Commercial and US Government Launch Vehicles > ULA - Delta, Atlas, Vulcan

ULA Atlas V Human Rating/Commercial Crew Threads

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Chris Bergin:
Whille we have this ULA specific section now live, we are continuing to keep the specific ULA/Atlas V threads relating to HR and Commercial Crew in the Commercial Crew Vehicle Section:

http://forum.nasaspaceflight.com/index.php?board=56.0

This section also includes the CST-100 and Dream Chaser threads, but for the specific Atlas V HR articles, see here:

NASA and ULA agree SAA to complete the human rating of Atlas V
http://forum.nasaspaceflight.com/index.php?topic=26059.0

Formation of ULA Human Launch Services Organization
http://forum.nasaspaceflight.com/index.php?topic=28588.0

NASA and ULA confirm Atlas V baseline for human rated launches
http://forum.nasaspaceflight.com/index.php?topic=29487.0

The Respected Rocket - Atlas V making the early strides of the transition
http://forum.nasaspaceflight.com/index.php?topic=27376.0

BrightLight:
I think with the latest launch of the Atlas V, this brings us to 31 out of 32 missions with 100% success or 96.875% payload to orbit.

Robotbeat:

--- Quote from: BrightLight on 08/30/2012 06:23 pm ---I think with the latest launch of the Atlas V, this brings us to 31 out of 32 missions with 100% success or 96.875% payload to orbit.

--- End quote ---
Or, considering that the customer considered it a success (it was a useful orbit), we can say 100% success, with an asterisk, just like how we say 133 out of 135 Shuttle flights were successful, even though STS-51F was an abort-to-orbit (engine out, so although it was a useful orbit and they did the rest of the mission, there was an underperformance of the launch system). STS-93, just like the Atlas V in question, also had a premature shutdown and ended up in a lower but still useful orbit, and just like Atlas V, the mission continued. But people RARELY call STS-51F and STS-93 actual mission failures, so the same standard should be applied to Atlas V.

Either:
Shuttle has a 98.5% success rate (133 successful, 2 flight failures) and Atlas V an 100% success rate (32 successful, 0 flight failures).
OR
Shuttle has a 97% success rate (131 successful, 4 failures) and Atlas V has a 97% success rate (31 successful, 1 failure).

Have to use the same standard. I prefer to use the same standard people usually apply to Shuttle, which is to say Atlas V has a 100% mission success rate (according to the customer).

BrightLight:

--- Quote from: Robotbeat on 08/30/2012 06:49 pm ---
--- Quote from: BrightLight on 08/30/2012 06:23 pm ---I think with the latest launch of the Atlas V, this brings us to 31 out of 32 missions with 100% success or 96.875% payload to orbit.

--- End quote ---
Or, considering that the customer considered it a success (it was a useful orbit), we can say 100% success, with an asterisk, just like how we say 133 out of 135 Shuttle flights were successful, even though STS-51F was an abort-to-orbit (engine out, so although it was a useful orbit and they did the rest of the mission, there was an underperformance of the launch system). STS-93, just like the Atlas V in question, also had a premature shutdown and ended up in a lower but still useful orbit, and just like Atlas V, the mission continued. But people RARELY call STS-51F and STS-93 actual mission failures, so the same standard should be applied to Atlas V.

Either:
Shuttle has a 98.5% success rate (133 successful, 2 flight failures) and Atlas V an 100% success rate (32 successful, 0 flight failures).
OR
Shuttle has a 97% success rate (131 successful, 4 failures) and Atlas V has a 97% success rate (31 successful, 1 failure).

Have to use the same standard. I prefer to use the same standard people usually apply to Shuttle, which is to say Atlas V has a 100% mission success rate (according to the customer).

--- End quote ---
In a statistical evaluation I try to be conservative thus, the 96.9 value. However, one can also easily claim LOM 0% (as you did  ;) and thus 32 out of 32 completed launches and payloads to useful orbits 100%. In the end, getting the payload up in one piece and in a productive orbit is what counts.

Robotbeat:

--- Quote from: BrightLight on 08/30/2012 07:07 pm ---
--- Quote from: Robotbeat on 08/30/2012 06:49 pm ---
--- Quote from: BrightLight on 08/30/2012 06:23 pm ---I think with the latest launch of the Atlas V, this brings us to 31 out of 32 missions with 100% success or 96.875% payload to orbit.

--- End quote ---
Or, considering that the customer considered it a success (it was a useful orbit), we can say 100% success, with an asterisk, just like how we say 133 out of 135 Shuttle flights were successful, even though STS-51F was an abort-to-orbit (engine out, so although it was a useful orbit and they did the rest of the mission, there was an underperformance of the launch system). STS-93, just like the Atlas V in question, also had a premature shutdown and ended up in a lower but still useful orbit, and just like Atlas V, the mission continued. But people RARELY call STS-51F and STS-93 actual mission failures, so the same standard should be applied to Atlas V.

Either:
Shuttle has a 98.5% success rate (133 successful, 2 flight failures) and Atlas V an 100% success rate (32 successful, 0 flight failures).
OR
Shuttle has a 97% success rate (131 successful, 4 failures) and Atlas V has a 97% success rate (31 successful, 1 failure).

Have to use the same standard. I prefer to use the same standard people usually apply to Shuttle, which is to say Atlas V has a 100% mission success rate (according to the customer).

--- End quote ---
In a statistical evaluation I try to be conservative thus, the 96.9 value. However, one can also easily claim LOM 0% (as you did  ;) and thus 32 out of 32 completed launches and payloads to useful orbits 100%. In the end, getting the payload up in one piece and in a productive orbit is what counts.

--- End quote ---
I always thought the fairest way to do it is to add an extra /half/ failure to an otherwise perfect record, then say you have an uncertainty of at least half a launch. Or rather, say the reliability is probably between one extra failure and perfect: Atlas V is 97-100% reliable.

But I still don't think it's fair to count that one early shutdown against Atlas V as a full failure, since people don't do that for Shuttle.

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