Did Apollo's velocity slow down after TLI due to Earth's gravity?
I assume Apollo's velocity slowed down after it left Earth orbit, for how long was it decelerating. Did it start accelerating as it approached the Moon. What was the rate of deceleration due to Earth's gravity?
the-moon crewed-spaceflight apollo-program trajectory
edited 5 hours ago
PearsonArtPhoto♦
80.5k16230443
asked 6 hours ago
Bob516Bob516
1,4171316
add a comment |
I assume Apollo's velocity slowed down after it left Earth orbit, for how long was it decelerating. Did it start accelerating as it approached the Moon. What was the rate of deceleration due to Earth's gravity?
the-moon crewed-spaceflight apollo-program trajectory
edited 5 hours ago
PearsonArtPhoto♦
80.5k16230443
asked 6 hours ago
Bob516Bob516
1,4171316
What do you mean? Rate of deceleration at what point? Much of the lunar transfer is unpowered. Can you clarify.
– Rory Alsop
6 hours ago
@RoryAlsop I did not say powered deceleration. The velocity of Apollo changed from TLI to until Lunar orbit insertion due to the gravity of the Earth and presumably the Moon. What what that rate of change?
– Bob516
6 hours ago
2
While the question could have been better formulated, I don't feel it merits being down voted, as judging on the basis of OP's record here, it was asked in good faith. What seems obvious to ourselves might not to somebody else, and that is something all of us ought to keep in mind when interacting here.
– Happy Koala
6 hours ago
@HappyKoala wouldn't it be cool to have some kind of program or website where you could click a button that plots separation from Earth and separation from Moon versus time on the same axis? Or a pair of plots with the distances in the first and their rates of change in the second? It could be calledplot range-rateanalogous to real delay-doppler measurements.
– uhoh
2 hours ago
add a comment |
I assume Apollo's velocity slowed down after it left Earth orbit, for how long was it decelerating. Did it start accelerating as it approached the Moon. What was the rate of deceleration due to Earth's gravity?
the-moon crewed-spaceflight apollo-program trajectory
edited 5 hours ago
PearsonArtPhoto♦
80.5k16230443
asked 6 hours ago
Bob516Bob516
1,4171316
I assume Apollo's velocity slowed down after it left Earth orbit, for how long was it decelerating. Did it start accelerating as it approached the Moon. What was the rate of deceleration due to Earth's gravity?
the-moon crewed-spaceflight apollo-program trajectory
the-moon crewed-spaceflight apollo-program trajectory
edited 5 hours ago
PearsonArtPhoto♦
80.5k16230443
asked 6 hours ago
Bob516Bob516
1,4171316
edited 5 hours ago
PearsonArtPhoto♦
80.5k16230443
asked 6 hours ago
Bob516Bob516
1,4171316
edited 5 hours ago
PearsonArtPhoto♦
80.5k16230443
edited 5 hours ago
PearsonArtPhoto♦
80.5k16230443
edited 5 hours ago
PearsonArtPhoto♦
80.5k16230443
80.5k16230443
asked 6 hours ago
Bob516Bob516
1,4171316
asked 6 hours ago
Bob516Bob516
1,4171316
asked 6 hours ago
Bob516Bob516
1,4171316
1,4171316
What do you mean? Rate of deceleration at what point? Much of the lunar transfer is unpowered. Can you clarify.
– Rory Alsop
6 hours ago
@RoryAlsop I did not say powered deceleration. The velocity of Apollo changed from TLI to until Lunar orbit insertion due to the gravity of the Earth and presumably the Moon. What what that rate of change?
– Bob516
6 hours ago
2
While the question could have been better formulated, I don't feel it merits being down voted, as judging on the basis of OP's record here, it was asked in good faith. What seems obvious to ourselves might not to somebody else, and that is something all of us ought to keep in mind when interacting here.
– Happy Koala
6 hours ago
@HappyKoala wouldn't it be cool to have some kind of program or website where you could click a button that plots separation from Earth and separation from Moon versus time on the same axis? Or a pair of plots with the distances in the first and their rates of change in the second? It could be calledplot range-rateanalogous to real delay-doppler measurements.
– uhoh
2 hours ago
add a comment |
What do you mean? Rate of deceleration at what point? Much of the lunar transfer is unpowered. Can you clarify.
– Rory Alsop
6 hours ago
@RoryAlsop I did not say powered deceleration. The velocity of Apollo changed from TLI to until Lunar orbit insertion due to the gravity of the Earth and presumably the Moon. What what that rate of change?
– Bob516
6 hours ago
2
While the question could have been better formulated, I don't feel it merits being down voted, as judging on the basis of OP's record here, it was asked in good faith. What seems obvious to ourselves might not to somebody else, and that is something all of us ought to keep in mind when interacting here.
– Happy Koala
6 hours ago
@HappyKoala wouldn't it be cool to have some kind of program or website where you could click a button that plots separation from Earth and separation from Moon versus time on the same axis? Or a pair of plots with the distances in the first and their rates of change in the second? It could be calledplot range-rateanalogous to real delay-doppler measurements.
– uhoh
2 hours ago
What do you mean? Rate of deceleration at what point? Much of the lunar transfer is unpowered. Can you clarify.
– Rory Alsop
6 hours ago
What do you mean? Rate of deceleration at what point? Much of the lunar transfer is unpowered. Can you clarify.
– Rory Alsop
6 hours ago
@RoryAlsop I did not say powered deceleration. The velocity of Apollo changed from TLI to until Lunar orbit insertion due to the gravity of the Earth and presumably the Moon. What what that rate of change?
– Bob516
6 hours ago
@RoryAlsop I did not say powered deceleration. The velocity of Apollo changed from TLI to until Lunar orbit insertion due to the gravity of the Earth and presumably the Moon. What what that rate of change?
– Bob516
6 hours ago
2
2
While the question could have been better formulated, I don't feel it merits being down voted, as judging on the basis of OP's record here, it was asked in good faith. What seems obvious to ourselves might not to somebody else, and that is something all of us ought to keep in mind when interacting here.
– Happy Koala
6 hours ago
While the question could have been better formulated, I don't feel it merits being down voted, as judging on the basis of OP's record here, it was asked in good faith. What seems obvious to ourselves might not to somebody else, and that is something all of us ought to keep in mind when interacting here.
– Happy Koala
6 hours ago
@HappyKoala wouldn't it be cool to have some kind of program or website where you could click a button that plots separation from Earth and separation from Moon versus time on the same axis? Or a pair of plots with the distances in the first and their rates of change in the second? It could be called
plot range-rate analogous to real delay-doppler measurements.– uhoh
2 hours ago
@HappyKoala wouldn't it be cool to have some kind of program or website where you could click a button that plots separation from Earth and separation from Moon versus time on the same axis? Or a pair of plots with the distances in the first and their rates of change in the second? It could be called
plot range-rate analogous to real delay-doppler measurements.– uhoh
2 hours ago
add a comment |
2 Answers
2
active
oldest
votes
Yes, in fact it did slow down with time, until it approached close enough that the Moon pulled it faster. That happened at a point very close to the Moon. In a diagram on this page, for Apollo 8 we can see that point was just after the second full day, and the speed was about 3578 km/hr.
answered 5 hours ago
PearsonArtPhoto♦PearsonArtPhoto
80.5k16230443
from your page: "At 2:50:37.79 GET (0141:37 AEST), the S-IVB stage burned for 5 minutes 17.7 seconds to boost the spacecraft’s velocity by 7,451.2 kilometres per hour, and Apollo 8 left Earth orbit and headed for the Moon at 38,959.4 kilometres per hour."
– bitchaser
3 hours ago
"Borman, Lovell and Anders were the first humans to leave the Earth’s gravity. They also never felt any physical change when the spacecraft slowed down to 3,578 kilometres per hour relative to Earth and crossed over into the Moon’s gravity field at 55:38:40 GET (0629:40 AEST). They were 326,415 kilometres from Earth and 62,598 kilometres from the Moon."
– bitchaser
3 hours ago
add a comment |
I assume Apollo's velocity slowed down after it left Earth orbit, for how long was it decelerating.
A pretty good analogy for TLI is throwing a baseball straight up into the air. The "throw" is the TLI burn; as soon as the ball leaves your hand it begins to slow down, trying to fall back towards Earth. The peak altitude of the "throw" is around where the moon will be three days later.
Did it start accelerating as it approached the Moon.
Yes, as noted in @PearsonArtPhoto's answer.
What was the rate of deceleration due to Earth's gravity?
The deceleration decreases the farther you get from Earth in an inverse-square relation:
$a=-{G M over r^2}$
Where $GM$ (aka $mu$) is the gravitational parameter of Earth (3.986e14) and $r$ is the distance from the center of Earth in meters. In LEO this is still 9.2 m/s2 or about 94% of Earth's surface gravity. By the time you're 3000 km up, though, it's only about 50% of surface gravity.
You can compare the results of the equations for the "downward"-pulling Earth component and the "upward"-pointing moon component, with the appropriate distances and gravitational parameters for the two bodies, to see what the crossover point is. Or use algebra if you're into that.
answered 4 hours ago
Russell BorogoveRussell Borogove
83.4k2281361
add a comment |
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2 Answers
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active
oldest
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2 Answers
2
active
oldest
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votes
Yes, in fact it did slow down with time, until it approached close enough that the Moon pulled it faster. That happened at a point very close to the Moon. In a diagram on this page, for Apollo 8 we can see that point was just after the second full day, and the speed was about 3578 km/hr.
answered 5 hours ago
PearsonArtPhoto♦PearsonArtPhoto
80.5k16230443
from your page: "At 2:50:37.79 GET (0141:37 AEST), the S-IVB stage burned for 5 minutes 17.7 seconds to boost the spacecraft’s velocity by 7,451.2 kilometres per hour, and Apollo 8 left Earth orbit and headed for the Moon at 38,959.4 kilometres per hour."
– bitchaser
3 hours ago
"Borman, Lovell and Anders were the first humans to leave the Earth’s gravity. They also never felt any physical change when the spacecraft slowed down to 3,578 kilometres per hour relative to Earth and crossed over into the Moon’s gravity field at 55:38:40 GET (0629:40 AEST). They were 326,415 kilometres from Earth and 62,598 kilometres from the Moon."
– bitchaser
3 hours ago
add a comment |
Yes, in fact it did slow down with time, until it approached close enough that the Moon pulled it faster. That happened at a point very close to the Moon. In a diagram on this page, for Apollo 8 we can see that point was just after the second full day, and the speed was about 3578 km/hr.
answered 5 hours ago
PearsonArtPhoto♦PearsonArtPhoto
80.5k16230443
from your page: "At 2:50:37.79 GET (0141:37 AEST), the S-IVB stage burned for 5 minutes 17.7 seconds to boost the spacecraft’s velocity by 7,451.2 kilometres per hour, and Apollo 8 left Earth orbit and headed for the Moon at 38,959.4 kilometres per hour."
– bitchaser
3 hours ago
"Borman, Lovell and Anders were the first humans to leave the Earth’s gravity. They also never felt any physical change when the spacecraft slowed down to 3,578 kilometres per hour relative to Earth and crossed over into the Moon’s gravity field at 55:38:40 GET (0629:40 AEST). They were 326,415 kilometres from Earth and 62,598 kilometres from the Moon."
– bitchaser
3 hours ago
add a comment |
Yes, in fact it did slow down with time, until it approached close enough that the Moon pulled it faster. That happened at a point very close to the Moon. In a diagram on this page, for Apollo 8 we can see that point was just after the second full day, and the speed was about 3578 km/hr.
answered 5 hours ago
PearsonArtPhoto♦PearsonArtPhoto
80.5k16230443
Yes, in fact it did slow down with time, until it approached close enough that the Moon pulled it faster. That happened at a point very close to the Moon. In a diagram on this page, for Apollo 8 we can see that point was just after the second full day, and the speed was about 3578 km/hr.
answered 5 hours ago
PearsonArtPhoto♦PearsonArtPhoto
80.5k16230443
answered 5 hours ago
PearsonArtPhoto♦PearsonArtPhoto
80.5k16230443
answered 5 hours ago
PearsonArtPhoto♦PearsonArtPhoto
80.5k16230443
answered 5 hours ago
PearsonArtPhoto♦PearsonArtPhoto
80.5k16230443
80.5k16230443
from your page: "At 2:50:37.79 GET (0141:37 AEST), the S-IVB stage burned for 5 minutes 17.7 seconds to boost the spacecraft’s velocity by 7,451.2 kilometres per hour, and Apollo 8 left Earth orbit and headed for the Moon at 38,959.4 kilometres per hour."
– bitchaser
3 hours ago
"Borman, Lovell and Anders were the first humans to leave the Earth’s gravity. They also never felt any physical change when the spacecraft slowed down to 3,578 kilometres per hour relative to Earth and crossed over into the Moon’s gravity field at 55:38:40 GET (0629:40 AEST). They were 326,415 kilometres from Earth and 62,598 kilometres from the Moon."
– bitchaser
3 hours ago
add a comment |
from your page: "At 2:50:37.79 GET (0141:37 AEST), the S-IVB stage burned for 5 minutes 17.7 seconds to boost the spacecraft’s velocity by 7,451.2 kilometres per hour, and Apollo 8 left Earth orbit and headed for the Moon at 38,959.4 kilometres per hour."
– bitchaser
3 hours ago
"Borman, Lovell and Anders were the first humans to leave the Earth’s gravity. They also never felt any physical change when the spacecraft slowed down to 3,578 kilometres per hour relative to Earth and crossed over into the Moon’s gravity field at 55:38:40 GET (0629:40 AEST). They were 326,415 kilometres from Earth and 62,598 kilometres from the Moon."
– bitchaser
3 hours ago
from your page: "At 2:50:37.79 GET (0141:37 AEST), the S-IVB stage burned for 5 minutes 17.7 seconds to boost the spacecraft’s velocity by 7,451.2 kilometres per hour, and Apollo 8 left Earth orbit and headed for the Moon at 38,959.4 kilometres per hour."
– bitchaser
3 hours ago
from your page: "At 2:50:37.79 GET (0141:37 AEST), the S-IVB stage burned for 5 minutes 17.7 seconds to boost the spacecraft’s velocity by 7,451.2 kilometres per hour, and Apollo 8 left Earth orbit and headed for the Moon at 38,959.4 kilometres per hour."
– bitchaser
3 hours ago
"Borman, Lovell and Anders were the first humans to leave the Earth’s gravity. They also never felt any physical change when the spacecraft slowed down to 3,578 kilometres per hour relative to Earth and crossed over into the Moon’s gravity field at 55:38:40 GET (0629:40 AEST). They were 326,415 kilometres from Earth and 62,598 kilometres from the Moon."
– bitchaser
3 hours ago
"Borman, Lovell and Anders were the first humans to leave the Earth’s gravity. They also never felt any physical change when the spacecraft slowed down to 3,578 kilometres per hour relative to Earth and crossed over into the Moon’s gravity field at 55:38:40 GET (0629:40 AEST). They were 326,415 kilometres from Earth and 62,598 kilometres from the Moon."
– bitchaser
3 hours ago
add a comment |
I assume Apollo's velocity slowed down after it left Earth orbit, for how long was it decelerating.
A pretty good analogy for TLI is throwing a baseball straight up into the air. The "throw" is the TLI burn; as soon as the ball leaves your hand it begins to slow down, trying to fall back towards Earth. The peak altitude of the "throw" is around where the moon will be three days later.
Did it start accelerating as it approached the Moon.
Yes, as noted in @PearsonArtPhoto's answer.
What was the rate of deceleration due to Earth's gravity?
The deceleration decreases the farther you get from Earth in an inverse-square relation:
$a=-{G M over r^2}$
Where $GM$ (aka $mu$) is the gravitational parameter of Earth (3.986e14) and $r$ is the distance from the center of Earth in meters. In LEO this is still 9.2 m/s2 or about 94% of Earth's surface gravity. By the time you're 3000 km up, though, it's only about 50% of surface gravity.
You can compare the results of the equations for the "downward"-pulling Earth component and the "upward"-pointing moon component, with the appropriate distances and gravitational parameters for the two bodies, to see what the crossover point is. Or use algebra if you're into that.
answered 4 hours ago
Russell BorogoveRussell Borogove
83.4k2281361
add a comment |
I assume Apollo's velocity slowed down after it left Earth orbit, for how long was it decelerating.
A pretty good analogy for TLI is throwing a baseball straight up into the air. The "throw" is the TLI burn; as soon as the ball leaves your hand it begins to slow down, trying to fall back towards Earth. The peak altitude of the "throw" is around where the moon will be three days later.
Did it start accelerating as it approached the Moon.
Yes, as noted in @PearsonArtPhoto's answer.
What was the rate of deceleration due to Earth's gravity?
The deceleration decreases the farther you get from Earth in an inverse-square relation:
$a=-{G M over r^2}$
Where $GM$ (aka $mu$) is the gravitational parameter of Earth (3.986e14) and $r$ is the distance from the center of Earth in meters. In LEO this is still 9.2 m/s2 or about 94% of Earth's surface gravity. By the time you're 3000 km up, though, it's only about 50% of surface gravity.
You can compare the results of the equations for the "downward"-pulling Earth component and the "upward"-pointing moon component, with the appropriate distances and gravitational parameters for the two bodies, to see what the crossover point is. Or use algebra if you're into that.
answered 4 hours ago
Russell BorogoveRussell Borogove
83.4k2281361
add a comment |
I assume Apollo's velocity slowed down after it left Earth orbit, for how long was it decelerating.
A pretty good analogy for TLI is throwing a baseball straight up into the air. The "throw" is the TLI burn; as soon as the ball leaves your hand it begins to slow down, trying to fall back towards Earth. The peak altitude of the "throw" is around where the moon will be three days later.
Did it start accelerating as it approached the Moon.
Yes, as noted in @PearsonArtPhoto's answer.
What was the rate of deceleration due to Earth's gravity?
The deceleration decreases the farther you get from Earth in an inverse-square relation:
$a=-{G M over r^2}$
Where $GM$ (aka $mu$) is the gravitational parameter of Earth (3.986e14) and $r$ is the distance from the center of Earth in meters. In LEO this is still 9.2 m/s2 or about 94% of Earth's surface gravity. By the time you're 3000 km up, though, it's only about 50% of surface gravity.
You can compare the results of the equations for the "downward"-pulling Earth component and the "upward"-pointing moon component, with the appropriate distances and gravitational parameters for the two bodies, to see what the crossover point is. Or use algebra if you're into that.
answered 4 hours ago
Russell BorogoveRussell Borogove
83.4k2281361
I assume Apollo's velocity slowed down after it left Earth orbit, for how long was it decelerating.
A pretty good analogy for TLI is throwing a baseball straight up into the air. The "throw" is the TLI burn; as soon as the ball leaves your hand it begins to slow down, trying to fall back towards Earth. The peak altitude of the "throw" is around where the moon will be three days later.
Did it start accelerating as it approached the Moon.
Yes, as noted in @PearsonArtPhoto's answer.
What was the rate of deceleration due to Earth's gravity?
The deceleration decreases the farther you get from Earth in an inverse-square relation:
$a=-{G M over r^2}$
Where $GM$ (aka $mu$) is the gravitational parameter of Earth (3.986e14) and $r$ is the distance from the center of Earth in meters. In LEO this is still 9.2 m/s2 or about 94% of Earth's surface gravity. By the time you're 3000 km up, though, it's only about 50% of surface gravity.
You can compare the results of the equations for the "downward"-pulling Earth component and the "upward"-pointing moon component, with the appropriate distances and gravitational parameters for the two bodies, to see what the crossover point is. Or use algebra if you're into that.
answered 4 hours ago
Russell BorogoveRussell Borogove
83.4k2281361
answered 4 hours ago
Russell BorogoveRussell Borogove
83.4k2281361
answered 4 hours ago
Russell BorogoveRussell Borogove
83.4k2281361
answered 4 hours ago
Russell BorogoveRussell Borogove
83.4k2281361
83.4k2281361
add a comment |
add a comment |
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What do you mean? Rate of deceleration at what point? Much of the lunar transfer is unpowered. Can you clarify.
– Rory Alsop
6 hours ago
@RoryAlsop I did not say powered deceleration. The velocity of Apollo changed from TLI to until Lunar orbit insertion due to the gravity of the Earth and presumably the Moon. What what that rate of change?
– Bob516
6 hours ago
2
While the question could have been better formulated, I don't feel it merits being down voted, as judging on the basis of OP's record here, it was asked in good faith. What seems obvious to ourselves might not to somebody else, and that is something all of us ought to keep in mind when interacting here.
– Happy Koala
6 hours ago
@HappyKoala wouldn't it be cool to have some kind of program or website where you could click a button that plots separation from Earth and separation from Moon versus time on the same axis? Or a pair of plots with the distances in the first and their rates of change in the second? It could be called
plot range-rateanalogous to real delay-doppler measurements.– uhoh
2 hours ago