Simulating rocket launches using excel

In summary, you are simulating the launch of a rocket to orbit and have a few problems with it. You have mentioned that angle of the rocket to the ground is a problem and air pressure has weird steps.
  • #1
TESLER
2
0
Hello everyone,
Over the past year, I have been trying to simulate the launch of a rocket to orbit using excel. I have been pretty successful, and I have what I think to be a mostly working product. However, it has some problems that may be affecting the results.

First, I'l explain roughly what I have done, and the main idea behind the project.

So anyone who is fairly well acquainted with modern rocketry knows that when a rocket takes off, most of its mass and volume are occupied by propellants at 85-90%, with maybe 8-10% being for the structure/infrastructure, and the remainder being payload. However, I was wondering if there could be a way of making rockets less expensive, by removing the need for some of that fuel. For this I have simulated launching the rocket at 45 degrees, using a mass driver to accelerate the rocket to around 1200m/s, and therefore improving the ratio of fuel to payload, and decreasing launch costs. The attached spreadsheet simulates the launch of a 7000kg LOX/RP-1 two stage rocket, capable of putting around 200kg in orbit (around 450 if the mass of the second stage is included). As a note, this is not intended to be a pure physics sim, and therefore it is not perfect. Instead, it is a simulation of a complex engineering problem, which provides a solid baseline for further inquiry.

However, there are a few problems which I can see affecting my results.

The first is that the angle of the rocket to the ground is quite a problem to figure out. Since the spreadsheet calculates for the rocket every 2 seconds, I assumed the angle would be the approximately the same as what it had been 2 seconds before. However, that assumes that the rocket is always pointing in the same direction as its velocity vector. If anyone has any other ideas for improvements, I would be very appreciative.


Unfortunately, the file is around 4mb, therefore too large to attach to this forum. Instead, download it here!

http://www.mediafire.com/view/?jgt7e0gc4wt4g47


Thanks, TESLER
 
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  • #2
However, that assumes that the rocket is always pointing in the same direction as its velocity vector.
You have column B (RCS) to avoid that, right?

Air pressure has some weird steps.
 
  • #3
Yeah, column B represents the control from engine gimbals/Vernier rockets/or fins in the exhaust that would allow the rocket to control its orientation. For the sake of simplicity, I had these inputs completely overpower the natural orientation of the rocket. Realistically, it would be slightly different, but I'm not hugely bothered about that...
 

1. How accurate is Excel for simulating rocket launches?

Excel can be a useful tool for simulating rocket launches, but it is not a substitute for more advanced simulation software. Excel can provide a basic understanding of the physics involved in a rocket launch, but it may not accurately capture all the variables and complexities of a real launch. It is important to use caution and validate your results against other sources.

2. What kind of data is needed to simulate a rocket launch in Excel?

To simulate a rocket launch in Excel, you will need data such as the rocket's mass, thrust, drag coefficient, and initial velocity. You may also need to consider external factors such as air density and wind speed. The more accurate and detailed your data is, the more realistic your simulation will be.

3. Can Excel account for factors like air resistance and gravity in a rocket launch simulation?

Yes, with the right equations and data, Excel can account for factors like air resistance and gravity in a rocket launch simulation. However, it is important to note that Excel may not be able to accurately simulate the complex interactions between these factors and other variables. It is always best to validate your results with other sources.

4. What are the limitations of using Excel for rocket launch simulations?

Excel is a powerful tool, but it has its limitations when it comes to simulating rocket launches. Excel may not be able to accurately account for all the variables and complexities involved in a real launch, and it may not be able to simulate all the stages of a rocket's flight. It is always best to use Excel as a starting point and validate your results with other sources.

5. How can I improve the accuracy of my rocket launch simulation in Excel?

To improve the accuracy of your rocket launch simulation in Excel, you can use more advanced equations and data, as well as incorporate more variables and factors. It is also important to validate your results with other sources and make adjustments as needed. Additionally, using more sophisticated simulation software may provide more accurate results.

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