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Edited on Fri Jul-22-11 06:14 AM by sofa king
They compare very favorably.
Both had 2 fatal missions, both had their first fatal mission in their fifth year, both have had numerous near-accidents and dangerous events. Shuttle killed 14 people while Soyuz only killed four. Soyuz has a longer service life, but has flown about 20 fewer missions.
Soyuz has a launch escape system which was successfully used at least once, a version of which might have saved the Challenger crew (it was actually designed for one, which is why at least some of the Challenger crew survived the explosion long enough to open some emergency lockers during their nine-mile fall into the sea). William Proxmire, among others, led the Congressional charge to remove both that system and fly-around rockets for landing. Having killed and injured a few of their own cosmonauts after reentry by failing parachutes, that system is now highly redundant on Soyuz, while the Shuttle had one chance and one only to land, with no redundancy at all (again, thanks to Congress).
Soyuz relies on inexpensive and highly reliable heat shields for reentry, while the Orbiter relied on tiles. The loss of those tiles was a primary concern for NASA for the entire life of the Shuttle, for obvious reasons since the loss of just a few of them on a critical leading edge killed the Columbia crew.
Other considerations do not compare so well. The Shuttle's heavy-lift capability versatility once aloft was beyond comparison to Soyuz. On the other hand, there is almost always one or two Soyuz systems ready to launch within a month or so, while turnaround time for the Shuttle fleet rarely approached that status. The reusability of the Shuttle is not even worthy of discussion, as that was a marketing scam designed to snooker Members of Congress into believing it would make the Orbiter cheaper. Instead, it wound up making it much more expensive, and the hard working parts on it were not actually reusable.
However, having said all that, I need to point out that I'm not a rocket scientist, but my father is. One day, I took him to the Air and Space museum to look at a bunch of Soviet manned space hardware. He wandered around, mouth agape, amazed at what the Soviets were getting away with. "Look at the lines going into that goddamned fuel tank--they're built out of plumbing parts," I remember him saying, then he took me over to the Skylab mock-up to show me how on American systems, every weld is machined flush, every wire is a direct connection with no splices, every metal-on-metal interface is carefully calculated so that they expand at the same or similar rates under heat load, and so on.
The problem, of course, is all that effort to build a launch system that was reliable out to "four nines," or 99.99%, was negated by building into the Shuttle system a number of fundamental flaws that could never be corrected enough to become that reliable.
Edit: Those of you who note an apparent contradiction between what I said and what Warren said above should know that I've counted Soyuz 1 and 11, both of which were fatal accidents using early Soyuz craft before they were redesigned. After the redesign, as Warren notes, Soyuz's reliability is amazingly high for such a no-frills operation.
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