Blue Origin Thread (merged)

[kerbiloid]

Meanwhile

https://www.wsj.com/articles/congressional-investigators-warn-of-spacex-rocket-defects-1486067874

http://www.theverge.com/2017/2/2/14490946/spacex-rocket-engine-safety-defect-congressional-investigation-wsj-report

(If I understand right, they found some cracks in turbine blades, and this lasts about a year)

Edited February 3, 2017 by kerbiloid

[Lukaszenko]

Seems like they were always aware of the cracks, and the turbines are designed with them in mind. Cracks are not an ideal thing to have, but they are not necessarily catastrophic as long as you are aware of them and the design can cope. Airliners routinely fly with cracks, for example, with exact specifications on how long they can grow to before refurbishment is needed.

The fact that SpaceX's turbopumps aren't really known for blowing up, despite numerous reuses, kind of aligns with SpaceX's explanation.

 

 

Edited February 3, 2017 by Lukaszenko

[kerbiloid]

1 hour ago, Lukaszenko said:

The fact that SpaceX's turbopumps aren't really known for blowing up,

In single flight. But they are to be reusable.

Airliners are not so good example, as pressures a little different.

[Streetwind]

Picture of the hole-digging: http://imgur.com/iHQshpU

[Streetwind]

1 hour ago, kerbiloid said:

In single flight. But they are to be reusable.

Well, consider that beaten-up JCSAT-14 booster that SpaceX has been using as a 'life leader'. The engines on that thing survived:

- a full mission duration test firing on the engine test stand, after production
- a full mission duration test firing on the first stage test stand, after integration
- a full mission duration firing... flying the actual mission
- boostback, reentry and landing burns in the most aggressive return profile flown so far
- ten (!) full mission duration test firings on the first stage test stand, without refurbishment after the mission or in between the tests
- assorted ignition tests, hotfires and other short-duration burns at various points

Turbopumps holding up well there, IMHO.   Now that doesn't mean that having cracked turbopumps is a good thing. But it gives me the impression that SpaceX has a pretty good idea of what they can do with their engines, and fairly high confidence in being able to fly reliably with the current state of engine production quality.

In fact, I'm pretty sure SpaceX has never had a single Merlin-1D failure, ever... and they flew 240 of them, not counting the ten on AMOS-6 that never lifted off but still did their full duration test firings successfully. The only time the F9 ever made use of its engine-out capability on ascent was on v1.0, using the older Merlin-1C engines. And that wasn't a turbopump explosion, but rather something going wrong in the combustion chamber causing a shutdown (IIRC, correct me if I'm wrong). CRS flight 7 and AMOS-6 were both helium tank failures.

Are these cracks even on flight hardware, by the way? Or is SpaceX just sorting out an unusually large amount of cracked turbine blades during production, causing concern among policymakers, even though the cracked parts never fly? I asked this last time this topic came up, and couldn't get a clear answer there.

[DerekL1963]

4 hours ago, Lukaszenko said:

Airliners routinely fly with cracks, for example, with exact specifications on how long they can grow to before refurbishment is needed.

We have, literally, billions of turbine hours worth of experience.  (And a least a couple of crashes killing all aboard.)  And yet we still have events like this, and problems like this one.

SpaceX doesn't have but a miniscule fraction of a percent of that.
 

58 minutes ago, Streetwind said:

But it gives me the impression that SpaceX has a pretty good idea of what they can do with their engines, and fairly high confidence in being able to fly reliably with the current state of engine production quality.

Confidence based on a small sample size and relative lack of experience is... often misplaced.

[Streetwind]

1 hour ago, DerekL1963 said:

Confidence based on a small sample size and relative lack of experience is... often misplaced.

How large would the sample size have to be, in your opinion? Consider that flight heritages above three digits for a single engine type don't exist in rocketry (so far). And the majority of engines never goes three-digit before getting retired.

[kerbiloid]

2 hours ago, Streetwind said:

- a full mission duration test firing on the engine test stand, after production
- a full mission duration test firing on the first stage test stand, after integration
- a full mission duration firing... flying the actual mission
- boostback, reentry and landing burns in the most aggressive return profile flown so far
- ten (!) full mission duration test firings on the first stage test stand, without refurbishment after the mission or in between the tests
- assorted ignition tests, hotfires and other short-duration burns at various points

It's nice. Why didn't re-fly?
They already have at least 6 of them.
Also, Space Shuttle main engine was designed for 50 flights lifespan. While IRL did average 8.5 per engine.

Cracks are residual deformations. They accumulate from launch to launch. The more cracks - they faster they grow.
So, cracks after a single flight can cause problems in the third flight.

31 minutes ago, Streetwind said:

How large would the sample size have to be, in your opinion?

At least its planned launch count (10 or what).
And as other human-rated rockets have about, say, 0.96 probability of successful flight, there would be at least ~5 successful 10-launch series to be sure.
Seems to me that F9 will stay unmanned.

Edited February 3, 2017 by kerbiloid

[Streetwind]

30 minutes ago, kerbiloid said:

It's nice. Why didn't re-fly?

Two reasons. One, they wanted to take their worst-shape recovered booster and be really mean to it, to see what's likely to break first. Second: they needed to get a customer who's willing to take the risk first. Small sample size and all that, right?

The third launch out from now will be a booster reflight. First, CRS flight 10 on the 14th, which is a regular LEO mission with nothing special about it. Then Echostar-23, provisionally placed on the 28th, which will be the first expendable F9 launch in a long while (and probably the last one ever). After that, SES-10, which will be the first ever to fly on a "flight-proven" booster, as SpaceX likes to call things. It will reuse the core from CRS flight 8. No date has been announced yet, but "sometime in March" is a fairly good bet.

[kerbiloid]

7 minutes ago, Streetwind said:

Second: they needed to get a customer who's willing to take the risk first.

If they don't re-launch those six, they just stay metal scrap.
Why not to launch it without payload, with a water cystern instead of 2nd stage and cargo? It's anyway scrap.

(If a booster is "flight-proven", then a man age of 80 is "age-powered").

How can they prove that CRS-10 uses exactly that, used, booster, rather than new one?

Edited February 3, 2017 by kerbiloid

[Streetwind]

45 minutes ago, kerbiloid said:

How can they prove that CRS-10 uses exactly that, used, booster, rather than new one?

SES-10 uses the new booster, not CRS flight 10. NASA won't accept reflown hardware for the current CRS contract (though it might for future ones).

How to prove? I dunno. But I suppose they, like all ITAR-compliant US aerospace companies, have some very strict auditing going on. You can't just build an object the size of the Falcon 9 and have it conveniently go missing from inventory in order to pretend it was an older stage, especially not while someone's looking over your shoulder... in a factory made up of glass cubicles on the production floor.

[DerekL1963]

2 hours ago, Streetwind said:

How large would the sample size have to be, in your opinion?

I don't have an opinion, and it's pretty disingenuous to ask for one.  You're a smart guy and you know dang well the risks of generalizing from small sample.

[Streetwind]

How's that disingenious? You clearly had enough of an opinion to enter the discussion. Is it wrong to ask you for your take, then?

My take is: The Merlin-1D is probably in the top 10% of all rocket engines ever flown when considering sheer volume. It's one of the largest sample sizes you can realistically have in this business. I'll agree that it is not as good an an arbitrarily larger amount, but aerospace doesn't have that luxury. Take the Ariane 5: over the past 11 years, it flew nearly 75 times, with zero failures. That's quite a lot, more than most rockets do during their lifetime, and it makes Ariane 5 the single most reliable heavy lifter in operation today. In fact, while I'm not fully sure about this, it might be the most reliable heavy lifter that has ever existed. But that's still only 70-odd Vulcain II-1 main engines. Mathematically speaking, it's a really small, borderline insignificant sample size. And yet, insurance underwriters in a hundreds-of-million-dollars business work with that number everytime a customer wants their launch insured, because they must. It's the only sample pool they have. Arianespace gets very favorable rates, which helps offset the expensive launchers and keeps it a market leader.

SpaceX does have a lot to prove in regards to the long-term endurance of its engines in a reusability context, no question there. But I personally feel like they have a pretty compelling empiric proof for the first flight capabilities of freshly produced engines at this point, especially when viewed in the context of the aerospace industry. Each of the 240 already flown engines went through at least three full mission duration firings in its liftime, and at least 30 more went through two. That's an adequate demonstration of short-term endurance in my eyes.

[magnemoe]

6 hours ago, DerekL1963 said:

We have, literally, billions of turbine hours worth of experience.  (And a least a couple of crashes killing all aboard.)  And yet we still have events like this, and problems like this one.
Confidence based on a small sample size and relative lack of experience is... often misplaced.

Relevant, now add that planes has an good engine out capability and that the engine housing is armored to keep turbine fragment from hitting plane. 
Good engine out is that plane can redirect and land in any setting if one engine dies (outside of short window during takeoff), earlier you needed 4 engines for long distance over ocean flights. 

And did not one of the fist falcon9 ISS resupply missions loose an engine so they had to dump an secondary payload in too low orbit? 

[Nibb31]

4 hours ago, kerbiloid said:

Why not to launch it without payload, with a water cystern instead of 2nd stage and cargo? It's anyway scrap.

Because launches aren't free. There are costs associated with mobilizing air force assets, enforcing no fly zones, transporting stages around the country, integrating them at a launch facility, planning a flight profile, etc... And of course, developing an expensive dummy 2nd stage, payload, and fairing just for a single pointless flight.

Pointless, because there is nothing that such a flight would prove that hasn't already been proven multiple times by a whole campaign of full duration burns at McGregor.

 

[Racescort666]

18 minutes ago, Nibb31 said:

Because launches aren't free. There are costs associated with mobilizing air force assets, enforcing no fly zones, transporting stages around the country, integrating them at a launch facility, planning a flight profile, etc... And of course, developing an expensive dummy 2nd stage, payload, and fairing just for a single pointless flight.

Pointless, because there is nothing that such a flight would prove that hasn't already been proven multiple times by a whole campaign of full duration burns at McGregor.

 

They could use a previously flown booster for the planned Dragon V2 In Flight LES test. 2 birds, 1 stone.

 

(Dragon/Falcon, Earth... too much?)

[kerbiloid]

7 hours ago, Nibb31 said:

Because launches aren't free. There are costs associated with mobilizing air force assets, enforcing no fly zones, transporting stages around the country, integrating them at a launch facility, planning a flight profile, etc... And of course, developing an expensive dummy 2nd stage, payload, and fairing just for a single pointless flight.

Wait-wait-wait. Isn't a total reusable Falcon conception based on assumption that all these things (including fuel) cost negligibly in comparison with the 1st stage?

As I can remember, 1st stage costs 80% of total launch price. Say, the rest 20% are 10% for the 2nd stage and 10% for what you've listed above.

So, launching just the 1st stage (it's reusable, don't forget) with a 100-t water tank on top they would spend about 10% of total price.
(60% returns as the 1st stage, 10% do not exist, 10% - you've listed + a tank for water let'it be a rusty unusable tank).

So, relaunching at least one of those stages from the storehouse several times they would spend just about a cost of a typical Falcon launch.
Is it too big price for a human-rated rocket?

Or are those returned after just one flight stages mostly in condition which weakly relates to the term "reusable"?

Edited February 4, 2017 by kerbiloid

[IncongruousGoat]

3 minutes ago, kerbiloid said:

<snip> Or are those returned after just one flight stages mostly in condition which weakly relates to the term "reusable"?

From what evidence we have, the stages that have been returned so far have been in good enough condition to be reused several times. Look at what was done with the JCSAT-14 booster, for instance.

[kerbiloid]

Just now, IncongruousGoat said:

From what evidence we have, the stages that have been returned so far have been in good enough condition to be reused several times. Look at what was done with the JCSAT-14 booster, for instance.

And a test flight would be the best evidence of this. They lay in the storehouse for several months and years.

[Nibb31]

2 hours ago, kerbiloid said:

Wait-wait-wait. Isn't a total reusable Falcon conception based on assumption that all these things (including fuel) cost negligibly in comparison with the 1st stage?

Nobody ever said those costs were negligeable. Even Musk has only claimed a 20% cost reduction through reusability.

2 hours ago, kerbiloid said:

As I can remember, 1st stage costs 80% of total launch price. Say, the rest 20% are 10% for the 2nd stage and 10% for what you've listed above.

No way is that even close to the actual ratios.

 

[monophonic]

1 hour ago, kerbiloid said:

And a test flight would be the best evidence of this. They lay in the storehouse for several months and years.

Maybe they would do a test reflight on company expense, if they did not have a paying customer already lined up for one. They are a business after all and expected to make a profit.

[CatastrophicFailure]

Oh for flarp's sake, people! 

SES-10 next month (maybe) is going to be the first reflight of a used booster. 

Those other recovered stages have all been test fired. Even test fired a lot.

Randomly launching them? SpaceX has ONE launch pad on the east coast! And it was pretty darn busy, right until it blew up. Now they still only have ONE launchpad. Maybe. Once they get around to at least test firing on it. 

They don't have the hardware or personnel to go randomly shooting rockets off when the test data from static firing is just as good. 

There were plans to use a used booster on the in-flight abort test. That was a while ago and has been pushed back so many times now, who knows what the current status is. 

The F9 has been designed from the get-go to be engine-out tolerant. Even from a catastrophic failure. They had one, primary payload got to space fine.

Of all the questions floating around about SpaceX's operations, the durability and reliability of their engines is NOT one of them!

 

ETA: also, this: https://spaceflightnow.com/2017/02/03/spacex-rocket-tagged-for-reuse-test-fired-in-texas/

Edited February 4, 2017 by CatastrophicFailure

[kerbiloid]

3 hours ago, Nibb31 said:

No way is that even close to the actual ratios.

Respectfully asking you for the actual ratios.

[Streetwind]

IIRC, the first stage was quoted to be about 70% of the price of the rocket. So between 40 and 45 million, for a rocket that costs 62 million.

Launch services and related stuff is extra.

[magnemoe]

52 minutes ago, Streetwind said:

IIRC, the first stage was quoted to be about 70% of the price of the rocket. So between 40 and 45 million, for a rocket that costs 62 million.

Launch services and related stuff is extra.

70% makes some sense, upper stage only has one engine and is smaller and lighter, on the other hand it need to be more advanced, it need rcs and other stuff an disposable first stage don't need. 
the other costs as in launch cost including integration and testing, but also development and overhead brings it down to 20% of the actual cost. 
More launches will bring the fixed cost down.