rocket_eq.py

"""
File: rocket_eq.py
Author: Halvard Sutterud
Email: halvard.sutterud@gmail.com
Github: https://github.com/halvarsu
Description: 
"""
import numpy as np
import sys

def load_data(filename):
    infile = open(filename, 'r')
    lines = infile.readlines()
    data = [int(lines[0])] # first line, outside_count
    for line in lines[1:]:
        data.append(float(line))
    return data

def rocket_eq(delta_v, drymass = 1100):
    ''' 
    Returns the fuel mass needed before boost
    '''
    print "Loading data from simulated engine..."
    data = load_data('gasInBox/data_dump.dat')
    outside_count   = data[0]
    m               = data[1]
    #force_up        = data[2]
    #fuel_per_box    = data[3]
    #dt              = data[4]
    gained_momentum = data[5]

    v_e = gained_momentum/(m*outside_count)
    print v_e / 9.81

    print "Calculating..."
    # To be given: 
    dry_mass = 1100
        
    fuel_mass = dry_mass*np.exp(delta_v/v_e) - dry_mass

    print "Satelite mass  : %11d kg"    % dry_mass 
    print "Delta v needed : %11.2f m/s" % delta_v
    print "Fuel needed    : %11.2f kg"  % fuel_mass
    #print "Boxes needed    : %11.2f s"   % boxes
    return fuel_mass 

def trip_mass_calculator(boosts, initial_mass = 1100):
    mass = initial_mass
    for boost in reversed(boosts):
        mass += rocket_eq(boost, mass)
    return mass



if __name__ == "__main__":
    try:
        delta_v = float(sys.argv[1])
        #time =  float(sys.argv[2])
    except IndexError:
        print "WrongUsageError! usage: python %s delta_v " %sys.argv[0]
        sys.exit()
    rocket_eq(delta_v)