Ephemera

None of this is worth anything if you have to take my word for it. Here is what you can run right now, and what still needs data this site does not publish yet. I would rather say which is which.

Fetch an independent copy and hash it. Each cycle's file list is pushed into the Wayback Machine the moment it is caught, so a copy exists that I do not control. For cycle 4315951240b7 that copy is here, and its SHA-256 is 4315951240b7eef30a5a4ed23330ad22882981a26721b0db6baccdab8302d0d2. Download it, hash it, and you have checked that the list of files I claim to have caught is the list the source was actually serving. Ten files from each cycle are copied the same way, and every copy URL and digest is in ledger.json.

Check which ten files were copied. I do not get to choose them. File number int(sha256(root + ":" + k), 16) mod n for k from 0 to 9, where n is the number of files in the list you just downloaded. Run that and you get the same ten names this site published.

Check the timestamp. Each cycle root is stamped through OpenTimestamps. Running ots verify root.txt.ots against a Bitcoin node shows this cycle's root committed in block 966725, which fixes the latest moment it could have been written. Nobody, including me, can move a root backwards once it is in a block. The proof files ship with the data release.

What you cannot do from this page alone is rebuild the Merkle root, because that needs the SHA-256 of every one of the 11,132 files in the cycle and this site publishes the summary rather than the full digest list. Those digests, and the exact byte format of the root file, come with the data release described below. The construction is the plain one: leaves are the file digests in manifest order, adjacent pairs are hashed as SHA-256 of the two digests joined end to end, and an odd trailing node is paired with a copy of itself.

• ledger.json carries every cycle, its root, its attestation, its witness state and every scored summary on this site, as machine-readable JSON. It is the same file the pages are built from.
• The globe's per-cycle pack, with the element sets and the scored separations, is at the newest cycle's pack (5.2 MB). Every scored cycle keeps its own, named by the cycle, so an older globe can be replayed.
• The full per-comparison rows, about 140,000 per cycle, are kept in the archive and are available on request. They move to public object storage once the storage layer is finished.
• The raw operator files are held as published, hashed and witnessed. They are not re-published here while the licence question below is open.

Licence. Code is MIT, and the repository is public, so the propagation, the frame handling and the cut every headline figure is taken at can be read and re-run rather than taken on trust. Figures derived by this project are intended for CC BY 4.0. The raw SpaceX files carry no stated licence; a written request went to SpaceX on 31 August 2026 and is unanswered as of this build, and any file comes down on request. Public element sets come from Space-Track.org and are redistributed under Space-Track's blanket approval for basic space situational awareness data, with citation.

Citation. Ryan, K. (2026). Ephemera: an archive of the public Starlink ephemerides and a daily measure of public catalogue visibility. https://ephemera.space, retrieved 2026-09-17 20:20 UTC.