1. [Cory Alban] [Mission Ops] [Locomotion]
100g
Toy Ball Mission Profile Toy Ball Integration & Structural Analysis ‘Fallback’ Lunar Circularization Concept
March 05, 2009
[Cory Alban] [Mission Ops] [Locomotion]
[1]

2. Toy Ball (100g payload) Design at 90% completion! Mass: 2.52kg
Power: Wh upon arrival (Self-Sufficient)
Volume: 0.25m diameter sphere (8.18*10-3m3)
Remaining tasks include:
Determining power requirements for transceiver and camera
Finding a camera better suited to our mission
Exploring possible commercial ventures ($$$)
Short mission time versus life of components
[Cory Alban] [Mission Ops] [Locomotion]
[2]
[Cory Alban] [Mission Ops] [Locomotion]

3. 100g Mission Profile (locomotion)
Time (min)
Tasks to be completed
Direction of Travel Received. Deployment from Lander. System Diagnosis. 1
Full speed ahead! Rover orients to path of travel. Accelerate to cruising speed of 1.04m/s. Travel for 8 minutes until 500m objective achieved. 9
Braking maneuver with a 90 degree orientation change to point camera toward Lander (most likely far less than 1 minute) 10
Snap photo of Lander from ball. Begin transmission to Lander. 18
Finish Photo Transmission. The end… or is it?
Total mission time outside of Lander < 20 minutes
[Cory Alban] [Mission Ops] [Locomotion]
[3]
[Cory Alban] [Mission Ops] [Locomotion]

4. Toy Ball Shell Material: Lexan
Pressure vessel calculations(1atm of N2 gas)
Minimum thickness: 1.58*10-5m
Impact strength calculations(1m/s slam into rock)
Minimum thickness:1.27*10-3m
Driving factor in shell thickness is impact strength. With a factor of safety of 3, total thickness =3.82*10-3m
[Cory Alban] [Mission Ops] [Locomotion]
[4]
[Cory Alban] [Mission Ops] [Locomotion]

5. Toy Ball Heavy Mass Components
Radiation Hardened Camera kg
Exterior Shell kg
(driven by system mass!)
Transceiver kg
For every half kilo of onboard mass we remove, we lower shell mass by 0.22kg!
Cascade effect onto power and volume reqs!
[Cory Alban] [Mission Ops] [Locomotion]
[5]
[Cory Alban] [Mission Ops] [Locomotion]

6. Fallback Lunar Circularization
Last week (Week 7) Kara Akgulian presented on a lunar circularization method of providing an instantaneous burn at lunar periapsis.
This method expands on her method by using the EP system to give a controlled burn for a finite time before and after periapsis. (See graphic on next slide)
[Cory Alban] [Mission Ops] [Locomotion]
[6]
[Cory Alban] [Mission Ops] [Locomotion]

7. Fallback Lunar Circularization
Last week (Week 7) Kara Akgulian presented on a lunar circularization method of providing an instantaneous burn at lunar periapsis.
This method expands on her method by using the EP system to give a controlled burn for a finite time before and after periapsis. (See graphic on next slide)
[Cory Alban] [Mission Ops] [Locomotion]
[7]
[Cory Alban] [Mission Ops] [Locomotion]

8. Fallback Lunar Circularization
By calculating orbit at periapsis, we can find out how long it will take for the craft to reach a theta_star of 45 degrees. We burn the EP engine until this point.
The craft will then coast until it reaches a negative 45 degree theta_star.
The engine will burn until we reach periapsis again, where we calculate the new orbit conditions.
The process continues until we reach a circular, or nearly circular orbit.
Results of matlab code are on the next slide.
[Cory Alban] [Mission Ops] [Locomotion]
[8]
[Cory Alban] [Mission Ops] [Locomotion]

9. Fallback Lunar Circularization
This process was run for fifty iterations.
Process will take a long time (>1 year based on thrust and initial conditions)
NOTE: This process does converge! Though not recommended, this process will eventually lead to a circular orbit and could be considered as a backup option.
[Cory Alban] [Mission Ops] [Locomotion]
[9]
[Cory Alban] [Mission Ops] [Locomotion]

10. Fallback Lunar Circularization
Here is a view of the circularization with the moon’s orbit included. Note that to fully circularize the moon will make its way around the earth many times over the course of the process. Red represents the circularization of the orbit around moon.
[Cory Alban] [Mission Ops] [Locomotion]
[10]
[Cory Alban] [Mission Ops] [Locomotion]