# Aerospace Simulating rocket launches using excel

1. Oct 21, 2012

### TESLER

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

2. Oct 21, 2012

### Staff: Mentor

You have column B (RCS) to avoid that, right?

Air pressure has some weird steps.

3. Oct 21, 2012

### TESLER

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...