SFINX Surveying Flying IN-situ eXplorer Old Dominion University Mars Exploration Vehicle Senior Design Project Mentors: Dr. Robert Ash & Dr. Colin Britcher Students: John Miller, David Covington, Bradley Dupont, Brian Meagher, Nelson Gosnell, Grant Jennings

The Planet Mars SFINX Surveying Flying IN-situ eXplorer Temperature: -207 F to 68 F, with an average of -81 F Pressure: 6 to 10 millibars (0.06% Earth pressure) Highest to Lowest point 40 km Atmosphere: 95.3% CO2 Evidence of a very different past!!!

Mars Exploration Vehicles SFINX Surveying Flying IN-situ eXplorer Mars Exploration Vehicles Current: Slow, delicate, inefficient, will take 1 million years to cover the surface Needed: Fast, robust, adaptable, reusable, with utilization of Martian resources. Answer: Build on previous research to design an aircraft using CO2 for propulsion

SFINX Surveying Flying IN-situ eXplorer Structures

SFINX Surveying Flying IN-situ eXplorer TAKE OFF FLIGHT LANDING No Improved Surfaces Rocky and/or Sandy Conditions FLIGHT Finite Flight Duration Stability vs. Maneuverability LANDING Forward Momentum Controllability

SFINX Surveying Flying IN-situ eXplorer FLIGHT TAKE OFF LANDING L = W = ½ ρ V2 S CL

SFINX X(s) G(s) Y(s) Surveying Flying IN-situ eXplorer Propulsion System X(s) G(s) Y(s)

Propulsion System: Inputs SFINX Surveying Flying IN-situ eXplorer Propulsion System: Inputs Input 1: Specific energy of CO2 fuel in tank

Propulsion System: Inputs SFINX Surveying Flying IN-situ eXplorer Propulsion System: Inputs Input 2: Heat supplied by a heater

Propulsion System: Transfer Function SFINX Surveying Flying IN-situ eXplorer Propulsion System: Transfer Function Variables Throat diameter: d* Affects thrust & exhaust time Tank volume: V Affects total impulse, weight,and required heat input Area ratio: AE/A* Affects flow properties: ME, AE/A*, PE/PO, TE/TO

Propulsion System: Outputs SFINX Surveying Flying IN-situ eXplorer Propulsion System: Outputs Impulse: tt Fuel mass: m(t) Maximum vehicle height: Solved by integrating velocity:

Propulsion System: Height SFINX Surveying Flying IN-situ eXplorer Propulsion System: Height

SFINX Surveying Flying IN-situ eXplorer Flight Controls Vehicle Controls Navigation Obstacle Detection and Avoidance

SFINX Surveying Flying IN-situ eXplorer Vehicle Controls Need attitude readings Pitch, Roll, Yaw, velocities, rates Need both absolute and wind-relative Wind-relative measured via differential pressure readings Pitot-static tubes, five-hole probes, etc. Absolute values measured via corrected inertial sensors Horizon readings, radar or laser velocity readings from the ground

SFINX Surveying Flying IN-situ eXplorer Navigation Accurately move from location to location Inertial system primary navigation Have to correct for inertial drift Celestial navigation Landmark navigation Corrections may not be necessary

Obstacle Detection and Avoidance SFINX Surveying Flying IN-situ eXplorer Obstacle Detection and Avoidance High probability of landing on rocky terrain Will use radar to measure terrain “suitability” Does not identify individual objects Very high speed

SFINX Surveying Flying IN-situ eXplorer Power System Solar Cells Light Spectrum Scattering of light Temperature Solar Cell Characteristics Available Solar Energy Batteries 180 Wh/kg 6.7 kg to store power gathered in one day.

SFINX Surveying Flying IN-situ eXplorer Communications Atmel SRAM based FPGA: Capable of functioning in harsh Martian environment, Tested at over 300krad, -55 to +125 C Micro-Transceiver: developed for low weight, low power Mars operations Capable of –100 to 25 C Over 100 krad hardening UHF: half duplex

SFINX Surveying Flying IN-situ eXplorer Questions?