Week in Space Data, every Friday.
Every change of more than a minute to this launch's date, as we observed it. Only a move between two dates known to the day counts as a slip; a placeholder such as “NET 2026” rolling to “2027” is shown but not counted. How we classify moves · on-time record by provider
The webcast for Vulcan · SDA Tranche 1 Tracking Layer B appears here once the provider posts it.
The broad sequence of an orbital launch. Details and times differ by rocket and mission; this is a guide, not live tracking.
In the last part of the count the rocket is fuelled, systems switch to internal power and the launch team is polled for a go.
The first-stage engines ignite and the rocket leaves the pad.
The moment of maximum aerodynamic pressure on the rocket during ascent.
The spent first stage separates and the upper stage takes over. Some rockets also drop side boosters earlier in the climb.
The upper stage burns to reach the planned orbit, sometimes in more than one burn with a coast in between.
The payload separates from the upper stage. On a crewed flight the capsule separates and flies on under its own power.
Chat opens two hours before liftoff once the launch time is set.
Telemetry and trajectory data shown is simulated for demonstration purposes. Real telemetry data would require integration with launch provider APIs.
Every entry is a change we recorded, not a forecast. Our sync checks Launch Library 2 every 15 minutes, so a time is when we saw the change and can trail the real moment. The liftoff time is the one the launch record states.
Target moved: placeholder roll, caught up late
Jun 30, 2026 (placeholder) to 2026. Launch Library 2 made this change earlier, while our sync was not refreshing this launch; the time shown is when we caught up, not when it changed.
recorded by the launch ledger
Vulcan Centaur (United Launch Alliance)
Vulcan Centaur uses two BE-4 engines on its first stage and a Centaur V upper stage with RL10 hydrogen engines. Solid rocket boosters strap on for heavier missions; the number is in the rocket’s configuration.
Source: ULA: Vulcan Centaur, checked 2026-09-27The provider's page for this flight
Checking for a discussion…
Part of a tracked program. See it on the SDA Proliferated Warfighter Space Architecture tracker, with the program's contracts, satellites and launch slips.