def set_target(self):
# initialize a mission target
from spaceobjects import SpaceCraft
self.target = SpaceCraft()
self.target.set_sma(42000.0)
self.target.set_i(0.0, 'Degrees')
self.target.set_f(180.0, 'Degrees')
class Mission:
'Mission class documentation string'
# initialization method
def __init__(self):
""" DEBUG """
self.DEBUG = False
if self.DEBUG: print '*** Mission Initialization ***'
# initialize a ntr for the mission
from spaceobjects import NTR
import solarsystem_objects_parameters as ss
# initializae an ntr spacecraft
self.ntr = NTR()
if self.DEBUG: print self.ntr.mass
# set the equations of motion of the ntr to 'S2B'
#+ for shooting methods
self.ntr.eom = 'S2B'
# initialize global parameters
# set the generic global decision vector for the mission
#+ and call the global optimizer setup
# the entries of global_decision_vector correspond with
# [0]: mission type
# [1]: launch vehicle
# [2]: payload fairing
self.set_global_decisions([1, 0, 0])
# initialize local parameters
# set the ntr to have initial conditions of a
#+ generic 'NSO' Nuclear Safe Orbit
self.nso_altitude = 1200.0
self.ntr.set_sma(ss.earth['Radius'] + self.nso_altitude)
# set the thrust level of the ntr core
self.ntr.core.thrust = 25000.0
self.ntr.core.set_thrust_derived_properties()
if self.DEBUG: print self.ntr.mass
# set a generic local decision vector for the mission
self.local_decision_vector = [self.nso_altitude, self.ntr.core.thrust]
# set a generic target for the mission
self.set_target()
# initialize a dictionary for storing relevant history information
self.history = {}
self.history['burnmass'] = []
# method for setting the payload
def set_payload(self, name, mass, height, radius):
# set attributes for the payload
self.payload_name = name
self.payload_mass = mass
self.payload_height = height
self.payload_radius = radius
# add the payload mass to the spacecraft
self.ntr.add_payload_mass(self.payload_mass)
# method for setting the specified target
def set_target(self):
# initialize a mission target
from spaceobjects import SpaceCraft
self.target = SpaceCraft()
self.target.set_sma(42000.0)
self.target.set_i(0.0, 'Degrees')
self.target.set_f(180.0, 'Degrees')
# method for setting global optimization variables
def set_global_decisions(self,
global_decision_vector = None,
mission_type = None, # (integer) [0, 4]
launch_vehicle = None, # (integer) [0, 15]
payload_fairing = None): # (integer) [0, 3]
# set the global decision vector if given as an argument
if global_decision_vector != None:
self.global_decision_vector = global_decision_vector
# set the global decision vector elements
if mission_type == None:
mission_type = self.global_decision_vector[0]
if launch_vehicle == None:
launch_vehicle = self.global_decision_vector[1]
if payload_fairing == None:
payload_fairing = self.global_decision_vector[2]
# convert mission type identifier to string
if mission_type == 0: self.mission_type = 'gto payload release, ' \
'gto tank release'
elif mission_type == 1: self.mission_type = 'gto payload release, ' \
'nso tank release'
elif mission_type == 2: self.mission_type = 'geo payload release, ' \
'geo tank release'
elif mission_type == 3: self.mission_type = 'geo payload release, ' \
'gto tank release'
elif mission_type == 4: self.mission_type = 'geo payload release, ' \
'nso tank release'
# convert launch vehicle integer identifier to string
if launch_vehicle == 0: self.launch_vehicle = 'AtlasV501'
elif launch_vehicle == 1: self.launch_vehicle = 'AtlasV511'
elif launch_vehicle == 2: self.launch_vehicle = 'AtlasV521'
elif launch_vehicle == 3: self.launch_vehicle = 'AtlasV531'
elif launch_vehicle == 4: self.launch_vehicle = 'AtlasV541'
elif launch_vehicle == 5: self.launch_vehicle = 'AtlasV701'
elif launch_vehicle == 6: self.launch_vehicle = 'AtlasV711'
elif launch_vehicle == 7: self.launch_vehicle = 'AtlasV721'
elif launch_vehicle == 8: self.launch_vehicle = 'AtlasV731'
elif launch_vehicle == 9: self.launch_vehicle = 'DeltaIVM42E'
elif launch_vehicle == 10: self.launch_vehicle = 'DeltaIVM52E'
elif launch_vehicle == 11: self.launch_vehicle = 'DeltaIVM54E'
elif launch_vehicle == 12: self.launch_vehicle = 'Falcon9'
elif launch_vehicle == 13: self.launch_vehicle = 'ArianeVECA'
elif launch_vehicle == 14: self.launch_vehicle = 'ProtonM'
elif launch_vehicle == 15: self.launch_vehicle = 'DeltaIVH'
# set the payload fairing type
# some launch vehicles only have 1 choice for payload fairings,
#+ others have up to 4
self.payload_fairing = payload_fairing
pass
# method for setting local optimization variables
def set_local_decisions(self,
local_decision_vector = None,
nso_altitude = None,
core_thrust = None,
permanent_tank_fuel = None,
mission_tank_fuel = None,
mission_tank_radius = None):
# set the local decision vector if given as an argument
if local_decision_vector != None:
self.local_decision_vector = local_decision_vector
# import statement
import solarsystem_objects_parameters as ss
# set the nso altitude
if nso_altitude == None: self.nso_altitude = self.local_decision_vector[0]
else: self.nso_altitude = nso_altitude
# set sma
self.ntr.set_sma(ss.earth['Radius'] + self.nso_altitude)
# set the core thrust and derived parameters
if core_thrust == None: self.ntr.core.thrust = self.local_decision_vector[1]
else: self.ntr.core.thrust = core_thrust
# update relevant ntr attributes
self.ntr.core.set_thrust_derived_properties()
# add the permanent tank
self.ntr.add_tank()
if permanent_tank_fuel == None:
self.ntr.tank[0].add_fuel(self.local_decision_vector[2])
self.ntr.tank[0].tank_size(-1, 5, geometry = 'spherical')
else:
self.ntr.tank[0].add_fuel(permanent_tank_fuel)
self.ntr.tank[0].tank_size(-1, 5, geometry = 'spherical')
# add the mission tank
self.ntr.add_tank()
if permanent_tank_fuel == None:
self.ntr.tank[1].add_fuel(self.local_decision_vector[3])
self.ntr.tank[1].tank_size(self.local_decision_vector[4], 5)
else:
self.ntr.tank[1].add_fuel(mission_tank_fuel)
self.ntr.tank[1].tank_size(mission_tank_radius, 5)
# method call for global optimization
def global_optimization(self, decision_vector = None):
# setup the global parameters if a decision vector is given
if decision_vector != None:
self.set_global_decisions(decision_vector)
# call the local optimizer
self.local_optimization()
# method call for local optimization
def local_optimization(self):
""" Inner-Loop Optimization Call Here """
# import scipy.optimize module
from scipy.optimize import minimize
from scipy.optimize import fmin_l_bfgs_b
from numpy import array
# the decision_vector that scipy.optimize OR equivalent can modify
# nso_alititude: (real) [400, 2000] (km) ic: 1200
# core_thrust: (real) [5000, 25000] (lbf) ic: 25000
# perm_tank_fuel: (real) [100, 600] (kg) ic: 400
# payl_tank_fuel: (real) [400, 5000] (kg) ic: 1000
# payl_tank_rad: (real) [LV Dependent] (m) ic: 1.5
# notes:
# for now, permanent tank assumed to be of type 'spherical'
#+ and payload tank assumed to be of type 'cylindrical'
#+ final version of code can move the decision of tank type to the
#+ outer loop level where a GA or Brute force method would trade each.
#+ a if-loop would need to be added within this method to setup the
#+ correct decision vector length based on which tank types have been
#+ chosen.
# perform inner-loop optimization
""" For whatever reason, the minimize() interface is not
working appropriately : 2014_06_22
, so using direct call to fmin_l_bfgs_b with
maxfun = 5. maxfun = 3 was sufficient for transfer
test problem """
# profit = minimize(mission.optimize,
# ((nso_altitude),),
# bounds = bnds, method = 'L-BFGS-B',
# options = {'disp': False, 'maxiter': 6})
self.bnds = ((400.0, 2000.0), (5000.0, 25000.0),
(100.0, 600.0), (400.0, 5000.0), (0.5, 2.0))
self.initial_guess = array([self.nso_altitude, self.ntr.core.thrust,
400.0, 1000.0, 1.5])
opt_result = fmin_l_bfgs_b(self._evaluate,
self.initial_guess,
bounds = self.bnds,
approx_grad = True,
epsilon = 100,
maxfun = 5)
# store the decision vector and obj. func.
self.local_decision_vector = opt_result[0]
self.objfunc = opt_result[1]
# return inner-loop optimization result to
#+ the global optimization routine
if self.DEBUG: print opt_result
if self.DEBUG: print opt_result[0]
if self.DEBUG: print opt_result[1]
# return profit
# return mission
# evaluate the mission (this is the "internal" call)
def _evaluate(self, decision_vector):
# import statements
import solarsystem_objects_parameters as ss
from numpy.linalg import norm
from numpy import array
from copy import copy, deepcopy
from revenue import calculate_revenue
from cost import calculate_cost
from time import sleep
# make a copy of the actual mission and its ntr to optimize on
mission_copy = deepcopy(self)
mission_copy.set_local_decisions(decision_vector)
# debug print statements
if self.DEBUG: print ('\n ---- Starting a New Iteration ---- \n')
if self.DEBUG: print ('--- Memory Locations ---')
if self.DEBUG: print (' mission level ')
if self.DEBUG: print mission_copy
if self.DEBUG: print self
if self.DEBUG: print ''
if self.DEBUG: print (' 1 sub level ')
if self.DEBUG: print mission_copy.ntr
if self.DEBUG: print self.ntr
if self.DEBUG: print ''
if self.DEBUG: print (' 1 obj sub level 1 attribute level ')
if self.DEBUG: print hex(id(mission_copy.ntr.mass))
if self.DEBUG: print hex(id(self.ntr.mass))
if self.DEBUG: print ''
if self.DEBUG: print (' 2 obj sub levels ')
if self.DEBUG: print mission_copy.ntr.core
if self.DEBUG: print self.ntr.core
if self.DEBUG: print ''
if self.DEBUG: print (' 2 obj ')
if self.DEBUG: print ('-----------------------')
if self.DEBUG: print mission_copy.ntr.mass
if self.DEBUG: print ('self.nso_altitude is: %f ' %self.nso_altitude)
if self.DEBUG: print ('copy.nso_altitude is: %f ' %mission_copy.nso_altitude)
if self.DEBUG: print ('nso_altitude: %.12f ' %decision_vector[0])
if self.DEBUG: print ('self.ntr.sma %f ' %self.ntr.sma)
if self.DEBUG: print ('copy.ntr.sma %f ' %mission_copy.ntr.sma)
if self.DEBUG: print ('mission_copy parameters')
if self.DEBUG: print ('core thrust is: %f ' %mission_copy.ntr.core.thrust)
if self.DEBUG: print ('core mass is: %f ' %mission_copy.ntr.core.mass)
if self.DEBUG: print ('ntr mass is: %f ' %mission_copy.ntr.mass)
if self.DEBUG: print ('self parameters')
if self.DEBUG: print ('core thrust is: %f ' %self.ntr.core.thrust)
if self.DEBUG: print ('core mass is: %f ' %self.ntr.core.mass)
if self.DEBUG: print ('ntr mass is: %f ' %self.ntr.mass)
if self.DEBUG: print 'sleep.....'
if self.DEBUG: sleep(5.0)
# execute the mission
mission_copy.execute()
# calculate if feasible/infeasible
pass
# call the revenue function, which calculates the
#+ revenue generated by the mission
calculate_revenue(mission_copy)
# call the cost function, which calculates the cost
#+ of the mission
calculate_cost(mission_copy)
# add a 'profit' attribute to the mission
mission_copy.profit = mission_copy.revenue - mission_copy.cost
# return the mission profit to the inner-loop solver
# return mission_copy.profit
if self.DEBUG: print ('Delta-V: %8.5f ' %(norm(array(mission_copy.ntr.dv1)))) #+ norm(array(self.ntr.dv2))
return norm(array(mission_copy.ntr.dv1)) # + norm(array(mission_copy.ntr.dv2))
# method for evaluating a decision vector
def evaluate(self,
global_decision_vector = None,
local_decision_vector = None):
# import statements
from revenue import calculate_revenue
from cost import calculate_cost
# setting global decision vector
if global_decision_vector == None: self.set_global_decisions()
else: self.set_global_decisions(global_decision_vector)
# setting local decision vector
if local_decision_vector == None: self.set_local_decisions()
else: self.set_local_decisions(local_decision_vector)
# execute the mission
self.execute()
# call the revenue function, which calculates the
#+ revenue generated by the mission
calculate_revenue(self)
# call the cost function, which calculates the cost
#+ of the mission
calculate_cost(self)
# add a 'profit' attribute to the mission
self.profit = self.revenue - self.cost
# execute the specified mission
def execute(self):
# import rocket equation for computing fuel usage
from auxiliary import tsiolkovsky
from numpy.linalg import norm
# reset the r and v history
self.ntr.r_history = []
self.ntr.v_history = []
# select and perform mission type
if self.mission_type == 'gto payload release, gto tank release':
pass
elif self.mission_type == 'gto payload release, nso tank release':
# ----------------
# NSO -> GTO
# ----------------
self.ntr.transfer(self.target.r, self.target.v,
Minimize_Energy = True)
# based on the transfer calculation, compute the fuel burn
fuel_used = self.ntr.mass - tsiolkovsky(norm(self.ntr.dv1),
self.ntr.nozzle.Isp,
self.ntr.mass)
if self.DEBUG: print ('ntr Isp: %f ' %self.ntr.nozzle.Isp)
if self.DEBUG: print ('Fuel Available at Start: %8.5f ' %self.ntr.fuel)
if self.DEBUG: print ('Fuel Used: %8.5f' %fuel_used)
if self.DEBUG: print ('Fuel Remaining: %8.5f ' %(self.ntr.fuel - fuel_used))
# store the burn history (i.e. fuel consumed at impulses)
self.history['burnmass'].append(fuel_used)
# remove whatever fuel is left in mission tank and then
#+ subtract the rest from permanent tank
if self.ntr.tank[1].fuel >= fuel_used:
self.ntr.tank[1].remove_fuel(fuel_used)
else:
self.ntr.tank[0].remove_fuel(fuel_used - self.ntr.tank[1].fuel)
self.ntr.tank[1].remove_fuel(self.ntr.tank[1].fuel)
if self.DEBUG: print ('CHECK -> Fuel Remaining: %f ' %self.ntr.fuel)
# -------------------
# GTO Insertion
# -------------------
fuel_used = self.ntr.mass - tsiolkovsky(norm(self.ntr.dv2),
self.ntr.nozzle.Isp,
self.ntr.mass)
if self.DEBUG: print ('ntr Isp: %f ' %self.ntr.nozzle.Isp)
if self.DEBUG: print ('Fuel Available at Start: %8.5f ' %self.ntr.fuel)
if self.DEBUG: print ('Fuel Used: %8.5f' %fuel_used)
if self.DEBUG: print ('Fuel Remaining: %8.5f ' %(self.ntr.fuel - fuel_used))
# store the burn history (i.e. fuel consumed at impulses)
self.history['burnmass'].append(fuel_used)
# remove whatever fuel is left in mission tank and then
#+ subtract the rest from permanent tank
if self.ntr.tank[1].fuel >= fuel_used:
self.ntr.tank[1].remove_fuel(fuel_used)
else:
self.ntr.tank[0].remove_fuel(fuel_used - self.ntr.tank[1].fuel)
self.ntr.tank[1].remove_fuel(self.ntr.tank[1].fuel)
# dropoff the payload in GTO
self.ntr.remove_payload_mass(self.payload_mass)
if self.DEBUG: print ('CHECK -> Fuel Remaining: %f ' %self.ntr.fuel)
# ----------------
# GTO -> NSO
# ----------------
fuel_used = self.ntr.mass - tsiolkovsky(norm(self.ntr.dv2),
self.ntr.nozzle.Isp,
self.ntr.mass)
if self.DEBUG: print ('ntr Isp: %f ' %self.ntr.nozzle.Isp)
if self.DEBUG: print ('Fuel Available at Start: %8.5f ' %self.ntr.fuel)
if self.DEBUG: print ('Fuel Used: %8.5f' %fuel_used)
if self.DEBUG: print ('Fuel Remaining: %8.5f ' %(self.ntr.fuel - fuel_used))
# store the burn history (i.e. fuel consumed at impulses)
self.history['burnmass'].append(fuel_used)
# remove whatever fuel is left in mission tank and then
#+ subtract the rest from permanent tank
if self.ntr.tank[1].fuel >= fuel_used:
self.ntr.tank[1].remove_fuel(fuel_used)
else:
self.ntr.tank[0].remove_fuel(fuel_used - self.ntr.tank[1].fuel)
self.ntr.tank[1].remove_fuel(self.ntr.tank[1].fuel)
if self.DEBUG: print ('CHECK -> Fuel Remaining: %f ' %self.ntr.fuel)
# -------------------
# NSO Insertion
# -------------------
fuel_used = self.ntr.mass - tsiolkovsky(norm(self.ntr.dv1),
self.ntr.nozzle.Isp,
self.ntr.mass)
if self.DEBUG: print ('ntr Isp: %f ' %self.ntr.nozzle.Isp)
if self.DEBUG: print ('Fuel Available at Start: %8.5f ' %self.ntr.fuel)
if self.DEBUG: print ('Fuel Used: %8.5f' %fuel_used)
if self.DEBUG: print ('Fuel Remaining: %8.5f ' %(self.ntr.fuel - fuel_used))
# store the burn history (i.e. fuel consumed at impulses)
self.history['burnmass'].append(fuel_used)
# remove whatever fuel is left in mission tank and then
#+ subtract the rest from permanent tank
if self.ntr.tank[1].fuel >= fuel_used:
self.ntr.tank[1].remove_fuel(fuel_used)
else:
self.ntr.tank[0].remove_fuel(fuel_used - self.ntr.tank[1].fuel)
self.ntr.tank[1].remove_fuel(self.ntr.tank[1].fuel)
if self.DEBUG: print ('CHECK -> Fuel Remaining: %f ' %self.ntr.fuel)
# transfer any additional fuel from the mission tank to the permanent
#+ tank if there is extra
if self.ntr.tank[1].fuel > 0:
fuel_that_can_be_added = self.ntr.tank[0].fuel_capacity - \
self.ntr.tank[0].fuel
if self.ntr.tank[1].fuel > fuel_that_can_be_added:
self.ntr.tank[0].add_fuel(fuel_that_can_be_added)
self.ntr.tank[1].remove_fuel(fuel_that_can_be_added)
else:
self.ntr.tank[0].add_fuel(self.ntr.tank[1].fuel)
self.ntr.tank[1].remove_fuel(self.ntr.tank[1].fuel)
# dropoff the payload specific tank in NSO
self.ntr.remove_tank(1)
# flow NSO -> GTO trajectory and save state information
elif self.mission_type == 'geo payload release, geo tank release':
pass
elif self.mission_type == 'geo payload release, gto tank release':
pass
elif self.mission_type == 'geo payload release, nso tank release':
pass
