Astronaut re entry (1 Viewer)

[StGeorgeDragons]

the astonaut sits transverse to the g force, lawys down, with eyeball in approach. i can see in the laucnh he is obviously facing up looking into space, but in the re entry, for eye ball in wouldnt he be facing the earth? the text book shows him facing the same way.

 

[jake2.0]

yeah its the same way cause the acceleration is in the same way, remember he's slowing down in re-entry

 

[StGeorgeDragons]

but the velocity is in the opposite direction. like reversing a car. when u accelrate eye balls in. when u go back eye balls out.


when ur coming down of coarse u accelerate. if ur facing the other way, the intertia would cause the eye balls to come out.

 

[word.]

you decelerate on re-entry because of atmospheric friction

 

[exa_boi87]

I assume re-entry requires the thrust from the landing vessel to overcome the accelerating force of gravity, hence craft fights the pull through accelerating upward in order to decelerate. Thats just how id assume it to be

 

[jake2.0]

i dont think there is any thrust involved, its just the atmospheric drag on the space crafts that slow them down

 

[exa_boi87]

Apologies, of course .. g-forces are always directed upward

 

[Necros87]

but the velocity is in the opposite direction. like reversing a car. when u accelrate eye balls in. when u go back eye balls out.


when ur coming down of coarse u accelerate. if ur facing the other way, the intertia would cause the eye balls to come out.

it may well be like reversing, but its more like putting the brake on when reversing, you get pushed back into the seat

 

[Abtari]

i think everyone is familiar with what happens during launch - accelerates to high speeds - lying flat on back - g forces not acting longitudinally - eyeballs pushed back due to inertia - eyeballs remain in the eyes

on returning to earth, i should think that the capsule (is that what the astronauts are in? someone verify me) comes down in the same direction. hence, the astronauts would be strapped facing the same way, i.e. away from the earth ground. Now, the eyeballs would still remain in the eyes. Why? well, in my opinion, the acceleration experienced by nauts in the spaceship on re-entry is nowhere near as great as during lift-off. It is almost like a freefall, under the action of gravity, with atmospheric drag further reducing the accelereation. So, there is no need to worry about whether eyes would pop out just because inertia is pushing them in a dirn out of the eyesocket.

i hope this is correct. not sure though.

 

[Haku]

yea thats right. they had a MC question on it and that was the solution.

using the formula F=(-ma+mg)/g the balls would stay in the socket due to g.

 

[boogie woogie]

Hi

When the spacecraft takes off, the astronaut is on his back in a seat specially contoured to his body. The acceleration is upwards, and the seat pushes against his back. The astronaut feels as if a huge weight is pushing onto his chest (eyeballs in direction), this is also the direction of the g-force.

When the spacecraft re-enters the atmosphere, the astronaut is on his back in the specially contoured seat. The spacecraft is decelerating, which means the acceleration is negative in the downward direction, which means it is positive in the upwards direction. The effect is the same as braking while reversing the car, the driver is pressed against the seat of the car. Similarly, the astronaut will be pressed against his seat, he feels a weight acting on his body in the eyeballs-in direction. This is the direction of the g-force.

Hence, for both lift-off and re-entry, the g-force is downwards (eyeballs in drection), when the astronaut lies on his back in the spacecraft.

 

[Azamakumar]

Question was asked 2 years ago, you might be a tad late.

 

[willC]

This is an interesting question, I always remeber the answer by imagining the force exerted on a parachuter when they open the chute (the parachute, of course, is used to decelerate). So easy to get wrong tho...its the opposite of what you'd think..