Sublimation process for deep space propulsion

[vikram_gupta11]

I just thought about "SUBLIMATION METHOD" for deep space propulsion.
As per sketch if camphor solid heated then the vapor will be ejected  and a thrust will be created to propell the craft.
The camphor vapor will be again deposited on a surface to reuse again and again.
The deposited camphor can be reused several time and it is technically possible.
Now my question is that should this method will work to propel the spacecraft without spring??
Second if it doesn't work without a spring and if i use a spring then should it work  as the deposited camphor will work to stretch the spring after each 3 second(the vapor will be ejected after each 3 seconds) and the spring will again compressed, pushing the craft.

[Welsh Dragon]

The deposition will cancel out the sublimation. Conservation of momentum.

[vikram_gupta11]

Yes you are correct but what about  stretching of spring at the time of depostion.
The sublimation will be cancelled out due to deposition but at the same time spring is being stretched so if spring compress again after 3 seconds then it must push the craft.
Sublimation=deposition+stretching the spring
But
Compression of spring??

[tyrred]

Yes you are correct but what about  stretching of spring at the time of depostion.
The sublimation will be cancelled out due to deposition but at the same time spring is being stretched so if spring compress again after 3 seconds then it must push the craft.
Sublimation=deposition+stretching the spring
But
Compression of spring??

It's not a perpetual motion machine.

[vikram_gupta11]

I am interested in compression of spring.

[tyrred]

I am interested in compression of spring.

Ok. Then show your work for what the spring is composed of and what work does. Springs are very well known.

I'm not trying to be a d*ck here.  If you are interested in proposing a new propulsion method, be aware that there is a very large data set of proposed ideas that have been proven to be not viable.

Consequently there is a smaller set of rigorously tested ideas that have borne fruit.

You can choose to be your own worst critic, pick apart every criticism you can imagine anybody else would have, and address how your proposal would win out against the criticisms, and then publish your work for peer review.

You can also propose a new idea, then push the work off onto others who may be interested.  Good luck with that.

[vikram_gupta11]

Dear sir,
You are right. I know about it.
I just thought about this Idea and consult with a scholar before posting it in this forum.
The scholar is also in confusion regarding the feasibility.
There is need of some work on it as it is a new propulsion method. I have consider every point about it.
It is very simple method that i myself is not finding any fault in it.
There is need of technic work on it. If i get technical support then can proove viability of this idea.
Thankyou Sir.

[Wicky]

You could build a small scale rocket to test your idea

Camphor has been used as a consituent in explosives - so you may risk harm to your person and gain the attention of your local police.

https://en.wikipedia.org/wiki/Ballistite

Maybe substitute a firework with a spring and plate underneath and stand very well back!

[Twark_Main]

I am interested in compression of spring.

This is probably futile, but...

When the spring compresses, it will pull the spaceship backwards with the same force × time = momentum as was used to stretch it (ie the forward thrust). Spring or no spring, it makes no difference to your design. This will not work, I'm 100% sure of it.

The only way this could produce net thrust is if some camphor leaks past the plate, but then a!l you've done is make a very inefficient rocket.

Conservation of momentum has no exceptions, I'm afraid. At least without relying on entirely new physics laws (which this design, as I'm sure even you will agree, does not).

It won't work. Sorry to have to be the one to burst your bubble.

You may be tempted to reply, "but _." Sorry, no buts. No exceptions. No loopholes. It just won't work.

[vikram_gupta11]

@Twark
Dear Sir,
You are forgetting that ejection of vapor to push the craft forward but at that time the vapor is getting deposited on the surface of plate or the forward force is being cancelled out due to stretching of spring or stretching of spring is already pulling back the craft.
So net force is 0.
But when spring will compressed again after 3 second then the compression will create thrust to push the craft.
What you are suggesting is already cancelled out but compression of spring will  be not cancel out and it will work as a thrust.
If spring doesn't compress again then net force is 0 but if it is compressing then there is thrust
Ejection=stretching of spring
Compression =thrust
If compression of spring will work to pull the craft then how will you define third law??

[vikram_gupta11]

Spring will get its initial position after stretching so i dont think it will bounce again and again.
It will be locked in its initial position after compression creating a thrust.
If spring doesn't bounce back after getting initial position or compression then it will not pull back the craft.

[Lee Jay]

@Twark
Dear Sir,
You are forgetting that ejection of vapor to push the craft forward but at that time the vapor is getting deposited on the surface of plate or the forward force is being cancelled out due to stretching of spring or stretching of spring is already pulling back the craft.
So net force is 0.
But when spring will compressed again after 3 second then the compression will create thrust to push the craft.
What you are suggesting is already cancelled out but compression of spring will  be not cancel out and it will work as a thrust.
If spring doesn't compress again then net force is 0 but if it is compressing then there is thrust
Ejection=stretching of spring
Compression =thrust
If compression of spring will work to pull the craft then how will you define third law??

Yeah, it will work, but not how you think.

The craft will move forward because the camphor moved to the back. Once all the camphor is at the back, it will stop moving. Because of conservation of momentum the center of gravity will not move and the velocity will not change from what it was at the beginning.

It's like propelling the ISS by an astronaut pushing off the front toward the back (velocity vector-wise). The ISS will move forward (slightly) until the astronaut stops at the back, thus slowing the whole thing back to original velocity.  Same thing.

Don't argue. Conservation of momentum isn't just a good idea...

Your idea isn't a rocket. The spring is entirely irrelevant.

[armchairfan]

[an idea]

The great thing about science is that you don't have to trust a bunch of "experts" who say that your idea won't work. (Though in most cases, including this one, you'll save time if you do.) You can do the experiment yourself.

Instead of using camphor and an elaborate system of heating, ejection, deposition, and recycling, just use a fan that exhausts air in the same direction as your camphor nozzle. The air will hit the far end of the rocket and automatically be pulled back and recycled to do it again. It's an easy experiment, too. Just put a small portable fan in a shoebox, close the lid, waterproof the bottom with aluminum foil, and put it in a bathtub. Note which direction the closed box moves.

It's a bit more of a challenge to add a spring to the experiment but you might decide that it wouldn't make any difference other than make your rocket expand a bit.

Now you might devise an elaborate method that repeatedly compresses a long spring and fires a projectile at the back of the box. You might even get this shoebox rocket to work (i.e., move) if you put it on a tabletop instead of in a bathtub.

Other scientists are trying to do something similar (unsuccessfully to date) to drive a probe into the Martian subsurface. (Check out the link. The animation might help build your intuition.)

The key in both cases is friction with the rocket's/probe's environment. However, it's best not to rely on friction with the environment when you're in space. 

[vikram_gupta11]

Dear sir,
Can you please explain that why spring is irrelevant in this mechanism if i stretch the spring with a fireball and spring again get its initial position, pushing the craft?

I did bathtub experiment using some rubber bands but results showed me feasibility.

[Crispy]

Dear sir,
Can you please explain that why spring is irrelevant in this mechanism if i stretch the spring with a fireball and spring again get its initial position, pushing the craft?

I did bathtub experiment using some rubber bands but results showed me feasibility.

Highschool physics should teach you that action=reaction. You cannot stretch the springs without transferring force. Your idea can be analysed as making a closed box move by jumping around inside it. Conservation of momentum means that no net movement is possible. Bathtub experiments are not neccesary, as these physcial laws were comprehensively proved centuries ago.

[vikram_gupta11]

So you mean it is a closed system and there is no momentum.
You mean spring will be not stretched in this mechanism if the camphor jet hit the plate connected with spring.
Is it correct?

[Crispy]

So you mean it is a closed system and there is no momentum.
You mean spring will be not stretched in this mechanism if the camphor jet hit the plate connected with spring.
Is it correct?

It's a closed system. Don't think about springs; they may as well be rigid when it comes to calculating the momentum of the whole object. Don't think about sublimation and condensation either; you're just moving  particles from one side to the other. It's like sitting inside a box, throwing wet clay at the other wall and expecting it to move. It won't.

[laszlo]

A bathtub is actually not a good place to test this. As the device's center of gravity moves, so does its center of buoyancy. Not only will the device oscillate forward and backwards, it will rock. Depending on the frequency, this can lead to the water acting as a brake in one direction and as reaction mass in the other. Momentum will be conserved and the device will appear to work. But it will only only work in a tub of water with the right frequency of oscillation. Take it out of the tub and put it into a vacuum between planets and it will just sit there.

[Lee Jay]

Dear sir,
Can you please explain that why spring is irrelevant in this mechanism

A spring doesn't do anything but store energy (mechanically) for later release.  It's not an energy source and so it can't be a source of thrust either.  Work = force * distance so, since a spring can do no net work, it can apply no net force through a distance.

[Twark_Main]

@Twark
Dear Sir,
You are forgetting that ejection of vapor to push the craft forward but at that time the vapor is getting deposited on the surface of plate or the forward force is being cancelled out due to stretching of spring or stretching of spring is already pulling back the craft.
So net force is 0.
But when spring will compressed again after 3 second then the compression will create thrust to push the craft.
What you are suggesting is already cancelled out but compression of spring will  be not cancel out and it will work as a thrust.
If spring doesn't compress again then net force is 0 but if it is compressing then there is thrust
Ejection=stretching of spring
Compression =thrust
If compression of spring will work to pull the craft then how will you define third law??

Sigh. What did I say about futility?

No, I did not "forget" the spring. It's just that the spring is totally irrelevant. And before you suggest it, it wouldn't work with magnets or tethers or pneumatic/hydraulic cylinders either. All of these various mechanical devices have been thoroughly studied, and they have all been found not to violate the conservation of momentum.

The spring and plate returning back to neutral will also impart no net thrust. In the first half of the return stroke the spring accelerates toward the craft, then in the second half of the return stroke it decelerates to match velocity with the craft. These two accelerations will exactly cancel out. Here I am assuming the spring mechanism is fully damped, but it would work exactly the same if the spring "bounced" multiple times.

Sorry, it simply won't work. Countless people before you have suggested the same type of idea (just as countless people have "invented" free energy devices), but none of these ideas actually work. A similar (and equally impossible) idea was posted on NSF just last month: https://forum.nasaspaceflight.com/index.php?topic=50263.0

And a few more (including some threads you yourself started):

https://forum.nasaspaceflight.com/index.php?topic=50106.0

https://forum.nasaspaceflight.com/index.php?topic=49294.0

https://forum.nasaspaceflight.com/index.php?topic=49647.0

https://forum.nasaspaceflight.com/index.php?topic=49285.0

We're not "confused" either (as you claimed of your unnamed scholar). We understand the idea perfect!y well, but we also understand that it's completely unworkable. Changing a few details won't fix it either; it's fundamentally impossible to make it work.