It might look like the interstellar version of Project Orion.
This is the interplanetary version, a mere "few thousand tons"
The largest interstellar one has a diameter of 20 km, and a weight of 10 million tons. An aircraft carrier would fit across its diameter 30 times over.
It's HUGE.
Project Orion (nuclear propulsion)
Theoretically it could reach getting on for 10% of the speed of light and is one of the few practical methods we have for interstellar travel.
It was projected to cost 1 year of the US GNP in 1968, and in 1968 dollars, a little short of 4 trillion dollars.
That is an enormous amount, but also - surprisingly low for such a huge rocket.
The reason was - that it was going to be powered by exploding nuclear bombs, one after another, with the bombs exploaded every 100 seconds.
It was eventually halted - but not for what might seem the most obvious reason - hazard to those on board. Because - turns out - that it is actually reasonably safe - so long as you have a nice thick "pusher plate".
It is the only spacecraft design I know of where it is actually a benefit for the spacecraft to be really heavy - to have something for the bombs to explode against and push forward.
And - it would have been able to take off from the Earth.
The big problem of course is fall-out for those who stay behind on Earth. But if a civilization was desperate for some reason - suppose we had an incoming planetesimal a thousand kms across say, and no way of avoiding it, we could evacuate a substantial part of the Earth's population in ships like this.
In that situation the fall-out would be a minor issue, if we were faced with impending destruction of the Earth.
However, there is just about zero chance of this happening. If you look at the cratering record, of the inner solar system, then there aren't any recent craters that big for the last few billion years, though they were common during the first few hundred million years of the solar system.
Also though Betelgeuse, or Eta Carinae could go supernova (and surely will some time in the next million years or so), of great interest to scientists, they are far too far away to be a threat to us on Earth. And even the more elusive Type Ia supernovae (which can be generated by a system as small as two white dwarfts) - still those also would need to be some distance away as we know our nearby interestellar neighbourhood pretty well. It doesn't seem too likely that there are undiscovered white dwarf binary pairs close enough to make humans extinct on going supernova.
Remember that we have technology, unlike the dinosaurs. Rather than build an interstellar spaceship, we could just build giant subs, and go down to the bottom of the oceans for a while, in worst case. Far cheaper, no need to launch from the surface. None of the suggested disasters would dry out the seas of the Earth, and tsunami are a surface phenomenon you wouldn't notice even 100 meters below the surface. And when it is all over, the Earth would remain by far the most habitable place in the solar system and also probably also far more habitable for humans than any planets around nearby stars.
After all we evolved here, so it wouldn't be surprising if this is one of the best places for humans. If there is an Earth like planet around a nearby star, it might have XNA based life on it - and that life might be hostile to DNA based life - at any rate we'd have no immunity to it or it to us. And the chance that we could eat the native vegetation on an exoplanet must surely be extremely low as the chance it even uses DNA of the Earth type must be tiny. The XNA based life would surely be either poisonous to us or inedible, except for some amazing coincidence.
Indeed even with no warning, the worst effects of all these disasters are over within a few hours. Anyone who happens to be in a sub at the time would survive unless they are actually in the impact zone of a giant asteriod. And when they emerge after the disaster - the worst they experience is a depleted ozone layer. This would cause mass extinctions due to the large quantities of harmful UV radiation.
But humans with technology could protect against it using sun creams or opaque suits to block out the UV. It can be blocked by anything opaque a few mms thick. As for food, even if a firestorm destroyed everything on land, humans would be able to eat sea food.
So - I see no way that any of these disasters could make humans extinct. Even if not prepared. And with preparation and warning, surely many would survive.
So it doesn't really make too much sense as a plot scenario in the near future I think. But if we needed to do it - say 500 million years from now if Mercury gets perturbed from its orbit by Jupiter (low probability event) and hits Earth (even lower chance) - and we can't do anything about it, we could do this.
Or further into the future, when the sun goes red giant, or even before then when the seas of the Earth boil dry.
But that is so far into the future, it is enough time for humans to evolve a second time all the way from the beginning of the Cambrian explosion. A microbe that is just making its first steps towards multi-cellularity right now could easily have evolved to a human or similar by then.
Still, it is nice to think that some being on that future Earth, perhaps descended from a present day microbe, could build interstellar spacecraft if they had the wish to do so and the technology.
Apart from that - well - it would need some other reason for interstellar travel. Perhaps some day we may get to the stage where we can build these nuclear bomb based spacecraft, but build them in space so that they don't contaminate the Earth with their fallout. Then, at that 10% of light speed - we could use it to send a human expedition to Alpha Centauri within the timescale of a human lifetime, 42 years to get there - perhaps for exploration.
There are other ideas for interstellar travel. But as you asked particularly for huge spaceships - this is the only method I know of that permits such huge spacecraft as big as 20 km in diameter with present day technology, and able to fly at 10% of the speed of light.
See also:
This is the interplanetary version, a mere "few thousand tons"
The largest interstellar one has a diameter of 20 km, and a weight of 10 million tons. An aircraft carrier would fit across its diameter 30 times over.
It's HUGE.
Project Orion (nuclear propulsion)
Theoretically it could reach getting on for 10% of the speed of light and is one of the few practical methods we have for interstellar travel.
It was projected to cost 1 year of the US GNP in 1968, and in 1968 dollars, a little short of 4 trillion dollars.
That is an enormous amount, but also - surprisingly low for such a huge rocket.
The reason was - that it was going to be powered by exploding nuclear bombs, one after another, with the bombs exploaded every 100 seconds.
It was eventually halted - but not for what might seem the most obvious reason - hazard to those on board. Because - turns out - that it is actually reasonably safe - so long as you have a nice thick "pusher plate".
It is the only spacecraft design I know of where it is actually a benefit for the spacecraft to be really heavy - to have something for the bombs to explode against and push forward.
And - it would have been able to take off from the Earth.
The big problem of course is fall-out for those who stay behind on Earth. But if a civilization was desperate for some reason - suppose we had an incoming planetesimal a thousand kms across say, and no way of avoiding it, we could evacuate a substantial part of the Earth's population in ships like this.
In that situation the fall-out would be a minor issue, if we were faced with impending destruction of the Earth.
However, there is just about zero chance of this happening. If you look at the cratering record, of the inner solar system, then there aren't any recent craters that big for the last few billion years, though they were common during the first few hundred million years of the solar system.
Also though Betelgeuse, or Eta Carinae could go supernova (and surely will some time in the next million years or so), of great interest to scientists, they are far too far away to be a threat to us on Earth. And even the more elusive Type Ia supernovae (which can be generated by a system as small as two white dwarfts) - still those also would need to be some distance away as we know our nearby interestellar neighbourhood pretty well. It doesn't seem too likely that there are undiscovered white dwarf binary pairs close enough to make humans extinct on going supernova.
Remember that we have technology, unlike the dinosaurs. Rather than build an interstellar spaceship, we could just build giant subs, and go down to the bottom of the oceans for a while, in worst case. Far cheaper, no need to launch from the surface. None of the suggested disasters would dry out the seas of the Earth, and tsunami are a surface phenomenon you wouldn't notice even 100 meters below the surface. And when it is all over, the Earth would remain by far the most habitable place in the solar system and also probably also far more habitable for humans than any planets around nearby stars.
After all we evolved here, so it wouldn't be surprising if this is one of the best places for humans. If there is an Earth like planet around a nearby star, it might have XNA based life on it - and that life might be hostile to DNA based life - at any rate we'd have no immunity to it or it to us. And the chance that we could eat the native vegetation on an exoplanet must surely be extremely low as the chance it even uses DNA of the Earth type must be tiny. The XNA based life would surely be either poisonous to us or inedible, except for some amazing coincidence.
Indeed even with no warning, the worst effects of all these disasters are over within a few hours. Anyone who happens to be in a sub at the time would survive unless they are actually in the impact zone of a giant asteriod. And when they emerge after the disaster - the worst they experience is a depleted ozone layer. This would cause mass extinctions due to the large quantities of harmful UV radiation.
But humans with technology could protect against it using sun creams or opaque suits to block out the UV. It can be blocked by anything opaque a few mms thick. As for food, even if a firestorm destroyed everything on land, humans would be able to eat sea food.
So - I see no way that any of these disasters could make humans extinct. Even if not prepared. And with preparation and warning, surely many would survive.
So it doesn't really make too much sense as a plot scenario in the near future I think. But if we needed to do it - say 500 million years from now if Mercury gets perturbed from its orbit by Jupiter (low probability event) and hits Earth (even lower chance) - and we can't do anything about it, we could do this.
Or further into the future, when the sun goes red giant, or even before then when the seas of the Earth boil dry.
But that is so far into the future, it is enough time for humans to evolve a second time all the way from the beginning of the Cambrian explosion. A microbe that is just making its first steps towards multi-cellularity right now could easily have evolved to a human or similar by then.
Still, it is nice to think that some being on that future Earth, perhaps descended from a present day microbe, could build interstellar spacecraft if they had the wish to do so and the technology.
Apart from that - well - it would need some other reason for interstellar travel. Perhaps some day we may get to the stage where we can build these nuclear bomb based spacecraft, but build them in space so that they don't contaminate the Earth with their fallout. Then, at that 10% of light speed - we could use it to send a human expedition to Alpha Centauri within the timescale of a human lifetime, 42 years to get there - perhaps for exploration.
There are other ideas for interstellar travel. But as you asked particularly for huge spaceships - this is the only method I know of that permits such huge spacecraft as big as 20 km in diameter with present day technology, and able to fly at 10% of the speed of light.
See also:
- Robert Walker's answer to What is the probability of a significant asteroid impact event by 2100?
- Is it okay to destroy the earth because it will any way be destroyed by sun/volcanoes/tectonic shifts/Earth axis wobble/geomagnetic shifts/galactic shifts/asteroids/meteors etc?
- Robert Walker's answer to What is the largest spacecraft that could currently be built (either in orbit or here on Earth) and used to travel around the solar system and beyond? Would it be larger or smaller than say, a Nimitz class aircraft carrier?
- Robert Walker's answer to Why do people want to settle on Mars?
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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