Space - Error in Physics Text Books (1 Viewer)

[Mathematician]

HAHA.

I think there is an error associated with the reasoning in the textbooks as to why so much heat is generated during re-entry.

They say the high heat is due to fast friction with the atmospheric layer and the spacecraft.

However i believe most heat is due to compression of the air. I think the spacecraft creates a pressure wave and then according to the ideal gas law PV= nRT because the Pressure increases so much the temperature must also increase so much to balance the equation. The temperature comes so extreme that it falicitates in creating a plasma that melts the spacecraft.

Friction does also create heat, but the extreme heat is from this.



COMMENT

 

[Lazarus]

Considering the ideal gas law (and the rest of thermodynamics) is first-year uni physics, and beyond the scope of the HSC syllabus, I'm not entirely surprised they left it out...

 

[stag_j]

I'm not sure about that. It may be the case, but it is beyond the scope of the HSC course definitely. However your mention of the pressure wave in front of the spacecraft can still be used when talking about how problems are dealt with - the reason that space-shuttles re-enter belly first is so that the blunt side will create a wave infront of it that will absorb much of the heat.

 

[Mathematician]

...

okay thanx

 

[Rahul]

Originally posted by stag_j
the reason that space-shuttles re-enter belly first is so that the blunt side will create a wave infront of it that will absorb much of the heat.

yes, thats correct. the shockwave does absorb the heat.

mathematician, i dont think we should worry ourselves with that. i truly think it is 'beyond' the scope. at this stage, if we write that the heat caused in the re-entry of the space craft is due to friction, it will be correct.

but i can understand why you feel that we arent getting to know the real reasons.