This is why I'm souring on static fires. Two days ago they didn't have an O2 leak, now they do. Should have launched on Wed instead of doing the dress rehearsal.Static fires don't prevent problems from happening later on.
Quote from: Norm38 on 06/26/2020 06:54 pmThis is why I'm souring on static fires. Two days ago they didn't have an O2 leak, now they do. Should have launched on Wed instead of doing the dress rehearsal.Static fires don't prevent problems from happening later on.Think about what you just said. You have 0 idea there was a leak when they fired, it’s possible there was hence why no immediate tweet from them. Also, if they launch the leak develops in flight, and ends in a loss of mission. Static fires really do help......
Quote from: RocketLover0119 on 06/26/2020 07:01 pmQuote from: Norm38 on 06/26/2020 06:54 pmThis is why I'm souring on static fires. Two days ago they didn't have an O2 leak, now they do. Should have launched on Wed instead of doing the dress rehearsal.Static fires don't prevent problems from happening later on.Think about what you just said. You have 0 idea there was a leak when they fired, it’s possible there was hence why no immediate tweet from them. Also, if they launch the leak develops in flight, and ends in a loss of mission. Static fires really do help......The opposite. I know there was no leak on Wed, else they wouldn’t have fired. You have no certainty this leak would have resulted in failure. And you can’t predict this leak. It’s the N+1 fallacy, I know. Flip the switch N times, that means N+1 won’t fail. No. Because I have seen test 501 fail. There is no benefit to making N large. Only more cost and lost time.
The opposite. I know there was no leak on Wed, else they wouldn’t have fired.
If you are afraid that removing a single test will miss things, your system is not robust by any definition.The N+1 fallacy works both ways.But entropy only moves right.
As far as I know, the leak rumour is only based on a post in Reddit. I would be careful to take such statements for fact.
Quote from: TorenAltair on 06/27/2020 08:39 amAs far as I know, the leak rumour is only based on a post in Reddit. I would be careful to take such statements for fact.A good indication of its legitimacy is that it was deleted. No idea why but SpaceX really cracks down on employees whenever they do the PR teams job of being transparent. I've seen a couple of different reddit users talk about SpaceX stuff that turns out to be true and they always delete the post and account an hour or so after posting.It's disappointing to see SpaceX crack down on transparency but it's a good indication that it's the truth.
A good indication of its legitimacy is that it was deleted.
Quote from: Norm38 on 06/27/2020 02:31 amIf you are afraid that removing a single test will miss things, your system is not robust by any definition.The N+1 fallacy works both ways.But entropy only moves right.Come on you know better. That's NOT a test. It was a WDR to shake things up for a 4 time flight old used rocket!
Quote from: king1999 on 06/27/2020 04:51 amQuote from: Norm38 on 06/27/2020 02:31 amIf you are afraid that removing a single test will miss things, your system is not robust by any definition.The N+1 fallacy works both ways.But entropy only moves right.Come on you know better. That's NOT a test. It was a WDR to shake things up for a 4 time flight old used rocket!If static fires are being done to “shake things up” and see what comes loose, I consider that to be a problem. The only reason to intentionally cycle a system as a test is if you know there are infant mortality failure modes to get past. After that cycles only add stress. But expendable rockets aren’t allowed to have infant mortality, and reusable ones aren’t either.
Regardless of the rest, which others have addressed, I’d like to point out that “transparency” is not a requirement in any fashion, and is not even a realistic expectation. We certainly shouldn’t feel any special entitlement to additional info. We certainly want them to relay lots of information. That’s great for us. But SpaceX is under no obligation to relay what’s going on. There are a ton of reasons they might not release information, many of them altogether boring.Even if they do say something - perhaps the time hasn’t come yet. They’ll sometimes give a quick passing statement about issues leading to launch, during the webcast.
Oh yeh by no means is SpaceX or anyone obligated to tell what they're doing. They don't even have to do a webcast. They're definitely one of the more open, if not the most open aerospace corporations. However, if you want to call yourself a transparent company, you better live up to that by telling about why things are delayed, don't ignore a landing failure for several weeks or pretend the fairing catch attempt never happened when it splashed down.
So SpaceX refurbished the rocket for the fourth times, and cleaning up some components here, changing a few parts there. Don't you think it is beneficial for them to do a WDR to make sure nothing is missed in the process? I think that's common sense to me.The MD engines are designed to work 10 flights without major maintenance. I don't think a few seconds of WDR firing would add any meaningful stress to them. If that's the case, I consider THAT to be a problem.