It is not an exaggeration to say that the stars are far away. The nearest star system, Alpha Centauri is about 4.3 light years away. That means it takes light traveling at 300,000 km/s over 4 years to get there (Earth time not photon time).
This is 40,681,440,000,000 km (40 trillion km) and at the speeds that humans can currently achieve for space ships this translates to a trip that could exceed several human lifetimes.
Enter The Generation Ship
One solution proposed for getting humans to the stars is called the Generation Ship. The idea is you launch a largish group of breeding humans and they are committed to creating replacement levels of children to populate and run the ship when the first generation ages and dies.
What the ship does with the parents' bodies is not something I want to think about (cough -- compost -- cough).
The second generation will themselves have children and so on and so forth until several generations later the ship arrives at the colony planet with a whole population of people who never knew Earth or even the first crew.
The trip to the distant star and new planet will take a very long time and equipment always breaks down. After several generations it is not reasonable to expect any of the machinery to still be functioning. This leads to the idea of the constantly renewed generation ship.
On board will be a database of absolutely everything, every pump, pipe, cable, computer chip, nut, bolt and toilet seat. The component list will stretch into the millions and it would be the goal of the crew to manufacture and replace and recycle each part on a continual basis.
This means that every part on the ship will need to be recycled and replaced on a predefined schedule and that the children will need to be trained on every aspect of ship manufacture. The ship itself will need to have machine shops and other manufacturing facilities and people will need to work regular 9 to 5 jobs making new parts for the ship.
3-D printers will come in handy for this task but that also means that the ship's crew will also need to know how to make new 3-D printers so that they can replace any printer that gives up and dies.
The invention of 3-D printers that can print 3-D printers would come in very handy here.
The ship could even carry with it large stores of pure ores and other raw materials to help them in their replacement work and to make up for inevitable losses. Large chunks of iron, nickel, titanium, aluminum, silicon and all of the other rare materials will be critically needed as cargo.
Even the ship's hull will need to be recycled and replaced to counteract the constant damage from micrometeors. A modular design in which one segment can be shut down, evacuated and replaced would be a necessary design feature.
An Antimatter-Powered Star Drive
Antimatter is very likely the only viable energy source to power ships for human travel between the stars. The sheer energy density of antimatter is staggering.
I have discussed antimatter in a few of my earlier posts and provided some mass-energy sample calculations:
- How Much Antimatter Was Needed To Blow Up Alderaan?.
- https://steemit.com/space/@procrastilearner/antimatter-ya-us-an-orbital-antimatter-factory
Our largest ship in space is the International Space Station (ISS) and it has a mass of 420,000 kg.
Let's say we sent a ship of this mass to the stars and let's say we accelerated it to 50% of the speed of light. At this speed relativistic mass gain is only 15% or so and we can ignore it without introducing much error.
A mass of 420,000 kg moving at 50% of the speed of light (150,000,000 m/s) has a kinetic energy of E = 1/2 mv2 which is 4.7 x 1021 J.
Using the mass-energy equivalence equation E = mc2 and solving for m we get m = E/c2.
Plugging in the numbers find that we would need to convert 52,500 kg of mass into energy. One half of this would be antimatter and the other half would be normal matter.
So this means that we would need to carry about 26,000 kg of antimatter on board the ship to get it up to a reasonable star traveling speed. Of course the ship will also need to be decelerated so the requirements are doubled which brings us back up to an antimatter fuel need of about 52,000 kg.
To get a 420,000 kg ship up to 50% light speed and back down to zero would need 52,000 kg of antimatter reacting with 52,000 kg of matter for a total of 104,000 kg or about 25% of the ship's mass.
If we used anti-water as the form of antimatter that would be 52,000 litres of anti-water or a cube about 37 metres wide.
Closing Words
In summary, to get anywhere in this galaxy fast would need an awful lot of antimatter. It is dangerous stuff so losing containment would mean that your ship would turn into the brightest star in the galaxy, for a few seconds.
Using less antimatter would be more likely which means a slower ship and a longer trip. This means the trip would be a multi-generational affair.
To keep the crew occupied and the ship running means that everything, and I mean everything, on the ship will need to be replaced. The crew would essentially turn into a large factory constantly recycling and rebuilding every component that there is. And yes, even the crew will need to be composted and recycled.
For a trip like this, the ship and crew that finished the trip would not be the ship and crew that started the trip.
Thank you for reading my post.
Post Sources
https://en.wikipedia.org/wiki/Generation_ship
https://en.wikipedia.org/wiki/International_Space_Station
https://en.wikipedia.org/wiki/Mass_in_special_relativity
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I think that for a great part of humans is difficult to understand how much it is light years. This because it is too long to have a clear demostration on the Earth and because almost all the people can "see" how much it is.
The solutions that you suggest in this post are really interesting, but they have a lot of problems inside and they are relly dangerous for the humans: first one for example, the atronauts and theie children will be too far from the Earth to be helped if they need.
In reality, a multi-generation ship will never work. Machinery will break down and the 4th or 5th generation simply will not be as technically capable or motivated.
Mutinies and civil wars could break out on the ship and all sorts of other Lord of the Flies type nonsense.
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A great and professional article! The fact is, people have to create a new type of engine that will actually increase the speed of our spacecrafts. Without a new engine, traveling to another star will remain a dream.
I agree, there seems to be no way around the need for antimatter in getting to the stars. Nothing else will get us there in enough time.
Could the Human body survive such a speed - half the speed of light ain't nothing? If it can, acceleration would have to be greatly controlled for us not to be obliterated by the g force.
Interesting article that has a nice scifi feel to it!
The human body can survive any speed, it is acceleration and deceleration that will kill you.
With an antimatter engine you can control the acceleration of the ship. Ideally one Earth gravity would be optimal also known as 1 g or 9.8 m/s2.
Once you reach your target speed turn off the engine and coast. The crew will then experience zero gee until it is time to decelerate and slow down.