Indeed, in the second half of the 20th century, NASA proposed the concept of "nuclear rockets," which was nothing more than "using a reactor to directly heat the propellant" and "ionizing the reacted spent fuel and then pushing it out as propellant."
It's just that this set of methods has never had any application opportunities.
The main thing is...
The pollution is terrible.
Spent fuel is something that can kill people. Unlike most radioactive elements that react instantly and cleanly after a nuclear explosion, spent fuel can really be poisonous for thousands of years.
Even if it is not the direct discharge of spent fuel, but the discharge of propellant that passes directly through the reactor, it is terrible enough.
But if the propellant is not heated directly by the reactor, but indirectly, then the thrust-to-weight ratio of the reactor will have no advantage compared with chemical energy rockets.
But this is not a problem at all for "Ogun".
This alien spacecraft has been sailing in deep space. The distance between the two stars is several light years, and no one will ever report that its radiation emissions exceed the standard.
In fact, the initial application scenario of nuclear rockets was to "launch outside the earth". On the moon or a space station far away from the earth.
The astronauts of that era were quite blindly optimistic about the future of mankind. They felt that mankind was only a short distance away from going to space, so even rockets that "can only be used in space" were
Imagined it.
After Xiangshan thought for a moment, he pondered: "Can we trace the origin of Ogun based on these high-radiation contrails? If it really used spent fuel as propellant."
After Xiangshan thought about it carefully, he felt that this might actually happen. Spent fuel is mostly radioactive elements with a relatively large mass, and it would indeed have a good effect if sprayed out.
David continued to smoke the coke: "Not sure, maybe they just threw it away. Besides, even if they really use this thing as a propellant, I can only say that your idea is very good. As for the radiation of the propellant
The dose cannot be seen even with the most sophisticated astronomical telescopes of mankind."
When talking about "Earth's environment", spent fuel propellant is "a thing with a terrible amount of radiation". But when talking about "the universe", the radiation from spent fuel is nothing.
The universe is really too big.
"Then there is a small problem." Xiang Shan continued to think: "Why do they cast uranium-235 and other things into a whole?"
"Save it."
"I know it needs to be preserved, but..." Mikaru Yamate gestured twice, "Just the preservation methods we have on earth, right, whether it's mixed with ceramics or other alloys..."
David said: "I have to correct you. Although the specific identification results have not yet come out, judging from the amount of radiation, the treasures we found are ordinary enriched uranium. They are not high-enriched and must be mixed with other things.
.And judging from the volume, the purity will not be very high, otherwise the radiation would be more than that..."
Xiang Shan looked up the formula, did some mental calculations, and nodded: "Yes... So, why do you want to make it into a whole piece? Isn't it good to save it in batches? Make it into such a big piece and accidentally exceed the critical limit.
What should I do if it becomes too bulky?”
"Not necessarily?" David said: "If I guess, it will be detected in the end. The elements of that large piece of stone are very unevenly distributed, and the uranium is enriched into clusters, and then between the uranium blocks and the uranium blocks
The middle is neutron absorbing material, such as graphite or lead."
"Then, the difference in strength and toughness between the neutron absorbing material and the enriched uranium block is so big that aliens can easily separate it by some means. Perhaps in our minds, this is the same thing as a whole piece of stone.
But to aliens, this may be fuel blocks buried in the sand of neutron-absorbing material."
"Then why not just use sand? Or a fixed frame or something."
David shrugged: "I don't know either. Maybe the aliens have some kind of processing technology that can easily separate the fuel blocks, so their ideas on this issue are obviously different from those of us on earth, or it may be simply
It’s a cultural difference and a cognitive difference.”
Xiang Shan pondered: "Well... speaking of which, you think Ogun should not have the capability to carry people, right?"
David nodded: "If it is a technology similar to that of the Earth, the size of the 'Ogun' core cannot accommodate a complete health system, unless those aliens are much smaller than humans - not monkeys, but mice.
However, you also know, right, that if it is much smaller than a human being, the number of nerve cells that the brain can integrate will be very limited...or should we say 'tissue similar to neural tissue'? In short, the basic unit of the thinking organ is
If it is too small, it will be difficult to form a complex structure. If the structure is too simple, it will limit the development of intelligence."
Xiang Shan said: "But I think the 'ingenuity of the structure' should be greater than the 'absolute number of neurons' - what about hibernation?"
"Are you kidding? The technological level of Ogun's builders is equivalent to that of humans. Even if their spaceship comes from Proxima Centauri, it would still take hundreds or thousands of years. Even if this alien is naturally good at suspended animation and hibernation, they
It is also impossible to spend a thousand times longer than one's normal life cycle in a state of suspended animation. If it is assisted by machines, they cannot build a hibernation device that can last for thousands of years."
"In other words, those fuel block reserves are basically used by machines?"
Since there is no one in "Ogun", there must be something that can operate and use resources including fuel blocks.
Then it must be a robot.
"If you can't build a hibernation device that can last for thousands of years, then you certainly can't build a robot that can last for thousands of years. That means they definitely need to be updated." Xiang Shan pondered: "One generation of robots will continue to create the next generation.
And then repeat all the way to the earth.”
David nodded: "Hmm, that's probably true. But if you put it that way...a person carries a small amount of supplies, and then comes out of the dormant chamber every one hundred years, undergoes a period of rehabilitation training, and hibernates
After the warehouse is updated with parts, go back to sleep... No, that area is still a little too small."
Xiang Shan mused: "In other words, such a small place can definitely fit a complete production equipment... But there is still a problem, how to store the technical data for the production of those parts? The deterioration of the hard disk is still very serious. Rely on constant renovation.
Storage device? What kind of material recycling technology can be developed with this thing? Also, it can ensure that there is no deterioration after countless copies..."
Xiangshan couldn't understand this question.
Of course, the answer soon appeared in front of him in an unexpected and reasonable way.
Humans have discovered many...carbon crystallized plates wrapped in copper alloy in the core layer of Ogun.