Crew Systems Analysis for 10-Day Round-Trip to Moon Ben Abresch Matt Marcus Sean Robert Nick Zarbo 10/18/2012
Mission Requirements 10 day nominal trip 3 contingency days Crew systems mass <1500kg Cone with half angle 25-32.5 Maximum Diameter 3.57m Wall thickness 0.1m
Breakdown Layout Shapes Orientations Accommodations Air Atmosphere Loss to EVA O2 in CO2 out Denitrogentation Climate Control Water & Food Waste Management EVAs Power Requirement Estimations Mass & Volume Estimations
Major Design Concepts for Module Layout Cone half angle 25 with outside diameter 3.57m Roughly 8 m 3 of interior volume Rounded exterior corners for structural advantage 0.15m radius of curvature Axis of symmetry lands parallel to ground on moon Vertical reference is parallel to circular side of module Crew seated vertically in chair during lunar landing and seated back down during Earth re-entry Crew sit against back of craft in a row of cushioned chairs Seats bottoms can be collapsed up against back wall for extra standing room Astronauts escape through door vertically downward of craft Exit door is mostly window that allows the pilot to view 25-42 below the horizontal
Model of Crew Vehicle 3 View of CAD model Side cutaway of vehicle
Further Concepts for Layout Extendable hand/footholds for climbing in and out of door Astronauts sleep horizontally across craft One person lays across seats, two use hammocks near top and bottom of capsule Straps, sleeping bags, and hammocks provided for sleeping support Space to right and left of astronaut is for stowage A port to each side is extruded for window view. A mirror provides sight lines to rear landing feet. Space beneath floor and seating for storage Space suits store below seats Ceiling space for stowage Overhead space for stowage
Cabin with astronauts sleeping Port for viewing of rear landing-gear can be seen in lower right corner
Controls and Avionics Layout Pilot (center seat) has joystick control of aircraft Joysticks and necessary piloting controls located on armrests which are rotatable back into seat Wiring runs along back wall through ceiling Switchboard and monitors located directly in front and above heads of crew when seated All masses and wiring are not considered part of the 1500kg crew systems limit and the volume is negligible Lighting will be done with LEDs 75W, 0 kg
Atmosphere Cabin Pressure 10 psi 26.5% O 2 by volume 73.5% N 2 by volume Assumed volume of air in spacecraft ~75% of total interior volume or 6 m 3 (4.85 kg) Assume that 1 cabin volume of air is already supplied at mission start. Need to resupply atmosphere after each EVA (four times) 24 m 3 Stored at 200atm, volume 0.0758 m 3, 19.4 kg Two spherical tanks with radius 0.213 m Including tank mass 58.2 kg
Oxygen Supply Each person consumes 1.2 kg O 2 /day 3.6 kg/day or 46.8 kg for the whole trip Stored at 3000psi, volume = 0.175 m 3 Cylindrical tank with spherical caps Mass including tanks is 140 kg
Gas tanks Air Supply Tank (x2) Oxygen Supply Tank 0.426 m
CO 2 Scrubbing Assume each astronaut exhales ~1kg-CO 2 /day LiOH: 6.27 kg/day or 81.5 kg Ca(OH) 2 : 9.15 kg/day or 119 kg 2BMS: 48 kg, 0.27 m 3, 231W 4BMS: 90 kg, 0.33 m 3, 510W 2BMS requires the least mass by far
Mass (kg) CO 2 Scrubbing 140 120 100 CO2/LiOH CO2/4BMS CO2/2BMS CO2 Removal 80 60 40 20 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Mission Days 2 Bed Molecular Sieve (2BMS) requires the least mass
Denitrogenation Prebreathing occurs at suit-atmosphere conditions (80% O 2, 20% N 2 ) Assuming a maximum safe tissue ratio of 1.4 When P tissue < Pp N2-max (7 psi), it is safe to depress to 5psi (suit pressure) Safe decompression can occur after 10 minutes, 38 seconds of prebreathing
Denitrogenation Slowest Tissue Fastest Tissue Tissue pressure during pre-breathe. Time for slowest tissue to reach 7 psi is 10.6mins
Climate Control Humidity control is done by using an Internal Thermal Control System cooling loops to move excess heat to heat exchangers and then moving that to the External Thermal Control System Triol is the heat transfer fluid Trace contaminant control is modeled after an industrial air filter 103 kg, 0.472 m 3, 360W
Water 300 Water requirements for 3 crew members 250 200 150 100 4.84L/person-day 5L/person-day 5.5L/person-day 6L/person-day 6.16L/person-day 50 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13
Water Each crew member consumes 2kg-H 2 O/day Assumed 2.84kg/person-day for hygiene water all days Total Water required is 189 kg (0.189 m 3 ) Multi Filtration Unit and Water Conditioning Unit to remove impurities and add minerals for palatability (25kg)
Food Consume three meals a day and one extra for each EVA Water Content - 1.15kg/person-day Food prep water - 0.79kg/person-day Solid food - 0.62kg/person-day Total food is about 3kg/person-day and comes to a total mass of 129kg including 12 extra meals for EVA days
Metabolic Energy Requirements Men Age Kcal per day 18-30 3286 30-60 3109.4 Women Age 18-30 2721 30-60 2465.8 Add in 500 kcal/person-day for EVA days 95 th percentile male age 18-30 requires 44718 kcal/person of energy from food
Waste Management Disposable Absorption Containment Trunks (DACTs) These are hygienic and replace having a toilet Mission should require about 3.8 kg/personday for hygiene supplies (148 kg) Waste will be stored in a container that will be vacuum dried to remove liquid
DACTs
Extra-Vehicular Activities Will be using Mark III suits (60 kg each) Breathable air supply will be siphoned from Oxygen and atmosphere supplies in capsule Using LiOH 2.09kg/person-day Total of 25.1 kg for EVA CO 2 scrubbing
Power Requirements Item Power Reqts Units Wattage Avionics 300 Lights 15 W/light 5 lights 75 2BMS 77 W/kg-CO 2 /day 3 kg-co 2 /day 231 CO2 Scrubbing 360 Water Filtration 100 Total 966
Mass Estimations Crew 246 Water 189 Water Filter 25 Food 129 Waste Management 148 Seating 75 Footholds 10 Interior Walls/Panels 25 3 Mk3 Suits 180 Mk3 LiOH 25.1 CO2 scrub 48 Air w/ tanks 58.2 O2 resupply w/ tanks 140 Air ventillation 103 All values are in kg and unknown values are estimates Total 1401.3 Mass Margin 0.0658
Volume Estimations Crew 3 Water 0.189 Water Filter 0.025 Food 0.125 Waste Management 0.15 Seating 0.5 Footholds 0.05 Interior Walls/Panels 0.5 3 Mk3 Suits 1 Mk3 LiOH 0.05 CO2 scrub 0.27 Air w/ tanks 0.076 O2 resupply w/ tanks 0.175 Air ventillation 0.472 All values are in m 3 and unknown values are estimates Total 6.582 Extra Volume 1.418
References http://spacecraft.ssl.umd.edu http://spaceflight.nasa.gov/shuttle/reference/fac tsheets/food.html http://settlement.arc.nasa.gov/teacher/course/ai r.html JSC-39502 JSC-47804 http://www.ecat.lighting.phillips.com SpaceX COTS C2+ Cargo Manifest http://www.apollosaturn.com/gnc.htm