100g
Toy Ball Mission Profile
Toy Ball Integration & Structural Analysis
‘Fallback’ Lunar Circularization Concept
March 05, 2009
AAE450 Spring 2009
[Cory Alban] [Mission Ops]
[Locomotion]
[1]
Toy Ball
(100g payload)
 Design at 90% completion!
– Mass: 2.52kg
– Power: 0.9984Wh 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
AAE450 Spring 2009
[Cory Alban] [Mission Ops]
[Locomotion]
[2]
100g Mission Profile (locomotion)
Time (min)
Tasks to be completed
0
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.
Braking maneuver with a 90 degree orientation change to point camera
toward Lander.
(most likely far less than 1 minute)
9
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
AAE450 Spring 2009
[Cory Alban] [Mission Ops]
[Locomotion]
[3]
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
AAE450 Spring 2009
[Cory Alban] [Mission Ops]
[Locomotion]
[4]
Toy Ball Heavy Mass Components
 Radiation Hardened Camera 0.725 kg
 Exterior Shell
0.872 kg
– (driven by system mass!)
 Transceiver
0.210 kg
 For every half kilo of onboard mass we
remove, we lower shell mass by 0.22kg!
– Cascade effect onto power and volume reqs!
AAE450 Spring 2009
[Cory Alban] [Mission Ops]
[Locomotion]
[5]
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)
AAE450 Spring 2009
[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)
AAE450 Spring 2009
[Cory Alban] [Mission Ops]
[Locomotion]
[7]
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.
AAE450 Spring 2009
[Cory Alban] [Mission Ops]
[Locomotion]
[8]
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.
AAE450 Spring 2009
[Cory Alban] [Mission Ops]
[Locomotion]
[9]
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.
AAE450 Spring 2009
[Cory Alban] [Mission Ops]
[Locomotion]
[10]