Head to head

Atlas V 551 vs Proton-M Briz-M

Two vehicles in the same payload class. Every figure below comes from the same two sources for both rockets, and a row appears only when both publish the input.

Payload to low Earth orbit

Relative

Atlas V 551: 18,850 kg

Proton-M Briz-M: 21,000 kg

Side by side

9 comparable figures

The highlighted value wins the row. Rows where neither direction is better, like length or stage count, highlight nothing.

Metric	Atlas V 551	Proton-M Briz-M
Flights flown	23	68
Success rate	100%	91.2%
Payload to LEO (kg)	18,850	21,000
Payload to GTO (kg)	8,890	4,500
Liftoff thrust (kN)	12,269	10,000
Length (m)	59.7	53
Diameter (m)	3.8	7.4
Launch mass (t)	573	712
Stages	2	4

Atlas V 551

Flight record

100% success rate23 of 23 flown

2006peak 2025 · 5 flights2026

Maiden flight 2006-01-19. Retired.

Proton-M Briz-M

Flight record

91.2% success rate62 of 68 flown · 6 failed

2001peak 2013 · 9 flights2023

Maiden flight 2001-04-07. Still flying.

Atlas V 551 is built by United Launch Alliance of the United States (company profile on Space Index).Proton-M Briz-M is built by Khrunichev State Research and Production Space Center of Russia (company profile on Space Index).

Full specifications and the complete launch history for each: Atlas V 551 · Proton-M Briz-M.

Specifications from Launch Library 2 by The Space Devs, launch records from Space Index. Derived figures are computed here; see sources and method.