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How do my spacefarers not get crushed accelerating to 0.2c?
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Inhabitants of another planet (their biology is yet undefined, and if helpful to solving the problem, suggestions can be included in the answer), have a spaceship in which they plan to accelerate to 0.2c over a two earth year period. Technology level is more or less undefined as it's an alien species who can have whatever tech is required.
Of course, F = ma means that the force of accelerating at 0.1c per year is still a big number, even for an entity that weighs something similar to ourselves.
0.2c is important as anything above this tends to incur significant time dilation, and any slower will mean too much time elapsed to reach their destination.
So my question is, How can I prevent my space explorers from being crushed by the acceleration? The parameters of time and final velocity are set and critical to my story, so can't be altered. I'd prefer a feasible but not necessarily completely hard science answer. If there really isn't any way to do this, then a plausible hand-wavy answer would suffice.
science-based space-travel spaceships
asked 3 hours ago
Jane S
227210
add a comment |Â
up vote
1
down vote
favorite
Inhabitants of another planet (their biology is yet undefined, and if helpful to solving the problem, suggestions can be included in the answer), have a spaceship in which they plan to accelerate to 0.2c over a two earth year period. Technology level is more or less undefined as it's an alien species who can have whatever tech is required.
Of course, F = ma means that the force of accelerating at 0.1c per year is still a big number, even for an entity that weighs something similar to ourselves.
0.2c is important as anything above this tends to incur significant time dilation, and any slower will mean too much time elapsed to reach their destination.
So my question is, How can I prevent my space explorers from being crushed by the acceleration? The parameters of time and final velocity are set and critical to my story, so can't be altered. I'd prefer a feasible but not necessarily completely hard science answer. If there really isn't any way to do this, then a plausible hand-wavy answer would suffice.
science-based space-travel spaceships
asked 3 hours ago
Jane S
227210
add a comment |Â
up vote
1
down vote
favorite
up vote
1
down vote
favorite
Inhabitants of another planet (their biology is yet undefined, and if helpful to solving the problem, suggestions can be included in the answer), have a spaceship in which they plan to accelerate to 0.2c over a two earth year period. Technology level is more or less undefined as it's an alien species who can have whatever tech is required.
Of course, F = ma means that the force of accelerating at 0.1c per year is still a big number, even for an entity that weighs something similar to ourselves.
0.2c is important as anything above this tends to incur significant time dilation, and any slower will mean too much time elapsed to reach their destination.
So my question is, How can I prevent my space explorers from being crushed by the acceleration? The parameters of time and final velocity are set and critical to my story, so can't be altered. I'd prefer a feasible but not necessarily completely hard science answer. If there really isn't any way to do this, then a plausible hand-wavy answer would suffice.
science-based space-travel spaceships
asked 3 hours ago
Jane S
227210
Inhabitants of another planet (their biology is yet undefined, and if helpful to solving the problem, suggestions can be included in the answer), have a spaceship in which they plan to accelerate to 0.2c over a two earth year period. Technology level is more or less undefined as it's an alien species who can have whatever tech is required.
Of course, F = ma means that the force of accelerating at 0.1c per year is still a big number, even for an entity that weighs something similar to ourselves.
0.2c is important as anything above this tends to incur significant time dilation, and any slower will mean too much time elapsed to reach their destination.
So my question is, How can I prevent my space explorers from being crushed by the acceleration? The parameters of time and final velocity are set and critical to my story, so can't be altered. I'd prefer a feasible but not necessarily completely hard science answer. If there really isn't any way to do this, then a plausible hand-wavy answer would suffice.
science-based space-travel spaceships
science-based space-travel spaceships
asked 3 hours ago
Jane S
227210
asked 3 hours ago
Jane S
227210
edited 3 hours ago
asked 3 hours ago
Jane S
227210
asked 3 hours ago
Jane S
227210
asked 3 hours ago
Jane S
227210
227210
add a comment |Â
add a comment |Â
2 Answers
2
active
oldest
votes
up vote
4
down vote
accepted
They won't be crushed. In fact, they will feel less than Earth gravity, so they will need exercize to preserve their bones and muscles' integrity.
0.2c equals 59,958,491.6 meters per second. Two years have exactly 63,115,200 seconds. What this means is that if they were to accelerate at 1m/s2, which is pretty close to 0.1g, they would be going faster than 0.2c relative to us in two years while feeling a gravity weaker than the Moon's.
You can dial those thrusters to 11 without fear. We were made for that.
answered 3 hours ago
Renan
32.9k768168
Oh dang, I should have done the math myself but I didn't trust myself to get it right :) I'll do the calcs and see if I get what you get :)
– Jane S
3 hours ago
1
I calculated out to 0.95m/s^2, which is what you said. They won't be getting squashed at all during that two-year burn :)
– Jane S
3 hours ago
add a comment |Â
up vote
2
down vote
They probably don't slam the accelerator to the floor.
Chemical rockets (like we use here on earth) are great for one thing; getting out of the Gravity Well. Why? Because they burn all their fuel really quickly, generating a MASSIVE amount of thrust all at once. They're so good at this, that we build our rockets in stages, allowing the expended fuel and engines drop to lighten what gets taken further by the next stage of the rocket.
If you're already out of the gravity well though, and you're considering interstellar travel in particular, you don't want to use rocket thinking. It's a long distance after all, and you're FAR better off using constant thrust the whole way. One reason is for exactly what you describe; accelerating constantly at 1G worth of force for half the distance (and then reversing attitude and thrusting at -1G for the second half of the trip) is going to be more comfortable on the crew, AND it's going to get you there a lot faster because your velocity is more of a ballistic curve.
Time Dilation isn't so much of an issue for you in this instance, even if at the halfway point you're travelling much faster than 0.2C. This is because you're not travelling at that speed for the entire journey, just for the peak of your velocity curve, right in the middle. At the beginning and end of your journey, you're travelling much slower in fact. I haven't run the numbers, but I suspect that you don't have that much of a difference overall. That said, your crew probably wouldn't mind a little time dilation if it appears to get them where they want to go faster.
Put simply, think less chemical rockets, more ion or plasma engines. Look these up as they're under active development by NASA for interplanetary and (potentially) interstellar probe engines of the future. In every other respect, it's like your car. It might be able to accelerate from 0-100Kph in 3 seconds, but it doesn't necessarily make it a good idea to do that.
answered 3 hours ago
Tim B II
21k44690
Just to be clear, it's a 2 year acceleration curve from 0 to 0.2c, then 20 years at 0.2c, then a two year deceleration curve from 0.2c to zero :)
– Jane S
3 hours ago
1
@JaneS yeah, you really wouldn't want to do that. Just put the slow burn on to the half way point, then turn around and use the other half of your fuel slowing down. You'll get there a LOT faster.
– Tim B II
3 hours ago
It's kinda important to my story to do the "quick" burn at the beginning and the end of the journey, so while it's more efficient the other way, it breaks some of my other logic that I'd prefer to keep :)
– Jane S
3 hours ago
@JaneS alright, if it's a story element, I get it. You might want to hang a lantern on it somehow though, as most folk are going to ask themselves 'why aren't they just constantly accelerating?'
– Tim B II
3 hours ago
I shall have a think and see if I can not break the story, but if I can't I will have to see how I can hand-wave the inefficiency :)
– Jane S
3 hours ago
 |Â
show 1 more comment
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
4
down vote
accepted
They won't be crushed. In fact, they will feel less than Earth gravity, so they will need exercize to preserve their bones and muscles' integrity.
0.2c equals 59,958,491.6 meters per second. Two years have exactly 63,115,200 seconds. What this means is that if they were to accelerate at 1m/s2, which is pretty close to 0.1g, they would be going faster than 0.2c relative to us in two years while feeling a gravity weaker than the Moon's.
You can dial those thrusters to 11 without fear. We were made for that.
answered 3 hours ago
Renan
32.9k768168
Oh dang, I should have done the math myself but I didn't trust myself to get it right :) I'll do the calcs and see if I get what you get :)
– Jane S
3 hours ago
1
I calculated out to 0.95m/s^2, which is what you said. They won't be getting squashed at all during that two-year burn :)
– Jane S
3 hours ago
add a comment |Â
up vote
4
down vote
accepted
They won't be crushed. In fact, they will feel less than Earth gravity, so they will need exercize to preserve their bones and muscles' integrity.
0.2c equals 59,958,491.6 meters per second. Two years have exactly 63,115,200 seconds. What this means is that if they were to accelerate at 1m/s2, which is pretty close to 0.1g, they would be going faster than 0.2c relative to us in two years while feeling a gravity weaker than the Moon's.
You can dial those thrusters to 11 without fear. We were made for that.
answered 3 hours ago
Renan
32.9k768168
Oh dang, I should have done the math myself but I didn't trust myself to get it right :) I'll do the calcs and see if I get what you get :)
– Jane S
3 hours ago
1
I calculated out to 0.95m/s^2, which is what you said. They won't be getting squashed at all during that two-year burn :)
– Jane S
3 hours ago
add a comment |Â
up vote
4
down vote
accepted
up vote
4
down vote
accepted
They won't be crushed. In fact, they will feel less than Earth gravity, so they will need exercize to preserve their bones and muscles' integrity.
0.2c equals 59,958,491.6 meters per second. Two years have exactly 63,115,200 seconds. What this means is that if they were to accelerate at 1m/s2, which is pretty close to 0.1g, they would be going faster than 0.2c relative to us in two years while feeling a gravity weaker than the Moon's.
You can dial those thrusters to 11 without fear. We were made for that.
answered 3 hours ago
Renan
32.9k768168
They won't be crushed. In fact, they will feel less than Earth gravity, so they will need exercize to preserve their bones and muscles' integrity.
0.2c equals 59,958,491.6 meters per second. Two years have exactly 63,115,200 seconds. What this means is that if they were to accelerate at 1m/s2, which is pretty close to 0.1g, they would be going faster than 0.2c relative to us in two years while feeling a gravity weaker than the Moon's.
You can dial those thrusters to 11 without fear. We were made for that.
answered 3 hours ago
Renan
32.9k768168
edited 3 hours ago
answered 3 hours ago
Renan
32.9k768168
answered 3 hours ago
Renan
32.9k768168
answered 3 hours ago
Renan
32.9k768168
32.9k768168
Oh dang, I should have done the math myself but I didn't trust myself to get it right :) I'll do the calcs and see if I get what you get :)
– Jane S
3 hours ago
1
I calculated out to 0.95m/s^2, which is what you said. They won't be getting squashed at all during that two-year burn :)
– Jane S
3 hours ago
add a comment |Â
Oh dang, I should have done the math myself but I didn't trust myself to get it right :) I'll do the calcs and see if I get what you get :)
– Jane S
3 hours ago
1
I calculated out to 0.95m/s^2, which is what you said. They won't be getting squashed at all during that two-year burn :)
– Jane S
3 hours ago
Oh dang, I should have done the math myself but I didn't trust myself to get it right :) I'll do the calcs and see if I get what you get :)
– Jane S
3 hours ago
Oh dang, I should have done the math myself but I didn't trust myself to get it right :) I'll do the calcs and see if I get what you get :)
– Jane S
3 hours ago
1
1
I calculated out to 0.95m/s^2, which is what you said. They won't be getting squashed at all during that two-year burn :)
– Jane S
3 hours ago
I calculated out to 0.95m/s^2, which is what you said. They won't be getting squashed at all during that two-year burn :)
– Jane S
3 hours ago
add a comment |Â
up vote
2
down vote
They probably don't slam the accelerator to the floor.
Chemical rockets (like we use here on earth) are great for one thing; getting out of the Gravity Well. Why? Because they burn all their fuel really quickly, generating a MASSIVE amount of thrust all at once. They're so good at this, that we build our rockets in stages, allowing the expended fuel and engines drop to lighten what gets taken further by the next stage of the rocket.
If you're already out of the gravity well though, and you're considering interstellar travel in particular, you don't want to use rocket thinking. It's a long distance after all, and you're FAR better off using constant thrust the whole way. One reason is for exactly what you describe; accelerating constantly at 1G worth of force for half the distance (and then reversing attitude and thrusting at -1G for the second half of the trip) is going to be more comfortable on the crew, AND it's going to get you there a lot faster because your velocity is more of a ballistic curve.
Time Dilation isn't so much of an issue for you in this instance, even if at the halfway point you're travelling much faster than 0.2C. This is because you're not travelling at that speed for the entire journey, just for the peak of your velocity curve, right in the middle. At the beginning and end of your journey, you're travelling much slower in fact. I haven't run the numbers, but I suspect that you don't have that much of a difference overall. That said, your crew probably wouldn't mind a little time dilation if it appears to get them where they want to go faster.
Put simply, think less chemical rockets, more ion or plasma engines. Look these up as they're under active development by NASA for interplanetary and (potentially) interstellar probe engines of the future. In every other respect, it's like your car. It might be able to accelerate from 0-100Kph in 3 seconds, but it doesn't necessarily make it a good idea to do that.
answered 3 hours ago
Tim B II
21k44690
Just to be clear, it's a 2 year acceleration curve from 0 to 0.2c, then 20 years at 0.2c, then a two year deceleration curve from 0.2c to zero :)
– Jane S
3 hours ago
1
@JaneS yeah, you really wouldn't want to do that. Just put the slow burn on to the half way point, then turn around and use the other half of your fuel slowing down. You'll get there a LOT faster.
– Tim B II
3 hours ago
It's kinda important to my story to do the "quick" burn at the beginning and the end of the journey, so while it's more efficient the other way, it breaks some of my other logic that I'd prefer to keep :)
– Jane S
3 hours ago
@JaneS alright, if it's a story element, I get it. You might want to hang a lantern on it somehow though, as most folk are going to ask themselves 'why aren't they just constantly accelerating?'
– Tim B II
3 hours ago
I shall have a think and see if I can not break the story, but if I can't I will have to see how I can hand-wave the inefficiency :)
– Jane S
3 hours ago
 |Â
show 1 more comment
up vote
2
down vote
They probably don't slam the accelerator to the floor.
Chemical rockets (like we use here on earth) are great for one thing; getting out of the Gravity Well. Why? Because they burn all their fuel really quickly, generating a MASSIVE amount of thrust all at once. They're so good at this, that we build our rockets in stages, allowing the expended fuel and engines drop to lighten what gets taken further by the next stage of the rocket.
If you're already out of the gravity well though, and you're considering interstellar travel in particular, you don't want to use rocket thinking. It's a long distance after all, and you're FAR better off using constant thrust the whole way. One reason is for exactly what you describe; accelerating constantly at 1G worth of force for half the distance (and then reversing attitude and thrusting at -1G for the second half of the trip) is going to be more comfortable on the crew, AND it's going to get you there a lot faster because your velocity is more of a ballistic curve.
Time Dilation isn't so much of an issue for you in this instance, even if at the halfway point you're travelling much faster than 0.2C. This is because you're not travelling at that speed for the entire journey, just for the peak of your velocity curve, right in the middle. At the beginning and end of your journey, you're travelling much slower in fact. I haven't run the numbers, but I suspect that you don't have that much of a difference overall. That said, your crew probably wouldn't mind a little time dilation if it appears to get them where they want to go faster.
Put simply, think less chemical rockets, more ion or plasma engines. Look these up as they're under active development by NASA for interplanetary and (potentially) interstellar probe engines of the future. In every other respect, it's like your car. It might be able to accelerate from 0-100Kph in 3 seconds, but it doesn't necessarily make it a good idea to do that.
answered 3 hours ago
Tim B II
21k44690
Just to be clear, it's a 2 year acceleration curve from 0 to 0.2c, then 20 years at 0.2c, then a two year deceleration curve from 0.2c to zero :)
– Jane S
3 hours ago
1
@JaneS yeah, you really wouldn't want to do that. Just put the slow burn on to the half way point, then turn around and use the other half of your fuel slowing down. You'll get there a LOT faster.
– Tim B II
3 hours ago
It's kinda important to my story to do the "quick" burn at the beginning and the end of the journey, so while it's more efficient the other way, it breaks some of my other logic that I'd prefer to keep :)
– Jane S
3 hours ago
@JaneS alright, if it's a story element, I get it. You might want to hang a lantern on it somehow though, as most folk are going to ask themselves 'why aren't they just constantly accelerating?'
– Tim B II
3 hours ago
I shall have a think and see if I can not break the story, but if I can't I will have to see how I can hand-wave the inefficiency :)
– Jane S
3 hours ago
 |Â
show 1 more comment
up vote
2
down vote
up vote
2
down vote
They probably don't slam the accelerator to the floor.
Chemical rockets (like we use here on earth) are great for one thing; getting out of the Gravity Well. Why? Because they burn all their fuel really quickly, generating a MASSIVE amount of thrust all at once. They're so good at this, that we build our rockets in stages, allowing the expended fuel and engines drop to lighten what gets taken further by the next stage of the rocket.
If you're already out of the gravity well though, and you're considering interstellar travel in particular, you don't want to use rocket thinking. It's a long distance after all, and you're FAR better off using constant thrust the whole way. One reason is for exactly what you describe; accelerating constantly at 1G worth of force for half the distance (and then reversing attitude and thrusting at -1G for the second half of the trip) is going to be more comfortable on the crew, AND it's going to get you there a lot faster because your velocity is more of a ballistic curve.
Time Dilation isn't so much of an issue for you in this instance, even if at the halfway point you're travelling much faster than 0.2C. This is because you're not travelling at that speed for the entire journey, just for the peak of your velocity curve, right in the middle. At the beginning and end of your journey, you're travelling much slower in fact. I haven't run the numbers, but I suspect that you don't have that much of a difference overall. That said, your crew probably wouldn't mind a little time dilation if it appears to get them where they want to go faster.
Put simply, think less chemical rockets, more ion or plasma engines. Look these up as they're under active development by NASA for interplanetary and (potentially) interstellar probe engines of the future. In every other respect, it's like your car. It might be able to accelerate from 0-100Kph in 3 seconds, but it doesn't necessarily make it a good idea to do that.
answered 3 hours ago
Tim B II
21k44690
They probably don't slam the accelerator to the floor.
Chemical rockets (like we use here on earth) are great for one thing; getting out of the Gravity Well. Why? Because they burn all their fuel really quickly, generating a MASSIVE amount of thrust all at once. They're so good at this, that we build our rockets in stages, allowing the expended fuel and engines drop to lighten what gets taken further by the next stage of the rocket.
If you're already out of the gravity well though, and you're considering interstellar travel in particular, you don't want to use rocket thinking. It's a long distance after all, and you're FAR better off using constant thrust the whole way. One reason is for exactly what you describe; accelerating constantly at 1G worth of force for half the distance (and then reversing attitude and thrusting at -1G for the second half of the trip) is going to be more comfortable on the crew, AND it's going to get you there a lot faster because your velocity is more of a ballistic curve.
Time Dilation isn't so much of an issue for you in this instance, even if at the halfway point you're travelling much faster than 0.2C. This is because you're not travelling at that speed for the entire journey, just for the peak of your velocity curve, right in the middle. At the beginning and end of your journey, you're travelling much slower in fact. I haven't run the numbers, but I suspect that you don't have that much of a difference overall. That said, your crew probably wouldn't mind a little time dilation if it appears to get them where they want to go faster.
Put simply, think less chemical rockets, more ion or plasma engines. Look these up as they're under active development by NASA for interplanetary and (potentially) interstellar probe engines of the future. In every other respect, it's like your car. It might be able to accelerate from 0-100Kph in 3 seconds, but it doesn't necessarily make it a good idea to do that.
answered 3 hours ago
Tim B II
21k44690
answered 3 hours ago
Tim B II
21k44690
answered 3 hours ago
Tim B II
21k44690
answered 3 hours ago
Tim B II
21k44690
21k44690
Just to be clear, it's a 2 year acceleration curve from 0 to 0.2c, then 20 years at 0.2c, then a two year deceleration curve from 0.2c to zero :)
– Jane S
3 hours ago
1
@JaneS yeah, you really wouldn't want to do that. Just put the slow burn on to the half way point, then turn around and use the other half of your fuel slowing down. You'll get there a LOT faster.
– Tim B II
3 hours ago
It's kinda important to my story to do the "quick" burn at the beginning and the end of the journey, so while it's more efficient the other way, it breaks some of my other logic that I'd prefer to keep :)
– Jane S
3 hours ago
@JaneS alright, if it's a story element, I get it. You might want to hang a lantern on it somehow though, as most folk are going to ask themselves 'why aren't they just constantly accelerating?'
– Tim B II
3 hours ago
I shall have a think and see if I can not break the story, but if I can't I will have to see how I can hand-wave the inefficiency :)
– Jane S
3 hours ago
 |Â
show 1 more comment
Just to be clear, it's a 2 year acceleration curve from 0 to 0.2c, then 20 years at 0.2c, then a two year deceleration curve from 0.2c to zero :)
– Jane S
3 hours ago
1
@JaneS yeah, you really wouldn't want to do that. Just put the slow burn on to the half way point, then turn around and use the other half of your fuel slowing down. You'll get there a LOT faster.
– Tim B II
3 hours ago
It's kinda important to my story to do the "quick" burn at the beginning and the end of the journey, so while it's more efficient the other way, it breaks some of my other logic that I'd prefer to keep :)
– Jane S
3 hours ago
@JaneS alright, if it's a story element, I get it. You might want to hang a lantern on it somehow though, as most folk are going to ask themselves 'why aren't they just constantly accelerating?'
– Tim B II
3 hours ago
I shall have a think and see if I can not break the story, but if I can't I will have to see how I can hand-wave the inefficiency :)
– Jane S
3 hours ago
Just to be clear, it's a 2 year acceleration curve from 0 to 0.2c, then 20 years at 0.2c, then a two year deceleration curve from 0.2c to zero :)
– Jane S
3 hours ago
Just to be clear, it's a 2 year acceleration curve from 0 to 0.2c, then 20 years at 0.2c, then a two year deceleration curve from 0.2c to zero :)
– Jane S
3 hours ago
1
1
@JaneS yeah, you really wouldn't want to do that. Just put the slow burn on to the half way point, then turn around and use the other half of your fuel slowing down. You'll get there a LOT faster.
– Tim B II
3 hours ago
@JaneS yeah, you really wouldn't want to do that. Just put the slow burn on to the half way point, then turn around and use the other half of your fuel slowing down. You'll get there a LOT faster.
– Tim B II
3 hours ago
It's kinda important to my story to do the "quick" burn at the beginning and the end of the journey, so while it's more efficient the other way, it breaks some of my other logic that I'd prefer to keep :)
– Jane S
3 hours ago
It's kinda important to my story to do the "quick" burn at the beginning and the end of the journey, so while it's more efficient the other way, it breaks some of my other logic that I'd prefer to keep :)
– Jane S
3 hours ago
@JaneS alright, if it's a story element, I get it. You might want to hang a lantern on it somehow though, as most folk are going to ask themselves 'why aren't they just constantly accelerating?'
– Tim B II
3 hours ago
@JaneS alright, if it's a story element, I get it. You might want to hang a lantern on it somehow though, as most folk are going to ask themselves 'why aren't they just constantly accelerating?'
– Tim B II
3 hours ago
I shall have a think and see if I can not break the story, but if I can't I will have to see how I can hand-wave the inefficiency :)
– Jane S
3 hours ago
I shall have a think and see if I can not break the story, but if I can't I will have to see how I can hand-wave the inefficiency :)
– Jane S
3 hours ago
 |Â
show 1 more comment
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