How would you solve the rocket problem in your scifi?

[Spacescifi]

On the one hand I understand. Rocket plumes look awesome. We also have a good working understanding of fuels and how rocket engines should look. That makes them easier to write than a fictional drive from scratch.

On the other hand, when scifi spaceships (star wars and many more) use what appear to be rockets to go everywhere and back, it does not sit right with me as a sci-fi writer. Knowing full well that staging is always the way to go if using rockets. It is the only way to maximize fuel efficiency beyond weak ion rockets, by shedding extra rockets when they go empty. So as not to be lugging around extra mass which cuts into fuel reserves harder.

I finally came to a solution. If I did not use rockets at all it would make all the research I ever did on them seem pointless. So I included them, even though my scifi has SSTO ships that can reach orbit using both oddly shaped choices (like saucers ) and practical ones ( long tube like a passenger jet minus the wings).

Rocket engines are used ONLY for leaving an atmosphere. But they are helped along by antigravity shielding which shields the ship from gravity, allowing it to float like a balloon in the air. With that assist, even saucer shaped ships are a viable means to escape the atmosphere.

In space itself, the ship uses a uniquely shaped space jet drive. Which uses vacuum as reaction mass, and space has plenty of that. For propulsion.

FTL drives are easy by comparison and did not require nearly as much thought.

Yet what I enjoyed about ny solution is that it made space-mining resources more likely in my scifi setting.

Since if you plan on navigating inside an atmosphere you need rocket fuel. Also if you plan on leaving in a reasonable time (floating like a balloon with antigravity would take a good while).

Yet in space, the vacuum jets allow constant acceleration, and they are quite useful for travel to asteroids and landing on airless moons. Also for orbital insertion near planets. Which means you will get fuel depots that ships can ressupply and be ressupplied rocket fuel from. In space and LEO of any atmospheric planet in frequent use.

For that matter, with a long enough hose a ship could suck up gas from a gas giant while it slowly flies above the atmosphere in space with it's gravity blocking shield up.

That is my solution for the rocket issue in scifi.

What is yours?

[Bill Phil]

Well some people just bite the bullet and accept long transfer times - going with already existing rocket technology (or future tech that isn't much better in terms of specific impulse but much improved in other aspects) and the consequences of that.

One interesting idea I had was to scale the whole thing down.

Like, for example: Star Wars takes place on and near multiple planets across a galaxy. But what if instead of that we made it take place in Jupiter's system of moons, along with man-made artificial structures (large habitats like O'Neill Cylinders)? Normal rockets could be used, maybe nuclear thermal ones. Hydrogen for propellant is abundant, and if fusion tech is around so is fusion fuel. Solar power is still a possibility, but a larger area is required for the same power. Then there can be issues based around who controls what, like parts of the different moons and so on. Saturn's moon system could be interesting as well. 

It doesn't have to be on a grand scale. If you scale it down enough, even rockets like we have today aren't necessary. For example, you could have a cluster of orbital habitats close together so that spacecraft with simple propulsion systems and low specific impulses could rapidly traverse the cluster. If the cluster is, say, 24 thousand miles across, then it would take less than 42 hours to traverse at relative velocities similar to your average airliner today. Total delta-V would be less than 1km/s (I'm assuming that since the orbit of such a cluster would be pretty large that everything is basically stationary in space relative to each other, of course orbital drift would need to be accounted for and station-keeping would be necessary, but with enough energy that shouldn't be an issue). And that 42 hours is a worst case scenario, most trips would be much shorter. Combat spacecraft in such an environment would be interesting.

Basically I think that if you have to have FTL in your sci-fi story , it may be worth it to scale it down. I try to keep stuff like FTL out of my work unless it's possible in general relativity, and even then it's usually stuff that requires a civilization that's already interstellar.

[Pthigrivi]

I’ve really enjoyed Andy Weirs approach to hard-boiled sci-fi, just adhering as closely as possible to the most technologically and economically likely approaches and dealing with the social and emotional outcomes. What would a society start to look like so separated by time and space from their home-world? What would this mean for relationships? Families? Power structures? Cultural traditions? Reactions to immigration and exodus? Just look at Dune—technology is always the backdrop, its how human relationships react that matters. 

Edited May 25, 2019 by Pthigrivi

[kerbiloid]

If the SW objects are 100 times smaller, the distances are 100 times shorter.

Spoiler

 

[Shpaget]

2 hours ago, Spacescifi said:

Rocket engines are used ONLY for leaving an atmosphere. But they are helped along by antigravity shielding which shields the ship from gravity, allowing it to float like a balloon in the air. With that assist, even saucer shaped ships are a viable means to escape the atmosphere.

If you have antigravity travelling through atmosphere would be much more efficient using air breathing engines, with rockets used perhaps only for transition between high atmosphere and vacuum.

[Spacescifi]

24 minutes ago, Shpaget said:

If you have antigravity travelling through atmosphere would be much more efficient using air breathing engines, with rockets used perhaps only for transition between high atmosphere and vacuum.

Yes I considered that, including thermal jet engines (shunt compressed air over the ship's reactor or power core and simply use the resulting hot plasma as reaction mass).

I did not nention it at first, but the rocket engines also serve as backup if the vacuum jets are damaged or disabled.

An air breathing jet engine is added weight for no returns in outer space. Meanwhile, a rocket engine has a simpler design (I am using a mettalic hydrogen flake/ice slush mix as fuel).

2 hours ago, Bill Phil said:

Well some people just bite the bullet and accept long transfer times - going with already existing rocket technology (or future tech that isn't much better in terms of specific impulse but much improved in other aspects) and the consequences of that.

One interesting idea I had was to scale the whole thing down.

Like, for example: Star Wars takes place on and near multiple planets across a galaxy. But what if instead of that we made it take place in Jupiter's system of moons, along with man-made artificial structures (large habitats like O'Neill Cylinders)? Normal rockets could be used, maybe nuclear thermal ones. Hydrogen for propellant is abundant, and if fusion tech is around so is fusion fuel. Solar power is still a possibility, but a larger area is required for the same power. Then there can be issues based around who controls what, like parts of the different moons and so on. Saturn's moon system could be interesting as well. 

It doesn't have to be on a grand scale. If you scale it down enough, even rockets like we have today aren't necessary. For example, you could have a cluster of orbital habitats close together so that spacecraft with simple propulsion systems and low specific impulses could rapidly traverse the cluster. If the cluster is, say, 24 thousand miles across, then it would take less than 42 hours to traverse at relative velocities similar to your average airliner today. Total delta-V would be less than 1km/s (I'm assuming that since the orbit of such a cluster would be pretty large that everything is basically stationary in space relative to each other, of course orbital drift would need to be accounted for and station-keeping would be necessary, but with enough energy that shouldn't be an issue). And that 42 hours is a worst case scenario, most trips would be much shorter. Combat spacecraft in such an environment would be interesting.

Basically I think that if you have to have FTL in your sci-fi story , it may be worth it to scale it down. I try to keep stuff like FTL out of my work unless it's possible in general relativity, and even then it's usually stuff that requires a civilization that's already interstellar.

If only it were that aimple I would bite the bullet as you say. Travel time is only a fraction of what realism entails. And i won't limit myself in that way. Because this is what it entails:

Cancer: Unless you rely on either fictional materials or a ship so heavy with thick walls that it would probably take it a month just to reach the moon!

Running out of fuel: How do you refuel? Gas giant skimming at orbital velocity is hardly safe. And I understand that shuttlecraft can do skimming for a mothership and return, but unless they have some uber plasma scramjets abd cad take the atmospgeric heating repeatedly, they will need to burn some of rhe gas they are storinfg for the mothership.

Zero habitability: Antiartica is a more reasonable choice if habitability is a concern. All known worlds in the solar system are death traps. Thus it defies my logic for any of them to have large populations if modern tech is all that is available.

 

[DDE]

6 hours ago, Pthigrivi said:

I’ve really enjoyed Andy Weirs approach to hard-boiled sci-fi, just adhering as closely as possible to the most technologically and economically likely approaches and dealing with the social and emotional outcomes. What would a society start to look like so separated by time and space from their home-world? What would this mean for relationships? Families? Power structures? Cultural traditions? Reactions to immigration and exodus? Just look at Dune—technology is always the backdrop, its how human relationships react that matters. 

But that's difficult. Can I just have my Western with rocketships, please?

3 hours ago, Spacescifi said:

Cancer: Unless you rely on either fictional materials or a ship so heavy with thick walls that it would probably take it a month just to reach the moon!

Aside from the various anti-rad meds and the very real possibility that are knowledge of the effects of gradual, long-term radiation exposure is entirely false, a lot of people would make that choice anyway.

3 hours ago, Spacescifi said:

Running out of fuel: How do you refuel? Gas giant skimming at orbital velocity is hardly safe. And I understand that shuttlecraft can do skimming for a mothership and return, but unless they have some uber plasma scramjets abd cad take the atmospgeric heating repeatedly, they will need to burn some of rhe gas they are storinfg for the mothership.

And what's your problem with that? All it means is reduced net productivity.

3 hours ago, Spacescifi said:

Zero habitability: Antiartica is a more reasonable choice if habitability is a concern. All known worlds in the solar system are death traps. Thus it defies my logic for any of them to have large populations if modern tech is all that is available.

And for significantly advanced tech, too.

[Spacescifi]

10 hours ago, Pthigrivi said:

I’ve really enjoyed Andy Weirs approach to hard-boiled sci-fi, just adhering as closely as possible to the most technologically and economically likely approaches and dealing with the social and emotional outcomes. What would a society start to look like so separated by time and space from their home-world? What would this mean for relationships? Families? Power structures? Cultural traditions? Reactions to immigration and exodus? Just look at Dune—technology is always the backdrop, its how human relationships react that matters. 

I tend to agree. Every watch Dust shorts? They are short shows, but they tend to use tech as a backdrop and focus on the characters as well. Instead of wondering what fictional tech can do (a fool's errand in my opinion since it is'nt real), they focus on WHAT would this charactet do, and by extension, you the viewer.

Check thid video out, it's one of the best Dust has to offer:

 

Edited May 25, 2019 by Spacescifi
Vid

[Nuke]

jus adding a coupole zeros to the specific impulse of current gen engines is usually enough to suffice. usually such gains in isp usually mean less thrust. but if you can have your cake and eat it too then why not.

[Guest]

Jesus man, how many threads have you started on the lounge this week? The thing's looking like a spam bot took over

[Vanamonde]

If a thread is not of interest to you, nobody's forcing you to click on it. 

[Guest]

I agree, however the spam-ish nature of these threads are pushing threads that not only me, but others who are not particularly interested in this subject, would be likely interested in to the second page, which is usually where threads are doomed to die off since it's rarely checked. 

Make a general thread about sci-fi discussion instead of posting 10 different ones, just like how the Science and Spaceflight subforum has a general "ask questions here" thread to avoid it. Not only that, I have a feeling that some of those spam threads aren't even in the right subforum (this should go in Science and Spaceflight)

 

Edit: I mean look at this, the guy has created 21 threads, twenty one threads over the course of 12 days. That's 1.75 new threads generally about the same subject per day by one guy. You're telling me this isn't spam?

Edited May 28, 2019 by Guest

[razark]

On 5/24/2019 at 9:46 PM, Spacescifi said:

But they are helped along by antigravity shielding which shields the ship from gravity, allowing it to float like a balloon in the air. With that assist, even saucer shaped ships are a viable means to escape the atmosphere.

There's your answer.  Throw on random bits of BS, and solve any problem you don't like the (real) answer to.

It's science fiction.  Whatever you need to make your story work is what you add.  Why assume the laws of physics for one thing hold true, if you can just put in a convenient exit ramp anywhere you want?

[Guest]

10 minutes ago, razark said:

Why assume the laws of physics for one thing hold true, if you can just put in a convenient exit ramp anywhere you want?

No, dude, you gotta spam new threads, right, just straight up spam new threads

Edited May 28, 2019 by Guest

[razark]

1 minute ago, Aperture Science said:

No, dude, you gotta spam new threads, right, just straight up spam new threads

The fact is, my response would be the same in nearly all the threads.

[Guest]

5 minutes ago, razark said:

The fact is, my response would be the same in nearly all the threads.

Exactly - it's 21 different shades of the same thing, self-answering questions that could've easily occupied only one thread instead of making it so that whenever you open up the lounge, oops there it is 30 pages of "inexistent technology how" or "theoretical aliens in practice how" instead of actually meaningful threads; this isn't even the right subforum

Edited May 28, 2019 by Guest

[DAL59]

I would recommend r/worldbuilding 

[Mikki]

If i would write Sci-Fi (which i don`t, but i read and know some classics),

I would go with a (alien-) drive that defies current human knowledge completly.

"My" aliens would travel the galaxy by drawing unlimited energy from a higher (or folded, unobserved) dimension, creating some kind of a warp "bubble" or a condition unknown to us around any desired shape/mass and move it around with way superluminal speeds, say, 100`000 c. They may be even capable to cross the voids between galaxies and superclusters. Any normal matter that crosses the trajectory of said "bubble" would simply desintegrate to nice vacuum energy and seize to exist. No problem crashing protons, molecules, dust specs, or solid planets. Planets may suffer serious punctuation nonetheless. 

They could travel through stars, black holes, neutronstars... (umm, maybe not...), whatever, since they simply "cop out" of our universe`s physical conditions.

There are no other "reasonable" means known to us doing so, but any advanced technology looks like magic to the ones that didn`t knew about before.

Edited May 28, 2019 by Mikki
spell

[Spacescifi]

4 minutes ago, Mikki said:

If i would write Sci-Fi (which i don`t, but i read and know some classics),

I would go with a (alien-) drive that defies current human knowledge completly.

"My" aliens would travel the galaxy by drawing unlimited energy from a higher (or folded, unobserved) dimension, creating some kind of a warp "bubble" or a condition unknown to us around any desired shape/mass and move it around with way superluminal speeds, say, 100`000 c. They may be even capable to cross the voids between galaxies and superclusters. Any normal matter that crosses the trajectory of said "bubble" would simply desintegrate to nice vacuum energy and seize to exist. No problem crashing protons, molecules, dust specs, or solid planets. Planets may suffer serious punctuation nonetheless. 

They could travel through stars, black holes, neutronstars... (umm, maybe not...), whatever, since they simply "cop out" of our universe`s physical conditions.

There are no other "reasonable" means known to us doing so, but any advanced technology looks like magic to the ones that didn`t knew about before.

Surely they have some limitations right?

Sounds interesting though. If they do classic 'alien' (READ human) stuff they will also conduct trade and war with other races.

The drive sounds familiar though

 Kind of like an upgraded like an upgraded alcubierre warp drive.

[Mikki]

2 minutes ago, Spacescifi said:

Surely they have some limitations right?

Sounds interesting though. If they do classic 'alien' (READ human) stuff they will also conduct trade and war with other races.

The drive sounds familiar though

 Kind of like an upgraded like an upgraded alcubierre warp drive.

Caveats are inevitable, like disappearing randomly to literrally nowhere by a certain chance, which makes the use of this propulsion rather "kafkaeske".

Imagine a tradejourney or a simple sunday morning coffee-and-cake meeting with the neighbours around ten stars away and oh crap, the whole shebang worth a million workhours including some "VIP"s went down the rabbithole, never to be found again.

 God-like technology, but with a horrible twist.

[linuxgurugamer]

I actually wrote up some fairly detailed background for a project (long since abandoned)

Essentially my universe would have multiple ways of doing FTL.  but I actually like the Honor Harrington universe and the way that David Weber approaches it.

One method of FTL, but wormholes allow you to shortcut the normal travel process.  Wormhole travel is instantaneous, but requires extremely precise entry both in vector and speed.  Hyperspace is an alternate parallel dimension, i which while still limited to about 60-70% of he speed of light, but the speed in hyperspace is a very large multiple of the speed in normal space, so traveling at 50% speed of light for a day would actually cover about 1/2 a lightyear; ie:  when you leave hyperspace, you would be about 1/2 lightyear from where you started

[Spacescifi]

11 minutes ago, Mikki said:

Caveats are inevitable, like disappearing randomly to literrally nowhere by a certain chance, which makes the use of this propulsion rather "kafkaeske".

Imagine a tradejourney or a simple sunday morning coffee-and-cake meeting with the neighbours around ten stars away and oh crap, the whole shebang worth a million workhours including some "VIP"s went down the rabbithole, never to be found again.

 God-like technology, but with a horrible twist.

Well, it that had better not be a 50% chance. Otherwise whobwould use it?

It would have to be reasonably reliable. At least as much as your average airliner I suppose.

[DDE]

17 hours ago, DAL59 said:

I would recommend r/worldbuilding 

While crossposting to somewhere like r/fantasyworldbuilding.

The massive mod team is pretty heavy-handed and insufferable, r/fantasyworldbuilding (name non-indicative, it is sci-fi-friendly) is full of people that got banned on its bigger progenitor.

[MaxxQ]

 

<----- HMS Fearless, modeled by me as a member of BuNine.  Other Honorverse ships can be seen here: https://www.deviantart.com/maxxqbunine

A few videos I made years ago: 

https://www.youtube.com/watch?v=byq68MjOlJU&amp;t=1s  

https://www.youtube.com/watch?v=i99Ufp_wAnQ

https://www.youtube.com/watch?v=fy8e-3lrKGE

 

On 5/28/2019 at 3:36 PM, linuxgurugamer said:

<minor snippage>

Essentially my universe would have multiple ways of doing FTL.  but I actually like the Honor Harrington universe and the way that David Weber approaches it.

One method of FTL, but wormholes allow you to shortcut the normal travel process.  Wormhole travel is instantaneous, but requires extremely precise entry both in vector and speed.  Hyperspace is an alternate parallel dimension, i which while still limited to about 60-70% of he speed of light, but the speed in hyperspace is a very large multiple of the speed in normal space, so traveling at 50% speed of light for a day would actually cover about 1/2 a lightyear; ie:  when you leave hyperspace, you would be about 1/2 lightyear from where you started