Critical Design Review: AAE 450 - Senior Design Alec Spencer Critical Design Review: Science Package 6 March 2001

Science Overview Greenhouse Pressurized Rover Mission Planning Materials and Structure Design Assembly Pressurized Rover Mission Planning

Greenhouse Envelope made of ETFE (ethyl-tetra-fluoro-ethylene) Similar to Teflon Self cleaning Chemical and heat resistance Restraint device Kevlar or Spectra cables Staked into soil Floor Substrate to cover soil Foam rubber base

Greenhouse Self-supporting inflatable geodesic dome 55 hexagon, 12 pentagon shaped pillows 3 layers of foil per pillow (outside, middle, inside) Reduces convective heat loss Redundancy if outer layer is punctured Floor and ground matting 1 cm foam rubber Reduce wear, puncture possibilities

Greenhouse Design Used code to optimize sizing Selection criteria 1 tonne maximum mass Useable floor space Ceiling > 2m Pressure requirements Heating requirements Packed volume

Greenhouse Design Iterated over inner radius and partial sphere angle Computed mass of foil envelope, floor space, and ground footprint

Code Results - Mass Includes two 25 kg space heaters and one 50 kg pressure regulator

Code Results – Floor Area

Code Results - Ceiling

Pressurized Rover Human Requirements Tanks sized for emergency Nominal Distant Excursion Emergency Habitat Tanks sized for emergency

Rover Power Breakdown Mobility power estimated as 0.1 W-hr/kg/km Methanol/LOX energy density 2129 W-hr/kg 2093 W-hr/L

Mission Planning Goals Maximize science return Minimum 10,000 km on rover odometer Cover maximum area on distant excursions

Mission Planning Built around flexibility 42 Full rest days Distant Excursions 14 days in rover 2 days rest 14 days analysis 1 day rest 78% of days on Mars are spent doing science

Mission Design 3 1 days travel to next site (167 km travel per day) 1 day stay at inner radius 2 days stay at mid and outer radius Max area covered Flexible schedule No need to stop needlessly 8 6 333 km 5 1 167 km 10 9 2 4 7