With the space shuttle Endeavour away on its final mission today, the United States will soon have no transportation to the International Space Station of its own. Between the final launch of the Atlantis, scheduled for June 28, and until affordable commercial rockets become available to NASA, astronauts will hitch a ride on Russia's Soyuz 2 rockets, the latest version in a line of Russian and Soviet spaceships stretching back to the early 1960s. The latest Soyuz rockets are cheaper and more versatile than space shuttles, but they don't have nearly the payload and despite their emergence as the carrier of choice for near-term space missions, they don't have as extensive a history of manned flight.
By the numbers, Soyuz has a better safety record than NASA so far. NASA's history has been marred by two major disasters -- the Columbia in 2003 and the Challenger in 1986 -- both of which resulted in the deaths of the entire crew. Soyuz has not been spared from mishaps, but it has fared better overall. The Smithsonian magazine breaks down some of the safety specifics in a blog post:
Through the most recent mission, STS-130 in February 2010, the shuttle has taken 788 people to orbit (“people” includes repeat fliers—so Franklin Chang Diaz’s seven flights would count as seven people). Fourteen astronauts lost their lives on Challenger and Columbia, which leaves a ratio of one fatality for every 56 people taken to orbit. Soyuz has orbited 250 people, not including two successful aborts: Soyuz 18a in April 1975, which occurred late in a launch 90 miles high, and Soyuz T-10-1 in September 1983, on the launch pad. The program has suffered four fatalities: one on Soyuz 1 in April 1967, and the other three on Soyuz 11 in June 1971. That’s one Soyuz fatality for every 63 people delivered to orbit. Based on those ratios, Soyuz is a little safer.
But remember, with far fewer manned missions flown--only 103 manned missions to the shuttle's 130--Soyuz has had fewer chances for disaster. As The Smithsonian's Mike Klesius points out, "Who knows if Soyuz might have a critical failure in the next 27 flights?"