USSF-51

USSF-51 is an American National Security Space Launch Mission under the vision of United States Space Force. The launch is significant as it is the Last launch for United Launch Alliance's Atlas V rocket for National Security Mission. After reaching orbit Three Satellite are deployed named USA-396, USA-397 and USA-398. In October 2025, one more satellite is deployed named USA-566.^{[1][2][3][4][5][6][7][8]}

USSF-51

USSF-51 Launch
Operator	USSF
Start of mission
Launch date	30 July 2024 10:45 UTC
Rocket	Atlas V 551 (AV-101)
Launch site	Cape Canaveral, SLC-41
Contractor	United Launch Alliance
Orbital parameters
Reference system	Geocentric orbit
Regime	Geosynchronous orbit
USSF Launch ← USSF-62 USSF-106 →

Overview

USSF had assigned USSF-106 Mission to ULA in 2020. At the time it was planned to be the first National Security Mission on Vulcan Centaur but after reassignment to an Atlas V, USSF-106 become the first National Security Mission on Vulcan Centaur.^[9]

This mission is also last use of Russian RD-180 engine on US National Security Missions which is used on ULA's Atlas V rocket and is replaced with American made BE-4 engines, two of them is used on ULA's Vulcan Centaur rocket starting with USSF-106 Mission in August 2025.^[10]

See also

• List of USA satellites
• List of USSF launches
• National Security Space Launch