Advantages of Multistage Rockets: Calculating the Benefits with an Example

  • Thread starter Januz Johansen
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In summary,Multistage rockets can have a larger delta-v (the change in velocity) than single stage rockets.
  • #1
Januz Johansen
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Poster has been reminded that they need to show their best efforts to answer the question

Homework Statement


Assess why there can advantageously be used multistage rockets, with a calculation example.

Homework Equations

-

The Attempt at a Solution


[/B]
Hello all,
i need to show why it is an advantage to use multistage rockets, with some mathematical proof, and I am a bit lost. I have done calculations on single-stage rockets, but I am not sure where to start with multistage rockets.
So it would be great if somebody could suggest some formulas to use to proof this.

(sorry for my english)
thanks
 
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  • #2
Hi,

PF culture insists you make the first move by proposing something. But to get you under way: Suppose you have a backpack full of bottles of water. Would you get further if you carried the empty ones with you on your trip through the desert ? Or would it be better to make use of the many recycle points they have on the way to the next oasis :smile: ?

And your english is just fine (said the dutchman)
 
  • #3

Homework Statement


Assess why there can advantageously be used multistage rockets, with a calculation example.

Homework Equations

-

The Attempt at a Solution

[/B]

Hello all,
i need to show why it is an advantage to use multistage rockets, with some mathematical proof, and I am a bit lost. I have done calculations on single-stage rockets, but I am not sure where to start with multistage rockets.
So it would be great if somebody could suggest some formulas to use to proof this.

I don't know if this is right but:

If i have tried to do some calculations on multi-stage rocket with the rocket equation,
dv=u*ln(m0/mf)+u*ln(m0-dm/mf-mr-dm) where dm is the propellant used, mr is the stage there are droped off, m0 is total mass, including propellant, i find the sum of the total delta V, in the first step i use the tsiolkovsky rocket equation, and i add it with again the tsiolkovsky rocket equation just with the new mass for the next stage.
i have tryed looking at det difference in delta V, ( the maximum change of velocity of the vehicle) but when i
comparer the numbers, the dV is a lot smaller with a 2-stage-rocket - can that be true?

thanks @BvU

(sorry for my english)
thanks
 
  • #4
Januz Johansen said:

Homework Statement


Assess why there can advantageously be used multistage rockets, with a calculation example.

Homework Equations

-

The Attempt at a Solution

[/B]

Hello all,
i need to show why it is an advantage to use multistage rockets, with some mathematical proof, and I am a bit lost. I have done calculations on single-stage rockets, but I am not sure where to start with multistage rockets.
So it would be great if somebody could suggest some formulas to use to proof this.

I don't know if this is right but:

If i have tried to do some calculations on multi-stage rocket with the rocket equation,
dv=u*ln(m0/mf)+u*ln(m0-dm/mf-mr-dm) where dm is the propellant used, mr is the stage there are droped off, m0 is total mass, including propellant, i find the sum of the total delta V, in the first step i use the tsiolkovsky rocket equation, and i add it with again the tsiolkovsky rocket equation just with the new mass for the next stage.
i have tryed looking at det difference in delta V, ( the maximum change of velocity of the vehicle) but when i
comparer the numbers, the dV is a lot smaller with a 2-stage-rocket - can that be true?

thanks @BvU

(sorry for my english)
thanks
I've not gone through what you wrote in detail, but it sounds like you have not done the right comparison. You need to compare a two stage rocket and a one stage rocket with the same payload and same total fuel.
 
  • #5
haruspex said:
I've not gone through what you wrote in detail, but it sounds like you have not done the right comparison. You need to compare a two stage rocket and a one stage rocket with the same payload and same total fuel.

Thanks- i see my mistake now, in my calculations for the masse i accidently changed the size of the payload's mass
 

1. What is a multistage rocket?

A multistage rocket is a type of rocket that is composed of multiple stages or sections, each with its own set of engines and fuel tanks. As the rocket travels through space, each stage is used and then discarded to reduce the weight of the rocket and increase its efficiency.

2. What are the advantages of using multistage rockets?

There are several advantages to using multistage rockets. First, they are more efficient than single-stage rockets as the discarded stages reduce the weight of the rocket, allowing it to reach higher speeds. Second, they have a higher payload capacity as the rocket can carry more weight due to its increased efficiency. Third, multistage rockets can travel further distances as they can reach higher speeds and carry more fuel. Lastly, they are more cost-effective as they require less fuel and resources compared to single-stage rockets.

3. Can you provide an example of how multistage rockets are more efficient?

One example is the Saturn V rocket, which was used by NASA for the Apollo missions to the moon. The Saturn V had three stages, each with its own engines and fuel tanks. As the rocket traveled through space, the stages were discarded, allowing the remaining stages to travel at higher speeds with less weight. This resulted in the Saturn V being able to carry heavier payloads and travel further distances compared to single-stage rockets.

4. Are there any other benefits to using multistage rockets?

In addition to their increased efficiency and payload capacity, multistage rockets also have a higher thrust-to-weight ratio. This means that they can produce more thrust compared to their weight, allowing them to accelerate faster and reach higher speeds. This is especially important for space travel where high speeds are necessary to escape the Earth's gravity and enter orbit.

5. Are there any disadvantages to using multistage rockets?

One potential disadvantage is the complexity of designing and building multistage rockets. They require precise engineering and coordination between the different stages, which can be challenging and costly. Additionally, the discarded stages can also contribute to space debris, which can be a problem for future space missions. However, the benefits of multistage rockets far outweigh these potential drawbacks.

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