howclose.to
CLOSED LOOP LIFE SUPPORT

The problemsEarth & SpaceClosed-Loop Life Support

Updated · July 2026

How close are we to closed-loop life support?Can a space habitat recycle everything?

Can a space habitat recycle everything?How close are we to closed-loop life support?

Water recycling is near exploration grade in orbit, but oxygen, food, waste and maintenance have never been closed together beyond Earth.The space station recycles almost all its water, but a self-sustaining habitat still has to close air, food and waste loops at the same time.

Current stageEngineeringEngineering a system that works outside the labBuilding a system that works outside the lab
Read the evidence Where we stand
The path so far

Recorded milestones

  1. Plant loop proposed

  2. Separate loops, not autonomy

Open tests · conceptual branches

TODAY
  1. OPEN TEST02 ↗
    Recover three quarters of the oxygenSeventy-five-percent oxygen recoveryISS Sabatier hardware averages about 47%; NASA's SCOR threshold is above 75%.Recover more than 75% of metabolic oxygen from crew carbon dioxide in flight.
  2. OPEN TEST03 ↗
    Grow most of the foodThree-quarter food regenerationA 105-day Lunar Palace test regenerated 55% of food; later high-closure results still used a defined ground-test boundary.Regenerate at least 75% of a nutritionally complete crew diet inside a year-long controlled habitat.
  3. OPEN TEST04 ↗
    Run the whole loop in spaceIntegrated off-Earth closureNo crewed flight habitat has integrated all four loops; the broadest closure demonstrations remain on Earth.Operate water, oxygen, waste-nutrient and staple-food loops together beyond low Earth orbit for at least one year.
TODAY
OPEN TEST02 ↗
Recover three quarters of the oxygenSeventy-five-percent oxygen recoveryISS Sabatier hardware averages about 47%; NASA's SCOR threshold is above 75%.Recover more than 75% of metabolic oxygen from crew carbon dioxide in flight.
OPEN TEST03 ↗
Grow most of the foodThree-quarter food regenerationA 105-day Lunar Palace test regenerated 55% of food; later high-closure results still used a defined ground-test boundary.Regenerate at least 75% of a nutritionally complete crew diet inside a year-long controlled habitat.
OPEN TEST04 ↗
Run the whole loop in spaceIntegrated off-Earth closureNo crewed flight habitat has integrated all four loops; the broadest closure demonstrations remain on Earth.Operate water, oxygen, waste-nutrient and staple-food loops together beyond low Earth orbit for at least one year.
Milestones are in recorded order. Open tests are separate questions, not a forecast.Milestones are in date order. Open tests are separate tests, not a promise.
Closed-Loop Life SupportWhere we stand

The path shows Separate loops, not autonomy. Open thresholds are separate tests in a conceptual map, not a forecast. No single percentage represents progress.

01 · Where we standWhere we stand

Where we standWhere we stand

The current stage, the evidence recorded, and the single threshold that gates the next stage.The stage reached, the evidence recorded, and the one test still blocking the next step.

What the evidence has shownWhat the evidence has shown

The space station recycles almost all its water, but a self-sustaining habitat still has to close air, food and waste loops at the same time.Water recycling is near exploration grade in orbit, but oxygen, food, waste and maintenance have never been closed together beyond Earth.

1 of 4 tests recorded1 of 4 thresholds achieved open
✓Recycle nearly all the waterExploration-grade water recoveryAchieved
Recover three quarters of the oxygenSeventy-five-percent oxygen recoveryOpen test
Grow most of the foodThree-quarter food regenerationOpen test
Run the whole loop in spaceIntegrated off-Earth closureOpen test

The next testBlocking threshold

Recover three quarters of the oxygenSeventy-five-percent oxygen recovery

An integrated flight demonstration must sustain oxygen recovery above 75% while managing methane and carbon deposits.An integrated flight demonstration must sustain oxygen recovery above 75% while managing methane and carbon deposits.

02 · Thresholds & evidenceThresholds & evidence

What would count as proof?What would count as proof?

A clear test, the evidence behind it, and the limits of the claim.A clear test, the evidence behind it, and what it still leaves open.

✓Achieved · Jun 2023

Recycle nearly all the waterExploration-grade water recovery

The ISS Brine Processor raised total water recovery from 93-94% to 98%.Recover 98% of crew wastewater in an operating space habitat.

Recorded result NASA demonstrated 98% total water recovery aboard the ISS.

Next test Sustain 98% during long operation beyond low Earth orbit without frequent Earth-supplied parts or consumables.

SOURCE RECORD

NASA ISS 98% water-recovery milestone ↗

Still to demonstrateWhat this does not establishA separate system can still have different conditions and results.The named measurement has no wider implication until the supporting system test is also shown.

View every evidence record

Achieved

Recycle nearly all the waterExploration-grade water recovery

The ISS Brine Processor raised total water recovery from 93-94% to 98%.Recover 98% of crew wastewater in an operating space habitat.

Recorded result: Jun 2023 · NASA demonstrated 98% total water recovery aboard the ISS.

Next test: Sustain 98% during long operation beyond low Earth orbit without frequent Earth-supplied parts or consumables.

NASA ISS 98% water-recovery milestone ↗

Open test

Recover three quarters of the oxygenSeventy-five-percent oxygen recovery

ISS Sabatier hardware averages about 47%; NASA's SCOR threshold is above 75%.Recover more than 75% of metabolic oxygen from crew carbon dioxide in flight.

Next test: An integrated flight demonstration must sustain oxygen recovery above 75% while managing methane and carbon deposits.

Open test

Grow most of the foodThree-quarter food regeneration

A 105-day Lunar Palace test regenerated 55% of food; later high-closure results still used a defined ground-test boundary.Regenerate at least 75% of a nutritionally complete crew diet inside a year-long controlled habitat.

Next test: Repeat for at least one year with 75% or more of a complete diet, stable crop yields and explicit accounting for stored inputs.

Open test

Run the whole loop in spaceIntegrated off-Earth closure

No crewed flight habitat has integrated all four loops; the broadest closure demonstrations remain on Earth.Operate water, oxygen, waste-nutrient and staple-food loops together beyond low Earth orbit for at least one year.

Next test: Demonstrate combined air and water regeneration beyond low Earth orbit; no dated staple-food-loop flight is committed.

03 · The recordThe record

The record behind the verdictThe record behind the verdict

Major milestones and smaller context events share one source-linked record. Scheduled targets are marked separately from recorded events.Milestones, smaller events and setbacks share one sourced record. Scheduled targets are marked separately from recorded events.

Event key
TheoryExperimentFundingSetbackPolicyDeployment Future / scheduled
1911-19711 event1 shown

Miniature Earths imagined

Recorded event: “Plants proposed for spacecraft”.

1911
Plants proposed for spacecraftTheory
Konstantin Tsiolkovsky proposed that carried plants could absorb wastes continuously and return food.
Konstantin Tsiolkovsky
1972-19903 events1 shown

Sealed habitats become experiments

This record spans “BIOS-3 closes human loops” to “MELiSSA idea takes flight”.

1972
BIOS-3 closes human loopsExperiment
Three people occupied the 315 m³ BIOS-3 ground habitat for 180 days with regenerated air and water and some plant-grown food.
Institute of Biophysics, Krasnoyarsk
1979
NASA establishes CELSS
NASA established a programme spanning food production, waste management, atmospheric regeneration, water purification and system control.
NASA
1991-20074 events2 shown

Ecologies reveal hidden instability

This record spans “Biosphere 2 crew enters” to “Integrated test reaches 91 days”.

1991
Biosphere 2 crew entersExperiment
Eight people began a two-year material-closure experiment whose farm supplied about 80% of their nutritional needs.
Biosphere 2
1993
Biosphere oxygen crashesSetback
Oxygen fell from 21% to 14% in 16 months as soil respiration and concrete chemistry defeated ecosystem balance.
Biosphere 2
1995
Lunar-Mars tests begin
NASA began four integrated crew tests with one person, 11.2 m² of wheat and a sealed chamber for 15 days.
NASA Johnson Space Center
2008-20173 events1 shown

Recycling reaches orbit

This record spans “ISS recycles urine” to “Lunar Palace runs 105 days”.

2014
Lunar Palace runs 105 days
Three people completed 105 days with oxygen and water recycled and 55% of food regenerated inside the ground habitat.
Beihang University
2018-20285 events2 shown

Closing separate loops

This record spans “Lunar Palace reaches 370 days” to “Gateway targets first launch” and includes scheduled targets.

2018
Lunar Palace reaches 370 daysExperiment
A ground test reported 100% oxygen and water regeneration and 98.2% defined material closure over 370 days.
Beihang University
2018
European loop reaches ISS
ESA's Advanced Closed Loop System launched to recycle about half of crew carbon dioxide and save about 400 L of launch water yearly.
European Space Agency
2024
ESA selects five circular studiesWe are here
Five studies target biomass reuse, air quality and resource-efficiency gaps in circular space habitats.
European Space Agency
2027
Gateway targets first launchDeploymentTarget
Gateway's PPE-HALO stack is scheduled no earlier than 2027; HALO is a partial habitat, not a self-sustaining loop.
NASA and Gateway partners
2017-20282 events0 shown

Additional records

This record spans “SCOR pursues more oxygen” to “Artemis IV adds life support” and includes scheduled targets.

2017
SCOR pursues more oxygen
NASA introduced SCOR to raise metabolic-oxygen recovery above 75%, with 100% as a stretch goal.
NASA Johnson Space Center
2028
Artemis IV adds life supportDeploymentTarget
Gateway assembly with Artemis IV is scheduled no earlier than September 2028; JAXA is supplying life-support hardware for Lunar I-Hab.
NASA, JAXA and Gateway partners
— end of record · 18 events shown —
04 · The dataThe data

The data behind the verdictThe data behind the verdict

Read each measure with its units, conditions, uncertainty and source; targets remain distinct from observations.Read each chart with its conditions, limits and source. Future targets remain distinct from recorded results.

Open figure in archive: Flight water recovery improved through hardware iteration; the 2022 point is the midpoint of NASA's reported pre-Brine-Processor 93-94% range.Open figure in archive: Duration alone does not equal closure: Biosphere 2 lasted longest but required oxygen intervention, while later tests used narrower engineered boundaries.Open figure in archive: Ground experiments have regenerated substantial food shares, but definitions and system boundaries differ and should not be treated as a trend.Open figure in archive: Beihang reported very high closure under its defined ground-system mass boundary; this is not a measurement of off-Earth autonomy.Open figure in archive: NASA must raise average estimated flight oxygen recovery by at least 28 percentage points to reach its exploration threshold.Open figure in archive: At 98% recovery, two pounds are lost from each hundred pounds of water circulated.Open figure in archive: Lunar Palace 365 reported 100% oxygen and water regeneration on Earth under a system boundary with 98.2% defined material closure.
Metabolic oxygen recovered from exhaled CO2Metabolic oxygen recovered from exhaled CO2
Scale

ISS Sabatier average estimate · 47 % · 2017 · verification unspecified

Metabolic oxygen recovered from exhaled CO2 over time, with measured values, projected values, and a goal at 100 %.5060708090100Flight oxygen recovery targ… · 75Metabolic oxygen recovered from exhaled CO2 · %Year2017GOAL 100 · SCOR stretch goal · target, not a…SCOR exploration threshold · target, not achievedISS Sabatier average estima…~53 % to goal
NOTE - NASA describes 47% as an average estimate for ISS Sabatier hardware. The 75% threshold and 100% stretch goal are programme targets, not flight results; water, food and total-material closure use different boundaries.
View data table
All metric observations
DateValueStatusCondition / labelVerificationCICensoringSource
201747 %observedISS Sabatier average estimateunspecified—noneNASA SpaceCraft Oxygen Recovery
AS OF July 2026
View every data figure
Metabolic oxygen recovered from exhaled CO2Metabolic oxygen recovered from exhaled CO2
Scale

ISS Sabatier average estimate · 47 % · 2017 · verification unspecified

Metabolic oxygen recovered from exhaled CO2 over time, with measured values, projected values, and a goal at 100 %.5060708090100Flight oxygen recovery targ… · 75Metabolic oxygen recovered from exhaled CO2 · %Year2017GOAL 100 · SCOR stretch goal · target, not a…SCOR exploration threshold · target, not achievedISS Sabatier average estima…~53 % to goal
NOTE - NASA describes 47% as an average estimate for ISS Sabatier hardware. The 75% threshold and 100% stretch goal are programme targets, not flight results; water, food and total-material closure use different boundaries.
View data table
All metric observations
DateValueStatusCondition / labelVerificationCICensoringSource
201747 %observedISS Sabatier average estimateunspecified—noneNASA SpaceCraft Oxygen Recovery
AS OF July 2026
Flight water recovery improved through hardware iteration; the 2022 point is the midpoint of NASA's reported pre-Brine-Processor 93-94% range.Flight water recovery improved through hardware iteration; the 2022 point is the midpoint of NASA's reported pre-Brine-Processor 93-94% range.

Independent records

Operational water recovery linear scale · % of wastewater

linear scale · % of wastewater
201575 % of wastewater

Conditioncrew test or system boundary varies by study; see source

Midpoint of NASA's 93-94% range202293.5 % of wastewater

Conditioncrew test or system boundary varies by study; see source

202398 % of wastewater

Conditioncrew test or system boundary varies by study; see source

Reference values · not observed records
  • Water recovery exploration goalWater recovery exploration goal98 % of wastewatertarget
observed self-reported target / pathway right-censored lower bound
View data table
All plotted observations
SeriesDateValueStatusCondition / labelVerificationCICensoringSource
Operational water recovery201575 % of wastewaterobservedOperational water recovery
crew test or system boundary varies by study; see source		unspecified—noneNASA ISS life-support operational lessons
Operational water recovery202293.5 % of wastewaterobservedMidpoint of NASA's 93-94% range
crew test or system boundary varies by study; see source		unspecified—noneNASA ISS 98% water-recovery milestone
Operational water recovery202398 % of wastewaterobservedOperational water recovery
crew test or system boundary varies by study; see source		unspecified—noneNASA ISS 98% water-recovery milestone
AS OF July 2026
Duration alone does not equal closure: Biosphere 2 lasted longest but required oxygen intervention, while later tests used narrower engineered boundaries.Duration alone does not equal closure: Biosphere 2 lasted longest but required oxygen intervention, while later tests used narrower engineered boundaries.

Independent records

Selected integrated crew-test duration linear scale · days

linear scale · days
1972180 days

Conditioncrew test or system boundary varies by study; see source

1993730 days

Conditioncrew test or system boundary varies by study; see source

199891 days

Conditioncrew test or system boundary varies by study; see source

2014105 days

Conditioncrew test or system boundary varies by study; see source

2018370 days

Conditioncrew test or system boundary varies by study; see source

observed self-reported target / pathway right-censored lower bound
View data table
All plotted observations
SeriesDateValueStatusCondition / labelVerificationCICensoringSource
Selected integrated crew-test duration1972180 daysobservedSelected integrated crew-test duration
crew test or system boundary varies by study; see source		unspecified—noneTimeline · BIOS-3 closes human loops
Selected integrated crew-test duration1993730 daysobservedSelected integrated crew-test duration
crew test or system boundary varies by study; see source		unspecified—noneTimeline · Biosphere 2 crew enters
Selected integrated crew-test duration199891 daysobservedSelected integrated crew-test duration
crew test or system boundary varies by study; see source		unspecified—noneNASA Lunar-Mars Life Support Test results
Selected integrated crew-test duration2014105 daysobservedSelected integrated crew-test duration
crew test or system boundary varies by study; see source		unspecified—noneLunar Palace 105 study
Selected integrated crew-test duration2018370 daysobservedSelected integrated crew-test duration
crew test or system boundary varies by study; see source		unspecified—noneLunar Palace 365 results
AS OF July 2026
Ground experiments have regenerated substantial food shares, but definitions and system boundaries differ and should not be treated as a trend.Ground experiments have regenerated substantial food shares, but definitions and system boundaries differ and should not be treated as a trend.

Independent records

Food regenerated inside selected tests linear scale · % of crew food

linear scale · % of crew food
Approximate share of overall nutritional needs199380 % of crew food

Conditioncrew test or system boundary varies by study; see source

201455 % of crew food

Conditioncrew test or system boundary varies by study; see source

Reference values · not observed records
  • Food regeneration dossier thresholdFood regeneration dossier threshold75 % of crew foodtarget
observed self-reported target / pathway right-censored lower bound
View data table
All plotted observations
SeriesDateValueStatusCondition / labelVerificationCICensoringSource
Food regenerated inside selected tests199380 % of crew foodobservedApproximate share of overall nutritional needs
crew test or system boundary varies by study; see source		unspecified—noneTimeline · Biosphere 2 crew enters
Food regenerated inside selected tests201455 % of crew foodobservedFood regenerated inside selected tests
crew test or system boundary varies by study; see source		unspecified—noneLunar Palace 105 study
AS OF July 2026
Beihang reported very high closure under its defined ground-system mass boundary; this is not a measurement of off-Earth autonomy.Beihang reported very high closure under its defined ground-system mass boundary; this is not a measurement of off-Earth autonomy.

Independent records

Defined total material closure in Lunar Palace linear scale · %

linear scale · %
201898.2 %

Conditioncrew test or system boundary varies by study; see source

Reference values · not observed records
  • Defined material closure boundaryDefined material closure boundary100 %reference
observed self-reported target / pathway right-censored lower bound
View data table
All plotted observations
SeriesDateValueStatusCondition / labelVerificationCICensoringSource
Defined total material closure in Lunar Palace201898.2 %observedDefined total material closure in Lunar Palace
crew test or system boundary varies by study; see source		unspecified—noneLunar Palace 365 results
AS OF July 2026
NASA must raise average estimated flight oxygen recovery by at least 28 percentage points to reach its exploration threshold.NASA must raise average estimated flight oxygen recovery by at least 28 percentage points to reach its exploration threshold.

NASA must raise average estimated flight oxygen recovery by at least 28 percentage points to reach its exploration threshold.

ISS Sabatier average estimate47 %
SCOR threshold75 % target · target

ConditionThis is a test target, not an observed result.SCOR threshold is a test target for recovery performance, not an observed result.

Each value is scaled against zero in its own unit; bar length is not a cross-unit comparison.
View data table
All aligned comparisons
ClaimABSource / provenance
NASA must raise average estimated flight oxygen recovery by at least 28 percentage points to reach its exploration threshold.47 % · ISS Sabatier average estimate75 % target · SCOR threshold · target
This is a test target, not an observed result.SCOR threshold is a test target for recovery performance, not an observed result.		NASA SpaceCraft Oxygen Recovery
AS OF July 2026
At 98% recovery, two pounds are lost from each hundred pounds of water circulated.At 98% recovery, two pounds are lost from each hundred pounds of water circulated.
Water returned98 lb per 100 lb
−96 lb per 100 lb · 0.02× of A
Water lost2 lb per 100 lb
Water returned98 lb per 100 lb
−96 lb per 100 lb · 0.02× of A
Water lost2 lb per 100 lb
View data table
All aligned comparisons
ClaimABSource / provenance
At 98% recovery, two pounds are lost from each hundred pounds of water circulated.98 lb per 100 lb · Water returned2 lb per 100 lb · Water lostNASA ISS 98% water-recovery milestone
AS OF July 2026
Lunar Palace 365 reported 100% oxygen and water regeneration on Earth under a system boundary with 98.2% defined material closure.Lunar Palace 365 reported 100% oxygen and water regeneration on Earth under a system boundary with 98.2% defined material closure.
Oxygen and water regeneration100 %
−1.8 % · 0.98× of A
Defined material closure98.2 %

Each square = 5 %

Oxygen and water regeneration100 %
Defined material closure98.2 %
1.8 % less from defined material closure than from oxygen and water regeneration
View data table
All aligned comparisons
ClaimABSource / provenance
Lunar Palace 365 reported 100% oxygen and water regeneration on Earth under a system boundary with 98.2% defined material closure.100 % · Oxygen and water regeneration98.2 % · Defined material closureLunar Palace 365 results
AS OF July 2026
05 · What it unlocksWhat it unlocks

If the remaining tests pass.If the remaining tests pass.

Downstream capabilities remain conditional on results that are not yet in.These are possible next capabilities, conditional on results that are not yet in.

TODAY
  1. PASSED · Jun 202301 ↗
    Recycle nearly all the waterExploration-grade water recoveryThe ISS Brine Processor raised total water recovery from 93-94% to 98%.Recover 98% of crew wastewater in an operating space habitat.
  2. OPEN TEST02 ↗
    Recover three quarters of the oxygenSeventy-five-percent oxygen recoveryISS Sabatier hardware averages about 47%; NASA's SCOR threshold is above 75%.Recover more than 75% of metabolic oxygen from crew carbon dioxide in flight.
  3. OPEN TEST03 ↗
    Grow most of the foodThree-quarter food regenerationA 105-day Lunar Palace test regenerated 55% of food; later high-closure results still used a defined ground-test boundary.Regenerate at least 75% of a nutritionally complete crew diet inside a year-long controlled habitat.
  4. OPEN TEST04 ↗
    Run the whole loop in spaceIntegrated off-Earth closureNo crewed flight habitat has integrated all four loops; the broadest closure demonstrations remain on Earth.Operate water, oxygen, waste-nutrient and staple-food loops together beyond low Earth orbit for at least one year.
PASSED · Jun 202301 ↗
Recycle nearly all the waterExploration-grade water recoveryThe ISS Brine Processor raised total water recovery from 93-94% to 98%.Recover 98% of crew wastewater in an operating space habitat.
TODAY
OPEN TEST02 ↗
Recover three quarters of the oxygenSeventy-five-percent oxygen recoveryISS Sabatier hardware averages about 47%; NASA's SCOR threshold is above 75%.Recover more than 75% of metabolic oxygen from crew carbon dioxide in flight.
OPEN TEST03 ↗
Grow most of the foodThree-quarter food regenerationA 105-day Lunar Palace test regenerated 55% of food; later high-closure results still used a defined ground-test boundary.Regenerate at least 75% of a nutritionally complete crew diet inside a year-long controlled habitat.
OPEN TEST04 ↗
Run the whole loop in spaceIntegrated off-Earth closureNo crewed flight habitat has integrated all four loops; the broadest closure demonstrations remain on Earth.Operate water, oxygen, waste-nutrient and staple-food loops together beyond low Earth orbit for at least one year.

Possible, if the open tests pass.

  1. Multi-year Mars missions

    This is a possible benefit only if multi-year mars missions works safely, reliably and at useful scale.Potential benefit only if the stated use (Multi-year Mars missions) is demonstrated with evidence for safety, reliability, affordability and scale.

  2. Permanent off-world habitats

    This is a possible benefit only if permanent off-world habitats works safely, reliably and at useful scale.Potential benefit only if the stated use (Permanent off-world habitats) is demonstrated with evidence for safety, reliability, affordability and scale.

  3. Resilient Earth systems

    This is a possible benefit only if resilient earth systems works safely, reliably and at useful scale.Potential benefit only if the stated use (Resilient Earth systems) is demonstrated with evidence for safety, reliability, affordability and scale.

These are possible outcomes, if the open tests pass. They are conditional, not promises.
06 · SourcesSources

Follow the evidence.Follow the evidence.

18 sources — every figure on this page traces to one.18 sources — every figure on this page traces to one.

Source · what this page citesScope and limits
  1. 01

    Scope: Not recorded. Limit: Not recorded.

  2. 02

    NASA ISS 98% water-recovery milestone

    Read source ↗nasa.gov
    Used on this page
    All 11 uses across 8 destinations

    Scope: Not recorded. Limit: Not recorded.

  3. 03

    Scope: Not recorded. Limit: Not recorded.

  4. 04

    Scope: Not recorded. Limit: Not recorded.

  5. 05

    ESA Advanced Closed Loop System

    Read source ↗esa.int

    Scope: Not recorded. Limit: Not recorded.

  6. 06

    Scope: Not recorded. Limit: Not recorded.

  7. 07

    Lunar Palace 365 results

    Read source ↗sciencedirect.com
    Used on this page
    All 9 uses across 5 destinations

    Scope: Not recorded. Limit: Not recorded.

  8. 08

    Scope: Not recorded. Limit: Not recorded.

  9. 09

    Biosphere 2 oxygen-loss analysis

    Read source ↗agupubs.onlinelibrary.wiley.com
    Used on this page
    All 2 uses across 2 destinations

    Scope: Not recorded. Limit: Not recorded.

  10. 10

    NASA Gateway schedule and life-support roles

    Read source ↗nasa.gov
    Used on this page
    All 2 uses across 2 destinations

    Scope: Not recorded. Limit: Not recorded.

  11. 11

    Scope: Not recorded. Limit: Not recorded.

  12. 12

    Scope: Not recorded. Limit: Not recorded.

  13. 13

    Timeline · NASA establishes CELSS

    Read source ↗ntrs.nasa.gov
    Used on this page
    All 2 uses across 2 destinations

    Scope: Not recorded. Limit: Not recorded.

  14. 14

    Scope: Not recorded. Limit: Not recorded.

  15. 15

    Scope: Not recorded. Limit: Not recorded.

  16. 16

    Timeline · European loop reaches ISS

    Read source ↗esa.int
    Used on this page
    All 2 uses across 2 destinations

    Scope: Not recorded. Limit: Not recorded.

  17. 17

    Timeline · ESA selects five circular studies

    Read source ↗esa.int
    Used on this page
    All 2 uses across 2 destinations

    Scope: Not recorded. Limit: Not recorded.

  18. 18

    Timeline · Gateway targets first launch

    Read source ↗nasa.gov
    Used on this page
    All 2 uses across 2 destinations

    Scope: Not recorded. Limit: Not recorded.

Sources describe evidence. Inclusion is not endorsement.