Mixing
Shorten trip to mars
Clash Royale CLAN TAG#URR8PPP
up vote
2
down vote
favorite
As someone advice me in previous treat I want ask related question to
Can you refuel chemical rockets to increase the speed?
If the numbers in comment and comment of @SteveLinton's answer are correct, why has SpaceX CEO E.Musk promised that their Big falcon rocket, gross mass 4,300 tons, with two stages and payload 100 tons (after refueling in orbit) can shorten trip to mars to 3 months.
Is this physically possible with this rocket ?
rockets science
edited 2 hours ago
uhoh
28.4k1392349
asked 2 hours ago
John Bambi
312
New contributor
John Bambi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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 |Â
show 2 more comments
up vote
2
down vote
favorite
As someone advice me in previous treat I want ask related question to
Can you refuel chemical rockets to increase the speed?
If the numbers in comment and comment of @SteveLinton's answer are correct, why has SpaceX CEO E.Musk promised that their Big falcon rocket, gross mass 4,300 tons, with two stages and payload 100 tons (after refueling in orbit) can shorten trip to mars to 3 months.
Is this physically possible with this rocket ?
rockets science
edited 2 hours ago
uhoh
28.4k1392349
asked 2 hours ago
John Bambi
312
New contributor
John Bambi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
2
Answers can move up and down, and comments can be deleted at any time. So instead of "3th,4th comment of second answer" I've added direct links. Can you double check that these are the one's you mean? Thanks!
– uhoh
2 hours ago
1
Also, if you can add some description of what it is that makes you wonder if it might not be physically possible, that would help a lot.
– uhoh
2 hours ago
Well, BFR have 8 x time size of F9 and for 3 months trip to mars you need delta v budget about 28 km/s ( including deacceleration ). So from SteveLinton numbers you will need six stage rocket with gross mass 2,4 million tons. Can we launch such big rocket from earth to orbit ?
– John Bambi
1 hour ago
The time of the trip to Mars is a money question. You can shrink the transit times down to 3 months but it requires burning a lot more fuel/refueling en route. Bringing extra fuel and extra fuel for fuel carriers is very expensive.
– Dragongeek
1 hour ago
They will almost certainly use the atmosphere of Mars to decellerate
– Steve Linton
1 hour ago
 |Â
show 2 more comments
up vote
2
down vote
favorite
up vote
2
down vote
favorite
As someone advice me in previous treat I want ask related question to
Can you refuel chemical rockets to increase the speed?
If the numbers in comment and comment of @SteveLinton's answer are correct, why has SpaceX CEO E.Musk promised that their Big falcon rocket, gross mass 4,300 tons, with two stages and payload 100 tons (after refueling in orbit) can shorten trip to mars to 3 months.
Is this physically possible with this rocket ?
rockets science
edited 2 hours ago
uhoh
28.4k1392349
asked 2 hours ago
John Bambi
312
New contributor
John Bambi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
As someone advice me in previous treat I want ask related question to
Can you refuel chemical rockets to increase the speed?
If the numbers in comment and comment of @SteveLinton's answer are correct, why has SpaceX CEO E.Musk promised that their Big falcon rocket, gross mass 4,300 tons, with two stages and payload 100 tons (after refueling in orbit) can shorten trip to mars to 3 months.
Is this physically possible with this rocket ?
rockets science
rockets science
edited 2 hours ago
uhoh
28.4k1392349
asked 2 hours ago
John Bambi
312
New contributor
John Bambi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 2 hours ago
uhoh
28.4k1392349
asked 2 hours ago
John Bambi
312
New contributor
John Bambi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 2 hours ago
uhoh
28.4k1392349
edited 2 hours ago
uhoh
28.4k1392349
edited 2 hours ago
uhoh
28.4k1392349
28.4k1392349
asked 2 hours ago
John Bambi
312
New contributor
John Bambi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 hours ago
John Bambi
312
asked 2 hours ago
John Bambi
312
312
New contributor
John Bambi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
John Bambi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
John Bambi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
2
Answers can move up and down, and comments can be deleted at any time. So instead of "3th,4th comment of second answer" I've added direct links. Can you double check that these are the one's you mean? Thanks!
– uhoh
2 hours ago
1
Also, if you can add some description of what it is that makes you wonder if it might not be physically possible, that would help a lot.
– uhoh
2 hours ago
Well, BFR have 8 x time size of F9 and for 3 months trip to mars you need delta v budget about 28 km/s ( including deacceleration ). So from SteveLinton numbers you will need six stage rocket with gross mass 2,4 million tons. Can we launch such big rocket from earth to orbit ?
– John Bambi
1 hour ago
The time of the trip to Mars is a money question. You can shrink the transit times down to 3 months but it requires burning a lot more fuel/refueling en route. Bringing extra fuel and extra fuel for fuel carriers is very expensive.
– Dragongeek
1 hour ago
They will almost certainly use the atmosphere of Mars to decellerate
– Steve Linton
1 hour ago
 |Â
show 2 more comments
2
Answers can move up and down, and comments can be deleted at any time. So instead of "3th,4th comment of second answer" I've added direct links. Can you double check that these are the one's you mean? Thanks!
– uhoh
2 hours ago
1
Also, if you can add some description of what it is that makes you wonder if it might not be physically possible, that would help a lot.
– uhoh
2 hours ago
Well, BFR have 8 x time size of F9 and for 3 months trip to mars you need delta v budget about 28 km/s ( including deacceleration ). So from SteveLinton numbers you will need six stage rocket with gross mass 2,4 million tons. Can we launch such big rocket from earth to orbit ?
– John Bambi
1 hour ago
The time of the trip to Mars is a money question. You can shrink the transit times down to 3 months but it requires burning a lot more fuel/refueling en route. Bringing extra fuel and extra fuel for fuel carriers is very expensive.
– Dragongeek
1 hour ago
They will almost certainly use the atmosphere of Mars to decellerate
– Steve Linton
1 hour ago
2
2
Answers can move up and down, and comments can be deleted at any time. So instead of "3th,4th comment of second answer" I've added direct links. Can you double check that these are the one's you mean? Thanks!
– uhoh
2 hours ago
Answers can move up and down, and comments can be deleted at any time. So instead of "3th,4th comment of second answer" I've added direct links. Can you double check that these are the one's you mean? Thanks!
– uhoh
2 hours ago
1
1
Also, if you can add some description of what it is that makes you wonder if it might not be physically possible, that would help a lot.
– uhoh
2 hours ago
Also, if you can add some description of what it is that makes you wonder if it might not be physically possible, that would help a lot.
– uhoh
2 hours ago
Well, BFR have 8 x time size of F9 and for 3 months trip to mars you need delta v budget about 28 km/s ( including deacceleration ). So from SteveLinton numbers you will need six stage rocket with gross mass 2,4 million tons. Can we launch such big rocket from earth to orbit ?
– John Bambi
1 hour ago
Well, BFR have 8 x time size of F9 and for 3 months trip to mars you need delta v budget about 28 km/s ( including deacceleration ). So from SteveLinton numbers you will need six stage rocket with gross mass 2,4 million tons. Can we launch such big rocket from earth to orbit ?
– John Bambi
1 hour ago
The time of the trip to Mars is a money question. You can shrink the transit times down to 3 months but it requires burning a lot more fuel/refueling en route. Bringing extra fuel and extra fuel for fuel carriers is very expensive.
– Dragongeek
1 hour ago
The time of the trip to Mars is a money question. You can shrink the transit times down to 3 months but it requires burning a lot more fuel/refueling en route. Bringing extra fuel and extra fuel for fuel carriers is very expensive.
– Dragongeek
1 hour ago
They will almost certainly use the atmosphere of Mars to decellerate
– Steve Linton
1 hour ago
They will almost certainly use the atmosphere of Mars to decellerate
– Steve Linton
1 hour ago
 |Â
show 2 more comments
1 Answer
1
active
oldest
votes
up vote
4
down vote
To answer this properly we need to look a bit more closely at how interplanetary travel actually works. There are lots of discussions on stack exchange (and elsewhere) which explore this. For instance this one which includes a very useful diagram, from which I take most of my information.
Launching from Earth it needs a delta-V of about 9.4 km/s to get into Low Earth Orbit (LEO) (a stable orbit a couple of hundred km up).
Once in orbit, a further boost of about 3.2 km/s will break you free of Earth's gravity. If a rocket applies that boost, it will enter an orbit around the Sun very similar to the Earth's and slowly drift further and further from the Earth.
To get to Mars, you need to boost still more, to change your orbit around the Sun into one which will meet Mars (as it goes around the Sun in its own orbit). This is actually a fairly small boost, about 0.6 km/s, but that gets you into an orbit which takes six months or more before it gets to Mars.
So to get to Mars sooner, you need to make a bigger change to your orbit around the Sun. The relationship between the boost needed to make that change and the time to get to Mars is not a simple one (and also depends on how long you are willing to wait to start, since Earth and Mars are also moving, opportunities come and go). It is usually visualised using something called a "porkchop plot". There is an online tool to calculate there here. Using that tool to look at departures in 2020 I get:
. So we can see, for instance, that the lowest delta-V transfer that year (middle of the pale blue area) takes about 6 months and leaves roughly in the middle of the year, with a delta-V required of about 3.6 km/s (I think that starts in LEO, but I'm not sure). On the other hand, the diagram also suggests that, for the right departure date you can get the transfer time down to 100 days or so, using a delta-V of maybe 5 km/s (if you use the online generator, you can hover over the diagram to get more detail of particular points).
Returning to the SpaceX plan, their mission calls for about six or seven launches from Earth (one spaceship and the rest tankers) so the total mass launched is about 30000 tons. They end up with 100 tons of payload and about 600 tons of propellant in their BFS in Low Earth Orbit, a fairly reasonable ratio for achieving 5km/s of delta-V to send the payload onto a 90 day Mars transfer. At Mars they will presumably slow down by grazing Mars' atmosphere, although they will probably need some fuel for landing. They plan to make fuel there for their return journey.
answered 41 mins ago
Steve Linton
3,6041328
Ohh what a nice porkchop!
– SF.
12 mins ago
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
4
down vote
To answer this properly we need to look a bit more closely at how interplanetary travel actually works. There are lots of discussions on stack exchange (and elsewhere) which explore this. For instance this one which includes a very useful diagram, from which I take most of my information.
Launching from Earth it needs a delta-V of about 9.4 km/s to get into Low Earth Orbit (LEO) (a stable orbit a couple of hundred km up).
Once in orbit, a further boost of about 3.2 km/s will break you free of Earth's gravity. If a rocket applies that boost, it will enter an orbit around the Sun very similar to the Earth's and slowly drift further and further from the Earth.
To get to Mars, you need to boost still more, to change your orbit around the Sun into one which will meet Mars (as it goes around the Sun in its own orbit). This is actually a fairly small boost, about 0.6 km/s, but that gets you into an orbit which takes six months or more before it gets to Mars.
So to get to Mars sooner, you need to make a bigger change to your orbit around the Sun. The relationship between the boost needed to make that change and the time to get to Mars is not a simple one (and also depends on how long you are willing to wait to start, since Earth and Mars are also moving, opportunities come and go). It is usually visualised using something called a "porkchop plot". There is an online tool to calculate there here. Using that tool to look at departures in 2020 I get:. So we can see, for instance, that the lowest delta-V transfer that year (middle of the pale blue area) takes about 6 months and leaves roughly in the middle of the year, with a delta-V required of about 3.6 km/s (I think that starts in LEO, but I'm not sure). On the other hand, the diagram also suggests that, for the right departure date you can get the transfer time down to 100 days or so, using a delta-V of maybe 5 km/s (if you use the online generator, you can hover over the diagram to get more detail of particular points).
Returning to the SpaceX plan, their mission calls for about six or seven launches from Earth (one spaceship and the rest tankers) so the total mass launched is about 30000 tons. They end up with 100 tons of payload and about 600 tons of propellant in their BFS in Low Earth Orbit, a fairly reasonable ratio for achieving 5km/s of delta-V to send the payload onto a 90 day Mars transfer. At Mars they will presumably slow down by grazing Mars' atmosphere, although they will probably need some fuel for landing. They plan to make fuel there for their return journey.
answered 41 mins ago
Steve Linton
3,6041328
Ohh what a nice porkchop!
– SF.
12 mins ago
add a comment |Â
up vote
4
down vote
To answer this properly we need to look a bit more closely at how interplanetary travel actually works. There are lots of discussions on stack exchange (and elsewhere) which explore this. For instance this one which includes a very useful diagram, from which I take most of my information.
Launching from Earth it needs a delta-V of about 9.4 km/s to get into Low Earth Orbit (LEO) (a stable orbit a couple of hundred km up).
Once in orbit, a further boost of about 3.2 km/s will break you free of Earth's gravity. If a rocket applies that boost, it will enter an orbit around the Sun very similar to the Earth's and slowly drift further and further from the Earth.
To get to Mars, you need to boost still more, to change your orbit around the Sun into one which will meet Mars (as it goes around the Sun in its own orbit). This is actually a fairly small boost, about 0.6 km/s, but that gets you into an orbit which takes six months or more before it gets to Mars.
So to get to Mars sooner, you need to make a bigger change to your orbit around the Sun. The relationship between the boost needed to make that change and the time to get to Mars is not a simple one (and also depends on how long you are willing to wait to start, since Earth and Mars are also moving, opportunities come and go). It is usually visualised using something called a "porkchop plot". There is an online tool to calculate there here. Using that tool to look at departures in 2020 I get:. So we can see, for instance, that the lowest delta-V transfer that year (middle of the pale blue area) takes about 6 months and leaves roughly in the middle of the year, with a delta-V required of about 3.6 km/s (I think that starts in LEO, but I'm not sure). On the other hand, the diagram also suggests that, for the right departure date you can get the transfer time down to 100 days or so, using a delta-V of maybe 5 km/s (if you use the online generator, you can hover over the diagram to get more detail of particular points).
Returning to the SpaceX plan, their mission calls for about six or seven launches from Earth (one spaceship and the rest tankers) so the total mass launched is about 30000 tons. They end up with 100 tons of payload and about 600 tons of propellant in their BFS in Low Earth Orbit, a fairly reasonable ratio for achieving 5km/s of delta-V to send the payload onto a 90 day Mars transfer. At Mars they will presumably slow down by grazing Mars' atmosphere, although they will probably need some fuel for landing. They plan to make fuel there for their return journey.
answered 41 mins ago
Steve Linton
3,6041328
Ohh what a nice porkchop!
– SF.
12 mins ago
add a comment |Â
up vote
4
down vote
up vote
4
down vote
To answer this properly we need to look a bit more closely at how interplanetary travel actually works. There are lots of discussions on stack exchange (and elsewhere) which explore this. For instance this one which includes a very useful diagram, from which I take most of my information.
Launching from Earth it needs a delta-V of about 9.4 km/s to get into Low Earth Orbit (LEO) (a stable orbit a couple of hundred km up).
Once in orbit, a further boost of about 3.2 km/s will break you free of Earth's gravity. If a rocket applies that boost, it will enter an orbit around the Sun very similar to the Earth's and slowly drift further and further from the Earth.
To get to Mars, you need to boost still more, to change your orbit around the Sun into one which will meet Mars (as it goes around the Sun in its own orbit). This is actually a fairly small boost, about 0.6 km/s, but that gets you into an orbit which takes six months or more before it gets to Mars.
So to get to Mars sooner, you need to make a bigger change to your orbit around the Sun. The relationship between the boost needed to make that change and the time to get to Mars is not a simple one (and also depends on how long you are willing to wait to start, since Earth and Mars are also moving, opportunities come and go). It is usually visualised using something called a "porkchop plot". There is an online tool to calculate there here. Using that tool to look at departures in 2020 I get:. So we can see, for instance, that the lowest delta-V transfer that year (middle of the pale blue area) takes about 6 months and leaves roughly in the middle of the year, with a delta-V required of about 3.6 km/s (I think that starts in LEO, but I'm not sure). On the other hand, the diagram also suggests that, for the right departure date you can get the transfer time down to 100 days or so, using a delta-V of maybe 5 km/s (if you use the online generator, you can hover over the diagram to get more detail of particular points).
Returning to the SpaceX plan, their mission calls for about six or seven launches from Earth (one spaceship and the rest tankers) so the total mass launched is about 30000 tons. They end up with 100 tons of payload and about 600 tons of propellant in their BFS in Low Earth Orbit, a fairly reasonable ratio for achieving 5km/s of delta-V to send the payload onto a 90 day Mars transfer. At Mars they will presumably slow down by grazing Mars' atmosphere, although they will probably need some fuel for landing. They plan to make fuel there for their return journey.
answered 41 mins ago
Steve Linton
3,6041328
To answer this properly we need to look a bit more closely at how interplanetary travel actually works. There are lots of discussions on stack exchange (and elsewhere) which explore this. For instance this one which includes a very useful diagram, from which I take most of my information.
Launching from Earth it needs a delta-V of about 9.4 km/s to get into Low Earth Orbit (LEO) (a stable orbit a couple of hundred km up).
Once in orbit, a further boost of about 3.2 km/s will break you free of Earth's gravity. If a rocket applies that boost, it will enter an orbit around the Sun very similar to the Earth's and slowly drift further and further from the Earth.
To get to Mars, you need to boost still more, to change your orbit around the Sun into one which will meet Mars (as it goes around the Sun in its own orbit). This is actually a fairly small boost, about 0.6 km/s, but that gets you into an orbit which takes six months or more before it gets to Mars.
So to get to Mars sooner, you need to make a bigger change to your orbit around the Sun. The relationship between the boost needed to make that change and the time to get to Mars is not a simple one (and also depends on how long you are willing to wait to start, since Earth and Mars are also moving, opportunities come and go). It is usually visualised using something called a "porkchop plot". There is an online tool to calculate there here. Using that tool to look at departures in 2020 I get:. So we can see, for instance, that the lowest delta-V transfer that year (middle of the pale blue area) takes about 6 months and leaves roughly in the middle of the year, with a delta-V required of about 3.6 km/s (I think that starts in LEO, but I'm not sure). On the other hand, the diagram also suggests that, for the right departure date you can get the transfer time down to 100 days or so, using a delta-V of maybe 5 km/s (if you use the online generator, you can hover over the diagram to get more detail of particular points).
Returning to the SpaceX plan, their mission calls for about six or seven launches from Earth (one spaceship and the rest tankers) so the total mass launched is about 30000 tons. They end up with 100 tons of payload and about 600 tons of propellant in their BFS in Low Earth Orbit, a fairly reasonable ratio for achieving 5km/s of delta-V to send the payload onto a 90 day Mars transfer. At Mars they will presumably slow down by grazing Mars' atmosphere, although they will probably need some fuel for landing. They plan to make fuel there for their return journey.
answered 41 mins ago
Steve Linton
3,6041328
answered 41 mins ago
Steve Linton
3,6041328
answered 41 mins ago
Steve Linton
3,6041328
answered 41 mins ago
Steve Linton
3,6041328
3,6041328
Ohh what a nice porkchop!
– SF.
12 mins ago
add a comment |Â
Ohh what a nice porkchop!
– SF.
12 mins ago
Ohh what a nice porkchop!
– SF.
12 mins ago
Ohh what a nice porkchop!
– SF.
12 mins ago
add a comment |Â
John Bambi is a new contributor. Be nice, and check out our Code of Conduct.
John Bambi is a new contributor. Be nice, and check out our Code of Conduct.
John Bambi is a new contributor. Be nice, and check out our Code of Conduct.
John Bambi is a new contributor. Be nice, and check out our Code of Conduct.
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2
Answers can move up and down, and comments can be deleted at any time. So instead of "3th,4th comment of second answer" I've added direct links. Can you double check that these are the one's you mean? Thanks!
– uhoh
2 hours ago
1
Also, if you can add some description of what it is that makes you wonder if it might not be physically possible, that would help a lot.
– uhoh
2 hours ago
Well, BFR have 8 x time size of F9 and for 3 months trip to mars you need delta v budget about 28 km/s ( including deacceleration ). So from SteveLinton numbers you will need six stage rocket with gross mass 2,4 million tons. Can we launch such big rocket from earth to orbit ?
– John Bambi
1 hour ago
The time of the trip to Mars is a money question. You can shrink the transit times down to 3 months but it requires burning a lot more fuel/refueling en route. Bringing extra fuel and extra fuel for fuel carriers is very expensive.
– Dragongeek
1 hour ago
They will almost certainly use the atmosphere of Mars to decellerate
– Steve Linton
1 hour ago