Spacescifi

Yeah... watched a video on space tethers... I presume same thing no? I think an orbital version of spin launch would be superior... inasmuch you only need the arm and you already have vacuum outside so no disk. Put enough of these in orbits and they become the 'roads' and 'intersections' of the solar system. Transfer windows to them would still matter though, so travel time would only be optimal when the spin arms were close enough... I am speaking of interplanetary spin launch satelites.

In an age where fuel is so precious, given the relative smaller size of spin launch to a coil tube, they could jump start space travel. From orbit that is. Just think, a rotating arm in orbit. I do not know the limit you can do on spin, but max it out, and then launch robot supply vessels to orbit or land on locations of interest. For manned spaceflight it would be slightly more complex. Involving multiple rotating arms and throwing a ship to be caught by each one until it reaches the final one and is launched for good. Who knew making our own 'orbit machines' could open up space travel?

I have. What my younger self learned... due to messing up enough for my boss to to even tell me... was be careful NOT to say what you are thinking. What I learned personally was never to get too casual with customers even though they did with me. At various points I was invited to parties after work by strangers (teenage customers). It's ok for a customer to say something frank because they do not have a job to lose... but not you if you have the job.

I do not have a problem with handwavium... I just believe less is more when it comes to handwavium. As much as I like star trek, I think they could probably fill pages with handwavium as much as they have. Less handwavium means solutions to problems are more rooted in reality.... at least with regard to what you do not use handwavium on. Star Trek has so much handwavium that often one watching the show can decide easier ways of solving problems than characters actually do. Whereas I prefer in writing fiction for characters to make logicallly the best choice available to them. I would expect as much of real people no less.

You are right... I just think matters through to how much the tech can be pushed to the limit. Which I often find scary... because the limit is... whatever. Undefined. Unknown. And I do not like unknowns. Ever. I prefer to have some basis. Something to build upon, something that is not royally overpowered that cannot be countered. One totally made up drive I just came up with is this: Anti-Inertia drive: If inertia is a resistance to a change in momentum, this drive lowers that at a constant acceleration rate equal to and in the same direction as your main rocket engine. In other words, you start off with rockets, but once you activate the anti-inertia drive field you will CONTINUE accelerating in a straight line even at the same rate as you were after cutting off the rocket engines. To change course you shut off the field and just point your ship in another direction and thrust your rocket engine to 'kickstart' your anti-inertia drive again where you wish to go. Best part is you do not need uber rockets for this... since the anti-inertia drive does most of the work, so any normal chemical rocket could 'kickstart' the process. Refueling still matters.... just less. With a drive like this we could reach mars at 1g travel times or anywhere else with propellant to spare! In this case the counter is obvious... other vessels with the same drive field and missiles that also have it. Just imagine the pure insanity a sprint missile could do with an anti-inertia field drive fitted to it. 100g probe around the solar system. Get to mars in a week or less probably lol.

Then why does scott manley say you cannot burn pure metallic hydrogen without mixing it with tamer propellants, lest you melt your engine? He must assume there are limits....

Originally I just wanted a classic scifi SSTO that could have adventures on it's own without a second stage. Come to think of it Sevenperforce, I prefer to limuit my handwavium to low varieties and numbers. I could honestly improve even modern spacecraft with a fictional metal hull that has a ridiculously high melting point... meaning the crew would get broiled alive with a glowing hull long before the hull actually melted. Let's say the stuff is as dense as tungsten but has a much higher melying point, enough that we could fly a metallic hydrogen rocket purely with liquid metallic hydrogen combustion. Too bad they don't have that. Even so I think we could actually make SSTO's right now if only we had engines with much higher melting points. Because we can design engines to take advantage of that right? Higher delta v and thrust all from running hotter? Who knows... maybe we could even get a sustained fusion reaction without uber magnetic fields too?

The NSWR rocket has a reaction going on that if it goes wonky can literally blow the ship up like a nuke. Bombs go off only when you set them off. Even chemical rockets blow up at times. Rockets are merely controlled flow bombs. The more advanced the more complex it must be. .. the rocket. But you are right in that we won't know for sure till we build and test them. Until then we have scifi to test the ideas we cannot yet do.

Still... the fact that we know how to build an orion and that a NSWR has a lot more that could go wrong in flight speaks for itself. Just as any advanced rocket will be a more complex machine than external pulse propulsion. It's high performance (advanced rocket) vs good enough (advanced externsl pulse propulsion).

OP tech that just works too well tends to break settings so much that arbritrary limits must be imposed to 'unbreak' them. Plus I just like the look of pusher plate spacecraft, and think combining the rocket and pusher plate tech is seldom seen in popular scifi. So let's debate two shall we? To end the debate once and for all. I just presumed project orion enhanced with futuristic bombs would have superior delta V and TWR to a futurstic rocket that used the same fuel source. Is that not true? I mean when you compare NSWR to project orion I do not think NSWR beats orion in the mileage department. And that is the closest appriximation we have of arguing torchship versus project orion. Advanced models in may not use the same fuels, but the end motion result should be the similar, whether even if it is an antimatter orion versus an antimatter rocket. It could also be said that apart from pusher plate breakdown, the orion system is less prone to things going horribly wrong... especially when dealing with very high powered fuels like MH or when using fusion reactions. I just presume a rocket is trying to contain chaos in a bottle, whereas external pulse propulsion just lets chaos rip outside, so barring an outer force blowing up the ship itself, it should never have engine problems that rockets are prone to have. With all due respect, we can predict some of the issues that may come up with constant firing of an advanced rocket engine, but whatever they are, I reckon a pusher plate is harder to break, and may be easier to fix with spare parts too.

Well yeah... I forgot about that that! I guess instead of poking holes in spaceships lasers would literally turn them into ovens cooking the crew alive... if the hull was made of some super material that did not melt easily. That's assuming liquid storage tanks did not leak and or combust depending on the chemical.... blowing up the entire ship. So coincidentally such a scifi ship would begin to have a glowing hull as it was zapped silly but still intact. Until it suddenly explodes. Regarding regenerative cooling it said the heat goes back into the propellant, which is either feed into the combustion chamber or a special gas generator. I presune for OP purposes simply feeding the heated propellant back into the combustion chamber would be ideal... since I really don't know what gas generators have to do with regenerative cooling.

You have a point but I dunno. I imagine even with a super material like any handwavium flavor such as duralium, duranium, or dura-steel that you could only use the engine for so long before you needed to to stop and let it cool off. The implications would be huge though: 1. Radiator fins would be made of the same metal, so engine heat could be transferred to them when engines are cut off to cool in space. 2. The hull would be made of the same stuff... actually you may as use your entire outer hull as as a radiator now... forget the fins. 3. Reentry would no longer be as much of a concern since your hull can tank MH engine heat without melting. 4. Lasers would be even less practical for space combat... since they would require them to be greater power hogs than they already are to even do any damage at all.

MH engines have to not use their full potential in theoretical designs because the engine would not survive the heat Thus the MH is watered down with another propellant mixed with it. That said, I am not very familar with how pulse jets work, but I presume a pulse blast big enough to launch an orion would need a nozzle larger than all modern nozzles we have. When you have a lot of heat as exhaust, whether plate or nozzle, it will be big it or at least thick it seems. That's not something that can be avoided I do not think. Another option is to do a Zubrin-esque MH rocket. In other words detonate MH pellets in pulses in the nozzle during ejection.

An MH bomb is a metallic hydrogen bomb... yes I know you sneer at MH, but I guess if pure fusion bombs are allowed so is MH. VTOL rocket exhaust will likely get all over pistons during launch. Might do damage sooner or later. And I reckon rockets would have to be retracted inside the vessel when the bombs go off otherwise the blast wave will probably damage their nozzles. Rockets have no shock absorbers unlike the plate, and to work they must extend outside the plate perimeter. I just do not see rockets not being damaged in an atmosphere unless they are retracted before the bombs go off. Ultimately using ladders with VTOL is something you do if you cannot afford to make loading/unloading easier with belly lander. Which I presume is quite possible with OP technologies. And additional problem with a tailsitter is the sheer longer time it takes to load up cargo. Especially if it is doing ISRU anywhere. Since a belly lander is closer to the ground, it can do ISRU refueling of it's own rocket engines a lot easier than a VTOL pusher plate, which would need significant modifications from the original design to be able to do VTOL on it's own while fully reusable. With a VTOL pusher plate you literally have pistons and a pusher plate between your ships fuel tanks and the ground (which could be your fuel source if on an icy moon). Belly lander does not have that as a concern.

Why not? The thermobaric bomb would only be used partway through the atmosphere. Not the whole way. The bomb would designed hopefully to be a shaped blast toward the pusher plate. And if this cannot work, surely there are other non-nucleaer bombs that could work... both real and theoretical (mh bombs). If there are no good IRL substitute bombs for nukes on the initial ascent then I will have to go with theoretical MH bombs instead, which could do the job given how much energy they yield and could be made into a shaped blast The belly lander design was because an orion cannot land on a pusher plate safely nor with the most stability. And trying to use rockets around a pusher plate and adding landing gear around that too would be what a tail sitter would need. A belly lander makes egress a lot easier, and the mass would be similar, only rearranged, as a tailsitter orion needs landing rockets just as belly lander does. The main difference is placement. Yes and no regarding the fusion rocket: Yes: Obviously they have a way of producing and storing enough antimatter safely enough to trigger a fusion reaction with the fuel. Likely a neutral non-reacting material is what is containing the AM securely. No: That does not mean they have engines made of materials that can survive the performance heat of fusion SSTO. A pusher plate avoids this by external pulse propulsion. It is quite notable that only theoretical design I know of that can do SSTO on Earth is Zubrin's NSWR. And even that does so by making the reaction occur outside the engine.

I am designing a scifi vessel for fiction, yet it's propulsion will be based on realistic/theoretical means. The spaceship is a project orion lying on it's belly at launch. Dual axis launch nozzles at both ends are capable of VTOL, at least until the vessel ascends high enough that it can flip over and detonate a thermobaric bomb. As it ascends higher into the atmosphere where thermobaric bombs do not work well, the spaceship switches over to basketball sized pure fusion bombs. https://en.m.wikipedia.org/wiki/Pure_fusion_weapon Questions: Is the design practical? Just assume that bombs exist already (even though they do not) The vessel is intended to be a true manned SSTO. Part of the challenge I presume will be finding room for the VTOL engines on the end that has a pusher plate on the rear. But I do not see why such is impossible Crew I presume would do egress from the middle of ship when landed on it's belly, since the ends would have space taken up by rocket VTOL engines. What do you think? I also presume a pure fusion bomb orion to orbit... will use bombs designed to minimize fallout, which means no uranium or plutonium is is used for the bombs. Yet to minimize neutron activation the vessel needs to ascend high enough that the blast won't cause neutron activation of the ground. That is why thermobaric bombs would be used initially in the ascent upward. So... is the design practical or did I overlook anything? Ironicaly this kind of vessel is better off as an SSTO, simply because if you staged it you risk damaging or destroying a resusable first stage rocket when you flip and light off a bomb. You would also risk neutron activation of the first stage from the pure fusion detonation. Meaning the first stage returns ... radioactive. Which is bad

Elon we need you... we know you have that boring company!

I just thought it would be better than rotating orbital tethers... since tethers need propellant to de-spin them on occasion.

True... at least we don't have the high gees over an hour of time problem we have with the catapult though. And perhaps it's an easier to fix or modify to work than spin launch?

What about a ballista instead?

Just curious whether or not such could compete or be viable. Two staging is a given. I mean if catapult to orbit is considered we may as well consider crossbows as well! I think the main limit is material strength, and you would need a long and massive vacuum launch chamber to get the most thrust from the launch. Is this mechanically viable? Just scale it up and use strong materials? At least the bow string is resuable!

I just had an idea which like most I am skeptical how practical it is IRL, but in theory it could work. What you need: 1. Electromagnetic space cannon launch tubes... in orbit. 2. Spider silk webbing or it's equavalent in space with the same adhesive properties it has in atmosphere. A ring will hold a large net. 3. A pair of Project orion vessels serve as anchors for the web ring on it's flanks. When EM launch cannon launches anything and is pushed backward into the web, the web catches it and releases it's momentum back to what was before. The orion's cancel out the momentum of the web ring with bomb propulsion as needed Thus no orbit degradation for either. 4. Launch web rings to orbit planets via spacecraft. Then launch fusion fuel pellet packets to hit the webs, which release them and launch the toward a caravan of ramscoop spacecraft which will 'eat' and burn the pellets in pulses for fuel. Main question: Would a web that had all the properties of spider silk be up for the job? Or would we need something stronger? I read somewhere that a large web of a few hundred meters or so could stop a jet airliner in midair!

The fun irony is that I read that Jules Verne criticized HG Wells story about using an antigravity spaceship to reach the moon BECAUSE it was not realistic. I guess Jules Verne was a hard scifi kind of guy.... funny to think the more tech changes the more people stay the same. He would no doubt have loved to see Gerard Bull's space cannon launches... which they did about 200 of them or so. Probably would have been sneering at HG Wells the whole time though lol.

Now I wanna see orion pusher plate spaceships shot out of a cannon on a mountain! In KSP.. since that is safer? Are space suborbital cannons and spin launch a thing in KSP? Should be if not. Someone probably will shoot stuff directly into orbit LOL

Sad but true....