Rocket Thrust!

Payton M -

Welcome back to my blog! It’s been a very busy week creating my final products (research paper and poster), working on the final presentation, and finishing the code. We’re currently looking into more trajectory options, like a flyby, to find paths with lower fuel requirements. The flyby option means we wouldn’t go into an elliptical orbit around Jupiter or Mars, and then depart to Eris, but rather flyby the planet, gaining velocity from the planet’s gravity without having to use fuel. Optimistically, this would significantly reduce fuel usage, but the faster final velocity we attain from the flyby, the faster we’re going during the plane change maneuver, causing more fuel required for that maneuver. So, in the MATLAB code, we’re trying to optimize these maneuvers which I will talk more about in next week’s post!

I wanted to share the algorithm we created for the fuel calculations. I’ve been talking a lot about fuel requirements, but how do we know exactly how much fuel we need for each maneuver? Using a modified version of the rocket equation shown in the image below, the change in velocities calculated from each maneuver, and three different fuel type isp values, a ratio of the change in mass (fuel expelled) over total mass of the fuel is outputted. In the diagram below, you can see the three different isp values (a measure of how efficient a certain fuel is) go into the equation mentioned above through a for loop. Using a for loop, three final values are outputted, one for each fuel type. Once these ratios are converted to a percentage, we have the percent of total fuel required for a specific change in velocity for a given maneuver. 

Thrust Calculation Algorithm

This algorithm is used at the end of each maneuver in the code, and added in various ways to produce the plots and final totals for each trajectory option. Check back in next week for the flyby post!

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