Head to head

Atlas V 551 vs Soyuz-U

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

Soyuz-U: 7,050 kg

Side by side

7 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	Soyuz-U
Flights flown	23	71
Success rate	100%	100%
Payload to LEO (kg)	18,850	7,050
Length (m)	59.7	34.54
Diameter (m)	3.8	2.95
Launch mass (t)	573	298
Stages	2	2

Atlas V 551

Flight record

100% success rate23 of 23 flown

2006peak 2025 · 5 flights2026

Maiden flight 2006-01-19. Retired.

Soyuz-U

Flight record

100% success rate71 of 71 flown

1982peak 1987 · 10 flights1995

Maiden flight 1982-12-23. Retired.

Atlas V 551 is built by United Launch Alliance of the United States (company profile on Space Index).Soyuz-U is built by Soviet Space Program of Russia.

Full specifications and the complete launch history for each: Atlas V 551 · Soyuz-U.

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