Demonstrate ship-to-ship propellant transfer in Earth orbit
On-orbit refilling is the capability the Artemis lunar landing architecture depends on. SpaceX plans to launch one Starship, then launch a second to rendezvous with it and transfer propellant between the two.
In progress
What do the status labels mean?
Announced: it has been said out loud, but we have not seen work toward it yet.
In progress: we can point to tests, hardware or contracts that show work under way.
Partially achieved: part of the job is done and shown, but not all of it.
Achieved: evidence matches the whole “done” description we wrote down.
Uncertain: sources disagree or are missing. We say so instead of guessing.
Paused or cancelled: a reliable source says work has stopped or the plan was dropped.
Full definitions →- Said on
- 30 October 2025
- First target In plain English
What is a target window?
A target window is when the company said something would happen. Sometimes that is an exact day. Often it is only a month, a quarter or a year.
We keep it exactly as vague or as precise as the company did. If they said “2026”, we show 2026. We never turn that into a made-up day in December.
When a company gives a new date later, we keep the old one too. You can always see how the plan moved.
Saying “I’ll visit this summer” is a window. Saying “I’ll visit on 14 July” is an exact date. They are not the same promise.
- 2026Year precision, stated 30 October 2025
- Current target
- 2026Year precision, stated 30 October 2025
- Last checked In plain English
Who checked this, and how?
Each record has a review note. It names who did the check and lists every claim that was compared with its source.
Right now these checks were done with AI help and have not yet been re-read by an independent human editor. We say this plainly on every page rather than hiding it.
A “review due” label means the record is older than two weeks and is scheduled for another look. The content is unchanged until then.
- 18 September 2026Next review due 2 October 2026
What would count as “done”
Two Starships rendezvous in Earth orbit and transfer cryogenic propellant from one vehicle to the other, as recorded by SpaceX or NASA.
Why we say this
SpaceX describes preparatory work rather than a completed demonstration: approximately five metric tons of cryogenic propellant transferred between tanks within a single vehicle in space, activation of a hardware-in-the-loop testbed for the propellant transfer flight test, and V3 vehicles equipped with docking drogues, ship-to-ship propellant feed connections and DragonEye navigation sensors. The transfer between two vehicles has not been recorded as flown.
Stated uncertainty. The stated 2026 window has not been restated or withdrawn in the September 2026 update, which describes the first orbital propellant transfer as one of the new flight tests beginning with orbital missions.
How the date moved In plain EnglishWhat is a target window?
A target window is when the company said something would happen. Sometimes that is an exact day. Often it is only a month, a quarter or a year.
We keep it exactly as vague or as precise as the company did. If they said “2026”, we show 2026. We never turn that into a made-up day in December.
When a company gives a new date later, we keep the old one too. You can always see how the plan moved.
Saying “I’ll visit this summer” is a window. Saying “I’ll visit on 14 July” is an exact date. They are not the same promise.
What is a target window?
A target window is when the company said something would happen. Sometimes that is an exact day. Often it is only a month, a quarter or a year.
We keep it exactly as vague or as precise as the company did. If they said “2026”, we show 2026. We never turn that into a made-up day in December.
When a company gives a new date later, we keep the old one too. You can always see how the plan moved.
Saying “I’ll visit this summer” is a window. Saying “I’ll visit on 14 July” is an exact date. They are not the same promise.
- Stated 30 October 2025 · recorded here 30 October 2025 · current target2026 (Year precision)
First stated target window. SpaceX also stated that exact timing would be driven by how the Starship V3 flight tests progress.
What actually happened
SpaceX reports the transfer of approximately five metric tons of cryogenic propellant between tanks while in space, which it describes as providing key data for future full-scale propellant transfer operations. The observation date is the date of the company statement, not of the test itself, which the source does not date.
Sources In plain EnglishWhere does the evidence come from?
Every status links to the page we read. We record who published it, when, and which part of it supports the claim.
A company saying something proves that the company said it. It does not prove the thing is true. When we can, we look for a second voice: a regulator, a partner like NASA, or an exchange.
If a page disappears later, we flag it. A missing page is not proof that a claim was wrong.
Source rules →
Where does the evidence come from?
Every status links to the page we read. We record who published it, when, and which part of it supports the claim.
A company saying something proves that the company said it. It does not prove the thing is true. When we can, we look for a second voice: a regulator, a partner like NASA, or an exchange.
If a page disappears later, we flag it. A missing page is not proof that a claim was wrong.
Source rules →Who checked this In plain EnglishWho checked this, and how?
Each record has a review note. It names who did the check and lists every claim that was compared with its source.
Right now these checks were done with AI help and have not yet been re-read by an independent human editor. We say this plainly on every page rather than hiding it.
A “review due” label means the record is older than two weeks and is scheduled for another look. The content is unchanged until then.
Who checked this, and how?
Each record has a review note. It names who did the check and lists every claim that was compared with its source.
Right now these checks were done with AI help and have not yet been re-read by an independent human editor. We say this plainly on every page rather than hiding it.
A “review due” label means the record is older than two weeks and is scheduled for another look. The content is unchanged until then.
Claims we compared with their sources
Starship flights 1 through 13 were deliberately placed on passively safe suborbital trajectories, and orbital missions begin with Flight 14.
The update states both the historical approach and the Flight 14 transition. It gives no date for Flight 14.
A long-duration flight test and an in-space propellant transfer flight test were both targeted to take place in 2026.
The source states the 2026 target and that exact timing depends on how the V3 flight tests progress. Recorded as a year-precision window.
Approximately five metric tons of cryogenic propellant have been transferred between tanks in space.
Supports an intra-vehicle transfer only. It does not support ship-to-ship transfer, and the source does not date the test, so the outcome is recorded against the statement date with that limitation stated on the record.
Starship V3 carries docking drogues and ship-to-ship propellant feed connections.
Used as evidence of preparatory hardware for propellant transfer, not of a completed demonstration.
What this check could not tell us
- This is an AI-assisted review, not independent human review. A human editor has not yet re-checked these findings.
- Every source checked in this review is a SpaceX company statement. Company statements establish what the company said; they do not independently establish the outcomes as fact.
- Source pages were read through a browser on 18 September 2026. The accessedAt time on each source is normalised to 12:00 UTC on that date rather than recording an exact retrieval instant.
- The SpaceX updates page is a single URL carrying dated sections. Locators identify the section by date and heading because per-update permalinks were not used.
- No regulator or mission-partner source has been checked for this batch, so no FAA, NASA or filed-document claims are published.