Spacescifi

The F1 was a challenge because it relied on chemical combustion for propulsion. Chemical combustion in larger chambers becomes harder somehow I read. As per the OP the main engine would either use pulsed or continous fusion reactions for propulsion so there is no inefficiency based on chemical propulsion with the main engines.

Heavy torchdrive SSTOs would change the nature and economy of space travel a lot. 1. Suddenly interplanetary tourism/trade becomes a thing, even if more expensive than spacestation trade. 2. Larger orbital stations could be built in less time due to heavy SSTO's hauling up the raw materials to assemble them. Conclusion: Heavy torchdrive SSTO's would open space resources/colonization up wide for the taking by mankind as never before.

In my quest to design scifi SSTO's I realized that not only is waste heat a factor but so is the pressure coming from the exhaust plume on the way out. Obviously heavy SSTO's would require performance and thrust higher than known chemical rockets, which also means their nozzle pressure would be higher than normal. I tend to think that using a single main engine nozzle is good for such advanced rocket engines (be they fusion or whatever) since bigger is better when it comes to handling high pressure exhaust without cracking or breaking. So in this discussion I am curious as to how big and thick such a nozzle would actually need to be for specific SSTO data that is shown below. 1. 100 ton SSTO capable of 3g pulse acceleration for 20,000 seconds of specific impulse. 2. 300 ton SSTO capable of 2g continous thrust for 10,000 seconds of specific impulse. 3. 1000 ton SSTO capable of 2g pulse acceleration for 1000 seconds of specific impulse. Are we talking truly gigantic nozzles? Since obviously these are not airbreathing rockets, they are relying on pure thrust to reach space via fusion or something like that that is high performance. Also I think regenerative cooling ringlets on the nozzle would be necessary so that propellant flowing through the nozzle could cool it. Just wanted to know what the nozzle of dreamy torchdrive SSTO's would look like if we COULD make them. I do not believe I am wrong in assuming that if torchdrive heavy SSTOs were a thing that singular large main engine nozzles would be preferred over multiple smaller ones, since extreme pressure is the price you pay for such high performance... the kind I believe would wreck the typical smaller rocket nozzle cluster you see with chemical rocketry. Now you may say, why not make multiple smaller torchdrive or pulse rocket engines so that multiple smaller rocket nozzles could handle the pressure so you could just fire them all at once in tandem? To that I say this. High thrust fusion rocket and torchdrives are complex processes, and I do think that making multiple smaller torchdrive engines would be more complex and difficult than simply building one big one. Nevermind the fact that clusters of rockets in IRL are often used in case some fail others will still work, and a torchdrive by definition should be more reliable than that. Compared to fusion or a torchdrive, chemical rocketry is downright simple, which is why they can utilize clusters of smaller rocket engines so often. Also bigger nozzles are often avoided at launch because of atmospheric pressure changes as the vessel ascends... yet with the high thrust of a torchdrive.... the plume will be going out fast that atmospheric pressure won't really effect it much in any way that effects performance.

No wings. Maneuvers with rocket RCS and main engines are used for forward thrust. No wings needed for takeoff as the ramp will send the SSTO up anyway From there it only needs to pulse thrust into space. 8000 tons is relative anyway for reentry, as some mass my have been shed (cargo delivery). To shed horizontal kinetic speed you just flip over and pulse fire main engines as needed. As for the exhaust it is a rocket plume, and I reckon the runway could be actively cooled to handle the heat from the plume. I agree the challenges are severe, but they are not impossible from a physics standpoint if you allow for the number one exception of a heavy SSTO and a pulsed fusion rocket. Physics does not say no, it just says it's difficult.

During my time here I have heard many times how impractical heavy SSTO's are. The reasoning has mainly to do with the fact that chemical rocketry is less efficient when you use a single stage... since it requires more propellant and therefore turns the ship into a giant fuel tank with very little practical room for much of anything else. I think I may have had a breakthrough though... and it is grounded.... mostly... in stuff we can actually do with a single exception which is point number one. 1. SSTO that weighs 8,000 tons and uses a runway and a ramp to take off. Relies on a pulsed fusion rocket with a large and thick bodied nozzle. Thrust can be throttled by detonating and expelling smaller fusion fuel or increased by detonating and expelling larger fusion fuel out the nozzle as plasma. Uses a vacuum reaction chamber lined with uber magnetic field generators which are able to compress and fuse and expel fusion fuel out the nozzle. A plasma window separates the vacuum chamber from air that would enter from the nozzle otherwise on planets. If you want to use smaller nozzles you will need more of them to get the same thrust... yet the good thing is that you can also throttle thust back for each nozzle by using less fusion fuel for each one... therefore the nozzle can handle the pressure without needing to be as big as it would need to be otherwise 2. To take off the ship uses a moderately lower thrust fusion pulse to allow it to drive on wheels down the runway and up the ramp and off into the sky. 3. Last of all the ship continues to detonate and expel fusion fuel to reach orbit. Conclusion: No I do not think we can currently do this as it requires uber magnetic fields that I doubt we can generate at such a scale of energy. Yet the ramp and runway seem sound enough. The way I see it, if the main engine is in the rear, why bother with VTOL at all... especially for an 8000 ton SSTO? Chemical rocketry is inefficient for heavy SSTO's anyway. Space: Since 8000 tons is a bit much to try to land using chemical rocketry onboard the ship, instead the 8000 ton ship will be an orbital cruiser, cruising from orbit to orbit. Reentry: At the end of the mission the 8000 ton SSTO will return to it's homeworld to land. How? By using a really long runway and landing with wheels. That's how. It will likely have to pulse fire the main engines to get some horizontal velocity before landing on the runway. Massive jet fans flanking the runway can slow the 8000 ton ship down more than it's wheels on the runway would, and eventually it comes to a stop. Thoughts?

Haha! I remember those theads. Yet here I was more focused on how a humanoid that looked nearly human for all intents (kryptonian or time lord) but with different inner organs may be able to pull off their special abilities. Thanl you for your and other's answers. The bones being modified to mechanically amplify sound would need to be able to de-amplify, otherwise such an alien humanoid race could go deaf or suffer hearing loss from a bunch of amplified sounds. I think that is why outer ears are made of soft cartilage instead of hard bone? since bone conducts sound while soft stuff absorbs it more.

Hmm.... I guess the same hearing as the barn owl will suffice... being able to heartbeats several meters away could be useful. Hearing sensitivity comparison of Barn Owls, Cats & Humans - As charted by M. Konishi, American Scientist Vol 61, 1973. Both the cat and the Barn Owl have much more sensitive hearing than the human in the range of about 0.5 to 10 kHz. The cat and Barn Owl have a similar sensitivity up to approximately 7 kHz. Beyond this point, the cat continues to be sensitive, but the Barn Owl's sensitivity declines sharply. Yet with some owls (barn owls I think) their ears are asymetrically placed, so that they can home in on targets by calculating on the slight delay between the time it takes the sound to reach both ears. https://www.allaboutbirds.org/news/how-can-an-owl-catch-a-mouse-underneath-a-foot-of-snow-in-total-darkness/ https://www.owlpages.com/owls/articles.php?a=6

Anyone familiar with superheroes knows that some of them have the sense of superhuman hearing. From a worldbuilding perspective, I am curious if the human body would allow for greater hearing ranges without modifying the shape of the outer ear? How great of a hearing range could a humanoid have if the inner ear were modified?

It's also a real time ansible for FTL communication with no light travel delay. I kind of like propellant being finite but energy being virtually unlimited (since it does not have to supply it's own power to lase the fuel other than powering the uber magnetic field and whatever FTL drive the ship has). Also allows every ship with portals to have uber laser cannon... since they are getting the lasers from a power plant back home. With this technology you can go far but are still dependent on finding propellant. Fortunately virtually any source will do so long it is solid and non-ferromagnetic. Could even use moon rock.

Feel free to correct if wrong, but if the energy to propel the propellent is high enough, then you can increase your mileage so to speak more than if you fired propellant continously with a less energetic method. I am thinking that rockets convert heat and pressure into kinetic energy, and what limits them are a combo of limited energy available and material stress limits. What if we could avoid both of those in a scifi setting? Scenario: Instead of fusion, let us try to mimic it's energy level using lasers and laser portals. What is a laser portal? You know about stargates in scifi right? Same idea, only it only can send laser beams across. The spaceship engine design: I am not giving up on a proper SSTO just yet... mainly to use as an efficient crew transport shuttle and nothing more. So ithe dea is that the engine reaction chamber is spherical and also a vaccuum chamber. It is also lined with hundreds of lasers on it's inner walls, and the walls can generate uber magnetic fields. Propellant: Spherical balls of ice a meter wide each. Function: Lasers from an uber powerstation back on the homeworld fire lasers through the laser portal, which are to hit an ice ball that enters the vacuum reaction chamber through a plasma window that seals the vacuum reaction chamber. The lasers vaporize and turn the ice ball into plasma, which reacts with uber magnetic fields of the reaction chamber to shoot it out as plasma exhaust. The magnetic field is so powerful that it repels any stray gases or plasma from the exposion of the ice ball and instead compresses all of it it rapidly before shooting it all out as exhaust as a powerful pulse of thrust. The fiction: Magnets that powerful are fiction but if we could make them so they could do just that. A sturdy and thick nozzle will be necessary to not crack under the massive pressure from the powerful pulse of thrust from the exhaust plume. Best of all? Fusion level pulse thrust but without ANY of the nasty neutron radiation or any other fusion problems! It's a scifi scenario as per the usual, but I think it could mimic pulsed fusion well enough. By the way, the reason I am relying on a vacuum chamber and pulsed rocketry is because firing arbitrarily high energy lasers through a portal that is INSIDE a reaction chamber full of liquid propellant just seems... foolish. May blow the ship up. With a vacuum chamber and uber magnetic fields to compress and direct the blast of the ice ball, it won't be allowed to blow up or damage the ship. Nevermind the fact that the temperature differences of being in cold liquid propellant one second and then an inferno from an uber laser the next would likely damage or destroy a portal gate inside the liquid propellant reaction chamber anyway. Which is why I opted for ice balls. Feel free to critique.

So for a little bit of fun... who here loses their job on the bridge? My guess... "Mr. Worf, you are relieved of duty. Riker you are dismissed." Riker: "When do I return?" Picard: "You don't unless I pass out or die. I am sending you for any away mission we have since last I checked, looking after the crew is your job. I look after the ship." Picard looks at Deanna Troi. "You may stay." "Why? I have less command authority than Worf or Riker." "Just in case we need your empath ability when we hail aliens.... and you're easier on the eyes than either of them. Geordi: "Will I stay? Picard: "Why are you still here? Off to engineering with you!" Data: "Captain, are you OK?" Picard: "Never been better. You are also dismissed." Data leaves Picard, Crusher and Deanna Troi on the bridge, giving Picard a suspicious look before exiting and says "May I ask you a question?" "No you may not."

Good point. Well. I guess what scifi gets wrong is the sheer amount of automation. I think the only things and times that they won't rely heavily on automation is when success or failure is not mission critical.

What is a pilot's job then? Are they out of a job? Because we can automate sea going and flying vessels right now but often choose not to.

It does not have wings, but it's RCS is linked to it's main drive so it uses that to maneuver. Thrust vectoring allows it to do airplane/helicopter like maneuvers in atmosphere. With the obvious side effect of really powerful exhaust that blows everything nearby away from exhaust gust alone. I saw no real need to expound on the details of the drive, but if you must know, I went full scifi on it. Nothing that we knows would indicate it is possible, but if it was the story will answer that question. Hyper-ray rocket: Photons provide very weak pressure. What if their pressure was increased a great deal? That is what a hyper pressure ray rocket does, called hyper ray for short. Since hyper means above or beyond, and it definitely goes beyond what normal light can do. Uses mirrored nozzles and an emitter down the throat to shine white rays that may as well be rocket plumes but are not. Same effect but all you see is the light in the nozzle while hearing the roar of it's thrust and seeing ground dust blown away at launch. It has a second application though not related to rocketry. Lasers. Hyper-lasers that rely on high pressure rather than excess heat to do damage. Even better is the fact that hyper lasers can use a wide continuous beam setting to simply blow a person back. Or use a concentrated narrow beam to punch holes in something via powerful pulses. Spaceships use the same weaponry, think of them as lasers that literally hit like kinetics. Of course with range the beams spread out so the damage they can do is reduced. Very good at missile point defense.

I just had a crazy idea that could work! Use spin launch to yeet a spacecraft up so that it is caught in adhesive netting in the 'hole' of a massive torus balloon, which is held in place by long tethers on the ground. Then boost the rocket until it reaches another net hole of another higher balloon. Allow the balloon to transfer gas as a fuel source so that it begins to descend, then release the rocket and boost and rinse and repeat with another balloon until you cannot. Could possibly SSTO with this with the rocket.

That will be a multi-kilometer wide balloon. You really won't need to pitch up though. Make a massive torus (donut shaped) balloon and have the spacecraft and booster hanging down the hole. Then once at altitude release and boost away. Would be slow but effective.

I read online that pilots will use foot pads for yaw so there is that. Since joysticks are only good for pitch and roll as far as I know. The ship does not have to do 3g nonstop for years. It can fly so long since it is designed for solo exploration. It only uses 3g to escape 1g planets with ease. Interplanetary cruise is 1g for the gravity for the crew. 3g in space would only be for emergencies or urgent missions.

It's been a long time.... yoke for the U-shaped double stick right? Flight yoke? Thanks.

The scenario: You have a scifi SSTO large vessel that can accelerare for years at a maximum acceleration of 3g or less when fully loaded with cargo, yet higher without it. It is capable of vertical lift off and landing as well as doing airplane like maneuvers in an atmosphere. What flight control instruments are best? My thoughts: I fancy the U-shaped double flight stick that airline jets use, only the one for the SSTO would have these features: Yaw (pivot the sticks away from you with your wrists) and you yaw the ship. Pitch by pulling up or pushing down the sticks, and roll by pulling sideward. I like it over a joystick because I dunno... joysticks look like.... cheap videogame. Unprofessional. What you think? For all I know joysticks may be better... at any rate some other control method would likely be needed for VTOL.... probably button or voice control.

I was thinking.... if it would be practical to create an airship to orbit SSTO? The idea would be to rise up into the high atmosphere, and then use plasma rocketry to reach orbital velocity. Possible or not?

Magnetic fields come from mass, amd I read somewhere that certain stars have uber magnetic fields that are so strong they would kill before a person's spacecraft ever hit the star. Question: Is the size of a magnetic field dependent on it's mass? And what is the limit of the strength of magnetic field dependent on? I presume magnetic field strength depends on magnet material strength as well as power avaliable and waste heat management

Math was and is a weakness of mine.... and my current situation hardly makes studying to improve it an easy thing to do.

I warmly suggest hybrid rockers using liquid oxygen and solid propellant potassium alloy. Better thrust than pure chemical rocketry and easier to process and manufacture as well too. I think wilderness refueling practically demands hybrid propellant rocketry. Pure chemical requires a bunch of heavy compressors and large tanks that take up a lot of volume, which can largely be reduced with hybrid propellant rocketry.

Hmmmm... how about the Python from Elite dangerous? Dimensions 87.9m x 58.1m x 18.0m Pilot Seats 2 Multicrew Yes Fighter Hangar No Hull Mass 350 t And I reckon any container ship due to it's sheer size would have g-force issues with the crew during maneuvers unless they are doing it really, really slow.

Video game type maneuvering? You know, like if I wanna roll aa a big ship I roll, not necessarily super fast, but it should not take say... more than say a few seconds to do a complete revolution... those kind of speeds.