1. Critical Design Review
Debbie Klein
Dynamics and Control
Tether Dynamics
2/27/01

2. Accomplished tasks
MATLAB code numerically integrates Euler’s equations using technique learned in AAE 507 (Principles of Dynamics)
Thrusters are ‘turned on’ when s/c is within 30° of thrusting point(s)
Code integrates in all three directions, but examples presented today deal only with in-plane thrusting
Two versions of code deal with single-point thrusting and coupled-thrusting

3. Last week’s questions thrusting point Nick Czapla:x y z
thrusting point
30
Rotates counter-clockwise v
Nick Czapla:
How are inertial properties of s/c modeled?
s/c is modeled as two cylinders and a thin-rod
Alec Spencer:
Why is a v created in the y-direction with coupled thrusting?
visual explanation required

4. Function inputs Single-point thrusting:
[vm1,wz,thetaz,t,T,dvx,dvy] = aae450tether2(thetaz0,thetazdot0,Mzi,tf)
Double-point (coupled) thrusting:
[vm1,wz,thetaz,t,T,dvx,dvy] = aae450tether3(thetaz0,thetazdot0,Mzi,tf)
where…
thetaz0 = initial s/c position wrt -x axis
thetazdot0 = initial z value
Mzi = torque about c.m. caused by thruster
tf = length of simulation

5. Specific Cases thetaz0 = 0 rad thetazdot0 = .14 rad/s
Mzi = 5.6 x 106 Nm
tf = 165 s
Single-point thrusting:
Double-point thrusting:
vx = m/s
vy = m/s
zf = rad/s
vx = m/s
vy = 0 m/s

6. Single thrusting point case: z vs. Time
z (rad/sec)
time (sec)

7. Single thrusting point case: vx vs. Time
vx (m/sec)
vx (m/sec)
time (sec)
time (sec)

8. Double (coupled) thrusting point case: z vs. Time
z (rad/sec)
time (sec)

9. Double (coupled) thrusting point case: vx vs. Time
vx (m/sec)
time (sec)
vx (m/sec)
time (sec)

10. Conclusions/Future work
Code complete and tested
Now can be used for out-of-plane burns
Function call to allow thrusting scheme for a given v will be added to code
Questions???