Every Shuttle in the fleet has had one or several extremely close scrapes with death. To look at the Shuttle record and see the history of calamity it's easy to think that we just had bad luck, but quite the opposite was the case. We were enormously lucky with the Shuttle, in a fairer world we would have lost more of them, and sooner. The Shuttle was plagued by many fundamental design flaws which combined to make it an inherently unsafe system. Within the last years of the program that knowledge finally started to sink in, which is why the Shuttle was essentially restricted to missions to the ISS.
Some of the achievements of the Shuttle program have been inspiring, and the vehicle itself is pretty to look at, but we should have canned that program long, long ago.
In that, the Shuttle was very much like the Concorde: a unique and complex system beyond the edge of knowledge (at its creation), full of flaws and working through a combination of sheer luck and heroic efforts.
Actually the space shuttle is the safest launch vehicle to date. From the ones that have at least 100 launches (in order to be able to properly compute stats for them), here are their failure rates as taken from http://www.ontonix.com/Blog/Outliers_-_understanding_Nature_... :
I was involved in a similar discussion a couple of weeks ago. I was looking at the same figures you were and complimented the space shuttle because of it.
I was wrong, and you're making the mistake that I did. Namely confusing reliability and safety. A reliable rocket is one that successfully does what it is supposed to. A safe rocket is one that doesn't kill people.
The US space shuttle has proven to be more reliable than the Soyuz. It is more likely to actually get you into space. But the Soyuz has been safer than the US space shuttle. If you try to get into space on it, you're less likely to die.
If this seems impossible, consider that in both Soyuz 18a in 1975 and Soyuz T-10-1 in 1983 the rocket failed, but the cosmonauts survived. (In the first case the rocket failure happened 90 miles in the air, but the cosmonauts survived.) The space shuttle, by contrast, had no successful aborts.
So, this is why you top-load the crew compartment, and not side-load like the shuttle. There's no eject-system that could have saved a space shuttle in a situation like that since it would be engulfed by flames together with the rocket itself. This is also how SpaceX are doing it and for exactly this reason iirc.
Well, you are definitely right that people should go on the top of rockets, not near the middle.
The Challenger explosion could have hypothetically been survivable though. In fact, the explosion itself was survived, likely by all of the crew. The crew cabin (http://upload.wikimedia.org/wikipedia/en/thumb/4/42/Challeng...) remained intact and possibly pressurized after vehicle breakup. The crew were almost certainly alive (and if the cabin remained pressurized, could have been concious as well) for nearly 3 minutes until it hit the ocean at over 200 miles per hour.
At some point during those 3 minutes, I don't know if the SR-71 ejection seats used for the first few Shuttle launches could have improved their chances of survival, but it seems at least somewhat possible that it could have. A parachute system for the crew cabin probably wouldn't work for the same reason the launch abort system on the proposed Ares was flawed (flying burning solid fuel going everywhere in the air is bad for parachutes)... nevertheless I think it is conceivable that you could build a Shuttle that would allow the crew to survive an accident like that.
But really, just stick the people on top. It makes way more sense. I know it is hard to compare the two accidents (though from what I understand, as far as solid fuel rocket failures go Challenger was pretty tame), but the contrast between Challenger and T-10-1 is something that lessons should be taken from.
I think it is reasonable to say the shuttle was supposed to "get into space on the day it was planned to launch".
I do not have data on it, but using that yardstick or even the more lenient "get into space within a month of the planned date", I think it was not very reliable. I also have the impression (but again: I do not have data) that the Soyuz is way more reliable in that respect.
The problem is that in the list there are manned and unmanned rocket mixed. For example, the Ariane rockets are still unmanned, so if they lost one it is only an insurance problem. The Soyuz had manned and unmanned mission. But all the missions of the Shuttle were manned, so each time they had a big problem they had casualties. It would be interesting to see that includes only the manned missions.
This is a very good point for a reason that you don't call out:
Man-rated systems are DESIGNED to be much safer. The trade-off involving dollars is entirely different. You can't criticize a non-man-rated system for blowing up any more than you can criticize a UDP packet for not getting through: that trade-off was engineered in.
Those figures are a bit misleading because they include a lot of the early development phase of a vehicle in the operational history. Is it fair to include, say, the safety record of the Model-T when considering the safety of a 2012 model Ford Focus?
I've tried to find other stats but I couldn't easily find more recent numbers. 2% is the lowest fatality rate I found. There are some statements at http://en.wikipedia.org/wiki/List_of_spaceflight-related_acc... but they're not changing the picture by much:
>> About five percent of the people that have been launched have died doing so. [..] About two percent of the manned launch/reentry attempts have killed their crew, with Soyuz and the Shuttle having almost the same death percentage rates.
100 is a bit of an artificial number. The only launch vehicle in history that has had 100 manned launches has been the Shuttle, but that was a factor more of the wealth of the US than the inherent reliability of the system. Consider that Russia/USSR have only had about 2/3 of 100 total manned flights of any kind on any launcher.
Would be better to compare the fatality rate, not the failure rate. I believe Soyuz has had at least one non-fatal failure, for example, while the Shuttle's failures were both fatal. When I recall running the numbers on that, the Shuttle and Soyuz came out similar, although it's been quite a while.
This is an important point and one which many overlook. I don't blame the shuttle designers, it was a new kind space craft. The truth was that the more folks looked, the more questions they asked, the more problems were uncovered that could only be fixed by 'a complete redesign of that subsystem.' And ultimately there were few places where a complete redesign could be undertaken.
At the risk of being a negative nelly, the Soyuz design is even older, and overall probably fundamentally safer. Also, the Shuttle is only ostensibly "reusable", in reality every single flight required months of refurbishment which included meticulous inspections of the TPS tiles, complete replacement of the payload bay liner, complete purging of all fuel in the system, and even replacement of the engines.
We certainly learned a lot from Shuttle operations but in terms of spacecraft design mostly we learned what not to do.
Some of the achievements of the Shuttle program have been inspiring, and the vehicle itself is pretty to look at, but we should have canned that program long, long ago.