The Global Positioning System publishes its own health in public, in plain text. The US Coast Guard’s Navigation Center hosts the notices the GPS Master Control Station issues about each satellite, the broadcast almanac in which each satellite declares its own health word, and a status file listing every outage since 1998. Read together they say that the newest satellite in the constellation has not yet been switched on for users.
GPS III SV-10 launched at 06:53 Greenwich Mean Time on 21 April 2026 — 2:53 in the morning Eastern time — and took the PRN 13 broadcast slot. Its launch notice, NANU 2026039, sets it unusable until further notice from the launch instant. As of 13:30 on 9 August that record is still open: 110.3 days. The Master Control Station’s status file carries 1,542 records and exactly one of them is current, and it is this one.
The almanac agrees. The file for GPS week 383, current as of 4 August, lists 32 satellites; PRN 13 carries health word 063, and every other entry reads 000. Reconstructing older captures of the same file from the Internet Archive shows PRN 13 healthy on 16 April, before the launch — that was the old satellite in the slot — and unhealthy on every capture since 21 May.
What makes the interval legible is that the same files record every previous GPS III commissioning. From launch to the notice declaring it active to service, SV01 took 386.2 days, SV02 223.3, SV03 92.9, SV04 26.1, SV05 342.0, SV06 29.4, SV07 36.7, SV08 26.1 and SV09 37.7. The median of the nine is 37.7 days. The programme’s early satellites were slow and its recent ones have been fast: the last four all landed between 26 and 38 days. SV-10 passed SV03’s 92.9 days on 23 July, and is now 2.9 times the median. It is the fourth-longest of the ten, and the only one still open.
There is no notice closing it. All nine of the previous satellites were set active by a notice of the type USABINIT; searching the whole 2026 sequence up to NANU 2026060, issued on 7 August, finds none for SV-10. The single missing file in this year’s sequence, 2026051, turns out from the Master Control Station’s own status record to be an outage summary for a different satellite entirely.
The constellation lost a satellite over the same period, and quickly. SVN 43, a Block IIR launched in 1997 that had been holding PRN 13, was set unusable at 19:23 on 24 April and decommissioned at 22:00 the same day — three and a half days after its replacement reached orbit. Since then 32 satellites have been broadcasting and 31 have been usable, one fewer than before, which is still seven above the 24 the GPS Performance Standard commits the government to maintaining. No user would notice.
The public-facing pages have not kept up. The Navigation Center’s constellation page still seats the decommissioned SVN 43 in plane A, slot 5, has no row for SVN 83 at all, and prints a block tally — five IIR, seven IIR-M, eleven IIF, nine III — identical to the figures the Space Force briefed to the civil GPS committee on 13 April, eight days before the launch. Lockheed Martin’s launch release said the mission “strengthened the Global Positioning System (GPS) constellation to its highest level ever achieved”.
Two caveats belong on this. The health read here is the coarse word in the broadcast almanac, not the authoritative health bits in the navigation message, though the two agree with the Master Control Station’s own file. And nothing in the public record states how long SV-10’s checkout was planned to take, so this is a long interval against its recent siblings rather than a delay against a published schedule.