Fun With Rocketry And Portals In The Solar System

[Spacescifi]

 

 

Realistically you will be putting moon regolith product in your propellant tank. Why?

Imagine we have portals that link propellant supply depots on Earth or elsewhere to spaceships in space. Max range of portals is 7 lightseconds.

Which is fine for Earth to moon constant acceleration travel... just feed the tank. But past the moon you would need to set up a moon supply base first with a portal. Extending range beyond the moon for 7 light seconds. After that your on your own. Coast away and use propellant judiciously.

 

Bonus question: How fast could we get to Mars with this tech setup? I know it makes SSTO's easy so long you are wiling to foot the propellant bill. But it also means that moons are now looked at as bases for propellant processing facilities. 

I guess one could in theory send up spacecraft to orbit every 7 lightseconds from Earth with portals. Extending portal range and therefore constant acceleration range dramatically.

Just chain portal swap propellant from Earth to any constant accelerating ships in range and continue the chain.

This would even allow astronauts to just wait out the trip on Earth until they get in low orbit of Mars for landing.

 

Edited December 12, 2019 by Spacescifi

[razark]

Instead of moving fuel with portals, why not just use the portals to transport people/things?

[Spacescifi]

4 minutes ago, razark said:

Instead of moving fuel with portals, why not just use the portals to transport people/things?

 

You can. But I put the 7 light second range for a reason. 

Just to make rocketry and ISRU still relavent.

 

In order to portal people from Earth directly to Mars would be expensive.

Mars at closest orbital approach is about 3 light minutes away.

So you would need a whole fleet of ships to chain portals every 7 light seconds to mars.

You would need over 30 vessels. Possibly 80 in the chain. And they would have to fly into position first. Which would take months of coasting.

 

[razark]

12 minutes ago, Spacescifi said:

In order to portal people from Earth directly to Mars would be expensive.

How expensive?  Without data, there's nothing to compare.

[Spacescifi]

29 minutes ago, razark said:

How expensive?  Without data, there's nothing to compare.

 

I am not counting the portals, as they are a plot device. Let's say portals are cheap.

 

So all main cost goes into the chain link fleet of spacecraft holding the portals.

 

EDIT: Mars us usually farther than 3 LM away. More like over twenty minutes at lightspeed.

 

Which would mean the fleet chain link every 7 light seconds would need to be.... massive in numbers. If we wanted an Earth to Mars direct line.

Edited December 12, 2019 by Spacescifi

[kerbiloid]

As I have suggested not once, build the portals between the atmospheres and terraform them all at once.

[Terwin]

6 hours ago, kerbiloid said:

As I have suggested not once, build the portals between the atmospheres and terraform them all at once.

That would take a very long time.

https://what-if.xkcd.com/53/

Indicates it would take hundreds of thousands of years to drain the oceans using a drain 10m in radius

https://www.quora.com/What-is-the-volume-of-air-in-Earth’s-atmosphere-and-volume-of-water-on-Earth

Indicates that if the entire earth's atmosphere were at sea-level density, there would be about three times the volume of air than there is of ocean.

So really, during a human life-time you would only make a powerful wind-tunnel and mess-up weather patterns, not even considering the slow-down from lower relative pressure as you drain the earth's atmosphere.

[kerbiloid]

11 minutes ago, Terwin said:

That would take a very long time.

I agree to wait a little, unless there are faster terraforming options.

12 minutes ago, Terwin said:

Indicates it would take hundreds of thousands of years to drain the oceans using a drain 10m in radius

And of course we shouldn't touch the Earth until other bodies reach terrestrial conditions.
We have a lot of carbon (dioxide), water ice, hydrocarbons and ammonia, hydrogen, deuterium, and helium in other places.
Let's make an Earth cocktail on the major ones (Moon, Venus, Mars, Callisto, Ceres, etc.) by eliminating the icy orbital junk and making a lot of plastic.
Better have + 2 Earth surface areas with normal conditions than keep discovering 10 m wide Jupiter "moons".

By the time when the conditions get decayed and start being uncomfortable (probably, many megayears) the post-human orbital megabrains in kilometer-sized tungsten skulls will abandon the depleted Solar System and use other thousands of systems they had colonized.

[Guest]

You want fast terraforming? 

Just don't ask how it actually works (but it sure does look impressive).  

Edited December 14, 2019 by Guest

[kerbiloid]

I did terraforming myself, and not once. Just without portals.
In Spore.

[sevenperforce]

Obligatory:

[kerbiloid]

Actually originally the idea came to me from the Ph.J.Farmer's "The World of Tiers".

Edited December 14, 2019 by kerbiloid

[KerikBalm]

Put a portal on mercury/ low jupiter orbit/low solar orbit, teleport a ship 7 light seconds out, let it fall back to the portal, teleport again, and again, and again, until it is arbitrarily close to the speed of light, teleport to 7 light seconds away, 180 degrees from where you've been teleporting it (so its velocity carries it away from the portal), enjoy your reactionless drive.

[AngrybobH]

The reactionless drive idea makes me ask the question, does the teleported object retain its' momentum? If it does, then teleporting fuel to ships from earth(or anywhere) could have some nasty consequences. If your fuel is now moving in any direction with a high velocity relative to the ship, you could have real problems. I'd prefer scifi as a genre to forget about teleportation.

[Spacescifi]

2 hours ago, AngrybobH said:

The reactionless drive idea makes me ask the question, does the teleported object retain its' momentum? If it does, then teleporting fuel to ships from earth(or anywhere) could have some nasty consequences. If your fuel is now moving in any direction with a high velocity relative to the ship, you could have real problems. I'd prefer scifi as a genre to forget about teleportation.

 

 

Scifi is a matter of separating physics  what does not work and keeping what does.

Cherry picking if you will.... necessary with capabilties we cannot conceive a way of acomplishing.

 

So here is what to do"

 

A: Spaceship retains original momentum... which makes all easy.

 

Teleport from the ground to deep space several light seconds from Earth. Gravity is so weak that any propellant teleported won't have that a big of a speed difference.

[kerbiloid]

11 hours ago, AngrybobH said:

The reactionless drive idea makes me ask the question, does the teleported object retain its' momentum? If it does, then teleporting fuel to ships from earth(or anywhere) could have some nasty consequences. If your fuel is now moving in any direction with a high velocity relative to the ship, you could have real problems. I'd prefer scifi as a genre to forget about teleportation.

It just can require a zero balance.
1 kg of water there
1 kg of rocks here

(In this case, of course, the reactionless drive looks problematic.
Though, terraforming is still ok.)

P.S.
This in turn, raises a question.
If the portal is a neutrally balanced matter exchanger, then it sends protons, neutrons, and electrons between two sites.

But they are similar!
So, why send the particles itself. instead of their rearranging in place.

All we need is information (a particle position scanner) and energy to relocate them.

Edited December 19, 2019 by kerbiloid

[KerikBalm]

11 hours ago, Spacescifi said:

Scifi is a matter of separating physics  what does not work and keeping what does.Cherry picking if you will.... necessary with capabilties we cannot conceive a way of acomplishing.

No, it isn't. That's fantasy, or as I like to call it, fictional science fiction. There's plenty of Sci-fi (what is normally called hard-sci fi) that absolutely obeys physics (and other branches of science) as we know it.

Quote

A: Spaceship retains original momentum... which makes all easy.

Teleport from the ground to deep space several light seconds from Earth. Gravity is so weak that any propellant teleported won't have that a big of a speed difference.

But if its retained momentum puts it on a trajectory toward the earth again, it will pick up velocity as it falls to earth, it can fall right into the portal over and over again to relativistic speeds.

As you said:

On 12/12/2019 at 9:37 PM, Spacescifi said:

Let's say portals are cheap.

Cheap or not, they become infinite energy devices, as the energy gained just keeps going up, you get a free energy device at some point, basically (just like previous FTL schemes that you've proposed that break conservation of momentum/energy, like your "SVL" drive).

I suppose this would be repeat gravity assist, and at first glance doesn't break conservation of momentum, but cheaply gaining such potential energy breaks conservation of energy.

[Spacescifi]

21 hours ago, KerikBalm said:

No, it isn't. That's fantasy, or as I like to call it, fictional science fiction. There's plenty of Sci-fi (what is normally called hard-sci fi) that absolutely obeys physics (and other branches of science) as we know it.

But if its retained momentum puts it on a trajectory toward the earth again, it will pick up velocity as it falls to earth, it can fall right into the portal over and over again to relativistic speeds.

As you said:

Cheap or not, they become infinite energy devices, as the energy gained just keeps going up, you get a free energy device at some point, basically (just like previous FTL schemes that you've proposed that break conservation of momentum/energy, like your "SVL" drive).

I suppose this would be repeat gravity assist, and at first glance doesn't break conservation of momentum, but cheaply gaining such potential energy breaks conservation of energy.

 

It appears we are talking past each other. This is not a jump drive.

 

Ever watch Stargate? 

Same concept, only range is per the OP and ships carry the gates to portal propellant through.

You could not do the gravity rinse/repeat super speed fall trick since portal gates are small to fit inside spaceships, not the other way around.

Edited December 20, 2019 by Spacescifi

[kerbiloid]

1. Put two portals horizontally onr above another, in a gravity field.

2. Make the lower one teleport things up to the upper one.

3. Enjoy.

Caution:
Very soon you'll get a Kugelblitz.

Edited December 20, 2019 by kerbiloid

[Spacescifi]

Heat from accelerating through air would destroy the object and probably damage the gate long before that.

 

On a place like the moon without atmosphere though... you could use the portals like a magnetic accelerator

 Only better, since as in stargate they are network linked,which means ypu cam start in one portal but fly out another halfway across the planet.

 

For spaceship SSTO's it make accelerating them to ramjet speed a trivial thing.

 

Thanks for the idea... 

[kerbiloid]

48 minutes ago, Spacescifi said:

Heat from accelerating through air would destroy the object and probably damage the gate long before that.

Destroy photons?

Btw, if presume a corpuscular nature of gravitation, the gravitons, should be also be teleported, shouldn't they?

Edited December 20, 2019 by kerbiloid

[KerikBalm]

5 hours ago, Spacescifi said:

Heat from accelerating through air would destroy the object and probably damage the gate long before that.

 

On a place like the moon without atmosphere though... you could use the portals like a magnetic accelerator

 Only better, since as in stargate they are network linked,which means ypu cam start in one portal but fly out another halfway across the planet.

 

For spaceship SSTO's it make accelerating them to ramjet speed a trivial thing.

 

Thanks for the idea... 

Put them in a vaccum tube, once up to speed (like .99 c), change the exit portal to one aimed at your target of choice.

Enjoy your super weapon.

Also there is an arbitrary size limit? Or you just build one big enough for ships, then every ship can start at a high fraction of c, and use a ramscoop and stored fuel to decelerate.

Also, stacked gates would allow you to move planets via a gravity tractor effect, plus it grows in power as the object accelerates and "gains" relativistic mass

[kerbiloid]

13 bln years ago someone tried...

[Spacescifi]

1 hour ago, KerikBalm said:

Put them in a vaccum tube, once up to speed (like .99 c), change the exit portal to one aimed at your target of choice.

Enjoy your super weapon.

Also there is an arbitrary size limit? Or you just build one big enough for ships, then every ship can start at a high fraction of c, and use a ramscoop and stored fuel to decelerate.

Also, stacked gates would allow you to move planets via a gravity tractor effect, plus it grows in power as the object accelerates and "gains" relativistic mass

 

No there is not a size limit, but the energy required to run a gate big enough for a large vessel tends to dwarf the energy needed to run large vessels. Smaller gates even require lots of power too, but not as much as large gates.

 

I like yout thinking though. With this logic of using gate acceleration you coukd fall through the gates for several months and then come out at high speed from an LEO gate. Then get to mars ot wherever else faster.

 

The challenge would be slowing down... since gate acceleration has more energy than your propellant will get you.

But to fix that problem you just put gate out ahead of you. Just make sure when you travel to it you fly through it. Not into the gate!

 

Actually... I can advance your gate logic further.

 

Easy Launch: Make vacuum chamber on Earth, make spaceship fall between gates until it has the speed you want, then fall out a portal either in Lunar or LEO orbit.

Easy Fast Space Travel: Carry a bunch of descending in size portal gates in your ship and a buncj of progressively smaller spacecraft.

What is this? Staging via portal gates. Accelerate a gate via a stack of portal gates, release and boom! Much faster launch of any craft you wanna launch. 

 

You could even send gates ahead of you then launch a slightly fast spacecraft to catch up with the portal to fly through it later.

 

The fun thing about this is that speed physics still applies.