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.
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
The post right above this one in my feed
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.
Jeff Bezos’ cock rocket is a questionable design
Questionable for technical reasons or because it looks too phallic?
Phallic hahaha
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.Orion engines weren’t ment for atmosphere propulsion
So the other 99% of the energy that doesn’t push push against the craft body just goes away? Plus the equal and opposite rule would make it more likely to move the small explosive device away rather than the big heavy rocket away from the device. You set off a bullet outside a gun and the light case moves more than the heavy lead…
I’m no rocket scientist but that sounds like a way to create the least efficient one ever
So the other 99% of the energy that doesn’t push push against the craft body just goes away?
You’re missing the insane energy density of a nuclear reaction. The first nuke used in war weighed 4700kg and produced about 88 terajoules of energy. That’s about 19 giga joule per kilo
1 kg of rocketfuel + oxidizer produces 13 megajoule.
So even at 1% energy conversion for a nuke and 100% conversion for rocketfuel, the nuke is still 15 times more energydense.
And if you don’t use nukes from the 40s, a modern thermonuclear bomb packs 2000TJ into 200 kilos, for a convenient 10TJ per kilo, or 7700 times more power per kilo than liquid rocket fuel.
Also the actual propulsive force would have been more like 50%, not 90. So more like almost 400,000x more power per kilo than liquid rocket fuel.
And you’d be wrong, it is high efficiency and high trust
The Orion concept offered both high thrust and high specific impulse, or propellant efficiency: 2,000 pulse units (Isp) under the original design and an Isp of perhaps 4,000 to 6,000 seconds according to the Air Force plan, with a later 1968 fusion bomb proposal by Dyson potentially increasing this to more than 75,000 Isp, enabling velocities of 10,000 km/s.[8] A moderate-sized nuclear device was estimated, at the time, to produce about 5 or 10 billion horsepower.[6][14]
https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)
I’m no rocket scientist but that sounds like a way to create the least efficient one ever
100% Efficiency isn’t always the pure aim of rocket engines. As an example, ion engines are the, hands down, most efficient method of powered space propulsion we have in use today. However it would take millions or billions of years for an ion engine to reach near the speed of light. Truthfully it never could because you couldn’t carry enough xenon or krypton because of how many years it would take.
Not quite as inefficient as that IIRC, though obviously the core idea was that nuclear bombs are so energy dense that only a fraction of the potential thrust needed to be captured to remain grossly superior to the mass equivalent of any other propellant.
It needs a relatively small amount of funding. Essentially a 100 gigawatt powerplant, strapped to a 1kmx1km array of lasers. Very lightweight probes (that could potentially be mass manufactured) propelled by these lasers.
If it comes to fruition, we could have probes that we can send to nearly our entire stellar neighborhood at significant fractions of the speed of light.
We could:
- Get a constant stream of pictures and data of exoplanets within our stellar neighborhood.
- Send these lightweight probes WITHIN HOURS/DAYS inside our solar system.
- Very rapidly send exploratory probes to any given object. Another Omuamua comes in? Yep, we’re getting to it in hours baybee.
Literally SciFi stuff that we can achieve with little bit of development in material science. Again, the bottleneck is FUNDING, not technological. But come on, it’s so worth it!
I’ve always been confused why Breakthrough Starshot always showed the square km laser array on the ground instead of a bunch of satellites in orbit. That way you wouldn’t have to account for atmospheric attenuation of the lasers PLUS you could probably get military funding for putting a gigawatt of laser capacity in orbit lmao.
Like sure, the likes of Starlink were still just getting going when Breakthrough Starshot was conceptualised, so the idea of a large satellite constellation probably wasn’t on their radar yet, but at the same time - they were talking about sending thousands of probes to Proxima Centauri so it’s a mystery to me why they didn’t see that kind of technological progress being possible by the time we were doing that
you could probably get military funding for putting a gigawatt of laser capacity in orbit
…and without causing political problems!
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).
Reminder that the new bobiverse book comes out in a couple days
Very fun series
Still need to finish book 5
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.
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 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?”
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!
Really unfortunate name though. I really hope it’s a coincidence.
A fan wiki entry suggests the name for that fictional scientist may have been chosen for its closeness to “Einstein.” One can hope.
Seems like the most likely explanation.
https://en.wikipedia.org/wiki/Skyhook_(structure)
Edit: better explanation imo
What is realistic: multiple of them as a “transfer device”, each one alternating between lifting payload up (lowering their own orbit) and slowing a payload down for orbital entry (lifting themselves up).
Maybe i’ll try that in KSP.
Are you talking about fictional rocket/spacecraft or actual designs proposed for construction with today’s technology and abilities?
Actual designs proposed
https://en.wikipedia.org/wiki/Laser_propulsion
The HX laser thruster always seemed like a great idea, but too radical for anyone to actually try. Keep all that expensive and heavy energy generation on the ground by using LASERs to vaporise the propellent on the rocket.
Real Engineering made a video about it recently
Deep Space 9.
The idea is just silly. It would make so much more sense to use a small moon instead for that purpose an then buildings are easier, everything goes easier.
There’s never a small moon close to a stable wormhole entrance when you really need one, amirite?
Station Deep Space Nine has thrusters to move around with, which a moon wouldn’t have. It’s also set up to directly dock in space with and service ships and their crews more efficiently than an outpost on land would.
