VITL Critical Design Review (Sec 2.1)

1. VITLCritical Design Review (Sec 2.1) Thursday, September 25, 2014 Team Members: Ryan Hickman, Chris Homolac, Jen Krupp, Kyle Ligon, Heather Love, Alex Paulson, Kathryn Rash, Veronica Vertucci

2. Objectives Overview Design and build a prototype for the locomotion system of a vehicle exploring a Europa-like surface capable of traversing 1 km of icy terrain in 7 days with characteristic obstacles. Vehicle for Icy Terrain Locomotion 2

3. Characteristic Mission Profile Aerial View Vehicle for Icy Terrain Locomotion 3

4. Characteristic Mission Profile Side View Not to Scale Vehicle for Icy Terrain Locomotion 4

5. What makes a Europa mission? Surface Characteristics Ice Friction (µ~0.55) and Hardness (~6 mohs) Obstacles Inclines, Bumps and Ruts Environment Low Temperature (100K) Reduced Gravity (1/6 g) Power Supply challenges-Solar power not viable Radiation (1MRad) Low Pressure (10-6 Pa) Scientific Objectives One of the best candidates for liquid water and life beyond Earth 3 proposed instruments (camera, magnetometer and radiation sensor) A Theoretical Europa Mission (TEM) would accommodate all of these. Theoretical Europa Mission (TEM) Vehicle for Icy Terrain Locomotion 5

6. The VITL locomotion will concentrate on: Surface Characteristics (previously shown) Simplified Environment Low Temperature 100K manufacturing and testing is infeasible due to resources and experience. Instead vehicle will be designed for 0°C operation Entire vehicle can be tested on a “cold” Earth day on frozen lake Design methods can be extended for TEM using materials for 100K operation Reduced Gravity Accommodate mass of a traditional power supply NOT worrying about pressure or radiation on Europa (out of scope) Simplified Scientific Objectives Accommodate mass of 10kg payload Additional locomotion and sensing requirements These form the design requirements of the Engineering Design and Manufactured Unit (EDMU) for Senior Projects TEM Simplification Vehicle for Icy Terrain Locomotion 6

7. Top Level System Requirements Vehicle for Icy Terrain Locomotion 7

8. Requirement Flow-down from TEM to EDMU TEM EDMU Vehicle for Icy Terrain Locomotion 8

9. Requirement Flow-down from TEM to EDMU TEM EDMU Vehicle for Icy Terrain Locomotion 9

10. Requirement Flow-down from TEM to EDMU TEM EDMU Vehicle for Icy Terrain Locomotion 10

11. Requirement Flow-down from TEM to EDMU TEM EDMU Vehicle for Icy Terrain Locomotion 11

12. EDMU System Breakdown Vehicle for Icy Terrain Locomotion 12

13. EDMU Preliminary Layout Science Payload TEM Power (dummy mass) Batteries Sonar and Proximity Sensor Laser Range Suspension and Drive train Attachments Motor Controller Thermal Strip Vehicle for Icy Terrain Locomotion 13

14. Structures EDMU Layout Accelerometer and Rate Gyro ThermalStrip For Analysis, assume Aluminum alloy Receiver, C&DH Board, and Motor Controller Vehicle for Icy Terrain Locomotion 14

15. Structures EDMU Layout Science Payload TEM Power (dummy mass) Batteries Sonar and Proximity Sensor Laser Range Thermal Strip and Motor Controller Suspension and Drive train Attachments Vehicle for Icy Terrain Locomotion 15

16. Electrical Interconnects Block Diagram Vehicle for Icy Terrain Locomotion 16

17. Fw Ff Fslip FN φincline Friction Analysis • Required Coefficient of Friction • μs = 0.36397 • Difficult to design to Vehicle for Icy Terrain Locomotion 17

18. F Fspike α Fslide FN φincline Penetration Analysis • Spike Penetration • Easy to design to • Fspike > Fslide • mrover = 70 kg • 20° Inclination • α < 70° Vehicle for Icy Terrain Locomotion 18

19. h w θroll Design System Calculations • Equivalent Earth Inclination φinclination,Earth = 2.62° • Rollover Angle Vehicle for Icy Terrain Locomotion 19

20. Structures Load Analysis – Load Distribution Science Payload Min FOS = 22 TEM Power (dummy mass) Vehicle for Icy Terrain Locomotion 20

21. CDR Prototyping • Traction tests • Surface hardness • Spike penetration • Slippage Vehicle for Icy Terrain Locomotion 21

22. Acronym List • ADC: Analog to Digital Converter • C&DH: Command and Data Handling • COTS: Commercial Off The Shelf • CPU: Central Processing Unit • EDMU: Engineering Design and Manufactured Unit • RF: Radio Frequency • RHU: Radioisotope Heater Unit • RTG: Radioisotope Thermoelectric Generator • RX: Receiver • TEM: Theoretical Europa Mission • TX: Transmitter • WBS: Work Breakdown Structure Vehicle for Icy Terrain Locomotion 22

23. References • Trudy Schwartz • SolidWorks 2005 • Vable, Madhukar. Mechanics of Materials. • www.onlinemetals.com • www.matweb.com • www.analog.com • www.pcb.com • www.thomasnet.com • www.globalspec.com • www.servosystems.com • www.sensotech.com • www.omega.com • www.powerelectrics.co.uk • www.quadratureencoders.com • www.panasonic.com • www.powerstream.com • www.all-battery.com • www.media.popularmechanics.com • www.maxon.com • www.nasa.gov Vehicle for Icy Terrain Locomotion 23

24. Objectives Overview Theoretical Europa Mission (TEM) Top Level System Requirements EDMU Preliminary Layout Electrical Interconnects Block Diagram CDR Prototyping Quick Links Vehicle for Icy Terrain Locomotion 24