Jump to content

A Spring/Gas Based Impulse Space Propulsion System


Recommended Posts

The concept: Springs. Gas. A heavy metal plate, and another plate of less weight to absorb the impact from the heavy metal plate, perhaps coated with rubber, and definitely with pistons to absorb the impact force.

Propulsion: The pusher plate is propelled via gas jet thrusters using stored gas. The plate is extended away from the ship as the coiled springs stretch. The gas does not escape into space because a fabric sheath stretches out along with the heavy plate as it extends.

The gas stops firing and wham! The plate smashes into the impulse receiver plate providing forward impulse.

Granted, you cannot reach orbit with this, but once in orbit I think it could be useful.


Could this work? Is there ANY reason in known physics why it would not? Because this seems like a way to NOT expend propellant and still get impulse, and it is a WHOLE lot easier than fission, fusion, antimatter and what have you.

The gas would also be recaptured when the plate ran low by suction fans inside the propulsion plate.

 

Want more impulse? Make tighter coiled or longer springs I presume.

 

What do you think?

Is this KISS at work?

Did I just unknowingly invent the reactionless drive (not actually but no propellant is lost so..)?

Link to post
Share on other sites

I dont even know where to begin

4 minutes ago, Spacescifi said:

Propulsion: The pusher plate is propelled via gas jet thrusters using stored gas. The plate is extended away from the ship as the coiled springs stretch. The gas does not escape into space because a fabric sheath stretches out along with the heavy plate as it extends

As the pusher plate moves in one direction, the rest of the vessel moves in the opposite direction

 

5 minutes ago, Spacescifi said:

he gas stops firing and wham! The plate smashes into the impulse receiver plate providing forward impulse.

The springs connected to the plate are also connected to the vessel, so as the plate gets plled towards the vessel, the vessel is pulled towards the plate.  The impact will result in nothing except possible RUD.

For every action, there is an equal and opposite reaction, resulting in zero effect

Link to post
Share on other sites

You know that astronauts in free-floating EVA can't get anywhere just by bending and stretching their legs, right ? They have thrusters for a reason...

(they could get somewhere IVA but that's more to do with having an atmosphere to practically swim around.)

Edited by YNM
Link to post
Share on other sites
28 minutes ago, linuxgurugamer said:

I dont even know where to begin

As the pusher plate moves in one direction, the rest of the vessel moves in the opposite direction

 

The springs connected to the plate are also connected to the vessel, so as the plate gets plled towards the vessel, the vessel is pulled towards the plate.  The impact will result in nothing except possible RUD.

For every action, there is an equal and opposite reaction, resulting in zero effect

 

It sounded good at first anyway.

I thought that if one part of the ship weighed heavier than the other that the impact might impart impulse.

 

I thought magnets may help but they also do the whole newtonian thing.

 

Link to post
Share on other sites

Accelerating a giant space bat to hit a ball won't save any energy compared to just putting a rocket on the ball.

If the pusher plate is in any way connected to the projectile, it will not move the projectile. "You gotta leave something behind."

Interstellar - Detach on Make a GIF

1 hour ago, Spacescifi said:

Did I just unknowingly invent the reactionless drive (not actually but no propellant is lost so..)?

Pro tip: If you ever find yourself asking this question, you need to draw a Free Body Diagram.

Link to post
Share on other sites

[snip]

Space manufacturing. Is. Hard.

Also expensive.

The ISS is primarily a research outpost for manned spaceflight science data.

They would have to retrofit the station in order to really make it an industrial base.

 

Challenge #1: Refining ore in Earth often involves water. Shipping water to and from the ISS regularly would be expensive, but possible. There are also many other components, like the need for a centrifuge due to the lack of gravity and making sure the whole station won't spin opposite when the industrial centrifuge starts spinning.

Challenge #2: Heavy station's deorbit faster. Weight still matters. If the ISS is heavy industry in LEO, we would have to reboost it more often. It's a cost factor, meaning if we are'nt even breaking even profit-wise...you already know. I actually covered this in:

https://forum.kerbalspaceprogram.com/index.php?/topic/197139-doa-scifi-tropes/page/4/

Edited by Snark
Redacted by moderator
Link to post
Share on other sites
33 minutes ago, Spacescifi said:

Heavy stations deorbit faster.

No, this is not true. Absent drag, nothing de-orbits. With drag, generally speaking, a heavier object experiences less deceleration due to drag (more force, but not as much more force as more mass, and acceleration = force/mass), and so it is more resistant to de-orbiting than a light object.

Although it will require more fuel to counter the drag, because this time the extra mass works against you.

But if you had one heavy station compared to two light stations of equal total mass, you probably need a little less fuel to keep the one heavy station in orbit than the two light stations.

Edited by mikegarrison
Link to post
Share on other sites
1 hour ago, Spacescifi said:

Heavy station's deorbit faster.

Drag is what makes things deorbit, not inertial/gravitational mass. Drag is related with surface area - L2 - while Mass is related to volume - L3.

That means that most singular/monolithic thing of larger mass will have less area per mass than a smaller thing.

Less area, less drag - more mass, more inertia, harder to push around.

Also this drag is only significant in the immediate vicinity of bodies with atmospheres.

What you're thinking is that it does need more fuel to keep it in orbit, but that's more to the increased mass, if you try to plug it into fuel needed per mass of object I'm sure you end up needing less.

6 hours ago, Aperture Science said:

You do not have to collect all the gases. You just have to need to collect some of it badly enough to be viable design.

So basically ion engines ? They already have a grid before the exhaust. (yes the grid is used for acceleration in this case but I'm sure they trap a thing or two, and making sure only certain ion charge get past)

5 hours ago, Aperture Science said:

Why do we need only multi ton or 100's of pound gold covered satellites when we could get away with much less and much more.

It's called Kapton. Much better both in strength/mass and in temperature tolerance than your garden variety trash bag already. Gold plating (which can be only a few atoms of gold thick, they might have got it down to only one layer of atom) has to do with having to make it reflective so it doesn't absorb much heat (which, in space, you can only release it again radiatively through black-body radiation).

Edited by YNM
Link to post
Share on other sites
1 hour ago, mikegarrison said:

No, this is not true. Absent drag, nothing de-orbits. With drag, generally speaking, a heavier object experiences less deceleration due to drag (more force, but not as much more force as more mass, and acceleration = force/mass), and so it is more resistant to de-orbiting than a light object.

Although it will require more fuel to counter the drag, because this time the extra mass works against you.

But if you had one heavy station compared to two light stations of equal total mass, you probably need a little less fuel to keep the one heavy station in orbit than the two light stations.

 

True...I was trying to avoid getting into the details so I misspoke.

Link to post
Share on other sites
11 hours ago, StrandedonEarth said:

These concepts remind me strongly of this, because that's about what it amounts to...

cdf98ec44d68c157f25edcb78870a146.gif

Who would work, you blow on the sail, the wind is reflected and this pushed the boat forward.
Mythbuster tested this with an huge fan and a sail, they did not expect the boat to move :)
This is obviously very inefficient over just pointing the fan backward, and fans are less efficient than propellers so they are only used then you can not use propellers as on swamp boats and hovercraft.
In space its no air you can move so you has to use reaction mass.

Yes its some tricks you can use, solar sails, using magnetic fields. An magnetic launcher will work, as in it works just like an cannon with recoil.
 

Link to post
Share on other sites
12 hours ago, Aperture Science said:

I don't see where the argument is against this.

Say it all goes according to plan, you accelerate the fuel and somehow end up with the oxidizer back.  What are you going to use the oxidizer for, exactly?  There's less fuel, so you're just ending up with extra weight, because of the fixed oxidizer/fuel ratio.  At this point, you should just use NTRs or ion thrusters.

Link to post
Share on other sites
15 hours ago, StrandedonEarth said:

These concepts remind me strongly of this, because that's about what it amounts to...

cdf98ec44d68c157f25edcb78870a146.gif

Well that actually could work, if you had a strong enough fan. Not efficient though.

Catching spent propellant for a rocket though... not gonna work. You'll get nowhere fast.

Link to post
Share on other sites
On 11/29/2020 at 9:49 AM, Spacescifi said:

Could this work?

No.

Quote

Is there ANY reason in known physics why it would not?

Yes. Physics.

Quote

Because this seems like a way to NOT expend propellant and still get impulse....

This is why it would not work.

[snip]

Edited by Snark
Redacted by moderator
Link to post
Share on other sites

Some content has been redacted and/or removed.

Folks, please don't troll or mock others.  This is a friendly community and we're all pals here (right?), and it's never okay to try to build yourself up by putting someone else down.

If you see someone making an argument that you think is silly or wrong, then by all means dispute them-- friendly debate is welcome.  ;)  But please, do so in good faith by explaining the reasons you think they're wrong, not by trying to ridicule.  It doesn't solve anything and just makes the forum less pleasant for everyone.  Or, if you think making a reasonable counter-argument would be too much trouble and can't be bothered, then just stroll on by.

Unfortunately, there was also some unavoidable collateral damage. Some posts by blameless participants also needed to be removed, as they were innocently responding to the removed content and their posts no longer made sense with the referents removed. To those thus affected, we're sorry. :(

Thank you for your understanding.  Unlocking the thread now-- I trust we can all play nicely?

Link to post
Share on other sites
22 hours ago, Bill Phil said:

Well that actually could work, if you had a strong enough fan. Not efficient though.

Catching spent propellant for a rocket though... not gonna work. You'll get nowhere fast.

Note that trust reversal on jet engines work just like this :)
You redirect the air from the turbofan to blow forward, no its not efficient but it help braking. 

Link to post
Share on other sites

To check if a propulsion system in space can work, you put a box around it and ask 3 questions:

1) does anything leave the box?

2) does anything enter the box?

3) do the contents of the box push/pull against something outside the box?

Unless you answer yes to at least one of those questions, the known laws of physics say that your box cannot move.

Rockets, ion thrusters, orion, etc,  say yes to #1

Solar sails and external laser propulsion say yes to #1 and #2(solar wind/laser enters, pushes on the craft, and then leaves the box)

Anything in orbit uses gravitational pull between that object and the earth for #3 (a tiny pull from the vessel on the huge planet, and a reciprocal pull from the huge planet on the tiny vessel)

The experimental magnetic systems I remember seeing also say yes to #3(pushing against the earth's magnetic field to make minor orbital adjustments if I remember correctly)

 

The amount of acceleration that is provided is equal to the energy of whatever is leaving compared to the remaining mass inside the box for #1, or the difference between entering and leaving compared to the mass inside the box for #2, and for #3, acceleration is the total force put on the external object compared to the mass inside the box.

This is true for any box of any size, so while sticking your arm outside the box might slightly shift the contents of that particular box(as the center of mass inside that box no longer includes your arm), but compared to a slightly larger box, the center of mass never moves.

(yes, a box around the solar system lets you measure how much your ship traveling from Earth to Jupiter moved the center of mass of the solar system based on how much of your expelled reaction mass leaves the box compared to the mass of the soar system.  Probably not at all unless you had a very high exhaust velocity however)

If there is a box that can be drawn around your ship where nothing enters, leaves, or acts on an outside body, then the laws of physics say that the center of mass of that box will not move, regardless of how you rearrange the contents of that box.

Edited by Terwin
Adding gravity pulls for orbits
Link to post
Share on other sites
2 hours ago, Terwin said:

To check if a propulsion system in space can work, you put a box around it and ask 3 questions:

1) does anything leave the box?

2) does anything enter the box?

3) do the contents of the box push/pull against something outside the box?

Unless you answer yes to at least one of those questions, the known laws of physics say that your box cannot move.

Rockets, ion thrusters, orion, etc,  say yes to #1

Solar sails and external laser propulsion say yes to #1 and #2(solar wind/laser enters, pushes on the craft, and then leaves the box)

Anything in orbit uses gravitational pull between that object and the earth for #3 (a tiny pull from the vessel on the huge planet, and a reciprocal pull from the huge planet on the tiny vessel)

The experimental magnetic systems I remember seeing also say yes to #3(pushing against the earth's magnetic field to make minor orbital adjustments if I remember correctly)

 

The amount of acceleration that is provided is equal to the energy of whatever is leaving compared to the remaining mass inside the box for #1, or the difference between entering and leaving compared to the mass inside the box for #2, and for #3, acceleration is the total force put on the external object compared to the mass inside the box.

This is true for any box of any size, so while sticking your arm outside the box might slightly shift the contents of that particular box(as the center of mass inside that box no longer includes your arm), but compared to a slightly larger box, the center of mass never moves.

(yes, a box around the solar system lets you measure how much your ship traveling from Earth to Jupiter moved the center of mass of the solar system based on how much of your expelled reaction mass leaves the box compared to the mass of the soar system.  Probably not at all unless you had a very high exhaust velocity however)

If there is a box that can be drawn around your ship where nothing enters, leaves, or acts on an outside body, then the laws of physics say that the center of mass of that box will not move, regardless of how you rearrange the contents of that box.

 

Thank you Terwin.

In simple terms, you cannot get forward mpulse with a closed system because the back wall will hit you and cancel out any forward impulse you gain.

 

Unless we broke physics.

You would have to cancel out the g-force from acceleration felt ONLY from inside the ship's hull that are caused from outer hull accelleration only, but let it remain with the outer hull.

With that, you could hit the forward inner  wall and that would be enough to push the ship forward.

 

 

Link to post
Share on other sites
On 12/1/2020 at 9:29 PM, magnemoe said:

Note that trust reversal on jet engines work just like this :)
You redirect the air from the turbofan to blow forward, no its not efficient but it help braking. 

Yeah but a turbofan takes external air and direct it back where it came from... while that might amount to some re-turning air, most of the air is still external-to-external.

7 hours ago, Terwin said:

If there is a box that can be drawn around your ship where nothing enters, leaves, or acts on an outside body, then the laws of physics say that the center of mass of that box will not move, regardless of how you rearrange the contents of that box.

To be fair it might be already moving in the first place, you just can't change how it moves.

7 hours ago, Terwin said:

Anything in orbit uses gravitational pull between that object and the earth for #3 (a tiny pull from the vessel on the huge planet, and a reciprocal pull from the huge planet on the tiny vessel)

Depends on what views do you take XD anything in perfect free-fall trajectory would simply follow the geodesic and not experience any change in acceleration according to the later-time 'theory' (really should be called something else as it's been proven to be true).

Edited by YNM
Link to post
Share on other sites
8 hours ago, Terwin said:

3) do the contents of the box push/pull against something outside the box?

What we really need to do is find something new outside the box to push/pull against. Antigrav, quantum foam, aether, fabric of space-time, zero-point energy, something. That is what we need for a propellantless space drive that's more energy-efficient than a photon drive.

Link to post
Share on other sites
4 hours ago, YNM said:

Yeah but a turbofan takes external air and direct it back where it came from... while that might amount to some re-turning air, most of the air is still external-to-external.

I was referring to using an forward blowing fan to blow at an sail to move forward who is inefficient compared to an rearward facing fan. 
However its an lightweight way to get forward trust. 

Link to post
Share on other sites
1 minute ago, magnemoe said:

I was referring to using an forward blowing fan to blow at an sail to move forward who is inefficient compared to an rearward facing fan. 
However its an lightweight way to get forward trust. 

Well the original drawing was someone blowing air around with their mouth... to be fair those air came from the surrounding air and not internal to the person.

Link to post
Share on other sites
This thread is quite old. Please consider starting a new thread rather than reviving this one.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...