FAA investigating SpaceX Falcon 9 rocket anomaly

[Admin]

The U.S. Federal Aviation Administration is requiring an investigation into the anomaly experienced by a SpaceX Falcon 9 rocket during a July 11 Starlink satellite launch.

FAA investigating SpaceX Falcon 9 rocket anomaly : Read more

 

[Unclear Engineer]

The failure was with the Merlin rocket motor on the upper, non-recoverable stage of the launch vehicle. That is the same rocket motor used in first stage, so I guess that is the issue the FAA is looking at.

I think the Dragon service module uses the Draco rocket motors, not the Merlins.

So, considering the number launches of the Falcon 9 rockets, with (9 + 1 =) 10 Merlin engines firing in each, what is the "failure rate" of a Merlin rocket motor? And, is that acceptable if it is a random problem rather than some sort of fabrication problem?

 

[Unclear Engineer]

I see some stats showing 354 Falcon ( launches and 10 Falcon Heavy Launches. There was one previous in-flight failure in 2015. On a vehicle basis , that looks like a 0.55% failure rate. On a per rocket motor basis, that looks like a 0.04% failure rate.

That still looks pretty good, compared to the competition. See https://www.bbc.com/future/article/20230518-what-are-the-odds-of-a-successful-space-launch .

That website says:
""Typically, first or second launch, you expect something like 30% of them to fail,"
"Then things start to get better thereafter, by the time you're up to the 10th flight, you're probably looking at a less than 5% failure rate.
"The launch failure rate (all time) for manned/human-carrying missions are lower at around 2%, and only around 1% involve a total failure to orbit,"
"Failure also includes the rocket's payload not reaching the intended orbit or it being significantly damaged in launch, not just failing to achieve orbit. Look at launches in the 1950s, in those first stumbling leaps of the space race, and the failures rates are shockingly different – more than 70%. It only took until the early 1960s for this number to start falling and it has hovered around the same point ever since – around 7% (9% if satellite-related launch failures are included).
"Proton's success rate and the European Ariane 4 and the American Delta II rocket, chalked up more than 100 successful launches in a row.
The Russian Proton vehicle had a failure every 20 to 25 flights.

So, perfection is not expected, and should not be required, although it should be the goal.

When it is not the goal, you get Boeing's recent performance.

 

[vitiral]

I see some stats showing 354 Falcon ( launches and 10 Falcon Heavy Launches. There was one previous in-flight failure in 2015. On a vehicle basis , that looks like a 0.55% failure rate. On a per rocket motor basis, that looks like a 0.04% failure rate.

That still looks pretty good, compared to the competition. See https://www.bbc.com/future/article/20230518-what-are-the-odds-of-a-successful-space-launch .

That website says:
""Typically, first or second launch, you expect something like 30% of them to fail,"
"Then things start to get better thereafter, by the time you're up to the 10th flight, you're probably looking at a less than 5% failure rate.
"The launch failure rate (all time) for manned/human-carrying missions are lower at around 2%, and only around 1% involve a total failure to orbit,"
"Failure also includes the rocket's payload not reaching the intended orbit or it being significantly damaged in launch, not just failing to achieve orbit. Look at launches in the 1950s, in those first stumbling leaps of the space race, and the failures rates are shockingly different – more than 70%. It only took until the early 1960s for this number to start falling and it has hovered around the same point ever since – around 7% (9% if satellite-related launch failures are included).
"Proton's success rate and the European Ariane 4 and the American Delta II rocket, chalked up more than 100 successful launches in a row.
The Russian Proton vehicle had a failure every 20 to 25 flights.

So, perfection is not expected, and should not be required, although it should be the goal.

When it is not the goal, you get Boeing's recent performance.

Regardless of previous track record, any failure requires an investigation in order to attempt to determine whether the issue is systemic or not. Maybe a small change in a manufacturing process or personnel is causing an increased failure rate in Merlin engines? All reasonable attempts should be made to identify and rectify such situations if possible before launching other vehicles.

It's important to not rest on your laurels for something as high-stakes and high-precision as rocket engineering.

 

[Unclear Engineer]

While it is true that it is important to investigate failures and determine causes, and then fix them, it is not clear that it always requires bureaucratic oversight, much less bureaucratic control.

For instance, I don't think the FAA grounds all aircraft that use a particular jet engine when one airplane has a single engine failure in flight.

I don't think the Dragon Capsule launches even use the same second stage as the StarLink launches. (But I may be wrong about that - can't find a good description for both.)

Anyway, clearly the FAA did not ground all Boeing 737 Max aircraft after the first crash, and get that problem fixed, considering that they had a second crash for the same reason with the same aircraft type.

The FAA just seems to be unusually hard to please when dealing with SpaceX.

 

[COLGeek]

The FAA just seems to be unusually hard to please when dealing with SpaceX.

This isn't true. Ask any company that works with the FAA post-incident.

I worked with them for several years, in a previous life, and found them to be quite professional. Fair, but firm. No favorites.

 

[Classical Motion]

It depends on what "work with" means. In my previous life I worked "with" several agencies.

Some with was consulting and an affirmation of policy.

And some with was for consulting and working under subject of policy.

And for me the attitude of our agencies has changed a lot over the years.

I sensed a built in bias. And tried to stay away from it later.

But that was just my experience. And not part of a study.

 

[COLGeek]

It depends on what "work with" means. In my previous life I worked "with" several agencies.

Some with was consulting and an affirmation of policy.

And some with was for consulting and working under subject of policy.

And for me the attitude of our agencies has changed a lot over the years.

I sensed a built in bias. And tried to stay away from it later.

But that was just my experience. And not part of a study.

My former agency worked directly with FAA at multiple levels. Zero bias. Just how I saw it from my former positions.

 

[Unclear Engineer]

I did not work for or with the FAA, but I did work for a Federal regulatory agency for a while, and it did have biases - which changed over the years.

At this point in time, with the FAA and SpaceX and Boeing, I seem to see a bias towards Boeing and against SpaceX. For instance, Boeing's capsule is now at the ISS, with the same thruster problems it had during its previous flight, and NASA is doing experiments at White Sands to "understand" the problem(s?) while a planned 10 day mission frags towards 90 days.. On the other hand, SpaceX twice launched at SuperHeavy + StarShip which stayed within its approved flight envelope, but FAA declared it a "mishap" because not everything worked right the first time. And, the Boeing flight is crewed, while the SpaceX flight was not crewed and was not expected to work perfectly.

So, from my perspective, SpaceX is doing what it should be doing to find and fix problems during a developmental launch sequence, while Boeing is supposed to be demonstrating that it has fixed its problems and can be "crew rated". So, which one is having unexpected problems and which one is getting more FAA limitations? Seems inconsistent to me.

So, I am not saying that the Falcon 9 upper stage motor RUD is inconsequential, I am just saying that I doubt the FAA is needed to get that analyzed and resolved. Boeing, on the other hand, has just pled guilty to a felony in its aircraft business due to failure to comply with a safety culture deficiency upgrade agreement it reached to avoid prosecution for its 737 Max crashes. Do you really think that the safety culture is different in their rocket divisions?

Speaking of biases, I note that Space.com has still not reported on the Boeing guilty verdict, but has reported on lawsuits by some of SpaceX's ex-employees alleging discrimination. That seems backwards for a publication supposedly focused on the science and engineering involved in space flight.