Editing Wikipedia

ThreatMatrix

Well-Known Member
Lifetime Member
Aug 28, 2014
16,540
26,088
So in my spare time I edit Wikipedia physics pages (j/k). The page in question
Tsiolkovsky rocket equation - Wikipedia
Had an apparent error in the derivation section where it said:
b6dff0803e6f4d77190268017f246e278c64c207
is the mass of the rocket at time t = 0

Noticing this blatant error I changed it to
b6dff0803e6f4d77190268017f246e278c64c207
is the mass of the rocket at time t = Δ t

Does this explain rocket failures over the years? Have designers been using the wrong equations?
Does it explain why this Falcon 9 blew up on the launch pad? Or was it aliens?

Of course I could be wrong. I wonder if anybody revues that shyt.
 

Detroitgator

Well-Known Member
Lifetime Member
Jul 15, 2014
28,240
46,752
So in my spare time I edit Wikipedia physics pages (j/k). The page in question
Tsiolkovsky rocket equation - Wikipedia
Had an apparent error in the derivation section where it said:
b6dff0803e6f4d77190268017f246e278c64c207
is the mass of the rocket at time t = 0

Noticing this blatant error I changed it to
b6dff0803e6f4d77190268017f246e278c64c207
is the mass of the rocket at time t = Δ t

Does this explain rocket failures over the years? Have designers been using the wrong equations?
Does it explain why this Falcon 9 blew up on the launch pad? Or was it aliens?

Of course I could be wrong. I wonder if anybody revues that shyt.

:lol:
 

CGgater

Gainesville Native
Lifetime Member
Jul 30, 2014
10,129
16,370
I remember when booby bowden’s Wikipedia page was the primary target for edits by this justice-minded group of Gators.
 

ThreatMatrix

Well-Known Member
Lifetime Member
Aug 28, 2014
16,540
26,088
Maybe this is a good place to talk about the Tyranny of the Rocket equation

So it’s all about Delta v. Every maneuver requires a certain amount of delta independent of the size of the space craft. Delta V is your ability to change your velocity to reach the velocities needed for each maneuver.

If you want to get into LEO it requires X of Delta V.
If you want to get to the moon it requires Y amount of Delta V.
If you to get into orbit around the moon it requires Z amount of Delta V
Over the course of a mission all those Delta V’s add up.

So the rocket equation tells us that our available Delta V is proportional to the velocity of the exhaust and the natural log of the initial mass of fuel divided by essentially mass flow rate.

dda48a06c75ce528e15e85174aca646cf9053379


Exhaust velocity (Ve) of a chemical rocket is limited by the fuel's energy density and in real world rocket design’s they get acceptably close. Rocket engines are also designed for the best mass flow rates (M1) that can be achieved. So in reality the driving component is the mass of the fuel (Mo). Of course you need enough fuel so that you don’t run out but why not just carry more? Well this is why:

The natural log of the mass of the fuel increases less and less.


So let’s say you double the amount of fuel then you only get a 26% increase in Delta V. Double that again and you only get a 24% increase in Delta V. And so on and so on. Not to mention that as you increase the amount of fuel you also are increasing the weight of the container and things get even worse. Plus now your rocket engine has to develop even more thrust to overcome the extra mass. And your burn times increase proportionally with the mass of fuel.

Basically this is what keeps us on the ground. For current engine technology we are severely limited by the amount of fuel that we can carry. Currently we burn RP-1 (kerosene), hydrogen and methane. At the end of the day the achievable exhaust velocities of these fuels aren’t much different. And each have other pluses and minuses.

We are at a limit of what can be done with chemical burning rockets. So ideas have been proposed to help along the journey. Refuel in space so that you don’t have to carry that initial mass. Of course it costs you to get that fuel in space. Or make the fuel at the destination. That’s one of the reasons that SpaceX and Blue Origin are developing methane rockets. On Mars, you can conceivably make methane by bringing along some hydrogen and combining it with the CO2 in the atmosphere to get 10x as much methane.

However this doesn’t solve the problem of how long the trip takes. To make the trip faster and use less fuel we need a new rocket engine technology and fortunately we’ve had one for over 50 years. Nuclear Thermal Rockets (NTR). Current engines technology hits a limit of around 450 ISP (proportional to Ve). I think the king of ISP, but too lazy to fact check, was the Shuttle Main Engines (SME) at 450 ISP. Even Elon’s new methane rockets are less than that. But NTR’s easily achieve 800 ISP and possibly up to 1200 ISP.ANd real engines were tested and built back in the 50's.

How do they do it? Glad you asked. Current engines burn the fuel, and the Ve is limited to the amount of energy in the fuel. NTR’s don’t burn the fuel. Instead they eject at a higher velocity like air out of a balloon. Of course anything with the word “nuclear” scares the **** out of the lay person. But we put nuclear (radioactive) fuel in space all the time. It’s what powers many long range satellites. NTR’s are different in that fission is happening but the material is no more dangerous in case of a RUD (Rapid Unplanned Disassembly). They don’t melt down or blow up like a bomb.

So why aren’t we developing them.First Clinton killed anything nuclear back in the 80. But now thanks to our forward thinking President NASA now has the budget to do so. NTR is the next step and it’s actual a very “small step for man”.
 

Thought Criminal

Well-Known Member
Lifetime Member
Jul 31, 2018
382
1,118
Maybe this is a good place to talk about the Tyranny of the Rocket equation

So it’s all about Delta v. Every maneuver requires a certain amount of delta independent of the size of the space craft. Delta V is your ability to change your velocity to reach the velocities needed for each maneuver.

If you want to get into LEO it requires X of Delta V.
If you want to get to the moon it requires Y amount of Delta V.
If you to get into orbit around the moon it requires Z amount of Delta V
Over the course of a mission all those Delta V’s add up.

So the rocket equation tells us that our available Delta V is proportional to the velocity of the exhaust and the natural log of the initial mass of fuel divided by essentially mass flow rate.

dda48a06c75ce528e15e85174aca646cf9053379


Exhaust velocity (Ve) of a chemical rocket is limited by the fuel's energy density and in real world rocket design’s they get acceptably close. Rocket engines are also designed for the best mass flow rates (M1) that can be achieved. So in reality the driving component is the mass of the fuel (Mo). Of course you need enough fuel so that you don’t run out but why not just carry more? Well this is why:

The natural log of the mass of the fuel increases less and less.


So let’s say you double the amount of fuel then you only get a 26% increase in Delta V. Double that again and you only get a 24% increase in Delta V. And so on and so on. Not to mention that as you increase the amount of fuel you also are increasing the weight of the container and things get even worse. Plus now your rocket engine has to develop even more thrust to overcome the extra mass. And your burn times increase proportionally with the mass of fuel.

Basically this is what keeps us on the ground. For current engine technology we are severely limited by the amount of fuel that we can carry. Currently we burn RP-1 (kerosene), hydrogen and methane. At the end of the day the achievable exhaust velocities of these fuels aren’t much different. And each have other pluses and minuses.

We are at a limit of what can be done with chemical burning rockets. So ideas have been proposed to help along the journey. Refuel in space so that you don’t have to carry that initial mass. Of course it costs you to get that fuel in space. Or make the fuel at the destination. That’s one of the reasons that SpaceX and Blue Origin are developing methane rockets. On Mars, you can conceivably make methane by bringing along some hydrogen and combining it with the CO2 in the atmosphere to get 10x as much methane.

However this doesn’t solve the problem of how long the trip takes. To make the trip faster and use less fuel we need a new rocket engine technology and fortunately we’ve had one for over 50 years. Nuclear Thermal Rockets (NTR). Current engines technology hits a limit of around 450 ISP (proportional to Ve). I think the king of ISP, but too lazy to fact check, was the Shuttle Main Engines (SME) at 450 ISP. Even Elon’s new methane rockets are less than that. But NTR’s easily achieve 800 ISP and possibly up to 1200 ISP.ANd real engines were tested and built back in the 50's.

How do they do it? Glad you asked. Current engines burn the fuel, and the Ve is limited to the amount of energy in the fuel. NTR’s don’t burn the fuel. Instead they eject at a higher velocity like air out of a balloon. Of course anything with the word “nuclear” scares the **** out of the lay person. But we put nuclear (radioactive) fuel in space all the time. It’s what powers many long range satellites. NTR’s are different in that fission is happening but the material is no more dangerous in case of a RUD (Rapid Unplanned Disassembly). They don’t melt down or blow up like a bomb.

So why aren’t we developing them.First Clinton killed anything nuclear back in the 80. But now thanks to our forward thinking President NASA now has the budget to do so. NTR is the next step and it’s actual a very “small step for man”.
Definitely.
 

AuggieDosta

I Don't Re Member
Lifetime Member
Aug 1, 2018
7,450
12,004
"But NTR’s easily achieve 800 ISP and possibly up to 1200 ISP.ANd real engines were tested and built back in the 50's. "

Ha! You wish.
 

Detroitgator

Well-Known Member
Lifetime Member
Jul 15, 2014
28,240
46,752
Best Wiki editing I ever saw was for the rapper Snow... it was hilarious
 

Pablos Tunnel

Well-Known Member
Lifetime Member
Sep 23, 2017
2,689
4,130
Maybe this is a good place to talk about the Tyranny of the Rocket equation

So it’s all about Delta v. Every maneuver requires a certain amount of delta independent of the size of the space craft. Delta V is your ability to change your velocity to reach the velocities needed for each maneuver.

If you want to get into LEO it requires X of Delta V.
If you want to get to the moon it requires Y amount of Delta V.
If you to get into orbit around the moon it requires Z amount of Delta V
Over the course of a mission all those Delta V’s add up.

So the rocket equation tells us that our available Delta V is proportional to the velocity of the exhaust and the natural log of the initial mass of fuel divided by essentially mass flow rate.

dda48a06c75ce528e15e85174aca646cf9053379


Exhaust velocity (Ve) of a chemical rocket is limited by the fuel's energy density and in real world rocket design’s they get acceptably close. Rocket engines are also designed for the best mass flow rates (M1) that can be achieved. So in reality the driving component is the mass of the fuel (Mo). Of course you need enough fuel so that you don’t run out but why not just carry more? Well this is why:

The natural log of the mass of the fuel increases less and less.


So let’s say you double the amount of fuel then you only get a 26% increase in Delta V. Double that again and you only get a 24% increase in Delta V. And so on and so on. Not to mention that as you increase the amount of fuel you also are increasing the weight of the container and things get even worse. Plus now your rocket engine has to develop even more thrust to overcome the extra mass. And your burn times increase proportionally with the mass of fuel.

Basically this is what keeps us on the ground. For current engine technology we are severely limited by the amount of fuel that we can carry. Currently we burn RP-1 (kerosene), hydrogen and methane. At the end of the day the achievable exhaust velocities of these fuels aren’t much different. And each have other pluses and minuses.

We are at a limit of what can be done with chemical burning rockets. So ideas have been proposed to help along the journey. Refuel in space so that you don’t have to carry that initial mass. Of course it costs you to get that fuel in space. Or make the fuel at the destination. That’s one of the reasons that SpaceX and Blue Origin are developing methane rockets. On Mars, you can conceivably make methane by bringing along some hydrogen and combining it with the CO2 in the atmosphere to get 10x as much methane.

However this doesn’t solve the problem of how long the trip takes. To make the trip faster and use less fuel we need a new rocket engine technology and fortunately we’ve had one for over 50 years. Nuclear Thermal Rockets (NTR). Current engines technology hits a limit of around 450 ISP (proportional to Ve). I think the king of ISP, but too lazy to fact check, was the Shuttle Main Engines (SME) at 450 ISP. Even Elon’s new methane rockets are less than that. But NTR’s easily achieve 800 ISP and possibly up to 1200 ISP.ANd real engines were tested and built back in the 50's.

How do they do it? Glad you asked. Current engines burn the fuel, and the Ve is limited to the amount of energy in the fuel. NTR’s don’t burn the fuel. Instead they eject at a higher velocity like air out of a balloon. Of course anything with the word “nuclear” scares the **** out of the lay person. But we put nuclear (radioactive) fuel in space all the time. It’s what powers many long range satellites. NTR’s are different in that fission is happening but the material is no more dangerous in case of a RUD (Rapid Unplanned Disassembly). They don’t melt down or blow up like a bomb.

So why aren’t we developing them.First Clinton killed anything nuclear back in the 80. But now thanks to our forward thinking President NASA now has the budget to do so. NTR is the next step and it’s actual a very “small step for man”.
Yep, what he said. My boy is wicked smart!
 

Gator515151

Well-Known Member
2018 Pick 'Em Champ
Aug 16, 2018
1,948
5,685
My snowflake daughter in law's father works for NASA. She says when she was in school she used to ask her father for help on her math homework. He always told her "Sierra I just don't understand why you don't get this". Her answer was always "But Dad you're a Fvkin rocket scientist",
 

AlexDaGator

Founding Member
The Hammer of Thor
Lifetime Member
Jun 19, 2014
12,702
31,647
Founding Member
Maybe this is a good place to talk about the Tyranny of the Rocket equation

So it’s all about Delta v. Every maneuver requires a certain amount of delta independent of the size of the space craft. Delta V is your ability to change your velocity to reach the velocities needed for each maneuver.

If you want to get into LEO it requires X of Delta V.
If you want to get to the moon it requires Y amount of Delta V.
If you to get into orbit around the moon it requires Z amount of Delta V
Over the course of a mission all those Delta V’s add up.

So the rocket equation tells us that our available Delta V is proportional to the velocity of the exhaust and the natural log of the initial mass of fuel divided by essentially mass flow rate.

dda48a06c75ce528e15e85174aca646cf9053379


Exhaust velocity (Ve) of a chemical rocket is limited by the fuel's energy density and in real world rocket design’s they get acceptably close. Rocket engines are also designed for the best mass flow rates (M1) that can be achieved. So in reality the driving component is the mass of the fuel (Mo). Of course you need enough fuel so that you don’t run out but why not just carry more? Well this is why:

The natural log of the mass of the fuel increases less and less.


So let’s say you double the amount of fuel then you only get a 26% increase in Delta V. Double that again and you only get a 24% increase in Delta V. And so on and so on. Not to mention that as you increase the amount of fuel you also are increasing the weight of the container and things get even worse. Plus now your rocket engine has to develop even more thrust to overcome the extra mass. And your burn times increase proportionally with the mass of fuel.

Basically this is what keeps us on the ground. For current engine technology we are severely limited by the amount of fuel that we can carry. Currently we burn RP-1 (kerosene), hydrogen and methane. At the end of the day the achievable exhaust velocities of these fuels aren’t much different. And each have other pluses and minuses.

We are at a limit of what can be done with chemical burning rockets. So ideas have been proposed to help along the journey. Refuel in space so that you don’t have to carry that initial mass. Of course it costs you to get that fuel in space. Or make the fuel at the destination. That’s one of the reasons that SpaceX and Blue Origin are developing methane rockets. On Mars, you can conceivably make methane by bringing along some hydrogen and combining it with the CO2 in the atmosphere to get 10x as much methane.

However this doesn’t solve the problem of how long the trip takes. To make the trip faster and use less fuel we need a new rocket engine technology and fortunately we’ve had one for over 50 years. Nuclear Thermal Rockets (NTR). Current engines technology hits a limit of around 450 ISP (proportional to Ve). I think the king of ISP, but too lazy to fact check, was the Shuttle Main Engines (SME) at 450 ISP. Even Elon’s new methane rockets are less than that. But NTR’s easily achieve 800 ISP and possibly up to 1200 ISP.ANd real engines were tested and built back in the 50's.

How do they do it? Glad you asked. Current engines burn the fuel, and the Ve is limited to the amount of energy in the fuel. NTR’s don’t burn the fuel. Instead they eject at a higher velocity like air out of a balloon. Of course anything with the word “nuclear” scares the **** out of the lay person. But we put nuclear (radioactive) fuel in space all the time. It’s what powers many long range satellites. NTR’s are different in that fission is happening but the material is no more dangerous in case of a RUD (Rapid Unplanned Disassembly). They don’t melt down or blow up like a bomb.

So why aren’t we developing them.First Clinton killed anything nuclear back in the 80. But now thanks to our forward thinking President NASA now has the budget to do so. NTR is the next step and it’s actual a very “small step for man”.


iu



Alex.
 

bradgator2

Founding Member
Rioting
Lifetime Member
Jun 12, 2014
9,507
24,945
Founding Member
So, small side story, but might as well slide it in here. In college at UF, my church had a tiny little ad in the weekly handout that said there was going to be an informational meeting one evening about the Cassini spacecraft and the dangers of the plutonium on board. (Launch in October 1997)

Since I was enrolled in the college of Nuclear Engineering, I thought it might be a good idea to gather up some of my classmates and attend this meeting.

It was held in a typical church hall room with donuts and stale coffee and fold out chairs. There might have been roughly 50 guests and the 5 of us just casually sat among them. The speaker was an ultra-hippie.

Cassini used an RTG as its power source. A radioisotope thermoelectric generator. It is a very simple electric generator that uses thermocouples to convert the decay heat of the plutonium. The plutonium is in a simple ceramic form, just like a coffee mug. This small RTG only produced about 600 watts of power, but for 20 years. There really is nothing "nuclear" about this design. Basically the only danger of any kind of radioactive spread would be if it blew up on launch or an accidental re-entry on its gravitational slingshot flyby. And even then, the plutonium would have to be blown up into some sort of ultra fine dust form.

So the hippie starts out talking and told everyone in the room they are about to die. He points to a pregnant woman and says her baby is about to die. I raise my hand for a question. He asks that all questions be held to the end. To which I replied, "there is no way I can keep track of all your nonsense for that long."

It was hilarious. He had no ability to adjust to the situation. He would read his next slide and my hand would raise for a question. I thought he was going to run out of there when I told him there was a nuclear reactor on campus a few hundred yards from where we were sitting. He only made it through like the first 4 slides of his presentation during that entire hour because we interrupted him so much. And stormed out of there at the end.

The room was roughly 50/50 on our presence. Half the people were really annoyed at us. The other half came up to us afterwards and were really thankful.

Fun times.
 

AlexDaGator

Founding Member
The Hammer of Thor
Lifetime Member
Jun 19, 2014
12,702
31,647
Founding Member
So, small side story, but might as well slide it in here. In college at UF, my church had a tiny little ad in the weekly handout that said there was going to be an informational meeting one evening about the Cassini spacecraft and the dangers of the plutonium on board. (Launch in October 1997)

Since I was enrolled in the college of Nuclear Engineering, I thought it might be a good idea to gather up some of my classmates and attend this meeting.

It was held in a typical church hall room with donuts and stale coffee and fold out chairs. There might have been roughly 50 guests and the 5 of us just casually sat among them. The speaker was an ultra-hippie.

Cassini used an RTG as its power source. A radioisotope thermoelectric generator. It is a very simple electric generator that uses thermocouples to convert the decay heat of the plutonium. The plutonium is in a simple ceramic form, just like a coffee mug. This small RTG only produced about 600 watts of power, but for 20 years. There really is nothing "nuclear" about this design. Basically the only danger of any kind of radioactive spread would be if it blew up on launch or an accidental re-entry on its gravitational slingshot flyby. And even then, the plutonium would have to be blown up into some sort of ultra fine dust form.

So the hippie starts out talking and told everyone in the room they are about to die. He points to a pregnant woman and says her baby is about to die. I raise my hand for a question. He asks that all questions be held to the end. To which I replied, "there is no way I can keep track of all your nonsense for that long."

It was hilarious. He had no ability to adjust to the situation. He would read his next slide and my hand would raise for a question. I thought he was going to run out of there when I told him there was a nuclear reactor on campus a few hundred yards from where we were sitting. He only made it through like the first 4 slides of his presentation during that entire hour because we interrupted him so much. And stormed out of there at the end.

The room was roughly 50/50 on our presence. Half the people were really annoyed at us. The other half came up to us afterwards and were really thankful.

Fun times.

Actual photo of Brad and his college chums:

iu





Alex.
 

Users who are viewing this thread

Help Users

You haven't joined any rooms.