As I was repairing my convection oven, replacing the heating element, I thought, could this be used to travel in space? The fan (propeller) blowing heat out of the rear of a space craft? Would this work? I look forward to reading your replies
It could work and it does work! Asteroids gain or lose orbital speed based on heat emission. If they rotate prograde (same direction as their orbit) then the sunlight will heat the surface and as they rotate a greater amount of heat is emitted in the direction that pushes them a tiny bit forward. Of course, retrograde rotation will have the opposite effect and slow them down.As I was repairing my convection oven, replacing the heating element, I thought, could this be used to travel in space? The fan (propeller) blowing heat out of the rear of a space craft? Would this work? I look forward to reading your replies
My emphasis.The fan (propeller) blowing heat out of the rear of a space craft? Would this work? I look forward to reading your replies
That's what I would like to know. CatThanks to all. I was thinking more along the lines of electricity heating the element and being recharged by the propellor? Can heat be used as an air substitute to push the vehicle along?
Yes, anything that comes off a body floating in space will behave according to Newton's law that states for any action there is an equal and opposite reaction.Thanks to all. I was thinking more along the lines of electricity heating the element and being recharged by the propellor? Can heat be used as an air substitute to push the vehicle along?
Yep, I was trying to address just the OP view.Helio, fair comment. I think you will have judged from my 'take' on the suggestion, that I am not overenthusiastic about the suggestion.
. Likewise wimpy Yarkovsky heating (Thanks Helio )wimpy IR photons (heat) radiating from a spaceship
I see that I said earlier that it could work, but I didn't mean to imply it could work for human space travel. I only meant it works in the realm of physics. This is more obvious by my info on solar sails.Fair enough, but do you see the Yarkovsky as a feasible means of controlling space travel?
I will guess sunlight pressure would move it outward by about 25x farther.Here are formulas telling how far an oven would travel in one year resulting from a given number of watts in a propulsion system using only heat (not expelled air) as thrust. Assume the oven has 1000 watts of power and weighs ten kilograms.
Force in newtons (1 newton equals about 100 grams) = number of watts divided by the speed of light (in meters per second) squared
The force will then result in a certain acceleration:
Acceleration = force in newtons divided by mass in kilograms
The velocity attained over a certain time, say one year, follows as:
V = Acceleration times time in seconds
The distance travelled:
Distance =1/2 times acceleration times time squared
For example: A 1000 watt microwave oven weighing ten kilograms allowed to go on for one year
Force = 1000 watts divided by (3e8)^2 = 1e-14 newtons
Acceleration = 1e-14 divided by 10 = 1e-15 meters per second squared
Velocity after one year = 1e-15 times 3e7 = 3.3e-8 meters per second
Distance after one year = 1/2 times 1e-15 times (3e7) squared = .45 meter
The oven would travel about half a meter.
If the photons are about 3x — I somehow thought 10x — the energy of IR photons, and you get double action in momentum (absorbed plus emitted), and at ~ 1370 watts/m at 1AU, then I crudely am now guessing a net of about 8x. But I’m goofing-off on this iPhone while visiting others.Well, I suppose sunlight pressure would be equivalent to its strength in watts which is 1300 per square meter, so it would probably be about the same, don't you think?
Oops, I forgot there would be more IR photons; a watt is a watt.Yes, must double the force due to reflection. Yes, heat oven photons are very weak but there are more of them to the watt. Counting watts causes photon energy to drop out.
Yes, but it is more an extremely poor propulsion method. Heat is often considered waste energy. [I know, of course, you know this as an engineer/scientist, but others might not.] If combustion engines could effectively use more of it, they would. Instead, they simply dump it out the exhaust.Using heat to travel in space
Are we agreed that this is not going to be a practical solution?
Never mind. It happens to all of us.I read it somewhere that astronauts use this method but don't have the source.