Edmunson, Jennifer

Fiske, Mike

NASA Technical Reports Server

Additive Construction with 
Mobile Emplacement (ACME)
3D Printing Structures with In-Situ Resources
Mike Fiske, Jennifer 
Edmunson, and the 
ACME Team
November 7, 2017
https://ntrs.nasa.gov/search.jsp?R=20170011110 2019-08-31T01:30:44+00:00Z
ACME Overview
ACME
• Partnership between NASA (MSFC, KSC), USACE, and Contour Crafting 
Corporation (NR-SAA with Caterpillar)
• Based on a collaboration between NASA/MSFC and USC/CCC (Dr. Behrokh
Khoshnevis) beginning in 2004.
• Funded by NASA/STMD-GCDP and USACE-ERDC
• Additional contributions from the University of Mississippi, University of 
Arkansas in Little Rock, East Carolina University, and the Pacific International 
Space Center for Exploration Systems (PISCES)
ACME-1 System
Contour Crafting
• An Additive Construction technology not limited to 
concrete or water-based binders
• The contour crafting process has been used to build structures of
• Gypsum
• Portland cement-based concrete
• Sulfur concrete
• Ceramics
• Future binder development includes Sorel-type cements and polymers
• Polymer-based construction material research already carried out 
at MSFC by Dr.’s Sen and Edmunson
• Lunar sulfur concrete work by Dr.’s Grugel and Toutanji at 
MSFC/UAH
• Dr. Khoshnevis/CCC has a NIAC to work on sulfur-based concrete 
for full-scale structures
Why Additive Construction?
• US Army Corps of Engineers (USACE) needs a technology 
that will help:
• Provide structures on-demand in a variety of settings
• Build a structure in 1 day (takes 5 days now)
• Reduce construction personnel from 8 to 3 per structure
• Reduce the amount of material brought into the field from 5 tons to 
less than 2.5 tons
• Improved security during construction
• Reduce construction waste from 1 ton to less than 500 pounds
• Build the structure to look like local housing using digital models; 
avoid becoming a target
• Adaptable design, multiple geometries
• State of Hawaii is interested (and is partially funding PISCES) 
to identify construction materials and techniques that do 
not require materials imported from the mainland.  KSC is 
working closely with PISCES on this effort.
Why Build ACME?
• NASA needs the technology to:
• Utilize in-situ resources to provide habitats, garages, 
berms, landing pads, radiation shielding, etc. (Deep 
Space Mission Infrastructure)
• Minimize the amount of material launched from Earth 
(estimated savings between 60% and 90%)
• Applies to Decadal Survey area AP10, Technology 
Roadmap areas TA04, TA07, TA12
• Project matures related technologies
• Regolith excavation and handling
• Contour crafting
• Optimized planetary structure design
ACME and ACES System 
Design
ACME-1 System
Undertook effort in 2005 to add 
a 3rd dimension of travel to allow 
fabrication of different 
geometries. Also began 
experimenting with different 
nozzle configurations.
USC as-delivered “2-D” system in 
2004 that translated in X & Z 
directions and head rotated, 
allowing for long, slender wall 
fabrication.
Also undertook a significant effort 
to match concrete composition 
using COTS products that are 
different in Alabama from those in 
California (Portland cement, 
stucco, additives).
ACME-1 System
Completed conversion to “3-D” 
system, resolved composition issues, 
and began programming and printing 
various simple geometries. 
Experimented with translation rate vs 
concrete cure time and strength to 
optimize overall process.
ACME-1 System Dome Development
Evolution from ACME-1 to ACME-2
Focus was on converting from a “batch”
system to a “continuous feed” system.
- Enables larger structures
- Eliminates poor layer-to-layer 
bonding from batch to batch
- Eliminated discontinuities between 
batches
Removed extrusion chamber and plunger
hardware, replaced with large mixer, 
continuous pump, accumulator, hoses, fittings, etc.
Incorporated use of slump measurements and viscosity measurements (Germann
Instruments) to characterize concrete properties/pump performance.
ACME-2 System
Gantry Mobility 
System (good x, 
y, z positioning)
Mixer
Pump
Accumulator 
(allows pump to 
stay on when 
nozzle closes for 
doors/windows)
Hose Nozzle Control System
Evolution from ACME-2 to ACES-3
Focus was on transition from sub-scale to 
full-scale.
Issues included:
- Optimum mobility system (gantry vs
truck/boom arm vs robotic arm, etc)
- Hose management
- Cleaning
- Positional accuracy
- Mobility
- Assembly/disassembly considerations
- Print speed/volumetric flow rate considerations
Key ACES-3 Requirements
- Relocate entire system in no more than three 8’ x 8’ x 20’ 
volumes (Army Conex box or PLS) – 10,000 lbs/PLS
- Complete set-up and alignment in 11 hours
- Print in X and Y axis at up to 500 in/min with a volumetric flow 
rate of up to 800 in3/min
- Nozzle positional accuracy of +/- 1/8” in all three axes during 
printing
- Operate entire system with no more than 6 personnel (goal of 3)
- Concrete composition to include up to 3/8” aggregate
- Automated dry goods (7) and liquid goods (5) feed system
ACES-3 System
Dry Good Storage Subsystem Liquid Storage Subsystem
Continuous Feedstock Mixing Delivery Subsystem (CFDMS)
• Accumulator
• Pump Trolley
• Gantry
• Hose Management
• Nozzle
• Electrical & Software
Dry Goods & 
Liquid Goods 
parked on side
ACES-3 System
ACES-3 System
ACES-3 System
ACES-3 System
ACES-3 System
ACES-3 System
ACME Planetary 
Materials
System Affects on Materials
Mixer Pump
Hoses and 
Accumulator
Gantry Nozzle
• Can 
inadequately 
mix
• Amount (batch 
size)
• Time to mix 
properly
• Can add air
• Can redistribute 
air bubbles
• Pressurizes the 
concrete
• Clogs (needs more 
vibration)
• Continuity of flow
• Can affect air 
distribution
• Settling
• Continuity of flow
• Material (friction)
• Dictates hose 
position (vertical 
and horizontal 
drops, kinks in 
hose)
• Size of printed 
structure
• Can stop flow
• Trowel needs to be 
easy to use
• Size of nozzle will 
dictate flowability and 
extrusion
• Material of the nozzle 
(friction/ abrasion)
ACME-1 Materials
• Standard mix contains Portland cement, stucco mix, 
water, and a rheology control admixture
• Martian simulant mix contains standard mix with 
JSC Mars-1A simulant
• Printed at terrestrial ambient conditions
ACME Materials
• The original composition of the mix dictates:
• Viscosity
• Extrudability / workability
• Initial set time
• Initial strength to support superimposed layers
• Temperature range acceptable for setting
• Pressure range in which it can be printed
• Functional temperature range for the cured material
• Resistance to material aging in a planetary surface 
environment
• How much material will need to be brought from Earth
Planetary Constraints
• Environment of deposition is the greatest 
constraint in the materials we choose for additive 
construction
Parameter Mars Moon
Gravity 1/3 that of Earth 1/6 that of Earth
Pressure at surface 3-10 Torr (4x10-3 to 1x10-2 ATM) 2x10-12 Torr (3x10-15 ATM)
Surface Temperatures -89 to -31 Celsius (Viking 1) -178 to 117 Celsius (equator)
Radiation
(solar wind particles, galactic 
cosmic rays)
Some protection offered by 
atmosphere
Some protection offered by Earth’s 
magnetic field
Surface reactivity Perchlorates (highly oxidizing)
Reduced material (nanophase iron, 
elemental sulfur)
http://nssdc.gsfc.nasa.gov/planetary/planetfact.html
Material Requirements
• For emplacement (extrusion) of additive construction 
material in a pressurized or ambient environment
• Must flow and de-gas well
• Must not set up (harden/cure) within the system
• Must not shrink significantly while setting
• Must allow for superimposed layer adhesion and support
• For accommodating internal pressurization
• Must have significant tensile strength or the design of the structure 
must place the material in compression (e.g., inverted aluminum 
can and/or regolith cover)
Material Requirements
• For radiation and micrometeorite protection / shielding
• Must have sufficient regolith cover and/or be composed of known 
shielding materials
• For long-duration use (resistance to aging)
• Must withstand extreme temperature swings of the exterior 
environment while withstanding heating/cooling of the interior
• Must withstand or self-heal damage due to radiation or 
micrometeorites by design or material
• Must not become brittle over time
• Must not be flammable, decompose, or become toxic when 
exposed to water, oxygen, or carbon dioxide (unless a liner/skin is 
used)
Material Considerations
• In-situ materials are site-dependent
• Terrestrial example (PISCES involvement in ACME): Hawaii is 
interested in creating construction materials from basalt; all 
Portland cement, asphalt, etc. building material has to be brought 
in from the continental US.
• Moon or Mars?  Poles or Equatorial Region?  Basalt or Sedimentary 
Rock?
• Binder selection must reflect and complement available materials
• USACE
• Variations in globally available concrete
• Need to regulate / accommodate for moisture in available materials
Available Materials - Mars
Mineral Other Materials
Major minerals Present everywhere (“dew”)
Feldspar (CaAl2Si2O8-(Na,K)AlSi3O8) Perchlorates (ClO4
-)
Pyroxene ((Ca,Mg,Fe)Si2O6) Atmosphere
Olivine ((Mg,Fe)2SiO4) CO2 (95.32%)
Minor minerals N2 (2.7%)
Hematite (Fe2O3) Ar (1.6%)
Magnetite (Fe3O4) O2 (0.13%)
Clays (Fe-Mg silicates, K-Al silicates) CO (0.08%)
Sulfates (gypsum-Ca; jarosite-K,Fe; epsomite-Mg) H2O (210ppm)
Carbonates (calcite-Ca, dolomite-Mg) NO (100ppm)
Poles – solid CO2 (both) and H2O (northern pole)
Available Materials - Moon
Minerals Permanently Shadowed Regions
Highlands (Major Minerals) LCROSS (ejected material)*
Anorthite (CaAl2Si2O8) Regolith (~85%)
Pyroxene ((Ca,Mg,Fe)Si2O6) CO (5.70%)
Olivine ((Mg,Fe)2SiO4) H2O (5.50%)
Mare (Major Minerals) H2 (1.39%)
Feldspar (CaAl2Si2O8-(Na,K)AlSi3O8) H2S (0.92%)
Pyroxene ((Ca,Mg,Fe)Si2O6) Ca (0.79%)
Olivine ((Mg,Fe)2SiO4) Hg (0.48%)
Minor / Trace Minerals NH3 (0.33%)
Baddeleyite (Zr oxide) Mg (0.19%)
Apatite (Ca phosphate) SO2 (0.18%)
Zircon (Zr, Si oxide) C2H4 (0.17%)
Spinel (metal oxide) CO2 (0.12%)
Ilmenite (Fe, Ti oxide) CH3OH (0.09%)
Whitlockite (Ca phosphate) CH4 (0.04)
Troilite (Fe sulfide) OH (0.002%)
Other phase of note – nanophase iron * Larson et al. (2013)
Material Considerations
• The mix should:
• Minimize water consumption
• Be adjustable for slightly different compositions of 
regolith; not require a very precise mix
• Be easy to emplace (including layer adhesion)
• The binder should:
• Require a minimal amount of processing and energy to 
produce from in-situ resources
• The regolith used should:
• Require a minimal amount of power to mine (i.e., use 
loose regolith when possible)
Some Previous Materials Work
• Sulfur used as a binder
• Studied at MSFC in 2004-2007 timeframe
with lunar simulant (R. Grugel, H. Toutanji)
• NIAC to Dr. B. Khoshnevis
• Scaling up contour crafting for full-scale sulfur printing
• Currently studied by Northwestern University (among others)
• Gypsum
• Polymers (e.g., Sen et al. 2010)
• Sintering
• Laser, microwave, oven
• Useful for Hawaiian material
• Basalt rebar/fibers
ACME Materials
• Binders currently under study
• Ordinary Portland Cement
• Magnesium oxide-based cements
• Sodium silicate (ACME and CIF)
• Geopolymers
• Polymers (KSC, Centennial Challenge Teams)
• Additives
• Carbon nanotubes
• Fibers
• Polymers
• Simulants JSC Mars-1A (martian) and JSC-1A (lunar)
Compression Test Samples
Sample prep in 4739
Test in 4602
Compression Test Samples
Sample prep in 4711 
and 4464
Test in 4602
Compression Test Results
Hypervelocity Impact Test Samples
• Three samples were cast into 15.24cm x 15.24cm x 
2.54cm molds
Martian simulant JSC 
Mars-1A, stucco mix, 
Portland cement, 
and water
Martian simulant JSC Mars-1A, MgO-MKP 
cement, boric acid (set retardant*) and 
water – sample fractured during shipping 
to JSC prior to testing
Lunar simulant 
JSC-1A, stucco 
mix, Portland 
cement, and 
water
*Set retardant used because this cement sets up very quickly and would solidify within the ACME system prior to extrusion
Hypervelocity Impact Test Samples
Martian simulant JSC Mars-1A, stucco mix, Portland 
cement, rheology control admixture, and water
25.40cm tall, 76.20cm long, 5.72cm thick wall
2 vertical layers and 2 horizontal layers printed per 
day; material was allowed to dry between prints
Hypervelocity Impact Test 
Samples
Martian simulant JSC Mars-1A, stucco mix, Portland 
cement, rheology control admixture, and water
Sample delaminated during 
shipping to JSC on a boundary 
between prints made on 
different days
Hypervelocity Impact Testing
• Hypervelocity impact tests were internally funded and 
performed at the White Sands Test Facility in Las 
Cruces, NM
• 2.0mm Al 2017-T4 (density 2.796g/cm3) impactor, 0.17-
caliber light gas gun, 0° impact angle, 1Torr N2 in 
chamber during test
• 7.0±0.2km/s velocity (approximate mean expected 
velocity of micrometeorites at the surface of Mars, and 
higher than expected velocity for bullets on Earth)
• Kinetic energy is equivalent to a micrometeorite with a 
density of 1g/cm3 and a diameter of 0.1mm traveling at 
a velocity of 10.36km/s, as well as a 9x17mm Browning 
Short bullet.
Hypervelocity Impact Test Results
JSC Mars-1A
Portland cement
Stucco Mix
Water
JSC Mars-1A
Portland cement
Stucco Mix
Admixture 
(Rheology Control)
Water
Photos courtesy of the Johnson Space Center Hypervelocity Impact Technology Group
Hypervelocity Impact Test Results
JSC Mars-1A
Sorel cement 
(MgO + MKP)
Boric Acid (Set 
Retardant)
Water
JSC-1A
Portland cement
Stucco Mix
Water
Photos courtesy of the Johnson Space Center Hypervelocity Impact Technology Group
Future Work
• Continue to monitor human landing site workshops for 
Mars; optimize binder/regolith mixes for those sites
• Continue to encourage planetary scientists to quantify 
available in-situ resources through remote sensing
• Establish an Artificial Neural Network to help optimize 
mixes
• Continue testing materials and identify promising new 
binders
• Spin-off technologies to industry
• Encourage involvement of the next generation in 
additive construction
3D Printed Habitat Challenge
https://bradley.edu/sites/challenge/


Additive Construction with Mobile Emplacement (ACME) 3D Printing Structures with In-Situ Resources

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