Bio-cemented regolith (microbially induced calcite precipitation) MICP
Calcium carbonate cement (calcite, with vaterite and aragonite) bonding lunar or Martian regolith simulant grains
Bio-cemented regolith is lunar or Martian regolith simulant bound with calcium carbonate that the bacterium Sporosarcina pasteurii precipitates.
Evidence level
2 of 5
Lab-measured
- 0Predicted only. No one has made it, or no measurement exists.
- 1Calculated. Only calculated or predicted values from sources.
- 2Lab-measured. Measured properties with their conditions stated.
- 3Space-relevant tests. Measured in conditions relevant to space, such as vacuum or atomic oxygen.
- 4Ground-qualified. Qualified for an application on the ground.
- 5Flown or field-proven. Flight or field results exist.
Lunar brick strength
5.65 MPa
Martian brick strength
3.3 MPa
Range in the preprint
40 kPa to 1.1 MPa
Mass loss on heating
about 5%
Recipe, share of the weight
- not statedLunar regolith simulant (LSS, ISRO)
- not statedCalcium carbonate (calcite, vaterite, aragonite)
- not statedSporosarcina pasteurii (ATCC 11859)
- not statedGuar gum
- not statedNickel chloride (NiCl2)
Best for
Laboratory casting of regolith bricks where a microbe grows the binder in place (in-situ resource concept, lab evidence only)
Weakest at
Strength without additives: the lunar bacteria-only brick reached 0.75 MPa, and no density, porosity, durability or space-environment data were reported
Risk at a glance
- People None found. Calcium carbonate is not classified for GHS hazards; the…
- If it fails Moderate. Bacteria-only brick too weak to test in uniaxial compression
- Corrosion No data. No corrosion data recorded
Why it exists
Bio-cemented regolith is a brick made from lunar or Martian regolith simulant, bound by calcium carbonate that a bacterium grows in place. The PLoS ONE authors frame local resource use as the goal for habitats on the Moon and Mars. The 2022 study reports compressive strengths of 0.75 MPa to 5.65 MPa for laboratory bricks made from simulant. No density or porosity is reported, so the bricks cannot yet be compared with conventional building materials by mass or pore structure.
Where it's used
Habitat bricks from in-situ resources (lab concept)
The authors state that habitats 'need to be built from available in situ resources on moon/Mars' and cast brick-like structures from regolith simulants by microbial calcite precipitation.
Microgravity experiment (proposal only)
The Space-Brick preprint describes a payload of four cartridges per cassette (three experiments and one control) for microgravity testing. It reports no experimental results.
Recipe
Calcium carbonate cement (calcite, with vaterite and aragonite) bonding lunar or Martian regolith simulant grains
Bio-cemented regolith is made by mixing regolith simulant with a bacterial culture, urea-based medium and additives. The bacteria then precipitate calcium carbonate that binds the grains. XRD identified calcite, vaterite and aragonite in the products.
| Ingredient | Share of the weight | What it does |
|---|---|---|
| Lunar regolith simulant (LSS, ISRO) | not stated | The matrix; the grains that the calcium carbonate binds together. |
| Calcium carbonate (calcite, vaterite, aragonite) | not stated | The cement formed by the bacteria. XRD identified these three forms in the products. |
| Sporosarcina pasteurii (ATCC 11859) | not stated | The bacterium that drives the precipitation. |
| Guar gum | not stated | Additive. 1% guar gum with 10 mM NiCl2 gave the highest lunar strength (5.65 MPa). |
| Nickel chloride (NiCl2) | not stated | Additive. 10 mM NiCl2 alone gave about 2.67 MPa in the Martian simulant. |
Weight shares are as printed in the sources.
What it can do
Lunar brick strength
5.65 MPa
measured
A lunar simulant brick with 1% guar gum and 10 mM NiCl2 reached 5.65 MPa in uniaxial compression (PLoS ONE, Sec. 3.3). The same study's bacteria-only lunar brick reached 0.75 MPa.
Martian brick strength
3.3 MPa
measured
A Martian simulant brick with the same additives reached 3.3 MPa (PLoS ONE, Sec. 3.2). The bacteria-only Martian brick was too weak to test, so the additives made that brick testable.
Range in the preprint
40 kPa to 1.1 MPa
measured
The bioRxiv preprint reports lunar simulant bricks from about 40 kPa (urease only) to a maximum of 1.1 MPa (1% guar gum, w/w).
Mass loss on heating
about 5%
measured
Thermogravimetric mass loss between 500 and 700 °C was about 5% for the lunar brick with guar gum and NiCl2 (PLoS ONE, Sec. 3.4).
How it compares
In the PLoS ONE study, laboratory bricks reach about 0.75 MPa to 5.65 MPa, and the bioRxiv preprint reports about 40 kPa to 1.1 MPa for its own mixes. The PLoS ONE introduction cites sintered JSC-1 lunar simulant at 103.2 to 232 MPa and 3D-printed regolith at about 5 MPa. Those are cited values from other work, so they give context and do not compare results. The two papers come from one research group and use different curing, so their values do not rank the routes.
The same measurements for each material, so you can compare them. Each row names the key condition under the value; the full conditions and methods are in the numbered notes under Technical details.
| Measurement | MICP |
|---|---|
| Other measurements | |
| Lunar simulant, bacteria with 1% guar gum and 10 mM NiCl2 | 5.65 MPa1 |
| Martian simulant, bacteria with 1% guar gum and 10 mM NiCl2 | 3.3 MPa2 |
| Lunar simulant, bacteria only (no additives) | 0.75 MPa3 |
| Lunar simulant, bacteria with 1% guar gum | 3.41 MPa4 |
| Martian simulant, bacteria with 10 mM NiCl2 (no guar gum) | 2.67 MPa5 |
| Martian simulant, bacteria with 1% guar gum (no NiCl2) | 1.1 MPa6 |
| Lunar simulant, urease only (no bacteria) | 40 kPa7 |
| Lunar simulant, bacteria with no guar gum | 120 kPa8 |
| Lunar simulant, bacteria with 1% guar gum (w/w), maximum | 1.1 MPa9 |
| Thermogravimetric mass loss, 500 to 700 °C, lunar simulant with 1% guar gum and 10 mM NiCl2 | 5 %10 |
| Thermogravimetric mass loss, 500 to 700 °C, lunar simulant with 10 mM NiCl2 (no guar gum) | 3.2 %11 |
| Thermogravimetric mass loss, 500 to 700 °C, Martian simulant with 1% guar gum and 10 mM NiCl2 | 4.2 %12 |
| Thermogravimetric mass loss, 500 to 700 °C, Martian simulant with 10 mM NiCl2 (no guar gum) | 3 %13 |
Why choose it, and why not
Good for
- Laboratory evidence that a bacterium can bind lunar and Martian simulant into a brick (PLoS ONE, 2022).
- Strength gain from additives. In the same study, 1% guar gum with 10 mM NiCl2 raised the lunar brick from 0.75 MPa to 5.65 MPa.
Watch out for
- No density, porosity or durability data in the two sources, and no flight or vacuum test.
- One research group and lab-scale cubes of 25 ± 2 mm. The two papers cure differently, so their values are not directly comparable.
- The bacteria-only Martian brick was too weak for uniaxial testing, so the choice of simulant and additives matters.
Bio-cemented regolith is a promising in-situ resource concept, with laboratory evidence of 5.65 MPa in lunar simulant. The sources read contain no density, porosity, durability or space-environment data, so treat it as lab-only.
Technical details
For scientists and researchers. Everything above comes from the record below: every number with its method, its conditions and its source.
Notes
The method, full conditions and any caveat for the numbered rows above.
| # | Measurement | Method | Conditions | Caveat |
|---|---|---|---|---|
| 1 | Lunar simulant, bacteria with 1% guar gum and 10 mM NiCl2 | Uniaxial compression test; the paper reports the mean for each treatment, with at least 3 specimens per treatment | simulant lunar simulant LSS (ISRO)additives 1% guar gum and 10 mM NiCl2organism Sporosarcina pasteurii ATCC 11859curing 5 days at 32 °C, then drying at 50 °C for 24 hbrick mass 50 g soil per brickspecimen 25 ± 2 mm cubesloading 1 mm/min in an Instron 5697 with a 5 kN load cell | — |
| 2 | Martian simulant, bacteria with 1% guar gum and 10 mM NiCl2 | Uniaxial compression test; the paper reports the mean for each treatment | simulant Martian simulant MSS (Class Exolith Lab, Florida)additives 1% guar gum and 10 mM NiCl2organism Sporosarcina pasteurii ATCC 11859curing 5 days at 32 °C, then drying at 50 °C for 24 hend caps 2 mm rubber sheets used for this treatment and for MSS with NiCl2 alone | — |
| 3 | Lunar simulant, bacteria only (no additives) | Uniaxial compression test; the paper reports the mean for each treatment | simulant lunar simulant LSS (ISRO)additives noneorganism Sporosarcina pasteurii ATCC 11859curing 5 days at 32 °C, then drying at 50 °C for 24 h | — |
| 4 | Lunar simulant, bacteria with 1% guar gum | Uniaxial compression test; the paper reports the mean for each treatment | simulant lunar simulant LSS (ISRO)additives 1% guar gum (no NiCl2)organism Sporosarcina pasteurii ATCC 11859curing 5 days at 32 °C, then drying at 50 °C for 24 h | — |
| 5 | Martian simulant, bacteria with 10 mM NiCl2 (no guar gum) | Uniaxial compression test; the paper reports the mean for each treatment | simulant Martian simulant MSS (Class Exolith Lab, Florida)additives 10 mM NiCl2 (no guar gum)organism Sporosarcina pasteurii ATCC 11859end caps 2 mm rubber sheets used for this treatment | Printed as ~2.67 MPa in the text. |
| 6 | Martian simulant, bacteria with 1% guar gum (no NiCl2) | Uniaxial compression test; the paper reports the mean for each treatment | simulant Martian simulant MSS (Class Exolith Lab, Florida)additives 1% guar gum (no NiCl2)organism Sporosarcina pasteurii ATCC 11859curing 5 days at 32 °C, then drying at 50 °C for 24 h | Printed as ~1.1 MPa in the text. |
| 7 | Lunar simulant, urease only (no bacteria) | Compression test per the preprint Methods (Sec. II.D); the page does not state the baseline for its percentage increases | simulant ISRO lunar soil simulant (LSS)binder jack bean urease at 1 mg/g LSS, no bacteria (sample URGG00LSS)incubation 14 daysdrying 45 °C for 12 hrtest height-to-diameter ratio 1.8 to 2.2 per ASTM C 39-04a, 5 mm/min, 5 samples per case | Printed as about 40 kPa. |
| 8 | Lunar simulant, bacteria with no guar gum | Compression test per the preprint Methods (Sec. II.D) | simulant ISRO lunar soil simulant (LSS)additives none (0% guar gum, sample SPGG00LSS)organism Sporosarcina pasteurii ATCC 11859incubation 14 daysdrying 45 °C for 12 hrtest height-to-diameter ratio 1.8 to 2.2 per ASTM C 39-04a, 5 mm/min, 5 samples per case | Printed as approximately 120 kPa for two sample codes (SPSMULSS and SPGG00LSS); this row is the SPGG00LSS sample. |
| 9 | Lunar simulant, bacteria with 1% guar gum (w/w), maximum | Compression test per the preprint Methods (Sec. II.D) | simulant ISRO lunar soil simulant (LSS)additives 1% guar gum (w/w)guar gum levels tested 0, 0.5 and 1% w/worganism Sporosarcina pasteurii ATCC 11859incubation 14 daysdrying 45 °C for 12 hrtest height-to-diameter ratio 1.8 to 2.2 per ASTM C 39-04a, 5 mm/min, 5 samples per case | Printed as a maximum of 1.1 MPa. The page reports a ~760% increase but does not state the baseline. |
| 10 | Thermogravimetric mass loss, 500 to 700 °C, lunar simulant with 1% guar gum and 10 mM NiCl2 | Thermogravimetric analysis; the page reports the decomposition loss as ~5% in the 500 to 700 °C region | temperature range 500 to 700 °Cheating about 10 mg sample from 0 to 1000 °C at 10 °C/minproduct LSS-SP-GG-Nadditives 1% guar gum and 10 mM NiCl2 | Printed as ~5%. The page gives no mass-loss values for the 50 to 250 °C or 300 to 500 °C regions. |
| 11 | Thermogravimetric mass loss, 500 to 700 °C, lunar simulant with 10 mM NiCl2 (no guar gum) | Thermogravimetric analysis; the page reports the decomposition loss as ~3.2% in the 500 to 700 °C region | temperature range 500 to 700 °Cheating about 10 mg sample from 0 to 1000 °C at 10 °C/minproduct LSS-SP-Nadditives 10 mM NiCl2 (no guar gum) | Printed as ~3.2%. |
| 12 | Thermogravimetric mass loss, 500 to 700 °C, Martian simulant with 1% guar gum and 10 mM NiCl2 | Thermogravimetric analysis; the page reports the decomposition loss as ~4.2% in the 500 to 700 °C region | temperature range 500 to 700 °Cheating about 10 mg sample from 0 to 1000 °C at 10 °C/minproduct MSS-SP-GG-Nadditives 1% guar gum and 10 mM NiCl2 | Printed as ~4.2%. |
| 13 | Thermogravimetric mass loss, 500 to 700 °C, Martian simulant with 10 mM NiCl2 (no guar gum) | Thermogravimetric analysis; the page reports the decomposition loss as ~3% in the 500 to 700 °C region | temperature range 500 to 700 °Cheating about 10 mg sample from 0 to 1000 °C at 10 °C/minproduct MSS-SP-Nadditives 10 mM NiCl2 (no guar gum) | Printed as ~3%. |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
The binder is calcium carbonate, which PubChem reports as not classified for GHS hazards. ATCC prints the biosafety level of the bacterium inconsistently, so confirm it before culturing.
- Calcium carbonate
- PubChem's ECHA-derived entries report that the substance is not classified for GHS hazards: 3180 of 3535 companies in one entry, and 100% (12 of 12) of reports in the other.
- The microbe
- ATCC lists Sporosarcina pasteurii ATCC 11859 as BSL 1 but also says the product is available only to customers who purchased a biosafety level 3 product. Confirm the level with ATCC before culturing.
- Nickel chloride
- PubChem's GHS record for dichloronickel (CID 24385) gives the signal word Danger, with H301 toxic if swallowed and H350i may cause cancer by inhalation, among other statements. The study used 10 mM NiCl2 (PLoS ONE).
- Dust
- No dust or inhalation data were found in the sources read.
Brick strength
Bacteria alone make weak bricks in these tests.
- Bacteria only
- The lunar bacteria-only brick reached 0.75 MPa, and the Martian bacteria-only brick was too weak for uniaxial testing (PLoS ONE, Sec. 3.2 and 3.3).
Handling and storage
- Simulant
- Both simulants were autoclaved at 121 °C and 15 psi for 30 min before use, according to the PLoS ONE Methods.
- Curing
- The two papers dry their bricks differently, at 50 °C for 24 h and at 45 °C for 12 hr. Treat the two procedures as separate.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Bacteria-only brick too weak to test in uniaxial compressionmoderate severity | Martian simulant cemented by bacteria alone, with no guar gum and no NiCl2The authors could not test this brick in uniaxial compression, so no strength value exists for it; the lunar bacteria-only brick reached only 0.75 MPa. |
Side effects on surrounding parts
| Affects | Effect |
|---|---|
| Process liquid, not characterised for disposal in either source | Ammonium ion concentration in the culture was about 1.7 times higher with NiCl2 supplementation. |
Handling and storage
- Both simulants were autoclaved at 121 °C and 15 psi for 30 min before use.
- The preprint dried its bricks at 45 °C for 12 hr in a hot-air oven after 14 days of incubation. The PLoS ONE study cured for 5 days at 32 °C and dried at 50 °C for 24 h, so the two procedures differ.
Supply and geography
How common the raw materials are and where they come from.
Calcium carbonate (limestone and dolomite, the binder)
USGS: an estimated 1.5 billion tons of crushed stone was produced in the United States in 2025, about 70% of it limestone and dolomite. USGS gives no world total and no country shares.
Nickel (source of the NiCl2 additive)
USGS: globally, nickel resources have been estimated to contain more than 350 million tons of nickel.
- Top producers (2025)
- Indonesia 66.7%, Philippines 6.9%, Russia 5.1%, Canada 3.6%, New Caledonia 3.6%
- Recycling
- USGS: most secondary nickel was in the form of nickel content of stainless-steel scrap, and most recycled nickel was used to produce new alloys.
- Substitutes
- USGS: Low-nickel, duplex, or ultrahigh-chromium stainless steels have been substituted for austenitic grades.
Lunar regolith (feedstock for the lunar simulant bricks)
Wikipedia, Lunar soil (Chemical constituents): 98-99% of the composition of lunar rocks and soil consists of seven elements.
Documents
Datasheets, safety data sheets, papers and standards you can open.
Full record
The complete spore, as stored. Free to reuse under CC-BY-4.0. Images keep the licence shown with each one.
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spore: profile
id: regolith-biocement
spore_version: 0.2
family: bio-cement
name: Bio-cemented regolith (microbially induced calcite precipitation)
abbreviation: MICP
role: Building brick made by growing calcite cement with Sporosarcina pasteurii in lunar or Martian regolith simulant
category: living
type: bio-grown-building-materials
summary: |
Bio-cemented regolith is lunar or Martian regolith simulant bound with calcium carbonate that the bacterium Sporosarcina pasteurii precipitates. In a 2022 PLoS ONE study, a lunar simulant brick with 1% guar gum and 10 mM NiCl2 reached 5.65 MPa, and a Martian simulant brick with the same additives reached 3.3 MPa. A lunar simulant brick with bacteria alone reached 0.75 MPa. All values are laboratory results on small cast bricks, and the study reports no density or porosity.
best_for: Laboratory casting of regolith bricks where a microbe grows the binder in place (in-situ resource concept, lab evidence only)
weakest_at: 'Strength without additives: the lunar bacteria-only brick reached 0.75 MPa, and no density, porosity, durability or space-environment data were reported'
identity:
formula: Calcium carbonate cement (calcite, with vaterite and aragonite) bonding lunar or Martian regolith simulant grains
source: dikshit2022
where: Abstract; Sec. 3.2 and 3.3 (XRD phases identified in the brick products)
tags:
environments: []
stresses: []
applications:
- structures
- habitats-and-suits
- in-space-manufacturing
properties:
- benchmark: compressive_strength
label: Lunar simulant, bacteria with 1% guar gum and 10 mM NiCl2
value: 5.65
unit: MPa
scope: material
conditions:
simulant: lunar simulant LSS (ISRO)
additives: 1% guar gum and 10 mM NiCl2
organism: Sporosarcina pasteurii ATCC 11859
curing: 5 days at 32 °C, then drying at 50 °C for 24 h
brick_mass: 50 g soil per brick
specimen: 25 ± 2 mm cubes
loading: 1 mm/min in an Instron 5697 with a 5 kN load cell
method: Uniaxial compression test; the paper reports the mean for each treatment, with at least 3 specimens per treatment
status: ground
source: dikshit2022
where: Abstract; Sec. 3.3 (Figs 5A and 7A)
- benchmark: compressive_strength
label: Martian simulant, bacteria with 1% guar gum and 10 mM NiCl2
value: 3.3
unit: MPa
scope: material
conditions:
simulant: Martian simulant MSS (Class Exolith Lab, Florida)
additives: 1% guar gum and 10 mM NiCl2
organism: Sporosarcina pasteurii ATCC 11859
curing: 5 days at 32 °C, then drying at 50 °C for 24 h
end_caps: 2 mm rubber sheets used for this treatment and for MSS with NiCl2 alone
method: Uniaxial compression test; the paper reports the mean for each treatment
status: ground
source: dikshit2022
where: Abstract; Sec. 3.2
- benchmark: compressive_strength
label: Lunar simulant, bacteria only (no additives)
value: 0.75
unit: MPa
scope: material
conditions:
simulant: lunar simulant LSS (ISRO)
additives: none
organism: Sporosarcina pasteurii ATCC 11859
curing: 5 days at 32 °C, then drying at 50 °C for 24 h
method: Uniaxial compression test; the paper reports the mean for each treatment
status: ground
source: dikshit2022
where: Abstract; Sec. 3.3
- benchmark: compressive_strength
label: Lunar simulant, bacteria with 1% guar gum
value: 3.41
unit: MPa
scope: material
conditions:
simulant: lunar simulant LSS (ISRO)
additives: 1% guar gum (no NiCl2)
organism: Sporosarcina pasteurii ATCC 11859
curing: 5 days at 32 °C, then drying at 50 °C for 24 h
method: Uniaxial compression test; the paper reports the mean for each treatment
status: ground
source: dikshit2022
where: Sec. 3.3
- benchmark: compressive_strength
label: Martian simulant, bacteria with 10 mM NiCl2 (no guar gum)
value: 2.67
unit: MPa
scope: material
conditions:
simulant: Martian simulant MSS (Class Exolith Lab, Florida)
additives: 10 mM NiCl2 (no guar gum)
organism: Sporosarcina pasteurii ATCC 11859
end_caps: 2 mm rubber sheets used for this treatment
method: Uniaxial compression test; the paper reports the mean for each treatment
status: ground
note: Printed as ~2.67 MPa in the text.
source: dikshit2022
where: Sec. 3.2
- benchmark: compressive_strength
label: Martian simulant, bacteria with 1% guar gum (no NiCl2)
value: 1.1
unit: MPa
scope: material
conditions:
simulant: Martian simulant MSS (Class Exolith Lab, Florida)
additives: 1% guar gum (no NiCl2)
organism: Sporosarcina pasteurii ATCC 11859
curing: 5 days at 32 °C, then drying at 50 °C for 24 h
method: Uniaxial compression test; the paper reports the mean for each treatment
status: ground
note: Printed as ~1.1 MPa in the text.
source: dikshit2022
where: Sec. 3.2
- benchmark: compressive_strength
label: Lunar simulant, urease only (no bacteria)
value: 40
unit: kPa
scope: material
conditions:
simulant: ISRO lunar soil simulant (LSS)
binder: jack bean urease at 1 mg/g LSS, no bacteria (sample URGG00LSS)
incubation: 14 days
drying: 45 °C for 12 hr
test: height-to-diameter ratio 1.8 to 2.2 per ASTM C 39-04a, 5 mm/min, 5 samples per case
method: Compression test per the preprint Methods (Sec. II.D); the page does not state the baseline for its percentage increases
status: ground
note: Printed as about 40 kPa.
source: kumar2020
where: Sec. III.A
- benchmark: compressive_strength
label: Lunar simulant, bacteria with no guar gum
value: 120
unit: kPa
scope: material
conditions:
simulant: ISRO lunar soil simulant (LSS)
additives: none (0% guar gum, sample SPGG00LSS)
organism: Sporosarcina pasteurii ATCC 11859
incubation: 14 days
drying: 45 °C for 12 hr
test: height-to-diameter ratio 1.8 to 2.2 per ASTM C 39-04a, 5 mm/min, 5 samples per case
method: Compression test per the preprint Methods (Sec. II.D)
status: ground
note: Printed as approximately 120 kPa for two sample codes (SPSMULSS and SPGG00LSS); this row is the SPGG00LSS sample.
source: kumar2020
where: Sec. III.A
- benchmark: compressive_strength
label: Lunar simulant, bacteria with 1% guar gum (w/w), maximum
value: 1.1
unit: MPa
scope: material
conditions:
simulant: ISRO lunar soil simulant (LSS)
additives: 1% guar gum (w/w)
guar_gum_levels_tested: 0, 0.5 and 1% w/w
organism: Sporosarcina pasteurii ATCC 11859
incubation: 14 days
drying: 45 °C for 12 hr
test: height-to-diameter ratio 1.8 to 2.2 per ASTM C 39-04a, 5 mm/min, 5 samples per case
method: Compression test per the preprint Methods (Sec. II.D)
status: ground
note: Printed as a maximum of 1.1 MPa. The page reports a ~760% increase but does not state the baseline.
source: kumar2020
where: Sec. III.A
- benchmark: tg_mass_loss
label: Thermogravimetric mass loss, 500 to 700 °C, lunar simulant with 1% guar gum and 10 mM NiCl2
value: 5
unit: '%'
scope: material
conditions:
temperature_range: 500 to 700 °C
heating: about 10 mg sample from 0 to 1000 °C at 10 °C/min
product: LSS-SP-GG-N
additives: 1% guar gum and 10 mM NiCl2
method: Thermogravimetric analysis; the page reports the decomposition loss as ~5% in the 500 to 700 °C region
status: ground
note: Printed as ~5%. The page gives no mass-loss values for the 50 to 250 °C or 300 to 500 °C regions.
source: dikshit2022
where: Sec. 3.4; Figs 6 and 8
- benchmark: tg_mass_loss
label: Thermogravimetric mass loss, 500 to 700 °C, lunar simulant with 10 mM NiCl2 (no guar gum)
value: 3.2
unit: '%'
scope: material
conditions:
temperature_range: 500 to 700 °C
heating: about 10 mg sample from 0 to 1000 °C at 10 °C/min
product: LSS-SP-N
additives: 10 mM NiCl2 (no guar gum)
method: Thermogravimetric analysis; the page reports the decomposition loss as ~3.2% in the 500 to 700 °C region
status: ground
note: Printed as ~3.2%.
source: dikshit2022
where: Sec. 3.4; Figs 6 and 8
- benchmark: tg_mass_loss
label: Thermogravimetric mass loss, 500 to 700 °C, Martian simulant with 1% guar gum and 10 mM NiCl2
value: 4.2
unit: '%'
scope: material
conditions:
temperature_range: 500 to 700 °C
heating: about 10 mg sample from 0 to 1000 °C at 10 °C/min
product: MSS-SP-GG-N
additives: 1% guar gum and 10 mM NiCl2
method: Thermogravimetric analysis; the page reports the decomposition loss as ~4.2% in the 500 to 700 °C region
status: ground
note: Printed as ~4.2%.
source: dikshit2022
where: Sec. 3.4; Figs 6 and 8
- benchmark: tg_mass_loss
label: Thermogravimetric mass loss, 500 to 700 °C, Martian simulant with 10 mM NiCl2 (no guar gum)
value: 3
unit: '%'
scope: material
conditions:
temperature_range: 500 to 700 °C
heating: about 10 mg sample from 0 to 1000 °C at 10 °C/min
product: MSS-SP-N
additives: 10 mM NiCl2 (no guar gum)
method: Thermogravimetric analysis; the page reports the decomposition loss as ~3% in the 500 to 700 °C region
status: ground
note: Printed as ~3%.
source: dikshit2022
where: Sec. 3.4; Figs 6 and 8
corrosion: []
risks:
hazards:
- text: PubChem reports calcium carbonate as not classified for GHS hazards. One ECHA-derived entry says 'Reported as not meeting GHS hazard criteria by 3180 of 3535 companies.' The other says 'This chemical does not meet GHS hazard criteria for 100% (12 of 12) of all reports.'
ghs: []
source: pubchem-caco3
where: GHS Classification (CID 10112), read through the PubChem REST view; entries EC 207-439-9 and EC 615-782-4
- text: ATCC lists Sporosarcina pasteurii ATCC 11859 as 'BSL 1', but the same page says the product is available only to customers who purchased 'this biosafety level 3 product'. The page does not resolve this, so confirm the level with ATCC before culturing.
ghs: []
source: atcc-11859
where: Product page, biosafety level line and product sheet text
- text: PubChem's GHS record for dichloronickel (nickel(II) chloride, CID 24385) gives the signal word Danger, with H301 toxic if swallowed, H331 toxic if inhaled, H350i may cause cancer by inhalation and H360D may damage the unborn child, among other statements. Only the first 4,000 characters of the record were read, so later statements are not transcribed.
ghs:
- H301
- H315
- H317
- H331
- H334
- H341
- H350i
- H360D
- H372
- H400
- H410
source: pubchem-nicl2
where: GHS Classification section of the PubChem record (REST view, record 24385); codes as transcribed from the first part of the record
failure_risks:
- mode: Bacteria-only brick too weak to test in uniaxial compression
trigger: Martian simulant cemented by bacteria alone, with no guar gum and no NiCl2
consequence: The authors could not test this brick in uniaxial compression, so no strength value exists for it; the lunar bacteria-only brick reached only 0.75 MPa.
severity: moderate
source: dikshit2022
where: Sec. 3.2 and Sec. 3.3
side_effects:
- text: Ammonium ion concentration in the culture was about 1.7 times higher with NiCl2 supplementation.
affects: Process liquid, not characterised for disposal in either source
source: dikshit2022
where: Sec. 3.5, Figs 9 and 10
handling:
- text: Both simulants were autoclaved at 121 °C and 15 psi for 30 min before use.
source: dikshit2022
where: Methods, simulant preparation
- text: The preprint dried its bricks at 45 °C for 12 hr in a hot-air oven after 14 days of incubation. The PLoS ONE study cured for 5 days at 32 °C and dried at 50 °C for 24 h, so the two procedures differ.
source: kumar2020
where: Sec. II.C
mitigations: []
uses:
- application: structures
device: Regolith brick for habitat walls (laboratory concept)
example: The authors state that habitats 'need to be built from available in situ resources on moon/Mars' and cast brick-like structures from regolith simulants by microbial calcite precipitation.
source: dikshit2022
where: Introduction (Sec. 1)
- application: in-space-manufacturing
device: Microgravity cartridge experiment (proposal only)
example: The Space-Brick preprint proposes a microgravity payload with four cartridges per cassette (three experiments and one control). It reports no experimental results.
source: kumar2020
where: Sec. III.C (microgravity)
supply:
- subject: Calcium carbonate (limestone and dolomite, the binder)
abundance: 'USGS: an estimated 1.5 billion tons of crushed stone was produced in the United States in 2025, about 70% of it limestone and dolomite. USGS gives no world total and no country shares.'
producers: []
critical_lists: []
substitutes: []
source: usgs-mcs2026-stone
where: Domestic Production and Use paragraph (2025 output and limestone and dolomite share); World Mine Production and Reserves table (world total not reported); World Resources paragraph ('Stone resources are plentiful throughout the world').
- subject: Nickel (source of the NiCl2 additive)
abundance: 'USGS: globally, nickel resources have been estimated to contain more than 350 million tons of nickel.'
producers:
- country: Indonesia
share_percent: 66.7
year: 2025
- country: Philippines
share_percent: 6.9
year: 2025
- country: Russia
share_percent: 5.1
year: 2025
- country: Canada
share_percent: 3.6
year: 2025
- country: New Caledonia
share_percent: 3.6
year: 2025
critical_lists: []
recycling: 'USGS: most secondary nickel was in the form of nickel content of stainless-steel scrap, and most recycled nickel was used to produce new alloys.'
substitutes:
- 'USGS: Low-nickel, duplex, or ultrahigh-chromium stainless steels have been substituted for austenitic grades.'
source: usgs-mcs2026-nickel
where: World Mine Production and Reserves table, 2025e column (world total 3,900,000 rounded, nickel content). Shares are calculated by Space Mushroom against that world total; USGS prints no shares. Recycling and Substitutes sections. The Executive Order 14285 passage names 'critical minerals such as nickel'; the chapter gives no separate list status.
- subject: Lunar regolith (feedstock for the lunar simulant bricks)
abundance: 'Wikipedia, Lunar soil (Chemical constituents): 98-99% of the composition of lunar rocks and soil consists of seven elements.'
producers: []
critical_lists: []
substitutes: []
source: wiki-lunar-soil
where: Chemical constituents section. The page gives no production or supply data. Simulant suppliers (the ISRO LSS and the Martian simulant) were not found in any source we hold.
media: []
documents:
- title: Microbial induced calcite precipitation can consolidate martian and lunar regolith simulants (PLoS ONE, 2022)
type: paper
url: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0266415
year: 2022
- title: Bacterial Growth Induced Biocementation Technology, Space-Brick (bioRxiv preprint, 2020)
type: paper
url: https://www.biorxiv.org/content/10.1101/2020.01.22.914853v2.full-text
year: 2020
- title: 'PubChem: Calcium carbonate (CID 10112), GHS classification'
type: database
url: https://pubchem.ncbi.nlm.nih.gov/compound/Calcium-carbonate
year: 2026
- title: Mineral Commodity Summaries 2026, Stone (Crushed)
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-stone-crushed.pdf
year: 2026
- title: Mineral Commodity Summaries 2026, Nickel
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
year: 2026
- title: 'PubChem: Dichloronickel (CID 24385), GHS classification'
type: database
url: https://pubchem.ncbi.nlm.nih.gov/compound/24385
year: 2026
gaps:
- No density, porosity or calcite-content value is reported. The PLoS ONE page gives none, and the preprint states that density and porosity were not reported.
- No durability, weathering, water-erosion or ageing data were found. A second search for MICP durability could not be run because the web search budget ran out during this task.
- No vacuum, radiation, thermal or flight result was found. The Space-Brick payload is a proposal with no results.
- 'Supply: the USGS stone summary gives no world total and no country shares for calcium carbonate, so no producer shares are listed for it. Simulant suppliers were not found: the Exolith Lab simulant page did not resolve (DNS error), so the Martian simulant supplier is named only as the PLoS ONE paper prints it.'
- The Wikipedia page for microbially induced calcite precipitation returned HTTP 404 and was not used.
- 'The two papers use different curing and drying conditions (PLoS ONE: 5 days at 32 °C, then 50 °C; preprint: 14 days, then 45 °C), so their values are not directly comparable.'
- The preprint abstract describes an approximate 10-fold increase from guar gum, but its own Sec. III.A figure of ~760% implies about 8.6-fold; the baseline is not stated.
- The PLoS ONE text says 10 mM NiCl2 roughly doubled strength compared with 1% guar gum alone, but its printed values (2.67 MPa vs ~1.1 MPa) give a ratio of about 2.4.
- Both sources come from one research group (Dikshit, Gupta, Dey, Viswanathan, Kumar and co-authors), so the results are not independent replications.
- 'Biosafety level conflict: ATCC prints BSL 1 and also refers to a biosafety level 3 product. Not resolved.'
- 'Literature values cited in the PLoS ONE introduction but not measured in this study: sintered JSC-1 lunar simulant at 103.2 to 232 MPa (ref. 23) and 3D-printed regolith at about 5 MPa (ref. 27). Context only.'
- compressive_strength and tg_mass_loss are not in spores/property-canon.yaml and are used as snake_case names.
- 'No corrosion or ageing data: none of the sources read gives durability, weathering or ageing results for these bricks (see the durability gap above). The corrosion section is therefore empty, and risks.failure_risks carries the failure mode instead.'
sources:
dikshit2022:
title: Microbial induced calcite precipitation can consolidate martian and lunar regolith simulants
id: 'doi:10.1371/journal.pone.0266415 (PLoS ONE 17(4): e0266415)'
url: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0266415
year: 2022
kind: paper
kumar2020:
title: Bacterial Growth Induced Biocementation Technology, 'Space-Brick' - A Proposal for Experiment at Microgravity and Planetary Environments
id: bioRxiv doi:10.1101/2020.01.22.914853 (version v2 as fetched)
url: https://www.biorxiv.org/content/10.1101/2020.01.22.914853v2.full-text
year: 2020
kind: paper
pubchem-caco3:
title: PubChem compound record, Calcium carbonate (CID 10112), GHS classification
id: CID 10112
url: https://pubchem.ncbi.nlm.nih.gov/compound/Calcium-carbonate
kind: database
atcc-11859:
title: Sporosarcina pasteurii (Miquel) Yoon et al., ATCC 11859, product page
id: ATCC 11859
url: https://www.atcc.org/products/11859
kind: datasheet
wiki-lunar-soil:
title: Lunar soil, Wikipedia (chemical constituents section)
id: en.wikipedia.org/wiki/Lunar_soil
url: https://en.wikipedia.org/wiki/Lunar_soil
kind: web
usgs-mcs2026-stone:
title: Mineral Commodity Summaries 2026, Stone (Crushed)
id: USGS MCS 2026, February 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-stone-crushed.pdf
year: 2026
kind: report
usgs-mcs2026-nickel:
title: Mineral Commodity Summaries 2026, Nickel
id: USGS MCS 2026, February 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
year: 2026
kind: report
pubchem-nicl2:
title: PubChem compound record, Dichloronickel (nickel(II) chloride), CID 24385, GHS classification
id: CID 24385
url: https://pubchem.ncbi.nlm.nih.gov/compound/24385
kind: database
license: CC-BY-4.0
updated: '2026-11-02'
review:
status: draft
method: assistant
checked_values: 13
unreachable: 2
caveats: 3
note: 'Read by an AI assistant on 2026-11-01 from the pages named in each entry. 13 values read from the PLoS ONE and bioRxiv pages (9 compressive strength, 4 thermogravimetric mass loss). Unreachable: Exolith Lab simulant page (DNS error) and the Wikipedia MICP page (HTTP 404). PubChem''s HTML page showed a CAPTCHA, so the GHS data were read from its REST view.'
story:
recipe:
line: Bio-cemented regolith is made by mixing regolith simulant with a bacterial culture, urea-based medium and additives. The bacteria then precipitate calcium carbonate that binds the grains. XRD identified calcite, vaterite and aragonite in the products.
parts:
- name: Lunar regolith simulant (LSS, ISRO)
share: 50 g soil per brick in the PLoS ONE study
role: The matrix; the grains that the calcium carbonate binds together.
- name: Calcium carbonate (calcite, vaterite, aragonite)
role: The cement formed by the bacteria. XRD identified these three forms in the products.
- name: Sporosarcina pasteurii (ATCC 11859)
role: The bacterium that drives the precipitation.
- name: Guar gum
share: 1% w/v in the PLoS ONE study; 0.5% and 1% w/w in the preprint
role: Additive. 1% guar gum with 10 mM NiCl2 gave the highest lunar strength (5.65 MPa).
- name: Nickel chloride (NiCl2)
share: 10 mM
role: Additive. 10 mM NiCl2 alone gave about 2.67 MPa in the Martian simulant.
risk_groups:
- title: For people
level: 0
verdict: Calcium carbonate is not classified for GHS hazards; the…
lead: The binder is calcium carbonate, which PubChem reports as not classified for GHS hazards. ATCC prints the biosafety level of the bacterium inconsistently, so confirm it before culturing.
points:
- label: Calcium carbonate
line: 'PubChem''s ECHA-derived entries report that the substance is not classified for GHS hazards: 3180 of 3535 companies in one entry, and 100% (12 of 12) of reports in the other.'
- label: The microbe
line: ATCC lists Sporosarcina pasteurii ATCC 11859 as BSL 1 but also says the product is available only to customers who purchased a biosafety level 3 product. Confirm the level with ATCC before culturing.
- label: Nickel chloride
line: PubChem's GHS record for dichloronickel (CID 24385) gives the signal word Danger, with H301 toxic if swallowed and H350i may cause cancer by inhalation, among other statements. The study used 10 mM NiCl2 (PLoS ONE).
- label: Dust
line: No dust or inhalation data were found in the sources read.
- title: Brick strength
lead: Bacteria alone make weak bricks in these tests.
points:
- label: Bacteria only
line: The lunar bacteria-only brick reached 0.75 MPa, and the Martian bacteria-only brick was too weak for uniaxial testing (PLoS ONE, Sec. 3.2 and 3.3).
- title: Handling and storage
points:
- label: Simulant
line: Both simulants were autoclaved at 121 °C and 15 psi for 30 min before use, according to the PLoS ONE Methods.
- label: Curing
line: The two papers dry their bricks differently, at 50 °C for 24 h and at 45 °C for 12 hr. Treat the two procedures as separate.
why: Bio-cemented regolith is a brick made from lunar or Martian regolith simulant, bound by calcium carbonate that a bacterium grows in place. The PLoS ONE authors frame local resource use as the goal for habitats on the Moon and Mars. The 2022 study reports compressive strengths of 0.75 MPa to 5.65 MPa for laboratory bricks made from simulant. No density or porosity is reported, so the bricks cannot yet be compared with conventional building materials by mass or pore structure.
uses:
- where: Habitat bricks from in-situ resources (lab concept)
line: The authors state that habitats 'need to be built from available in situ resources on moon/Mars' and cast brick-like structures from regolith simulants by microbial calcite precipitation.
- where: Microgravity experiment (proposal only)
line: The Space-Brick preprint describes a payload of four cartridges per cassette (three experiments and one control) for microgravity testing. It reports no experimental results.
can_do:
- label: Lunar brick strength
benchmark: compressive_strength
value: 5.65 MPa
line: A lunar simulant brick with 1% guar gum and 10 mM NiCl2 reached 5.65 MPa in uniaxial compression (PLoS ONE, Sec. 3.3). The same study's bacteria-only lunar brick reached 0.75 MPa.
- label: Martian brick strength
benchmark: compressive_strength
value: 3.3 MPa
line: A Martian simulant brick with the same additives reached 3.3 MPa (PLoS ONE, Sec. 3.2). The bacteria-only Martian brick was too weak to test, so the additives made that brick testable.
- label: Range in the preprint
benchmark: compressive_strength
value: 40 kPa to 1.1 MPa
line: The bioRxiv preprint reports lunar simulant bricks from about 40 kPa (urease only) to a maximum of 1.1 MPa (1% guar gum, w/w).
- label: Mass loss on heating
benchmark: tg_mass_loss
value: about 5%
line: Thermogravimetric mass loss between 500 and 700 °C was about 5% for the lunar brick with guar gum and NiCl2 (PLoS ONE, Sec. 3.4).
compare: In the PLoS ONE study, laboratory bricks reach about 0.75 MPa to 5.65 MPa, and the bioRxiv preprint reports about 40 kPa to 1.1 MPa for its own mixes. The PLoS ONE introduction cites sintered JSC-1 lunar simulant at 103.2 to 232 MPa and 3D-printed regolith at about 5 MPa. Those are cited values from other work, so they give context and do not compare results. The two papers come from one research group and use different curing, so their values do not rank the routes.
compare_rows:
- label: Lunar brick, 1% guar gum and 10 mM NiCl2
benchmark: compressive_strength
- label: Lunar brick, bacteria only
benchmark: compressive_strength
- label: Mass loss, 500 to 700 °C, lunar brick with guar gum and NiCl2
benchmark: tg_mass_loss
handling:
- Autoclave simulant at 121 °C and 15 psi for 30 min before use (PLoS ONE Methods).
- Use the curing and drying steps of the paper you follow. PLoS ONE dried at 50 °C for 24 h and the preprint at 45 °C for 12 hr.
- Confirm the biosafety level with ATCC before culturing Sporosarcina pasteurii.
good_for:
- Laboratory evidence that a bacterium can bind lunar and Martian simulant into a brick (PLoS ONE, 2022).
- Strength gain from additives. In the same study, 1% guar gum with 10 mM NiCl2 raised the lunar brick from 0.75 MPa to 5.65 MPa.
watch_out:
- No density, porosity or durability data in the two sources, and no flight or vacuum test.
- One research group and lab-scale cubes of 25 ± 2 mm. The two papers cure differently, so their values are not directly comparable.
- The bacteria-only Martian brick was too weak for uniaxial testing, so the choice of simulant and additives matters.
verdict: Bio-cemented regolith is a promising in-situ resource concept, with laboratory evidence of 5.65 MPa in lunar simulant. The sources read contain no density, porosity, durability or space-environment data, so treat it as lab-only.
References
Every number above carries a reference number. Click one to see the source and where in it the value comes from.
| # | Source | Type | Year | Used for |
|---|---|---|---|---|
| Microbial induced calcite precipitation can consolidate martian and lunar regolith simulants | paper | 2022 | 15 values | |
| Bacterial Growth Induced Biocementation Technology, 'Space-Brick' - A Proposal for Experiment at Microgravity and Planetary Environments | paper | 2020 | 5 values | |
| PubChem compound record, Calcium carbonate (CID 10112), GHS classification | database | 1 value | ||
| Sporosarcina pasteurii (Miquel) Yoon et al., ATCC 11859, product page | datasheet | 1 value | ||
| Lunar soil, Wikipedia (chemical constituents section) | web | 1 value | ||
| Mineral Commodity Summaries 2026, Stone (Crushed) | report | 2026 | 1 value | |
| Mineral Commodity Summaries 2026, Nickel | report | 2026 | 1 value | |
| PubChem compound record, Dichloronickel (nickel(II) chloride), CID 24385, GHS classification | database | 1 value |
Updated