Spacescifi

Pure fusion bombs would not produce the fallout nukes do... in theory it may even be possible to create small fusion bombs as powerful as nukes or less. Pure fusion does not even produce an EMP does it? It's the bomb a manned Orion deserves!

I think ground launch is totally possible. Yes you would lose the launch platform but that is all... the launch center itself would be farther away. My idea of an Orion belly lander with a rear pusher plate ship is T-shaped with a pusher plate at the tail end. I think using a disposable first stage series of rockets for initial launch is great idea. Yes the boosters would be huge but it's the price that has to be paid. The idea of a belly lander would work best for low gravity places like the moon and asteroids and comets. Returning to earth. Could be done with a bunch of second stage boosters sent to connect with the Orion in LEO before it does reentry maneuvers, the last of which would be reusuable since the ship would belly land with them. So in actuality, a heavy belly lander is not a an SSTO to anywhere, bit rather mostly to moons and preferably asteroids or comets with lots of ice. The main advantage one gains with pure fusion bombs is the ability to 'throttle down' the blast potential of the bomb. Which means you can in theory launch lighter weight orion vessels than possible with traditional fission triggered nukes. Which also means that onboard chemical rockets could lift it without the help of a disposable first stage array of rockets. Yet it all ends with optimization. A lighter orion belly lander that could VTOL with it's own chemical rockets would have slim margins for non-fuel payload compared to an orion that relied on disposable first stage rocketry. You can get more utility out of the second stage orion, at the expense of needing 'help' from ground control to ever return to an earth world. Any ship that is an SSTO however large is a glorified shuttle and nothing more. Anything extra makes it worse at it's job of shuttling. A large SSTO orion serving as a shuttle only needs seats for the crew and BARE minimum life support. Since the shuttle orion will link up with the second stage orion for crew transfer anyway in orbit. Then it can land using it's onboard rockets and remaining chemical propellant reserves.

Understood... this changes things for me. Alright... I am beginning to see a picture. Space only rockets for space, and chemical or air breathing rockets for air flight. By space only I mean mini-mag with fusion. I am going to have ditch some cherished scifi ideas and go places I never considered. Will be fun though. There is an awful lot you can do with modern tech if you can suspend the flow of gravity from effecting anywhere near your spacecraft before launch. Ha... you could even make zeppelins SSTO's so long they ride a grav-suspending rocket to space. And reusable chemical rockets would be popular for first staging as well. Chemical rockets with grav-suspension could save a lot of fuel, since all they have to do is burn and drift into space. Takes longer but there is no need to rush. What is an hour vs 8 minutes if you are saving tons upon tons of fuel?

Are you sure? Did not the designers intend the Orion to detonate bombs in atmosphere part way to space?

Alright feel free to correct me if I am wrong.... thanks for the info... you and everyone else. Why cannot a pure fusion Orion work in the atmosphere? The reasons I suspect you are going to say are: 1. While you could do it it would cause neutron activation and therefore radiation if the blast wave occurs near the ground. It's not a show stopper but does mean that you will have to watch the last of the first stage rocketds be blown to smithereens by the pure fusion blast. The first set of the first stage rockets could in theory be reusable and land on their own. You would need plenty of altitude to avoid neutron activation before you engage the orion drive. 2. Obviously landing an Orion is a no go... too heavy. Sure you could slow it down with pure fusion blasts, but the heat from the air I reckon would mess up the pistons over time since you are falling into inferno clouds again and again. Ironically.... the only way I can even see an Orion as a viable safe SSTO is if it could generate gravity suspension field bubbles around the ship. I know, I know, scifi super tech meets the obsolete, but it woumd still work. With gravity no longer in play making spacecraft get to space would be easy We could spin launch the thing and wait an hour for it to drift into space, and also spinlaunch a 100 meter radius habitat ring to attach with it in space as well.

I think what you are saying is with an uber magnetic field with the right configuration, it can be used to literally squeeze liquid hydrogen until it fuses and then spit it out magnetically for a rocket plume. Using small pellets I know works by using magnetic nozzles, and I would love to think a magnetic nozzle would work fine in atmosphere.... but IRL I think the magnetic truss shaped like a cone would be blown up from the air pressure wave which is not magnetic. Unless the magnetic field is SO uber that it deflects the air blast wave as well. This is in theory possible, but at that point you may as well have a solid magnetic nozzle since the heat won't conduct to it anyway.

High thrust and efficiency are hard to pair together with rocketry. I reckon that mixing propellant with pure fusion bomb plasma rapidly again and again via pulse would require both a level of complexity and power the world has not seen. So let's make it simpler... somewhat. Instead of using liquid propellant at all for the pulse rocket, just detonate a high yield pure fusion bomb inside a vacuum super high compression magnetic chamber with a hole leading to the exit nozzle. Let's presume the bombs are on par with nukes. So what you end up with is a rocket with better performance than project orion because of the nozzle pointing the plume only rearward... with the side effect of leaving mushroom clouds in it's wake during launch. At least the radiation is less than nuclear. Now when I say efficiency I mean less bombs per ton need to be expended to reach orbit (because more energetic) than the tons upons tons of chemical propellant that would be required otherwise. Ultimately the way we currently know physics, any Star Trek adventures would be at LEAST two spaceships. 1. A large SSTO.... basically it is the shuttle to anywhere and back. 2. The orbiter. With rotating arms for crew to live in. They would live here and only transfer to the SSTO when they wanted to explore. The main difference between commonly depicted media scifi and this is that instead of a small accessory of tiny shuttlecraft, you get one large SSTO spaceship that no one lives in until they need to try to land anywhere. It is too hard and also unrealistic to try to get an SSTO to do all the things an orbiter needs to do with rotational gravity. It always pays to optimize.

Picture this.... a large belly lander SSTO, using reusable chemical rockets for VTOL to get in the air, and the it starts to nearly flip backward before firing it's main rear engine which has a single, thick bodied nozzle. The main engine shoots out a long straight plume of bluish white fire in a single pulse, and despite the spaceship being large and heavy it literally shoots off with acceleration that is rapid.. like a tiny bottle rocket. No slow rising here! This rocket engine has oomph to spare! What is it? Pure Fusion Pulse rocket: I basically considered what matterbeam wanted for a pure fusion orion and thought why not use that tech for a rocket? What it would probably take to make: Some sort of vacuum chamber lined with powerful super magnetic coils or devices. A pure fusion bomb would be inserted into a chamber and detonated, and the resulting fusion plasma would be shunted via magnetic fields into a reaction chamber where it would mix with the propellant as it leaves the nozzle. Realistically I am not sure we have magnetic coils powerful enough and small enough that they do not need to be gigantic to pull off a feat of directing the plasma on par with a nuke for energy. But we would need smaller more uber magnet tech to ever havs scifi SSTO's that take off like Star Wars on their bellies. Unlike Star Wars I do not see constant flow pure fusion rocket SSTO's being a thing. Why not? Powerful high g pulsed acceleration is more fuel efficient than constant flow lower g acceleration. High g pulsed acceleration does generate waste heat, but with sufficient ingenuity I don't see why that cannot be averted by dumping the heat into the propellant as it leaves the nozzle. So... I think, if heavy SSTO's ever are made, they will be pure fusion pulsed rockets. Using chemical rocketry to land. Unlike project orion you do not have to lug around a heavy pusher plate and pistons, but I think the main advantage is that critical mass for a fission reaction no longer matters. If I read correctly, pure fusion reactions can be scaled up or down as needed, which means if you want a smaller acceleration you can have it... not all your pulses need to be fusion death beams that leave a mini-mushroom dirt cloud where you launched from lol.

I thought the small size may be the cause. That's good. Means there is still hope for manned space travel. It hinges most on effective gravity via rotation, since 1g via torchship is not realistic and who knows if it ever will be. Even those would need rotating arms since in orbit you are not under thrust.

Sadly an experiment with small centrifuges is claimed to have had zero effect on preventing intraocular presssure on eyes. Not sure if scaled up rotational designs will make any difference. If not then that means that means that even rotational gravity is not enough for crew health.

Quite right. An alternative to Orion is a type of antigravity light ray drive. So long the drive is charged it generates an invisible gravity canceling field around the vessel, but the nozzle can also emit antigravity rays to propel the vessel which depletes the drive's charge. Long story short is that the ship is immune to gravity and must rely on it's antigrav ray for propulsion until it's charge is fully depleted, upon which gravity will pull on the ship again. With the drive depleted it is useless until it is recharged of the local strength of a gravitation field multiplied by the drive's max g-force rating. It can accelerate at lower rates but it does not effect the charge depletion time like normal rockets. Type 3 would multiply antigravity ray acceleration by 3 max for 3 hours of charge. You cannot recharge until fully depleted of tge previous charge. Scenario: Fly into space, you cannot truly orbit as gravity no longer pulls you, you accelerate and coast to mars and retro thrust to slow down. Eventually using all your charge up so you could get there quickly as possible but also 'refuel'. You refuel at with mars gravity for a few hours. Result: Mars surface gravity scceleration multiplied by 3 for 3 hours.

But what if they did not require the same energy? That is the point of scifi really is it not? We all know that the sheer amount of energy required to pull of feats in scifi is almost always greater than the ship could pull off without melting. Orion is optimized for both air and space travel, but certainly not a master of either. Just good enough.

For a setting with heavy lift SSTO's being common I think cheating would be necessary but the type of cheating matters. I focused on Orion so much because it was effective while not OP. But scifi means to an end that are make believe are all too often very OP especially after I actually think outside the box and use it in ways it was not intended. I think a pure fusion Orion would require a very specific cheat that would also help all rockets. Namely a scifi gravity inhibition field generator. In a setting where rockets and project Orion vessels could peform as if weightless on Earth. Now I looked up Z-pinch and like other fusion rocket schemes a magnetic nozzle is involved so it is a space only type of propulsion. The merits of Orion are multiple: 1. Can perform well both in atmosphere and space. 2. Much easier to make compared to fusion rocketry. 3. Safer than the NSWR by Zubrin on any given day. So in a scifi setting with gravity canceling tech, project Orion vessels would be stiil be less complex and cheaper than actual fusion rockets I think. The easiest pure fusion rockets to make are pulse rockets based on squeezing small amounts of fusion fuel and detonating it while throwing it rearward with magnetic nozzles. Which as I said do not play well inside atmospheres. So project orion really would fit the classic scifi SSTO role well so long gravity can be canceled.

I never intended to rotate under thrust, rotate while drifting was the plan. Also the thing about CMG's and reaction wheel counterweights is that they will become saturated over time. Forcing a vessel to use RCS to counter the failure of the CMG's. Unless you are saying that two counter rotating wheeld cancel each other put from rotating the entire spaceship? If that is the case then I would expect a manned orbiter transfer vessel to be a long rocket with an array of counter rotating arms with habitat pods at their ends. At the very least I would say it would need to counter rotating arms with habitat pods. Even better is something with two counter rotating rings... held to the main engine rocket by 100 meter arms.

Wow... I had no clue about T-shape being unstable. So in other words, T-shaped vessel may have to exhaust more RCS propellant for stabilization than a more balanced shape? On the other hand one could exploit the instability. For example a T-shaped space fighter could use it to flip around suddenly to turn toward a target while drifting or to be unpredictable in it's movements.

Cool... too bad I did not know that lol.

Would it be useful for nuclear space travel in some way? Would it boost thrust in any meaningful way? Beyond that I think it would make crew life safer and would not require a shadow shield from a reactor. What else can we do with neutron mirror materials if we had them?

If I recall correctly project Orion was supposed to tumble for gravity on a planned mars trip. And Orion would have lots of extra fuel anyway for it's size so it should not run out merely by tumbling. I don't. I was merely playing devols advocate with Vanemonde's idea.

How would it cause problems for the engine's direction of thrust? Main engine would not do the tumbling, RCS thrusters would.... which would also stop the tumble when necessary. And in real life would not the rotation of the crew compartment cause the rest of the vessel to counter spin? Just like would happen if you tried slinging objects by spinning them with tethers from a spaceship?

According to kerbiloid you only need 100-200 meters.... If I quote him correctly, to get 1g rotation without messing up a human's equilibrium (sense of balance so they can walk without falling). I know at a thousand meters you only need one rotation per minute (RPM), but at 100 or 200 meters I know it will be more than 1 RPM. So how would that look? A ship spinning fast like fan blades? A blur? Or more like a thrown rotating knife? Fast but not so fast you can't notice the rotation without having to focus on it. Tumbling VS Rolling for gravity: Which you choose really decides how the spaceship is built and where crew will live inside it. Tumbling: Crew would live in the frontal part of the spaceship, since when you tumble, g-force is felt at the farthest end under rotation, and the other end would have the engine and fuel tanks anyway so it's space is already taken up. The main advantage of tumbling is that you do not need a really big spaceship, you only need one that is at least 100-200 meters long to reap gravity from it. I can see a T-shaped cylindrical shape being quite useful for a tumbling spaceship, since the broadside frontal cylinder could have a rotating inner habitat cylinder in it which rotates and stops itself in the direction of the gravity coming from the tumbling, so that down is toward the nose of the ship. Such a shape would grant more room for the crew than if you only had a rocket or pure cylindrical shape, since the only space on the ship that would matter to the crew under tumbling rotation is anywhere inside near the nose. Tumbling for gravity is also arguably the easiest type of realistic gravity types if your vessel is an SSTO. Rolling: To roll and get the same gravity from 100-200 meters you would need tethers deployed at or near that length. The alternative is to build a spaceship 100-200 meters wide, which frankly would make reaching orbit with it a proper pain. Generally speaking, oblong shapes are more reasonable to reach oribit than fat ones because the less air resistance the easier it is to reach orbit in the first place. The main advantage of rolling is it can open up more space for gravity for the crew, yet such an internal structure would not favor SSTO's but rather pure orbiters.

It can make for great comedy if done right. I read an excerpt from an old TOS star trek book where klingons patrolling a sector with no action actually became excited when they saw an asteroid on sensors... it was so sad it was funny. Meanwhile the Klingon Captain's inner monologue was that it was an 'honor' being out there, since he was actually being sarcastic. When the Enterprise shows up the Klingons are delighted for the break in monotony.

You are absolutely right... I just have trouble thinking a manned or intelligent life race will really take to the stars in greater numbers without technology that is more fantastic like star trek. I mean really... if we stuck a warp drive on a spaceX starship that could go 1 LY per hour the only people going on that mission would be pros. Wjich frankly is not exciting unless they are in danger or hilarious with each other being cooped up for so long. But they could only go few places if not one anyway because of fuel expense. In other words... in real life, doing the star trek thing requires a proper star fleet... not a single orbiter with shuttles. You would need an entire fleet of orbiters to allow you to visit several locations with them.

The problem is that none of those solutions work well for going to unexplored or places lacking infrastructure. You cannot even do a star trek like setting. The second issue I have is that dedicated manned orbiters will sooner or later need replacement of components. Not designed to land means a fleet of second stage shuttles would be the way to fix problems. But again, this does not really allow the lone ship to warp into a solar system, explore, and warp out on the regular. At best it would all be pre-planned and after every mission they would be forced to either go all the way back to base or a find, mine, and process propellant from an asteroid, moon, or gas giant. Which also involves exhausting precious propellant so you had better be sure the fuel source is a good one beforehand. The why of space opera is a big deal... the goal is to transplant the concept of sea exploration to the stars. Real technologies are hardly capable of that without infrastructure in place already. A sailing ship could go anywhere so long it had food for the crew. Space is far harsher and travel times longer while physics put limits on spinning things up for gravity and getting to places in a more reasonable time on par with sailing ships Therefore making it up is necessary in that case.

Orion has it's merits, but it is hardly ideal for how I wanted to use it as an SSTO.

You are kind as are other moderators... I did not feel you were heavy handed. At this point I more or less feel that making up stuff in scifi is necessary unless one wants to make viewers suppose rocketry can do things far better than they actually do and without melting the engine. My current scifi drive in mind may be a bit overpowered, but it gets the job done. And no it's exhaust is not rocket exhaust, but rather high pressured synthesized light. Normal light is low pressure so it can barelly push anything. Not so with pressor rays. T3: Type 3. Means max acceleration at 3g or less for 3 hours. Other types go all the way up to T9. Most manned vessels use T3's as that is all you need for LEO and beyond. Missiles: Use T9's but there is a catch. Large vessels carry large generators that allow for the gradual release of acceleration of the drive over time. Missile drive generators are too small for that so instead they use all their drive's stored acceleration in a single pulse. In other words... 9 hours of 9g acceleration is shot out their nozzle in a single pulse. All missiles are two staged, as the T9 missile drive is the the first stage and the second is an ordinany chemical missile with RCS. Because of drive generator scaling issues, only large vessels and missiles use it. Small manned shuttlecraft do not use the drive and are something of a bygone era. Big ships just land and take off on their own. Obviously FTL/ways to shorten interplanetary trips also exist that do not rely on the drive discussed here.