive might come out of ion or VASIMR drives. Lets assume (big assumption) these can be adjusted to provide an exhaust velocity of 1E6 m/s (I believe VASIMR is designed for about 1E5 m/s).

Let's assume a 10 ton vehicle and 990 tons of propellent. Rocket equation gives a final speed of 4600km/s, or 1.5% of c, so 250 years to Alpha Centurai (plus acceleration time).

We also need a break through in power supply. Our 990 tons of fuel needs a kinetic energy of 4.95E17 Joules. Assume some inefficiencies and we need 8E17 Joules. Let's assume our reactor goes for 50 years - feasible for Thorium or very highly enriched Uranium. That gives an average power over 50 years of 523MW. Woops.

I can't see a 5 ton reactor (leaving mass for fuel tank and comms) giving 500MW, ever. Not with the radiators needed to cool the thing down.

5MW might be feasible, run with an exhaust velocity of 1E5m/s. But then we're talking 0.15% of C, or 2500 years. Not worth it. Such a probe would be more than enough for Kuiper belt missions though. Assume one quarter the speed to allow for deceleration and a lower start mass, and you have 14 days per AU. (though of course acceleration is the limiter). Neptune in 1 year. Sedona in 3 years. About there we start to need lunar suppliers of propellent if we want to repeat this mission.

For interstellar transport, the only current* technology that will work is beamed propulsion - e.g Star whisp or RL Forwards laser drive.

*Current = we can do it today. We just need to scale it up a billion fold, and put in orbit. But that's just engineering.
« Last Edit: 11/29/2011 09:34 AM by alexterrell »

Online douglas100

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #68 on: 11/29/2011 10:16 AM »
I agree that we don't need FTL for interstellar travel. If we could travel at say 0.9c that would be plenty.

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

That's true. Just don't hit anything at 0.9c!

We don't need to travel at 0.9c anyway: the energy required is enormous even for a small vehicle. 0.1c is much easier and safer. Good links have been given on this thread to sites which examine interstellar flight options in detail.

This enterprise is far beyond anything the human race has ever attempted. Short term thinking is completely inappropriate. We need to learn patience.
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Offline mlorrey

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #69 on: 11/30/2011 05:41 AM »
As all money from Nasa is using to the mid 2020 for the SLS there will be no new advances propulsion technology available in 2030.
Do we really need *another* thread flogging this particular horse ?

Regardless of SLS, there's no realistic chance of an interstellar mission in this time frame. Look at the costs estimates for the studies I mentioned. SLS wouldn't even be in the noise.

Looking to NASA for the advancement of anything is a fools errand. Private enterprise is doing just fine on its own.
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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #70 on: 11/30/2011 05:45 AM »
I agree that we don't need FTL for interstellar travel. If we could travel at say 0.9c that would be plenty.

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

eggzactly. Have a polywell fusion system powering a mach effect engine. The only real question is do you use a ram scoop to collect interstellar hydrogen for fuel or not? Use p-B11 fusion to get it up to ram speed, or avoid the friction losses a big EM ram scoop would create but wind up with fuel limits on max speed. The remaining question is whether you can develop warp fields with your mach effects any time this century or not, even then, being stuck to impulse mach effect thrust, you can still reach relativistic speeds.
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Offline kkattula

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #71 on: 11/30/2011 06:45 AM »
Reiterating the point: you don't need FTL for inter-stellar travel.

Using currently understood technology, it's going to be pretty slow, but it's possible.

Moving off into highly speculative territory, what is really needed is control over gravity. AIUI, no-one really understands gravity yet, but if one day it could be manipulated (huge if), then perhaps one could impart arbitarily high accelerations to spacecraft. Without squishing the crew. That would allow high fractional c travel. Still take more than a year to travel each light year, but time dilation kicks in, so subjective time could be only weeks.

You would not really need gravity control.
A spacecraft could nearly attain light speed if it accelerated at 1g for 354 days.

An advanced sub light interstellar mission in theory could even be designed to keep the vehicle under acceleration or deceleration for much of the duration of the trip with the decks organized along the line of thrust.
The need for artificial gravity is such a small, relatively easy thing to engineer that it's not even worth mentioning. Might as well talk about how the Enterprise has replicators.

I'm not talking about artifical gravity for crew comfort, but rather gravity control as the propulsion method.  How do you produce a constant 1g for a year?

Imagine projecting a strong gravity 'source' at some distance in front of the vehicle.  The entire vehicle and contents would be accelerated towards it at the same rate. (Assuming it's far enough ahead to eliminate tidal effects) The crew would be in zero-g the whole time (unless other steps were taken to produce an apparent 1g). The actual acceleration could be 1g, 10g, 100g, who knows?

One way to think of it is as warping space-time in front of the vehicle so it is constantly 'falling' into a deep hole.  I have no idea how to do this or if it's even possible, but it would be nearly the ultimate in sub-c propulsion

Note:  At high sub-c velocity, one would need some serious forward protection. Even just incoming star light is doppler shifted to x-rays.
« Last Edit: 11/30/2011 06:46 AM by kkattula »

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #72 on: 11/30/2011 12:28 PM »
Quote
Imagine projecting a strong gravity 'source' at some distance in front of the vehicle. 

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Offline Robotbeat

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Re: Flagship mission to Proxima Centauri or Epsilon Eridani?
« Reply #73 on: 11/30/2011 03:43 PM »
Reiterating the point: you don't need FTL for inter-stellar travel.

Using currently understood technology, it's going to be pretty slow, but it's possible.

Moving off into highly speculative territory, what is really needed is control over gravity. AIUI, no-one really understands gravity yet, but if one day it could be manipulated (huge if), then perhaps one could impart arbitarily high accelerations to spacecraft. Without squishing the crew. That would allow high fractional c travel. Still take more than a year to travel each light year, but time dilation kicks in, so subjective time could be only weeks.

You would not really need gravity control.
A spacecraft could nearly attain light speed if it accelerated at 1g for 354 days.

An advanced sub light interstellar mission in theory could even be designed to keep the vehicle under acceleration or deceleration for much of the duration of the trip with the decks organized along the line of thrust.
The need for artificial gravity is such a small, relatively easy thing to engineer that it's not even worth mentioning. Might as well talk about how the Enterprise has replicators.

I'm not talking about artifical gravity for crew comfort, but rather gravity control as the propulsion method.  How do you produce a constant 1g for a year?

Imagine projecting a strong gravity 'source' at some distance in front of the vehicle.  The entire vehicle and contents would be accelerated towards it at the same rate. (Assuming it's far enough ahead to eliminate tidal effects) The crew would be in zero-g the whole time (unless other steps were taken to produce an apparent 1g). The actual acceleration could be 1g, 10g, 100g, who knows?

One way to think of it is as warping space-time in front of the vehicle so it is constantly 'falling' into a deep hole.  I have no idea how to do this or if it's even possible, but it would be nearly the ultimate in sub-c propulsion

Note:  At high sub-c velocity, one would need some serious forward protection. Even just incoming star light is doppler shifted to x-rays.
That's soft scifi.
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To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

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