I have a hypothetical question about atmospheric reentry and speed for ya?
marcusviii_bloodfin1 asked:
Let’s suppose that you have a craft with a device that can reduce the earths gravitational effect to a point of neutral balance. So that In effect you space craft can sit in a stationary orbit Geosynchronous/geostationary at any altitude at relative low ground speeds but still have enough gravitational effect to keep it from being left behind as the earth and solo system moves throw space.
Let’s suppose that you have a craft with a device that can reduce the earths gravitational effect to a point of neutral balance. So that In effect you space craft can sit in a stationary orbit Geosynchronous/geostationary at any altitude at relative low ground speeds but still have enough gravitational effect to keep it from being left behind as the earth and solo system moves throw space.
Now the reason I ask this is as I understand it for a “Real” space craft for example the Space shuttle to return to earth it must decelerate so that gravity can pull it back in to the earth’s atmosphere but because of its still relative high speed it needs heat shields to protect it form the airs friction ,blah, blah,
Now I was think if this hypothetical craft didn’t have this problem to contend with but could enter the atmosphere at the same relative speed of air it would it have the same heating effect and thus not need heat shielding.
Am I correct and did I state this question clearly
Your idea, though fanciful, is sound. If there was a way to counteract the force of gravity on the satellite, it wouldn’t need to be in orbit at all, and could enter the atmosphere at speeds which would be more like the fall of a parachute.
Yep, your idea makes sense. In addition to what you state about the shuttle, the atmospheric friction also helps to slow it down.
So if there were a way to bring it from approx 17,000 miles per hour to relative zero OUTSIDE the atmosphere, it would simply enter the atmosphere at normal falling velocity, or a few hundred MPH maximum probably, not really enough to generate massive heat.
Sure – the only reason for a heat shield is to protect it from the frictional heat generated from the necessarily high speed of re-entry.
Take away the need for speed – take away the friction. And no heat shield would be needed.
Take a look at Space Ship One – it went straight up , and (more or less) straight down – it didn’t have to eliminate orbital speed, so it didn’t need a heat shield.
If you had a space craft with an anti gravity device to where you can stay at any given altitude, and not get left behind by the Earth.
First problem, beings the Earth is rotating, to stay over one certain point, you will have to be moving as well.
look at it this way, you rise up to lets say 20.000 foot straight up, then you stay at that point, when you come back down beings the Earth is rotating, you will come down further west from where you lifted off, plus with out forward or reverse speed, the wind would take the craft along with it.
Example, a plain flying from lets say the state of Ohio going south to Florida, and the wind is coming out of the west, if the plain flies straight south they will never see Florida because the wind has blown them to the East, the only way a plain can fly straight to another place is if there is no wind at all.
And to stay over a location on the Earth, you will have to be moving along with the Earth, so you can’t be left behind by the Earth.
You would need to have some sort of tractor beam in order to do this.
You would basically tractor beam your self to the planet and then slowly free fall at the same point. You would still be in motion, the force of the earth’s rotation would propel your ship at the same speed. But since you would be traveling at the same speed as the rotation it would seem like you are not moving at all.
This is the concept behind the space elevator. Since the elevator would be in the same spot the only energy needed would be to lift the elevator.
Physics, Physics. It can’t be done.
Gravity is omni-present in the universe. Nobody really understands it, let alone can oppose it.
Also, if there was a anti-grav technology, it would need an energy source. That means fuel of some kind is needed. That means extra weight, blah, blah
If you could carry all that fuel, you could simply fire retros with a downward component (like a jump jet) to keep the thing in orbit until the craft slowed down enough to simply free-fall. That technology is available, but the rocketry to carry the massive amount of fuel is not.
I’m not sure I understand this. Would your magic craft then be stationary, 150 miles up, above the atmosphere? And you want to know if it would need heat shields to get down to earth?
It would be a wild ride, but I don’t think it would need heat shields. It would need wings or at least some aerodynamic shape.