/*
 *  Compute how long to fire horizontal thrusters so that the total fuel
 *  consumed is minimized.  The minimum value of the function is the total
 *  amount of fuel that will be used.  The 'time' parameter is the length
 *  of time that the horizontal thruster should be fired (in seconds).
 */
Title "Compute fire time for thruster to minimize total fuel consumption";
Constant G=1.67;	// Gravitational acceleration on moon (meters/sec^2)
Constant A=1.10;	// Acceleration from horizontal thruster (meters/sec^2)
Constant burnrate=2.3;	// Kg/sec fuel burn rate to produce 1 G acceleration
Constant dist=200;	// Horizontal distance to be moved (meters)
Parameter time;		// Number of seconds to fire horizontal thruster
Double hfuel;		// Fuel burned by horizontal thrusters
Double vfuel;		// Fuel burned by vertical thrusters
/*
 *  Compute fuel burned by vertical thruster.
 */
vfuel = time * G * burnrate;
/*
 *  Compute fuel consumed by horizontal thrusters (start and stop).
 */
hfuel = 2 * time * A * burnrate;

Function burnrate*(2*time*A/G + 2*time + (dist - A*time^2)/(A*time));
Data;