Russia’s Soyuz rocket may have failed to place Progress M-12M into orbit, but it has a very good track record over the decades according to statistics complied by Jonathan McDowell.

McDowell is an x-ray astronomer at the Harvard-Smithsonian Center for Astrophyiscs, who, in his spare time, produces an excellent, free newsletter, Jonathan’s Space Report. It provides details on space launches on a roughly monthly basis. The most recent edition, No. 646, includes statistics on launch successes and failures of the various versions of the Soyuz rocket over time.

According to his count, since 1966, there have been 1,209 launches of nine variants of the Soyuz rocket on both orbital and suborbital missions of which 37 failed to reach orbit or to reach the correct orbit. That yields a 97 percent success rate.

The Soyuz FG, used to launch crews to the International Space Station, has a 100 percent success rate since 2001 according to his statistics. By comparison, the Soyuz U, which failed in launching Progress M-12M, has had 20 failures in 761 launch attempts since 1973 based on his numbers. That translaters to a 97.4 percent success rate.

A Russian investigation determined that the Progress M-12M failure was due to a clogged fuel line, which the Russian space agency, Roscosmos, considered to be a random event. No official announcement has been made as to when Soyuz rocket flights with crews will resume. One or two successful satellite launches on Soyuz rockets are expected before committing to launching the next crew.