3 minute read•Updated 12:22 PM EDT, Tue August 12, 2025
CAPE CANAVERAL, FL – United Launch Alliance’s (ULA) Vulcan rocket is counting down toward its first-ever launch carrying a U.S. national security payload. The USSF-106 mission, flying for the U.S. Space Force’s Space Systems Command, is scheduled to lift off tonight from Space Launch Complex-41 at Cape Canaveral Space Force Station, Florida.
The launch window runs from 7:59 to 8:59 p.m. EDT (2359–0059 UTC), with liftoff targeted within that one-hour period. If successful, the Vulcan will deliver two satellites directly into geosynchronous orbit, marking a major milestone for the new rocket and its role in the National Security Space Launch (NSSL) program.
Weather Holding at 80% GO
Launch Weather Officer Jimmy Taeger of the 45th Weather Squadron reports conditions remain favorable, with an 80 percent chance of acceptable weather at liftoff.
The forecast calls for scattered clouds, good visibility, southeasterly winds of 9 to 14 knots, and a temperature near 84°Fat launch time.
Countdown in Progress
ULA began the launch day countdown at 10:09 a.m. EDT (1409 UTC) from a T-minus 8 hour, 50 minute mark. Over the course of nearly 10 hours, teams will conduct extensive testing and preparation before liftoff. Two pre-planned built-in holds are part of the schedule:
T-minus 4 hours, 30 minutes – 30-minute hold before fueling
T-minus 7 minutes – 30-minute hold before entering Terminal Count
Current operations include powering up the Vulcan booster and Centaur V upper stage to verify all systems are ready for cryogenic propellant loading. Over the next several hours, teams will complete:
Centaur V liquid oxygen & liquid hydrogen preps
First stage pneumatics, propulsion & hydraulic system checks
Guidance system and flight control testing for both stages
GPS Metric Tracking system validation
S-band telemetry relay system checks
Internal battery verifications
Rocket Overview:
Today’s mission will use the Vulcan VC4S configuration, designated V-003. The rocket stands 202 feet (61 meters) tall and will weigh 1.74 million pounds (791,000 kg) when fully fueled.
Liftoff thrust will come from two BE-4 main engines and four solid rocket boosters, producing three million pounds (13 megaNewtons) of thrust to power the rocket off the pad and on its way to geosynchronous orbit.
Mission Overview
USSF-106 will be the first NSSL mission to fly on a Vulcan rocket. The payload consists of two classified satellites, which will be deployed directly into geosynchronous orbit to support U.S. national security operations.
This mission will demonstrate Vulcan’s ability to meet the direct-to-GEO requirement of the U.S. Space Force and pave the way for future high-priority national security launches.
Live Launch Coverage
Our live countdown-to-launch coverage will starting at T-1 hour, offering real-time updates and commentary as Vulcan prepares for this historic mission. https://youtube.com/live/3zFVwE8Ldo4?feature=share
GO Vulcan! GO Centaur! GO USSF-106!
