Where lunar time is needed

Five missions and programmes whose own documents ask for one lunar time scale: who runs each, the window our sources give in their own words, and what a shared clock is for.

How a record gets on this page

A mission gets a record here when our registry holds checked facts about it: three or more, each with its own document behind it, and at least two reasons why one time scale matters to it. Dates are the part that goes wrong most easily, so the rule on this page is narrow: the window is printed in the words of the source, and where the source gives no date, the column says so instead of naming a year.

Nothing on this page runs on lunar time. No lunar time scale has been realized, and every clock value on this site is a model value computed from published rates ^[6]. Who decides the standard is in the organizations hub; where each track stands today is on the tracker.

Who runs it, when, and why time matters

The table below is the whole page in one view. The window column is the one to read carefully: 2027 and 2028 are the words of NASA's architecture update ^[2]Official, and the rest of our sources give no date at all.

The five records

Each record carries the same structure: a table of what the mission is, key facts with sources, why one time scale matters to it, and the pages on this site it connects to. What a microsecond is worth in metres is inwhy microseconds matter; the model behind every number here is inour methodology.

1. Artemis III

   NASA — Planned — 2027

   Artemis III is the flight NASA moved into low Earth orbit. The architecture update of 27 February 2026 adds a mission to the programme, makes this one a test in 2027 and moves the first crewed landing to Artemis IV. The address on this page is that update, because our registry holds no mission page of its own. Which time scale the flight would use is not stated anywhere in the registry: the United States strategy for lunar time is not due until the end of 2026.

2. Artemis IV

   NASA — Planned — 2028

   Under the architecture NASA published on 27 February 2026, Artemis IV carries the first crewed landing of the programme, in 2028. That is two years after the date by which the United States is to have a finalized lunar time implementation strategy, which makes this mission the first one that would fly under whatever the strategy says. The address on this page is the same architecture update: our registry holds no page of the mission's own.

3. LunaNet

   NASA — In development — No date in our sources

   LunaNet is a framework rather than a spacecraft: agreed standards, protocols and interface requirements so that lunar communication and navigation services from different agencies work together. NASA states that it will develop a lunar time standard for its own missions and for LunaNet, and a common lunar reference time is one of the framework's requirements. Our registry gives no date for the framework itself, so the window on this page says that rather than naming a year. No such service is running, and no lunar time scale has been realized anywhere.

4. Moonlight

   ESA — In development — No date in our sources

   Moonlight is the European Space Agency's lunar communication and navigation programme. The European case for a shared clock starts a year before the programme page: ESA reported that agencies meeting at ESTEC in November 2022 agreed a common lunar reference time was both important and urgent. Our registry holds the programme page and that report, and no schedule for the service, so this page names none.

5. NovaMoon

   ESA — Proposed — No date in our sources

   NovaMoon is a reference station proposed as a scientific and navigation payload for ESA's Argonaut lander. It is designed as a local differential, geodetic and timing station for the Moon's south polar region, carrying laser retroreflectors, atomic clocks and radio links. Our registry records no decision to fly it, no cost and no schedule, so none appear here. It is on this page because a clock on the surface is what would turn a defined lunar scale into a reading, and this is the one such station our sources describe in full.

Who is missing, and why

Our plan for this page named six missions. Artemis II and the Gateway station are not here: our registry of sources does not mention either of them once, and a record with a window and no source behind it would look exactly like the five that have one. Chang'e 7 is not here either — the only mention of the Chinese programme we hold is a press report about two countries working towards different lunar time arrangements^[9], which is context, not a fact about a mission. What the Chinese papers do state is set out inChina and lunar time.

Their places are taken by Artemis IV, which the same architecture update covers ^[2]Official, and by NovaMoon, a timing station our sources describe in full^[8]. When a source for the others appears in the registry, the records will follow.

Last verified 24 August 2026