Space ships and manoeuvrability

In summary, the reason why space ships cannot use propellers or conventional airplane jets to move in space is because there is no air for them to use. While there may be some cosmic dust and hydrogen and helium atoms in space, it is such a tenuous amount that it would not be enough to use for propulsion. Additionally, the mean free path between collisions in space is thousands of kilometers, making it impossible for propellers and jets to work effectively. While there may be the possibility of using electromagnetic wings to interact with the thin space-plasma, it would require immense volumes and energies, making it impractical for regular spacecraft design.
  • #1
jsea-7
14
0
The question is why space ships cannot use propellers or conventional airplane jets to move in space?
 
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  • #2
There is no air for them to use. Space is a vacuum.
 
  • #3
Stratosphere said:
There is no air for them to use. Space is a vacuum.

I presumed that. But I also thought that space contained cosmic dust and hydrogen and hellium atoms, therefore it can't be a total vacuum.
 
  • #4
You would of course be correct, but such a dust is so tenuous that any propeller type design would be extraordinarily un-feasible. That is why for practical purposes relating to aircraft and spacecraft design, space is considered a vacuum.
 
  • #5
just imagine those tiny dust particles as micro meteors. Any propellar would be ripped to shreads. Also, there is no where near enough hydrogen or dust to use a propellar let alone a jet engine.
 
  • #6
ecao said:
just imagine those tiny dust particles as micro meteors. Any propellar would be ripped to shreads. Also, there is no where near enough hydrogen or dust to use a propellar let alone a jet engine.

How exactly would a propeller be ripped to shreads?
 
  • #7
I don't think it would exactly be ripped to shreds, but objects we put in orbit get damaged - essentially eroded away - over time due to the speed of the particles hitting them.
 
  • #8
jsea-7 said:
I presumed that. But I also thought that space contained cosmic dust and hydrogen and hellium atoms, therefore it can't be a total vacuum.

Propellers and jets work because the gas (usually air) they encounter is dense enough to have very small mean-free-paths - thus the particles of gas collide with each other within a short distance and can be relied on to behave like a thin "liquid" in which pressure differences are significant.

In space the mean free path between collisions is thousands of kilometres typically, thus particles pass each other easily and essentially exert no pressure. Of course if you could collect the gas from a huge volume in front of you and apply energy to it to expel as a jet, then it would work. That's how a Bussard ramjet works BUT the volumes and energies required are much, much larger than for regular propellers and jets.

Is there the equivalent of a space plane? There might be. A vehicle might be given immense electromagnetic wings that interact with the thin space-plasma and "ride" the currents that fill space, much like a glider can ride thermals and use dynamic soaring to reach high speeds. The wings would need to be very large and probably supported dynamically.
 

1. How do space ships maneuver in space?

Space ships use thrusters or rockets to maneuver in space. These thrusters provide thrust in a specific direction, allowing the space ship to change its velocity and direction.

2. How fast can space ships travel?

The maximum speed at which a space ship can travel is determined by its propulsion system and the laws of physics. Currently, the fastest space ship, NASA's Juno spacecraft, has reached speeds of up to 165,000 miles per hour.

3. Can space ships change direction in space?

Yes, space ships can change direction in space by using their thrusters to provide thrust in a different direction. However, due to the lack of air resistance in space, it takes a longer time for space ships to change direction compared to airplanes in Earth's atmosphere.

4. How do space ships turn in space?

Space ships turn by using a combination of their thrusters and their reaction wheels. The thrusters provide the initial thrust to change the direction of the space ship, while the reaction wheels help maintain that direction.

5. How do astronauts control the maneuverability of a space ship?

Astronauts can control the maneuverability of a space ship through various control systems, such as joysticks, control panels, or computer systems. They also receive training on how to operate the thrusters and reaction wheels to control the direction and speed of the space ship.

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