Crawling from under my rock for a moment... I usually do not feel qualified to participate in many of the discussions here, but this one is approaching my area of interest.I have seen a couple of posts trying to relate past performance to reliability. That is not entirely correct. I saw one post mention the Columbia accident, which is germane to this discussion but IMHO to prove that historical success (or failure) is not a sign/confirmation of reliability. There is an interesting paper on hindsight bias and near-misses by Robin Dillon and Catherine Tinsley that relates to this topic: http://www18.georgetown.edu/data/people/tinsleyc/publication-40246.pdf.One could argue that, prior to the AMOS-6 incident, the reliability of the Falcon 9 rocket was x. Following the failure investigation and accounting for all resulting corrective actions, the reliability of a Falcon 9 rocket now is >x. In other words, although it may sound counterintuitive on the surface, a failure (and subsequent corrective actions) usually result in increased reliability.
Quote from: garcianc on 07/06/2017 03:02 amCrawling from under my rock for a moment... I usually do not feel qualified to participate in many of the discussions here, but this one is approaching my area of interest.I have seen a couple of posts trying to relate past performance to reliability. That is not entirely correct. I saw one post mention the Columbia accident, which is germane to this discussion but IMHO to prove that historical success (or failure) is not a sign/confirmation of reliability. There is an interesting paper on hindsight bias and near-misses by Robin Dillon and Catherine Tinsley that relates to this topic: http://www18.georgetown.edu/data/people/tinsleyc/publication-40246.pdf.One could argue that, prior to the AMOS-6 incident, the reliability of the Falcon 9 rocket was x. Following the failure investigation and accounting for all resulting corrective actions, the reliability of a Falcon 9 rocket now is >x. In other words, although it may sound counterintuitive on the surface, a failure (and subsequent corrective actions) usually result in increased reliability.There is no entirely correct way to calculate reliability, especially with this small a sample. But there are plenty of wrong ways to do it. In any case, the F9 rockets before, during, and after AMOS were all different, and it's different again now, and will change again in a few months. We have no way of knowing if Block 5 will be more or less reliable (at least for its first 10-20 launches) than the current vehicle, because we don't know what the changes are or whether they will introduce new unknown failure modes. SpaceX/customers/insurers know the changes, but not the effects, so they are only slightly better off than we are.
Historically SpaceX was limited by various issues, production rate, failures and are now limited by pad capacity. But what if they don't encounter another failure soon? Once LC40 and LC39A are both up they will be capable of launching almost weekly, and they actually have an *inventory of boosters* to support this. SpaceX launch rate will go up like crazy. So far this year they are already #1 by launches, responsible for fully a quarter of all successful orbital missions.So far existing providers have felt a pressure to reduce costs but did not yet encounter issues finding enough payloads to launch. If SpaceX can keep increasing their launch rate then this will change.
Quote from: envy887 on 07/06/2017 03:12 amQuote from: garcianc on 07/06/2017 03:02 amCrawling from under my rock for a moment... I usually do not feel qualified to participate in many of the discussions here, but this one is approaching my area of interest.I have seen a couple of posts trying to relate past performance to reliability. That is not entirely correct. I saw one post mention the Columbia accident, which is germane to this discussion but IMHO to prove that historical success (or failure) is not a sign/confirmation of reliability. There is an interesting paper on hindsight bias and near-misses by Robin Dillon and Catherine Tinsley that relates to this topic: http://www18.georgetown.edu/data/people/tinsleyc/publication-40246.pdf.One could argue that, prior to the AMOS-6 incident, the reliability of the Falcon 9 rocket was x. Following the failure investigation and accounting for all resulting corrective actions, the reliability of a Falcon 9 rocket now is >x. In other words, although it may sound counterintuitive on the surface, a failure (and subsequent corrective actions) usually result in increased reliability.There is no entirely correct way to calculate reliability, especially with this small a sample. But there are plenty of wrong ways to do it. In any case, the F9 rockets before, during, and after AMOS were all different, and it's different again now, and will change again in a few months. We have no way of knowing if Block 5 will be more or less reliable (at least for its first 10-20 launches) than the current vehicle, because we don't know what the changes are or whether they will introduce new unknown failure modes. SpaceX/customers/insurers know the changes, but not the effects, so they are only slightly better off than we are.This is so wrong I don't know where to begin...
Quote from: M.E.T. on 07/05/2017 08:45 amWill we ever get to a point where a higher failure rate - on unmanned flights - becomes an acceptable price to pay for dramatically lower launch costs?Say 5 failures in every 100 launches, but in exchange for an order of magnitude drop in launch costs?5 percent is the overall current failure rate for orbital launch vehicles world-wide, expendable or not. Falcon 9 has an 8 percent failure rate so far if AMOS 6 is included. SpaceX will have to improve that rate no matter what it charges for a launch if it wants to compete with Arianespace and ULA, which have demonstrate 1-3% failure rates. - Ed Kyle
Will we ever get to a point where a higher failure rate - on unmanned flights - becomes an acceptable price to pay for dramatically lower launch costs?Say 5 failures in every 100 launches, but in exchange for an order of magnitude drop in launch costs?
Quote from: edkyle99 on 07/05/2017 01:27 pmQuote from: M.E.T. on 07/05/2017 08:45 amWill we ever get to a point where a higher failure rate - on unmanned flights - becomes an acceptable price to pay for dramatically lower launch costs?Say 5 failures in every 100 launches, but in exchange for an order of magnitude drop in launch costs?5 percent is the overall current failure rate for orbital launch vehicles world-wide, expendable or not. Falcon 9 has an 8 percent failure rate so far if AMOS 6 is included. SpaceX will have to improve that rate no matter what it charges for a launch if it wants to compete with Arianespace and ULA, which have demonstrate 1-3% failure rates. - Ed KyleThe better reliability of Ariane 5 compared to Falcon 9 comes courtesy of the former rocket having flown more often than the latter.Now, let's do apples to apples:- Ariane 5 suffered two (2) complete failures and two (2) partial failures in it's first 38 launches.- Falcon 9 suffered two (2) complete failures and one (1) partial failures in it's first 38 launches.So, comparing vehicle reliablity, based on a similar number of launches, the Falcon 9 is actually more reliable than Ariane 5 was back then. And that little fact becomes more remarkable considering that it took SpaceX just seven (7) years to do those 38 launches whereas it took 12 years for the first 38 launches of Ariane 5.
ULA is retiring Atlas and Delta not due to competition, but because it is being forced to stop using RD-180.
Quote from: AncientU on 07/05/2017 02:29 pmDelta is 100% being retired because it is not cost competitive -- nothing to do with RD-180. The supply of RD-180s extends to the horizon due to political boosterism. Atlas V as-is is not cost-competitive... and its renowned reliability is insufficient to overcome that fact. As the new Block 4/5 come into play, the Atlas V 531/541/551 versions will be even less competitive because they are all going up against the same Falcon as the 401.If Atlas 5 is not competitive, why does it keep winning new launches? If Delta 4 is not competitive, why is it slated to most-likely out-last Atlas 5? Did SpaceX even make a profit launching Bulgariasat for $60 million, or whatever it was (given the company's $1 billion cost to develop first stage recovery)? My guess is that ULA made money launching WGS 9, etc.. - Ed Kyle
Delta is 100% being retired because it is not cost competitive -- nothing to do with RD-180. The supply of RD-180s extends to the horizon due to political boosterism. Atlas V as-is is not cost-competitive... and its renowned reliability is insufficient to overcome that fact. As the new Block 4/5 come into play, the Atlas V 531/541/551 versions will be even less competitive because they are all going up against the same Falcon as the 401.
I'll start. Initial assumption is that SpaceX change stuff for every flight. This is almost certainly true. BUT, its also true of all the other launch providers - there are changes to Ariane, or Delta for every flight. I know this because Jim said it a year or so back. So incorporating that to SpaceX probability without also taking it in to account for other providers is wrong.
Of course, we know that SpaceX are making changes for block 5 to improve reliability and reusability. So to say we don't know whether it will improve reliability is to basically saying the engineers don't know what they are doing, and Block 5 is a waste of time. We CAN assume that changes made specifically to improve reliability are going to actually improve reliability. Its not proven until they fly of course, but we can make that assumption.
Elon Musk’s SpaceX is out-launching its biggest competitors for the first time ever
This is what it looks like when a start-up disrupts an existing industry.With its successful launch of a communications satellite last night, SpaceX has flown ten rockets this year. Elon Musk’s rocket company has now beat its own annual record, and the firm is on pace to out-launch its key rivals in the commercial launch market, Europe’s Arianespace and United Launch Alliance (ULA), a joint venture of Boeing and Lockheed Martin.It has taken just seven years since the company’s first Falcon 9 rocket flew for SpaceX to dominate the launch market by offering cheaper and, increasingly, faster service to orbit.
QuoteOf course, we know that SpaceX are making changes for block 5 to improve reliability and reusability. So to say we don't know whether it will improve reliability is to basically saying the engineers don't know what they are doing, and Block 5 is a waste of time. We CAN assume that changes made specifically to improve reliability are going to actually improve reliability. Its not proven until they fly of course, but we can make that assumption. Block 4/5 is not just fixing reliability issues. We know there is a thrust upgrade coming from running Merlin harder. You can assume that's going to make it more reliable, but customers and insurers will assume its a potential failure mode.
Near-misses offer evidence of both a system’s resilience (failure averted) and its vulnerability (failurenarrowly averted) (March et al. 1991). Therefore, a near-miss resembles a success in terms of ultimateoutcome, but resembles a failure in other details, such as problems arising before the outcome. However,consistent with outcome bias (Baron and Hershey 1988), we believe that decision makers will evaluatea near-miss like a success based on the ultimate outcome. Thus, we expect near-misses to be judged in asimilar manner as successes and in a significantly different manner from failures despite the fact that suchnear-misses would have been failures except for an element of chance.
Quote from: garcianc on 07/06/2017 03:02 amCrawling from under my rock for a moment... I usually do not feel qualified to participate in many of the discussions here, but this one is approaching my area of interest.I have seen a couple of posts trying to relate past performance to reliability. That is not entirely correct. I saw one post mention the Columbia accident, which is germane to this discussion but IMHO to prove that historical success (or failure) is not a sign/confirmation of reliability. There is an interesting paper on hindsight bias and near-misses by Robin Dillon and Catherine Tinsley that relates to this topic: http://www18.georgetown.edu/data/people/tinsleyc/publication-40246.pdf.One could argue that, prior to the AMOS-6 incident, the reliability of the Falcon 9 rocket was x. Following the failure investigation and accounting for all resulting corrective actions, the reliability of a Falcon 9 rocket now is >x. In other words, although it may sound counterintuitive on the surface, a failure (and subsequent corrective actions) usually result in increased reliability.Wow, great article! Thanks for making it available.One gem on Outcome Bias (emphasis mine):QuoteNear-misses offer evidence of both a system’s resilience (failure averted) and its vulnerability (failurenarrowly averted) (March et al. 1991). Therefore, a near-miss resembles a success in terms of ultimateoutcome, but resembles a failure in other details, such as problems arising before the outcome. However,consistent with outcome bias (Baron and Hershey 1988), we believe that decision makers will evaluatea near-miss like a success based on the ultimate outcome. Thus, we expect near-misses to be judged in asimilar manner as successes and in a significantly different manner from failures despite the fact that suchnear-misses would have been failures except for an element of chance.Sounds familiar...
Quote from: AncientU on 07/06/2017 05:18 pmQuote from: garcianc on 07/06/2017 03:02 amCrawling from under my rock for a moment... I usually do not feel qualified to participate in many of the discussions here, but this one is approaching my area of interest.I have seen a couple of posts trying to relate past performance to reliability. That is not entirely correct. I saw one post mention the Columbia accident, which is germane to this discussion but IMHO to prove that historical success (or failure) is not a sign/confirmation of reliability. There is an interesting paper on hindsight bias and near-misses by Robin Dillon and Catherine Tinsley that relates to this topic: http://www18.georgetown.edu/data/people/tinsleyc/publication-40246.pdf.One could argue that, prior to the AMOS-6 incident, the reliability of the Falcon 9 rocket was x. Following the failure investigation and accounting for all resulting corrective actions, the reliability of a Falcon 9 rocket now is >x. In other words, although it may sound counterintuitive on the surface, a failure (and subsequent corrective actions) usually result in increased reliability.Wow, great article! Thanks for making it available.One gem on Outcome Bias (emphasis mine):QuoteNear-misses offer evidence of both a system’s resilience (failure averted) and its vulnerability (failurenarrowly averted) (March et al. 1991). Therefore, a near-miss resembles a success in terms of ultimateoutcome, but resembles a failure in other details, such as problems arising before the outcome. However,consistent with outcome bias (Baron and Hershey 1988), we believe that decision makers will evaluatea near-miss like a success based on the ultimate outcome. Thus, we expect near-misses to be judged in asimilar manner as successes and in a significantly different manner from failures despite the fact that suchnear-misses would have been failures except for an element of chance.Sounds familiar...We also shouldn't discount the huge advantage of being able to land your boosters, inspect them, and compare observed wear rates/etc against the predicted/modeled ones, and using it to improve your design. This is an advantage that right now only SpaceX enjoys.
It seems more and more like the strategy for SpaceX's competitors is "hope they get RUDs and we don't"However, using this 'strategy' is going to have diminishing returns. ULA or Arianespace could have a RUD, and the business case for their higher prices disappears.