AAE450 Senior Spacecraft Design Project Aquarius Kowalkowski - 1 Mike Kowalkowski Week 4: February 8 th 2007 Project Aquarius Power Engineering Habitat & Rover Power Sizing

AAE450 Senior Spacecraft Design Project Aquarius Kowalkowski - 2 Mars Surface Layout Conceptual Design –Effective regulated power delivery system with minimal radiation exposure: manned –Partially regulated power to ISPP plants Assumptions –400 m minimum human distance from reactor 1 –Human line of sight maintained (Kirk Akaydin) –Distribution efficiency ~ 89% P / M / V – Mars Surface –Power: 1.05 MWe capacity –Mass: 7 mt –Volume: 16 m^3 All rovers are fuel cell dependent and autonomous. EPS2 Backup ISPP 2 H 2 &O 2 HAB 1 HAB 2 Aux. Power Supply CRYO System 10MWe deliverable 1.05 MWe received 150 kWe required 750 kWe required 15 kWe required

AAE450 Senior Spacecraft Design Project Aquarius Kowalkowski - 3 Rover Power Requirements Mars Rover (Manned) Power System: –Mass: 1000 kg –Volume: 1.7 m^3 –Peak Power: 48 kWe –Idle Power: 10 kWe –See attached MATLAB code to size power for all vehicles –Total mass: 5 mt.9 mt – Human Factors 2.5 mt – Structures.6 mt – Towing / Storage 1 mt – Fuel Cells & Battery Backup Capabilities and Sizing: –Max level velocity: 40 km/hr –Max range: 50 km 1-way (25 km reserve) –Max incline: 30 o –Max speed at incline: 3 km/hr –Time at incline: 10 minutes –12 hour autonomous operation –Utilizes in-situ fueling station

AAE450 Senior Spacecraft Design Project Aquarius Kowalkowski - 4 Backup Slides Week 4 Readiness Level

AAE450 Senior Spacecraft Design Project Aquarius Kowalkowski - 5 Mars Surface Power Budget Power budget - Surface –75 kWe per HAB 25 kWe life support systems –(Courtesy: Kate Mitchell) 35 kWe ground control systems, communications, 25% margin for science operations –750 kWe total ISPP (Courtesy: Steve Kassab) –15 kWe CRYO / excess Launch pad, no bleed cryo system –2 hour HAB Li-Ion Backup PMAD losses –8.3% power budget (Courtesy: Larson & Pranke) Resistance losses –2% power budget (Courtesy: Larson & Pranke) –Next step includes assessment of power distribution losses as a function of distance

AAE450 Senior Spacecraft Design Project Aquarius Kowalkowski - 6 Mars Surface M / V Calculations Primary System: HAB –PMAD & Nuclear PMAD mass ~ 11.1 kg/kW e 1 Wiring ~ 0.5 kg/m 1 System requires 150 kWe Secondary System: HAB –Direct fuel cell system PEM fuel cells are capable of running in reverse. In the case that both nuclear power systems are offline, the ISPP production facility can begin generating power to sustain the HAB indefinitely. Primary System ISPP –Electrolysis Partially regulated 1 10,000 mt propellant produced in 2 years According to Steve Kassab, requirement is 750 kWe between the two plants over that time period. –Assume 90% efficiency CRYO storage tanks budgeted 15 kWe. Need more information to finalize.

AAE450 Senior Spacecraft Design Project Aquarius Kowalkowski - 7 Mars Rover Power Assumptions Directed Fuel Cell –Specific Energy: 1 kg/(kW-h) fuel 2 –Densities LOX 692 kg/m^3 2 LH kg/m^3 2 –Fuel Cell Machinery 4 kg / kW –(Courtesy: Kassab) 1.5 W e /cm^3 density 3 –Tank Mass LH2 2.4 kg/kg H 2 LOX.25 kg/kg O 2 Level power 90% efficiency –Power = m*g mars *c f *v 4 Graded power 90% efficiency –Power = v*(m*g mars *c f *cos(theta) + m*g mars *sin(theta)) 4 See attached code for calculations. –½ credit to Steve Kassab for helping create fuel cell code. Top 50 km/hr –~1650 kg system

AAE450 Senior Spacecraft Design Project Aquarius Kowalkowski - 8 Calculations Calc. Theory from Human Spaceflight: Mission Analysis and Design, Larson & Pranke pgs – MATLAB code to come shortly

AAE450 Senior Spacecraft Design Project Aquarius Kowalkowski - 9 Power Systems Trade Study ISPP vs. Solar Panel Backup System 5 –Referenced Ryan Scott’s solar panel code 6 –ISPP fuel cells use fuel already in the ground at Mars that has been electrolyzed by a nuclear reactor that is already budgeted into the mission. Turning that system around in the event of an emergency saves weight compared to solar panels. –Solar panels require additional weight and a lot of volume. Power: 150 kWe – Martian Surface Weight: 2.5 mt Volume: 486 m^3; Area: 3827 m^2

AAE450 Senior Spacecraft Design Project Aquarius Kowalkowski EP Systems Available 7

AAE450 Senior Spacecraft Design Project Aquarius Kowalkowski - 11 Cited References 1 Larson, Wiley J. and Linda K. Pranke. Human Spaceflight, Mission Analysis and Design. Ch. 13 – “Designing, Sizing, and Integrating a Surface Base.” McGraw Hill. 2 Larson, Wiley J. and Linda K. Pranke. Human Spaceflight, Mission Analysis and Design. Ch. 14 – “Planetary Surface Vehicles.” 3 “PEM Fuel Cell Cost Status.” Carlson, Eric, et al. November Available online. Nov17/Carlson_Eric_392.PDF Nov17/Carlson_Eric_392.PDF 4 “Power – Physics.” Wikipedia. Available online Landis, Geoffrey. “Photovoltaic Power Options for Mars.” October Available Online Scott, Ryan. Arraysize.m. February 8, Attached. 7 Landau, Dr. Damon. “Strategies for the Sustained Human Exploration of Mars.” Dec