Space Inflatables Robert Dyck Ardeco Aerospace Requirements Temperature
Space Inflatables Robert Dyck Ardeco Aerospace
Requirements Temperature: LEO -120°C…+150°C Mars -111°C…+27°C Moon mean: -153°C (shade) … +107°C (daylight) maximum: -223°C (polar) … +123°C Oxygen/nitrogen impermeability UV durability transparency Non-reactive to superoxides, alkali feldspar, acid jarosite, salt, or mono-atomic oxygen Flexible, fold for storage No outgassing
Fluoropolymers Only polycarbonate and fluoropolymers can handle cold 1 -mil film FEP Tefzel PCTFE Tensile strength 3000 psi 6000 psi 5300 psi Bursting strength 11 psi 33 psi 19. 4 psi 54. 6 g/m 2 44. 38 g/m 2 54. 1 g/cm 2 Density Service temperature -240. . . +204°C -185. . . +150°C -240. . . +132°C Storage temperature +204°C Gas permeability of 1 -mil film at 25ºC in cm 3/m 2·day·atm CO 2 25900 3875 N 2 5000 465 O 2 1600 1550 14. 5 107 water permeability in g/m 2·day H 2 O 7. 0 0. 3 <0. 1
Outgas PCTFE has the least outgassing of any transparent film. total mass loss, TML: 0. 01% collected volatile condensable materials, CVCM: 0. 00% water vapour regained, WVR: 0. 00%
Transparency
Pup tent Cylinder: 2 metre long, 1 metre diameter, 1. 3 kg Dome: 2 metre diameter, 1 metre head room, 2. 6 kg 85 cm ring door seal, clamps along inside • twists to ½ size for storage like child’s pop-up tent 2 -mil PCTFE film, aluminized, window with cover flap 4 -mil air mattress, pressurized and tufted 1 -mil interior layers suspended (spaced) by threads “muffin fan” to circulate air from air mattress bottom to top, controlled by thermostat to dissipate heat into ground, powered by PLSS battery O 2 and CO 2 control by suit PLSS, sublimator turned off
Greenhouse Temperature control: • double layer, gap filled with argon gas • spectrally selective coating • trench around base, filled with argon filled balloon bags – use ground as thermal mass • aluminized Mylar curtain Support roof by air pressure, hold-down straps Gap pressurized between interior and Mars ambient UV & X-ray blocked by spectrally selective metal coating Deploy at low altitude, Mars atmosphere blocks heavy ions
Walking tube Connection between habitats is important to build a base. Connection to the greenhouse is required for practical operation. Same material as greenhouse envelope. Pressure will tend to expand it to a cylinder, but shaped somewhat with a rigid floor. 2 metre waist cylindrical corridor permits 2 people to pass, no need to shape further.
Composite cryogenic tank Graphite/epoxy LH 2 tank on DC-XA Graphite & LOX combust, must be separated Fluoropolymer liner makes existing tank usable with LOX LH 2: -252. 8°C, LOX: -182. 96°C PCTFE service temperature to -240°C most impermeable to O 2 of any polymer that handle <-60°C stronger & lighter than FEP
Collapsible Propellant tank LOX: -182. 96°C LCH 4: -161. 6°C Mars Pathfinder: -8°C…-77°C ERV or MAV: land with collapsed propellant bladder, inflate with in-situ propellant for launch. Nest LOX bladder inside LCH 4, chill LOX Support with basket, coiled into ring during descent, deployed in a hemisphere during ascent. reduce tank mass, reduce aeroshell during descent Future shuttle: collapse ET for storage in cargo bay.
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