The catalogue of everything in orbit has outgrown the format the world reads it in. On 11 July the US Space Force assigned its last available five-digit catalogue number and began issuing six-digit numbers starting at 100000. The two-line element set, the fixed-width text block that has carried orbital data since the 1970s, has a five-character field for that number and no way to widen it, so nothing catalogued since then can be expressed in it — not by CelesTrak, and not by any TLE feed anywhere. The objects exist in full in the newer formats.
The cleanest demonstration involves a spacecraft with people aboard. Soyuz MS-29 launched from Baikonur on 14 July carrying the NASA astronaut Anil Menon and the Roscosmos cosmonauts Pyotr Dubrov and Anna Kikina, and docked to the International Space Station’s Prichal module the same afternoon; the crew is due to stay eight months. It was catalogued as object 100057. Request CelesTrak’s space-stations group as CSV and 22 objects come back, including MS-29 with a full element set — epoch 3 August, inclination 51.63 degrees, 15.49 revolutions a day, values identical to the station it is attached to. Request the same group as TLEs and 21 objects come back. Same query, same 200 response, one spacecraft fewer, and nothing in the file to say so.
Asked by catalogue number the answer is worse in a different way: a request for object 100057 as a TLE returns HTTP 404 and the words "No GP data found", for a spacecraft whose orbital elements the same server will hand over in three other formats without complaint.
The scale is already substantial. CelesTrak publishes a standing query for everything catalogued in the past thirty days; on Monday it returned 375 objects as CSV and 199 as TLE. The 176 missing are exactly the objects numbered 100000 or above — 47% of the recent catalogue.
The catalogue never reached 99999, which is the detail most likely to catch people out. Of the 70,177 objects in the public satellite catalogue, the highest five-digit number in use is 69999, and the range from 70000 to 99999 contains nothing at all. The usable public space therefore ended 30,000 numbers below the format’s own ceiling, which is why the exhaustion arrived years earlier than estimates based on that ceiling would suggest. CelesTrak says the legacy fixed-field version of the catalogue will keep updating but will only ever contain objects numbered below 70000.
The 179 objects now carrying six-digit numbers are largely one company’s. A hundred and thirty are American: 104 Starlink satellites, 21 Praetorian spacecraft built for the Space Development Agency, four still unnamed, and USA 619, which was catalogued on 30 July and currently sits at the very top of the catalogue at 100178. Twenty-three are Chinese, twenty Russian, three Indian and two Portuguese. A hundred and seventy-one are payloads rather than rocket bodies or debris, and 178 of the 179 are in orbit — 0.51% of the 34,746 objects up there.
None of this arrived unannounced. CelesTrak has published the replacement — the Orbit Mean-Elements Message, a Consultative Committee for Space Data Systems standard available in XML, key-value, JSON and CSV — since May 2020, and has spent six years telling users to migrate. Its forecast was good: an estimate made on 9 May put the exhaustion at about 12 July, and it happened on the 11th. The obvious shortcut of extending the field with letters was considered and rejected, because the Space Force is already assigning analyst numbers nine digits long, in the 799,000,000 range, which no five-character scheme can represent.
There is a fitting piece of bookkeeping at the boundary. The very last five-digit number, 69999, was not given to anything new: it went to VANGUARD DEB, international designator 1958-002D — a fragment of the launch that put Vanguard 1 into orbit on 17 March 1958, and which is still up there, the oldest artificial object in space. The number immediately before it, 69998, is a Starlink satellite launched on 11 July 2026, the same day the scheme ran out. Sixty-eight years of orbital cataloguing, closed out by two consecutive entries.