Stupid Launch Question
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tl8
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myles
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No, my science teacher told me it's counter clockwise, and so does just about every other site: http://www.esse.ou.edu/fund_concepts/Fundamental_Concepts1/Solar_System/Earths_Rotation.htm
"[SIZE=+2]Earth rotates around its axis (in a counter-clockwise direction, when viewed looking down on the North Pole)"[/SIZE]
"[SIZE=+2]Earth rotates around its axis (in a counter-clockwise direction, when viewed looking down on the North Pole)"[/SIZE]
Urwumpe
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yes - but how do you use this velocity best? You want to launch into space. You can get 469 m/s on the equator for free when you launch from West to East - and have to counter 469 m/s velocity when you launch in the opposite direction.
dutchpirate
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Analogy: Picture a playground merry-go-round being spun counter clockwise at some insane speed that only kids can enjoy:lol:. If you want to throw a baseball as fast as possible, what's the best direction to throw it?...Obviously you throw it with the rotation, not against it.
thomasantony
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Bj
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look at this
this is a stationary point in space, now which way do you have to launch to use the least amount of fuel?
edit; wow, were 4 people posting at the same time? :lol:
Bj
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So you get 469 m/s at equator, how would you find what the speed is at a given latitude?
Zatnikitelman
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Earth's gravity well isn't spinning. As long as you start out stationary on the surface, you're already matched with the rotation of Earth. If the gravity well was spinning, then technically yes, you would have to match to the rotation speed then on up, but for all intents and purposes, the gravity well is stationary. So just think of it as throwing something out ahead of a moving car. You add the speed of the thrown object to the speed of the car.
tblaxland
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When you are standing on the Earth, you are already matched up with Earth's rotation!
Remember also that orbital velocity is not relative to the surface of the Earth, it is relative an inertial frame that moving with the Earth around the sun. The Earth is rotating within that inertial frame. Geosynchronous orbit is a good example, the speed relative to the Earth's surface is zero yet you are orbiting the earth in a counter-clockwise direction. Geosynchronous orbital period just happens to match the Earths rotation period.
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Like the previous posts has said, you are stationary on earth.
remember, you need more speed to get into orbit.
Zatnikitelman
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Lary Niven explored this in Ringworld, but theoretically, if Earth was spinning fast enough, you wouldn't require much extra energy to get into orbit, just a gentle nudge away. Just thought of that now.
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If the earth really was spinning that fast, it wouldn't have formed into a planet as the centrifugal forces wouldn't allow gravity to get the stuff to clump together.
polaris149Tiberius
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Either that
Either that or we'd all be made of vanilla waffers.
Just to mention the Radii thing. Your tangent velocity or your speed along curved surface of the earth at the earth's surface is enough to keep your radial velocity at -9.8m/s^2 and safely out of Earth's orbit.
You can try to climb a tall mountain but that wont get you moving any faster in fact your moving slightly slower than you did down at the Cape.
Gravity is more radial than centrifugal. To escape it you must get your centrifical force or your tangent velocity fast enough to counter the pull of gravity. That is all an orbit is. Your speed in a tangent direction to the earths surface begins to pull you forward and counters the pull towards the center of the earth. When your velocity toward the earth reaches 0 and is sustained for the period of the radii or altitude your are from the center of the earth then your in a stable orbit.
Sometime we can talk about decay.
On the surface, your centrifical force is not enough to fling you out into space and similerly, if you go against earth's rotation than you will loose any centrifical energy or tangent potential energy you had the second you leave the ground. It just takes a while to register the loss of that centrifical velocity until you start to vector into a clockwise direction. If you jump 10ft into the air you actually do start to decelerate but the time it would take for you to be visibly slowed down to an observer is longer than it takes for you to get back to the earth and thus you look like you just jumped up and down to us.
Just going up wont increase your centrifical force but going forward and up will and is exactly how you insert into a LEO.
Once there you must accelerate more to gain altitude and slow down to loose altitude. It all depends on your azimut on how cost effecient your launch is but after your in orbit you can change your obit plane at the same cost in fuel as it does to go to another and it wont cost any more than the first because your velocity vector is changed and there is no friction to keep you from going from an equilateral orbit to a polar orbit and back. When you launched there was atmosphere and you already had some velocity stored up standing on the earth.
I suggest you try it in Orbiter. Take off and turn to a 90* azimut and do a standard orbit plan that you pitch at the exact same times to make an orbit at whatever altitude you can get into and then do it with a 270* azimut with the same orbit insertion plan and see which uses more fuel. Its best to use a tailsitter for this because there will be less anomalies during the turn phase. In a tailsitter you would call it a roll program.
I will be happy to do this experiment with you and report my findings. We could compare costs of our different flights.
Either that or we'd all be made of vanilla waffers.
Just to mention the Radii thing. Your tangent velocity or your speed along curved surface of the earth at the earth's surface is enough to keep your radial velocity at -9.8m/s^2 and safely out of Earth's orbit.
You can try to climb a tall mountain but that wont get you moving any faster in fact your moving slightly slower than you did down at the Cape.
Gravity is more radial than centrifugal. To escape it you must get your centrifical force or your tangent velocity fast enough to counter the pull of gravity. That is all an orbit is. Your speed in a tangent direction to the earths surface begins to pull you forward and counters the pull towards the center of the earth. When your velocity toward the earth reaches 0 and is sustained for the period of the radii or altitude your are from the center of the earth then your in a stable orbit.
Sometime we can talk about decay.
On the surface, your centrifical force is not enough to fling you out into space and similerly, if you go against earth's rotation than you will loose any centrifical energy or tangent potential energy you had the second you leave the ground. It just takes a while to register the loss of that centrifical velocity until you start to vector into a clockwise direction. If you jump 10ft into the air you actually do start to decelerate but the time it would take for you to be visibly slowed down to an observer is longer than it takes for you to get back to the earth and thus you look like you just jumped up and down to us.
Just going up wont increase your centrifical force but going forward and up will and is exactly how you insert into a LEO.
Once there you must accelerate more to gain altitude and slow down to loose altitude. It all depends on your azimut on how cost effecient your launch is but after your in orbit you can change your obit plane at the same cost in fuel as it does to go to another and it wont cost any more than the first because your velocity vector is changed and there is no friction to keep you from going from an equilateral orbit to a polar orbit and back. When you launched there was atmosphere and you already had some velocity stored up standing on the earth.
I suggest you try it in Orbiter. Take off and turn to a 90* azimut and do a standard orbit plan that you pitch at the exact same times to make an orbit at whatever altitude you can get into and then do it with a 270* azimut with the same orbit insertion plan and see which uses more fuel. Its best to use a tailsitter for this because there will be less anomalies during the turn phase. In a tailsitter you would call it a roll program.
I will be happy to do this experiment with you and report my findings. We could compare costs of our different flights.
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