How to build a starship - and why we should start thinking about it now With a growing number of Earth-like exoplanets discovered in recent years, it is becoming increasingly frustrating that we can’t visit them. After all, our knowledge of the planets in our own solar system would be pretty limited if it weren’t for the space probes we’d sent to explore them. The problem is that even the nearest …
We've become too shallow to seek the stars any more, it's all about Profit and Self. A project as large as planetary and interstellar exploration requires sacrifice - it takes massive amounts of funding, massive amounts of time for research & development and massive amounts of commitment to get it all done. We are too impatient, too self-centered and too attuned to the Results Now mentality to do this type of hard, grinding, long-term non-immediately-profitable work any more.
Much sadness :(
In a comment below someone mentions asteroid mining. Yes, this and other "enterprises in space!" are indeed the answer. Why? Because no one - well, no majority vote - is going to suggest using 50% or even 10% of your GPP (gross planetary product?) for 'bullshit' like moonshots to exoplanets.
But if you get so much going on at ground-level plus all that's possible out in the home system, that's today's economy on steroids! Once you have even small two digit multipliers in effect, hey, who cares about splurging 1% of so much more than we had before? Catering to a vocal minority (like those durn explorationists) is much easier when it doesn't hurt (the politicians) at all.
The sad reality isn't that "We've become too shallow to seek the stars any more" but that it's just not possible without fusion energy, and although fusion research is still on-going we're still quite some way from a working solution.
Without a high efficiency energy source, where efficiency equates to duration, there's just no way a probe could accelerate for long enough to achieve a high enough % of 'c' to reduce the journey time to less than millennia before it ran out of fuel.
Well, that depends on how you do it...
Personally, I think a dive toward the sun, then use (rather large) magnetic fields to catch a ride on a solar ejection would get rather close to 1%, possibly faster depending on which one and how the energy is used (magnetic fields can act like springs...)
Suitable for probes...
"...a dive toward the sun, then use (rather large) magnetic fields to catch a ride on a solar ejection..."
I think not. Some numbers from Wikipedia: "The Sun has a magnetic field that varies across the surface of the Sun. Its polar field is 1–2 gauss (0.0001–0.0002 T), whereas the field is typically 3,000 gauss (0.3 T) in features on the Sun called sunspots and 10–100 gauss (0.001–0.01 T) in solar prominences."
...and...
"The Sun's dipole magnetic field of 50–400 μT (at the photosphere) reduces with the inverse-cube of the distance to about 0.1 nT at the distance of Earth."
For comparison: the magnetic flux density at the surface of a neodymium magnet is about 1.25 T
So, even discounting the issue of finding the energy to generate a large magnetic field for the probe, it's not going to have much of a field from the Sun against which to operate, even within the Solar System, let alone between the stars. And that's assuming that, instead of using high-mass radiation shielding, you can use the probe's magnetic field to protect it from the intense radiation it'll experience when it passes close to Sol.
You did a fine job in expressing my first two points about the inability of humanity to """think big""", those being
1) Greed (in all of its forms, such as the intense desire to accumulate wealth, essential resources or political domination), and
2) Instant Gratification (patience is NOT a virtue, the I """must have it now""" mentality).
and, then we can include
3) Conflict (and the failure to avoid it),
4) Arrogance (in all of its forms, on a personal, organizational, religious or governmental level),
5) Indifference (to the plight/suffering of others).
If you can espouse others, then please feel free to pile on.
Unless, and until humanity can get these areas of concern resolved, then humanity is doomed.
Until humanity can co-cooperatively work to improve the existence of ALL of us, and learn to co-exist peacefully with one another. we are doomed to continue to repeat the violence and destruction that has plagued humanity since the dawn of recorded history.
One of the most visceral examples of that mentality in the past century. was espoused in the concept of a Master Race, and the evil that resulted from it being unleashed upon the world; and the resulting global conflict to destroy that evil.
The waste in human lives and the destruction of the planet, and the unleashing of new weapons of mass destruction, established a mentality of mutually assured destruction that gripped the world in fear for the last half of the last century.
That fear (of global destruction) has been replaced by a new fear of pointless mass killings by those who would impose their concept of 'tribal God imagery' upon others who do not share their narrow religious views with butchery as punishment for resisting such imposition.
As I have said humanity is doomed. It may be too late.
Has anyone done some calculations on how many people would be needed to maintain an acceptable level of civilization so that, for example, clothing* could be replaced, strange infectious diseases could be treated, dropped mobile phones could be repaired/replaced, trans-new-world transport could be built and run, new generations could be educated and scientific /engineering progress maintained etc etc.
It seems to me that the numbers of people required for a successful autonomous colony would be impracticable, and that those left behind on Earth would be a bit reluctant to finance continuous re-supply missions.
*For example, stone age clothing was very low tech, today's clothing requires advanced agriculture, synthetic materials, specialized machinery, efficient transportation and (I think) specialized retail industries.
We need warp drive and replicator technology before even thinking of space colonization.
300 people are needed for acceptable genetic diversity. Damned near everything else can be done by robots. Most of your colonists would end up biologists/medics or robotics engineers. The rest would be developers. You'd be surprised what you can do with robots when you have the budget. Even with today's technology. We really only use people for anything anymore because they're cheaper, or they have expertise in pattern recognition that is still too difficult to code and execute on silicon.
I am afraid I can't agree. Look at these projects:
1) LHC
2) James Webb Space Telescope
3) ISS
4) Worldwide climate modelling efforts
5) Serious discussions about moving towards a zero carbon world
All of the above are expensive, and the last will be expensive and painful.
Humans are tackling large scale problems, but not starships. Yet.
We've become too shallow ...
The malaise you're lamenting has been around for at least all of the Modern era (so for a few centuries in European and European-derived cultures). There are grounds1 for suggesting it has been the condition of humanity for all of history.
it's all about Profit and Self
Since those motivators are pretty much exclusively responsible for the technology we currently enjoy, it seems a bit rich to blame them for our supposed failure to put it to use.
1Essays from contemporary commentators bemoaning the laxity of present times, in comparison to some prelapsarian past.
Every sub-atomic particle has an antimatter companion that is virtually identical to itself, but with the opposite charge. When a particle and its antiparticle meet, they annihilate each other while releasing a huge amount of energy that could be used for propulsion. However, we currently cannot produce and store enough antimatter for this to work.
What you need are Dilithium crystals, they can contain and control matter / antimatter reactions.
I thought everyone knew this?
Too late, I'm afraid. The cat's eaten them, you see. (3mins 20 secs in)
Isn't one of the main problems with sending a probe out to another star the distance for sending information back to Earth? Sure, it may take 36 years to get to another star system and start orbiting, but then it will take at least 4.3 years for the data to start coming back to Earth.
You not only need a probe which can survive getting to another system, but it would need to have some sort of AI to ensure that if any problems pop up, the probe can fix them itself without any human help, cause lets face it, waiting 8.6 years for a command won't work.
So, we need a probe that can last at least 36 years of interstellar travel. Be able to travel at 10% of the speed of light (avoiding any debris along the way, I figure if you hit even a tiny object at those speeds you're going to need more than a call out to the AA). An AI which can control the probe and react to any issue, including ones that us meat slabs haven't thought about yet. A way to communicate data over 4.3 light years without any loss of signal issues.
Probably not in our life times, but I think that eventually we'll be able to solve the issues, apart from the actual distance for communication from anything we send out there.
> we need a probe that can last at least 36 years of interstellar travel. Be able to travel at 10% of the speed of light (avoiding any debris along the way...)
I wonder just how feasible (and how protective) the Ice Shield which Arthur C Clarke used in The Songs of Distant Earth would be at these speeds.
Anyone know?
@Graham Marsden
Just offhand I would recon an ice shield is a bad idea.
A small projectile at very high speed might punch a hole through a thin hull on entry and exit, perhaps vaporising an area 10 to 20 times larger than its size, so an object roughly the size of a marble would leave entry and exit holes maybe basketball sized.
But hitting a thick surface like an ice shield would absorb much much more of its energy vaporising an area maybe 70 to 80 times its size and also creating a very large explosion from the resulting superheated steam rapidly expanding.
(these numbers are NOT scientific but are guestimates based on watching a nasa/boeing docu about firing hypersonic projectiles from a very big gun in a vacuum into various surfaces/compounds)
> hitting a thick surface like an ice shield would absorb much much more of its energy vaporising an area maybe 70 to 80 times its size and also creating a very large explosion from the resulting superheated steam rapidly expanding.
Ok, but explosions tend to take the path of least resistance, ie I'd think that the steam would expand forwards, rather than backwards and, of course, given the cold of deep space, it would probably then tend to freeze back onto the shield, with only some loss.
Try running the numbers on the power levels required to send a radio signal over interstellar distances - I don't think we will be getting a radio signal from our probes, we will need to wait for them to return with their data.
Hence, its likely that any such endeavour would not get any results in the lifetime of those that sent it. That would make it a fairly hard sell to get funding.
"Hence, its likely that any such endeavour would not get any results in the lifetime of those that sent it. That would make it a fairly hard sell to get funding."
It's already hard enough to get funding for projects that won't be ready until after the next election. Can't have the opposition basking in the glory of a successful project that the current lot started.
I sometimes wonder if this is why so many government projects fail or go over budget or both. The incumbents don't expect to win the next election so deliberately sabotage them.
"Hence, its likely that any such endeavour would not get any results in the lifetime of those that sent it. That would make it a fairly hard sell to get funding".
Not necessarily.
Consider the situation faced by Majikthise and Vroomfondel when Deep Thought tells them how long it would take to calculate the Answer.
Admittedly, it would take a politician more talented than the common variety to properly spin things.
More practically, while the results of the expedition -- if any -- will only be learned by future generations -- if any -- the engineering developed to pull something like this off would be available for use immediately.
If we have the technology to build a probe capable of reaching 0.05 to 0.1c, then it would be no problem a large space based receiving antenna that can pick up the signals from a probe 4 LY away. This would also get it away from all of the earth based interference.
Since the DSN can pick up signals from 100 a.u. with 70m dishes, this implies that 70 km diameter would pick the same signal source from a couple of light years.
We will have to wait 'till we know more, i.e. enough 'bout entangled fundamental particles, using gluons that bind them. Then we will be able to communicate ''instantly'' in ''real time''. It's possible but will take time to develop, and to develop/think of the theory behind it. Perhaps when we've gotten that far we will have solved the problem of ''speed''/acceleration also.
No need to invoke concerns about alien intelligent life as a danger for motivation. The simplest motivation is humanity (or parts thereof) surviving random events. Which can be presumed to occur much more often than "take me to your leader", given the witness of our planet's history. We must diversify!
The trouble is pace of development. Its a common enough science fiction scenario. You send off your slower than light starships, which will take 300 years to reach their destination, and 300 years later they get there, to be greeted by the crews of the FTL starships who had left base 3 months before...
@JimC
That's possible, yes.
But what is probable, given our understanding of the universe, is that if you keep waiting for FTL then you'll never leave.
Besides, if a ship with colonists from any part of the world 300 years ago were to sail into any port on the planet, wouldn't both humanity and the lost colonists be better off for it...?
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