Head to head

Soyuz 2.1b 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

Soyuz 2.1b: 8,200 kg

Soyuz U: 6,900 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	Soyuz 2.1b	Soyuz U
Flights flown	25	714
Success rate	100%	97.2%
Payload to LEO (kg)	8,200	6,900
Length (m)	46.3	51.1
Diameter (m)	2.95	2.95
Launch mass (t)	312	313
Stages	3	3

Soyuz 2.1b

Flight record

100% success rate25 of 25 flown

2008peak 2021 · 4 flights2026

Maiden flight 2008-07-26. Still flying.

Soyuz U

Flight record

97.2% success rate694 of 714 flown · 20 failed

1973peak 1979 · 47 flights2017

Maiden flight 1973-05-18. Retired.

Soyuz 2.1b is built by Progress Rocket Space Center of Russia (company profile on Space Index).Soyuz U is built by Russian Federal Space Agency (ROSCOSMOS) of Russia.

Full specifications and the complete launch history for each: Soyuz 2.1b · 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.