Imagine a ship full of nuclear bombs. The ship has a blast shield at its back end. The ship poops out a series of bombs, each of which explode and push the craft forward.
This was a seriously funded research project. They launched functional (non-nuclear) prototypes and penciled out a Mars mission using this technology. The project was thankfully cancelled due to the signing of the 1963 partial nuclear test ban treaty.
Because maybe detonating a bunch of nukes in the atmosphere isn’t such a good idea, when most of us still need that atmosphere after the rocket is gone.The medusa drive.
@kersploosh@sh.itjust.works already talked about Orion - scientists looked at that and said “hey, the blast plate would need to be at least a metre thick. That’s not efficient use of weight. Why don’t we fire the bombs into a super-tough parachute ahead of the ship and let it drag the payload along?”
Real concept put into practice? Voyager 1 & 2. Launched in the 70s, still transmitting data from outside of our heliosphere. And NASA has tweaked certain functions over the years to keep extending the life of the space craft so they can still transmit data to Earth
I was young when the Voyagers were launched. It’s really freaky to me that I’m retired now and they’re barely out of the solar system. Also that their puny computers, which my phone outperforms by many orders of magnitude, are not only still working but updatable after all this time.
The Epstein Drive, from a fictional book series, The Expanse, but decently grounded in science. It resolves an important shortcoming in current propulsion, which is how to sustain acceleration for an entire voyage. With sustained acceleration, you can both make trips great distances in reasonable time and do so while maintaining normal earth gravity or slightly more to some withstandable extent.
while maintaining normal earth gravity or slightly more
…or so much more that it breaks your arms so you can’t reach the controls to get home. Ooopsie!
Are you talking about fictional rocket/spacecraft or actual designs proposed for construction with today’s technology and abilities?
Actual designs proposed
A von nueman satellite, real idea but also used in the bobiverse book series. Basically take a rocket, add in a Ai controller and then strap on both a 3d printer which has the ability to reprint itself and a method of resource collection to get material to reprint itself.
Basically it would be able to explore the entire universe given enough time, and that time is not as long as you think because the rate of exploration grows exponentially with each satellite created(since they can also create more satellites).
and a method of resource collection to get material to reprint itself.
That would probably be the hardest part. How do you take a rocket and have it be able to collect resources while on the move? Microscopic space dust probably wouldn’t be enough because it would be a mixture of random stuff. Anywhere with larger debris would likely destroy the thing immediately, and it can’t just land on a planet to take a break and build because there’s no guarantee it’d get fuel again to achieve escape velocity.
Maybe it could cling to an asteroid for a while, but even then there’s no guarantee that it would have the correct composition of materials needed to produce a copy. Not to mention just the difficulty of having to set up some sort of inbuilt foundry system that can make workable components out of raw materials without knowing what conditions you will even have.
On top of all that, you run into a potential issue similar to compression algorithms. If it can’t perfectly reproduce itself, it will end up with copies that are less and less capable of producing adequate copies themselves.
Actually your last paragraph is a major plot point of several of the bobiverse books. To get the “Ai” they basically take a human brain and put it in the first satallite but as copies are made of copies they are not “identical” and yeah… No spoilers.
They basically hand wave away the resource gathering, think like a replicator on star trek… It just needs matter and can make anything.
It’s a very interesting book series if you are into sci-fi. It’s very unique and I haven’t seen a similar book series before or after.
There was some discussion around using ClF3 as an oxidizer, which would work but there were problems around containment/storage of a material that is hypergolic with sand and most metals.
And, as the legendary John Clark has noted, with such things as cloth, wood, and test engineers.
“Ignition!” Was a really entertaining read.
It’s super oxidative, AND corrosive. When you pour a normal oxidizer on metal, you get a thin layer of oxidized metal, and the reaction stops.
But CIF3 will dissolve that oxide, and keep going. And keep going fast enough that stuff catches on fire.
It’s a chemical used to clean vapor deposition chambers, in tiny little ampules. The idea of using it rocket-sized volumes should make every sane person run for the hills.
OP did ast for crazy ideas
run for the hills
I don’t think that’s far enough.
Space elevators. I used to be a huge fan but I’ve lost faith in the concept. For one thing, there’s been little progress toward creating the unfathomably long carbon fiber tether - about 35,000 km (22000 mi). Then there’s the tether’s vulnerability to damage or destruction - a fixed target in an unstable world. A break means total failure. We also have no idea how the material would degrade over time. Not that the technology is impossible, I just expect space travel to become cheap enough to make space elevators obsolete long before the tech is there to build them.
there’s been little progress toward creating the unfathomably long carbon fiber tether
When space elevators were first discussed, there were no materials that could possibly be used. Now we have carbon nanotubes that may be strong enough. That’s huge progress.
But yeah, the political issues will prevail. If we can’t even agree enough to build California high speed rail, think of the impossibility of a major infrastructure project several orders of magnitude bigger and more complex, several orders of magnitude more costly, and where a failure is essentially a weapon of mass destruction affecting hundreds of millions of people.
In 2003 Liftport forecast they would build the first space elevator by 2018. Since then, nobody has been able to solve the problem of catalysts gradually degrading, and other issues that limit the length of carbon nanotubes to about half a meter. So research has mostly given up on trying to make really long nanotubes tubes and is focused on weaving shorter ones together into a “yarn”. But the yarn has only 1 or 2% of the tensile strength of individual nanotubes - too weak to be a tether material.
So it’s not like there’s a steady stream of progress. The field seems to be waiting for a new revolutionary nanotube making process that avoids the original problems. Recent forecasts I’ve seen don’t expect the tech to get here until near the end of this century. With climate change becoming a more pressing issue (finally) my bet is more like well into the next century. That’s what makes me think better, cheaper rocket propulsion will come along sooner.
I liked the idea that any space elevator might be built elsewhere, such as mars. The lower gravity makes it less impossible, the lower population reduces the impact of catastrophe, and you are more likely to have space based trading and supply once you’re outside earths gravity
Very interesting idea! I never thought about a space elevator on a moon, like say Titan.
The length of the tether depends on the planet or moon’s gravity and how fast it rotates. Lower gravity and faster rotation make for a shorter tether. A Mars one would only have to be about 3/4 as long as on Earth. Unfortunately, a space elevator tether on any planet or major moon in the solar system would be tens of thousands of kilometers long - all on the same scale of difficulty in terms of materials science.
One of my assumptions is getting off earth will always be the most expensive part of any space activity. Implications are
- getting bulk materials from other than earth will be critical to make it sustainable
- some degree of local manufacturing and farming is vital
- mining in space will never be worth returning to earth
Therefore even relatively small permanent presences in space might quickly turn to “trade”. If we can refine mineral X on the moon it may be cheaper to ship to a Europa base than for Europa to find it locally, and both be far cheaper than bringing it up from earth
