Head to head

Atlas V 551 vs Soyuz 2.1b/Fregat-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

Soyuz 2.1b/Fregat-M: 8,200 kg

Side by side

11 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 2.1b/Fregat-M
Flights flown	23	36
Success rate	100%	100%
Payload to LEO (kg)	18,850	8,200
Payload to GTO (kg)	8,890	3,250
Launch cost	$153M	$48.5M
Cost per kg to LEO	$8,117	$5,915
Liftoff thrust (kN)	12,269	4,150
Length (m)	59.7	46.3
Diameter (m)	3.8	10.3
Launch mass (t)	573	313
Stages	2	4

Atlas V 551

Flight record

100% success rate23 of 23 flown

2006peak 2025 · 5 flights2026

Maiden flight 2006-01-19. Retired.

Soyuz 2.1b/Fregat-M

Flight record

100% success rate36 of 36 flown

2017peak 2021 · 8 flights2026

Maiden flight 2008-07-26. Still flying.

Atlas V 551 is built by United Launch Alliance of the United States (company profile on Space Index).Soyuz 2.1b/Fregat-M is built by Progress Rocket Space Center of Russia (company profile on Space Index).

Full specifications and the complete launch history for each: Atlas V 551 · Soyuz 2.1b/Fregat-M.

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