Title
Simulation Control
time step: Time step for the numerical integration routine
time: Duration of the simulation periond in seconds

Description
A flexible spacecraft is modeled as a central rigid body with two massless beams
attachd symmetrically to the side of the central body. Each beam has a
concentrated mass at the tip. The flexibility comes from the flexural rigidity EI of
the beams. Although the flexible elements are constrained to move in 1-2 plane
only, the applet is able to simulate the effect of flexibility on the spacecraft
attitude in three dimensional space.
2D Flexible Spacecraft Illustration
Inputs
Ixx, Iyy, Izz:             Principal moments if inertia
m:                            Tip mass (kg)
a:                             Distance as indicated in the illustration (m)
L:                             Length of the beam as illustrated (m)
EI:                             Flexural rigidity (N m2)

Initial Condition
u1:                         Position of the first mass
u2:                         Position of the second mass
psi, theta, phi:         Euler angles in a sequence of 3-2-1
u1Dot:                     Velocity of the first mass
u2Dot:                     Velocity of the second mass
psiDot:                     Time rate of psi angle
thetaDot :                 Time rate of theta angle
phiDot:                     Time rate of phi angle