Parasitic drag in space

[RobbyQbit]

In aviation/fluid dynamics aircraft experience parasitic drag proportional to the square of the velocity due to air. In space do vehicles experience any form of drag given it's a vacuum. Are there any resistive forces on the vehicle?

 

[Pogo]

Yes, there certainly is drag in space, primarily gravity.
Consider the ISS, Newton said that it should go in a straight line unless acted upon by an outside force, that would be gravity that keeps it in a elliptical orbit around the Earth. The Voyagers and other spacecraft were sent on missions and are leaving the solar system, but, not in a straight line, but, in a hyperbolic orbit because of the gravity of the Sun.
In addition, there is a very minute drag due to gas molecules and dust in interplanetary (and interstellar) space, certainly not like the atmosphere of the Earth. The ISS is subject to a tiny drag because of the very thin air up there. It slowly loses altitude and has to be boosted to its higher orbit a couple time a year.

 

[RobbyQbit]

Yes, there certainly is drag in space, primarily gravity.
Consider the ISS, Newton said that it should go in a straight line unless acted upon by an outside force, that would be gravity that keeps it in a elliptical orbit around the Earth. The Voyagers and other spacecraft were sent on missions and are leaving the solar system, but, not in a straight line, but, in a hyperbolic orbit because of the gravity of the Sun.
In addition, there is a very minute drag due to gas molecules and dust in interplanetary (and interstellar) space, certainly not like the atmosphere of the Earth. The ISS is subject to a tiny drag because of the very thin air up there. It slowly loses altitude and has to be boosted to its higher orbit a couple time a year.

Thanks Pogo. Interesting response. But isn't gravity an attractive force and not resistive? But I guess the vehicle could be being pulled as in decelerated.

 

[Pogo]

Correct. But, other than turbulance, as a passenger, I don’t believe you could distinguish the difference as to the effect on the vessel.

 

[Brenton The Curios]

Thanks Pogo. Interesting response. But isn't gravity an attractive force and not resistive? But I guess the vehicle could be being pulled as in decelerated.

I think Pogo was suggesting the very slight centrifugal force of the ISS's orbit would tend to resist gravity. Obviously its a very fine line between having any object too close or too far out

 

[billslugg]

There is drag even in intergalactic space. There, a cubic meter of space might have one atom, likely an ionized atom of hydrogen. A one meter cross section space ship traveling near light speed would encounter 300 million such particles per second. The energy of their collision roughly equal to their mass. With 6e23 atoms to the mole (1 gram in this case) and 9e16 joules to the kilogram, the drag force would be about 0.05 watt.

 

[Atlan0001]

There is drag even in intergalactic space. There, a cubic meter of space might have one atom, likely an ionized atom of hydrogen. A one meter cross section space ship traveling near light speed would encounter 300 million such particles per second. The energy of their collision roughly equal to their mass. With 6e23 atoms to the mole (1 gram in this case) and 9e16 joules to the kilogram, the drag force would be about 0.05 watt.

I hate to disagree with you, Bill, but they won't be there to block, tangle, or entangle with the ship. Or, rather, the ship will go through the field like a great mass or packet of ghost particles, a soliton wave, when the meeting and combined momentum goes beyond the speed of light. That will happen well below, well short of, the speed of light. There will be no relativity between the ship and the local environment short of the mass of a planet, a star, or a black hole . . . and maybe not even such objects, especially such objects, as these are (it will depend on the ship's velocity as to whether or not it is has any certain position relative to the massive object. The spacetime the ship is in could bend around the planet or star, or even black hole, as if it, the bend around in spacetime, were an absolutely straight line). It, a soliton wave, doesn't even create a wake behind it, just a bow wave. it just bends spacetime, and mass-energy, around it even as a water wave (from what I understand). It is a "solitary" wave. A very unusual wave in nature.

 

[billslugg]

Yes, this explanation is but one of many possibilities.