Author Topic: ULA Atlas V Human Rating/Commercial Crew Threads  (Read 14302 times)

Online 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

Offline BrightLight

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Re: ULA Atlas V Human Rating/Commercial Crew Threads
« Reply #1 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.

Offline Robotbeat

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Re: ULA Atlas V Human Rating/Commercial Crew Threads
« Reply #2 on: 08/30/2012 06:49 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.
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).
« Last Edit: 08/30/2012 06:54 PM by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline BrightLight

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Re: ULA Atlas V Human Rating/Commercial Crew Threads
« Reply #3 on: 08/30/2012 07:07 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.
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).
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.

Offline Robotbeat

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Re: ULA Atlas V Human Rating/Commercial Crew Threads
« Reply #4 on: 08/30/2012 08:10 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.
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).
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.
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.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline edkyle99

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Re: ULA Atlas V Human Rating/Commercial Crew Threads
« Reply #5 on: 08/30/2012 08:44 PM »
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.

I do, in both cases.  Fail is fail.  Success is success.  I measure launch vehicle hardware performance strictly as fail/succeed, because it either works or it doesn't.

Centaur's RL-10 leaked propellant during coast - due to a faulty valve - and the stage ran out of propellant during its second burn, falling short of its planned final velocity.  That's a vehicle failure, regardless of the mission outcome.  (But FWIW, I've heard that the customer was not happy.)

Others may keep track of mission fail/success, which is a different measurement.

 - Ed Kyle
« Last Edit: 08/30/2012 08:45 PM by edkyle99 »

Offline rcoppola

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Re: ULA Atlas V Human Rating/Commercial Crew Threads
« Reply #6 on: 08/30/2012 08:50 PM »
Nobody would begrudge their excellent success rate. But truth be told, the Gov't pays an awful lot of money to ensure that. Justifiably so with regards to the expense of most of its' payloads.

I am curious as to see them maintaining that success but now do it within the context of competing in an open commercial competition, not an artificial Gov't one.

I'll be curious to see the cost difference to NASA between CST-100 on AV compared to Dragon on F9. After all, that is what this is all about, right?
Lower costs through competition?

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Offline Robotbeat

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Re: ULA Atlas V Human Rating/Commercial Crew Threads
« Reply #7 on: 08/30/2012 09:03 PM »
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.

I do, in both cases.  Fail is fail.  Success is success.  I measure launch vehicle hardware performance strictly as fail/succeed, because it either works or it doesn't.

Centaur's RL-10 leaked propellant during coast - due to a faulty valve - and the stage ran out of propellant during its second burn, falling short of its planned final velocity.  That's a vehicle failure, regardless of the mission outcome.  (But FWIW, I've heard that the customer was not happy.)

Others may keep track of mission fail/success, which is a different measurement.

 - Ed Kyle
By this standard, no one would ever use redundant engines, because it's still considered a failure... In the data storage industry, that's a little weird... you don't count single drive failures (in a RAID 5 or 6 or 1 or 10, etc) as system failures even if there's a performance degradation, because your data still is intact and usable. But I digress.

I can respect your view, Ed, because it's consistent, even if I think it's a little weird to count failures or underperformances as full failures when the spacecraft is intact and usable for its original purpose.
« Last Edit: 08/30/2012 09:14 PM by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline BrightLight

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Re: ULA Atlas V Human Rating/Commercial Crew Threads
« Reply #8 on: 08/30/2012 10:02 PM »
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.

I do, in both cases.  Fail is fail.  Success is success.  I measure launch vehicle hardware performance strictly as fail/succeed, because it either works or it doesn't.

Centaur's RL-10 leaked propellant during coast - due to a faulty valve - and the stage ran out of propellant during its second burn, falling short of its planned final velocity.  That's a vehicle failure, regardless of the mission outcome.  (But FWIW, I've heard that the customer was not happy.)

Others may keep track of mission fail/success, which is a different measurement.

 - Ed Kyle
By this standard, no one would ever use redundant engines, because it's still considered a failure... In the data storage industry, that's a little weird... you don't count single drive failures (in a RAID 5 or 6 or 1 or 10, etc) as system failures even if there's a performance degradation, because your data still is intact and usable. But I digress.

I can respect your view, Ed, because it's consistent, even if I think it's a little weird to count failures or underperformances as full failures when the spacecraft is intact and usable for its original purpose.
In verification and validation (V&V) there can be system performance (provider requirements)and mission performance (customer requirements) metrics. Very often they are combined in some set of requirements that the provider and customer agree upon.  From a systems perspective, pass/fail is used to determine if the system i.e. the AV LV has performed its job, so far that's 31 out of 32 launches (97%).  In contrast, the mission requirements might be more subjective as in "did the payload get to a usable orbit" and it would appear to be 32 out of 32 launches (100%).  I didn't know the customer was not happy with NRO L-30 placement.

Offline Robotbeat

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Re: ULA Atlas V Human Rating/Commercial Crew Threads
« Reply #9 on: 08/30/2012 10:23 PM »
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.

I do, in both cases.  Fail is fail.  Success is success.  I measure launch vehicle hardware performance strictly as fail/succeed, because it either works or it doesn't.

Centaur's RL-10 leaked propellant during coast - due to a faulty valve - and the stage ran out of propellant during its second burn, falling short of its planned final velocity.  That's a vehicle failure, regardless of the mission outcome.  (But FWIW, I've heard that the customer was not happy.)

Others may keep track of mission fail/success, which is a different measurement.

 - Ed Kyle
By this standard, no one would ever use redundant engines, because it's still considered a failure... In the data storage industry, that's a little weird... you don't count single drive failures (in a RAID 5 or 6 or 1 or 10, etc) as system failures even if there's a performance degradation, because your data still is intact and usable. But I digress.

I can respect your view, Ed, because it's consistent, even if I think it's a little weird to count failures or underperformances as full failures when the spacecraft is intact and usable for its original purpose.
In verification and validation (V&V) there can be system performance (provider requirements)and mission performance (customer requirements) metrics. Very often they are combined in some set of requirements that the provider and customer agree upon.  From a systems perspective, pass/fail is used to determine if the system i.e. the AV LV has performed its job, so far that's 31 out of 32 launches (97%).  In contrast, the mission requirements might be more subjective as in "did the payload get to a usable orbit" and it would appear to be 32 out of 32 launches (100%).  I didn't know the customer was not happy with NRO L-30 placement.
And yet, how many people count those two Shuttle missions failures? Very, very few.

The customer of NRO L-30 considered the launch a success.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline notsorandom

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Re: ULA Atlas V Human Rating/Commercial Crew Threads
« Reply #10 on: 08/30/2012 10:49 PM »
Counting historical failure rates is at best a rough way of determining a system's safety. For one thing once a failure happens the system is changed to minimize or eliminate the risk on future launches. This was very visible in the SSP with the SRB joint, and ET redesign after the losses. Actually there were a lot of other potential failure modes that got fixed on both those RTF efforts. SpaceX tweaked the Falcon 1 design until they got it right. So its not very meaningful to add all the launches of a rocket together in one statistical basket. The last launch of a rocket or program is going to be safer then the first.

Its also assuming that all payloads and orbits are the same. Higher orbits require longer burn times, more engine starts, and sometimes more stages. There are a few recent Proton launches which would have been successful if they were launched into LEO. The failures happened in the Breeze-M or Block-DM stages.

Offline edkyle99

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Re: ULA Atlas V Human Rating/Commercial Crew Threads
« Reply #11 on: 08/31/2012 02:00 PM »
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.

I do, in both cases.  Fail is fail.  Success is success.  I measure launch vehicle hardware performance strictly as fail/succeed, because it either works or it doesn't.

Centaur's RL-10 leaked propellant during coast - due to a faulty valve - and the stage ran out of propellant during its second burn, falling short of its planned final velocity.  That's a vehicle failure, regardless of the mission outcome.  (But FWIW, I've heard that the customer was not happy.)

Others may keep track of mission fail/success, which is a different measurement.

 - Ed Kyle
By this standard, no one would ever use redundant engines, because it's still considered a failure... In the data storage industry, that's a little weird... you don't count single drive failures (in a RAID 5 or 6 or 1 or 10, etc) as system failures even if there's a performance degradation, because your data still is intact and usable. But I digress.

I can respect your view, Ed, because it's consistent, even if I think it's a little weird to count failures or underperformances as full failures when the spacecraft is intact and usable for its original purpose.

To clarify, my standard is based on insertion orbit parameters - did the vehicle put the payload where it was supposed to go?  If a vehicle has a hardware failure that is "saved" by a backup system and the orbit is achieved, then "success". 

 - Ed Kyle

Offline edkyle99

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Re: ULA Atlas V Human Rating/Commercial Crew Threads
« Reply #12 on: 08/31/2012 02:15 PM »
Counting historical failure rates is at best a rough way of determining a system's safety. For one thing once a failure happens the system is changed to minimize or eliminate the risk on future launches. This was very visible in the SSP with the SRB joint, and ET redesign after the losses. Actually there were a lot of other potential failure modes that got fixed on both those RTF efforts. SpaceX tweaked the Falcon 1 design until they got it right. So its not very meaningful to add all the launches of a rocket together in one statistical basket. The last launch of a rocket or program is going to be safer then the first.
If all vehicles are measured the same way, pass/fail from the first launch, then a side-by-side comparison is available that should be combined with a measure of uncertainty based on the number of "samples".  Ariane 5 failed on its first launch, but obviously a then 0% success rate was far from the final result.  On the other hand, Falcon 1's 0 for 3 start does, I believe, tell something about the design.  Compare, for example, Pegasus which failed once in its first three tries.  Pegasus flew on for more than two decades.  Falcon 1 will likely never fly again.
Quote
Its also assuming that all payloads and orbits are the same. Higher orbits require longer burn times, more engine starts, and sometimes more stages. There are a few recent Proton launches which would have been successful if they were launched into LEO. The failures happened in the Breeze-M or Block-DM stages.
This is true.  It is best to compare rockets with similar functions.  Commercial bigsat GTO rockets can be compared, for example.  Ariane 5 ECA (35/36) leads that class.  Atlas 5 (31/32) is second, but hasn't really handled much commercial comsat business.  Proton M/Briz M (53/58) is next, followed by CZ-3(A) (33/36) and Sea Launch Zenit (30/33). 

 - Ed Kyle

Offline baldusi

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Re: ULA Atlas V Human Rating/Commercial Crew Threads
« Reply #13 on: 08/31/2012 02:36 PM »
Its also assuming that all payloads and orbits are the same. Higher orbits require longer burn times, more engine starts, and sometimes more stages. There are a few recent Proton launches which would have been successful if they were launched into LEO. The failures happened in the Breeze-M or Block-DM stages.
That's why Ariane 5 has just three stages and the EELVs just two (and Falcon 9, too). More stages means more risk. You might be interested in stage's performance, but what matter is end performance. Obviously, different missions might have different inherent risk. And not all vehicles can do all missions (Ariane 5 ECA, for example, can't do GSO).

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