Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Simulating rocket launches using excel

  1. Oct 21, 2012 #1
    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. jcsd
  3. Oct 21, 2012 #2

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

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

    Air pressure has some weird steps.
     
  4. Oct 21, 2012 #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...
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Simulating rocket launches using excel
Loading...