Antares launch/failure discussion.

[Sky_walker]

They didn't do a thing to the combustion chamber, nozzle or turbopump, exactly as I'd already said.

Exactly what you said is that they changed "5 valves" and "the control unit" - which is clearly not what happened.

If you want to pretend welding on a few hydraulic actuators could have anything to do with what happened, go ahead.

If you want to pretend you know what actually happened ahead of both: NASA and Orbital Sciences, go ahead. I'm not going to jump into some silly conclusions after watching a few videos. And no: I never said that their modifications got anything to deal with the accident as I have no idea if they did or if they didn't.

And just to remind everyone - these engines passed Aerojet quality control, so in the end it was up to them to decide whatever engines are flightworthy or not and it was their responsibility, not Kuznetsov.

Edited October 30, 2014 by Sky_walker

[Kryten]

Exactly what you said is that they changed "5 valves" and "the control unit" - which is clearly not what happened.

It is what happened. If welding on side hydraulics is a 'change', then so's welding that to the rest of the rocket.

If you want to pretend you know what actually happened ahead of both: NASA and Orbital Sciences, go ahead. I'm not going to jump into some silly conclusions after watching a few videos.

Care to give any scenario through which some hydraulics could cause the failure we saw? This will be a turbopump failure, probably due to FOD, you can bet on that, and orbital and NASA will have come to the same conclusion; they just won't say anything until the full report is done.

[Sky_walker]

It is what happened.

Let's end it here.

This will be a turbopump failure, probably due to FOD, you can bet on that,

Yes, that's what I would guess too after seeing videos and a few photos, though again: I don't have any material to back it up, so it's sort of meaningless speculation at this point. Could have been something else. And again - if that's the cause and we're to look for who is guilty then Aerojet quality control would be where I'm looking first, though knowing US press it'd end up with pointing fingers at Russians. It wouldn't be the first time when Aerojet got problems with QC, and probably not the last time - 2011 failure should have been a lesson.

[Kryten]

The FO in the FOD could be Ukrainian just as well as Soviet or American. Yuzhmash's own quality control hasn't been all that lately.

[Sky_walker]

Fair point.

[Bill Phil]

Considering the engines had "passed" the ground testing, I suspect it's just faulty equipment. That engine's number came up and it's fairly likely that it had a bad pump or bad pipes.

[TythosEternal]

Fair point.

Awe, man... Does this mean the Kryten-Sky showdown is over? I was really starting to enjoy it, and was anticipating the forum to spectacularly implode under so much titanic fury.

[PakledHostage]

Awe, man... Does this mean the Kryten-Sky showdown is over? I was really starting to enjoy it, and was anticipating the forum to spectacularly implode under so much titanic fury.

Or maybe they've set an example of how to be gentlemanly and, rather than implode under titanic fury, we'll all hold hands and sing kumbaya?

[Space_Coyote]

Now from what i hear the rocket suffered an "Anomaly" and my guess is that one of the engtines on the Aneres First stage actually failed but this caused what I call a "Cascade Failure (what a Cascade Failure is this, ONe engine blows apart, sending shrapnel into the area around the rest of the rocket engines, then another one fails, then another in quick rapid succession like a stack of dominoes. Now what probably happeend was that someone on the gorund noted this and informed the Flight Safety Officer and the Range Safety Officer about this and quickly the decided the only thing lieft to do to prevent this rocket from falling into a dangerous area like a populated area, was to literally send the Destruct or abort signal to the rocket..

(And yes i know and have seen this a couple of times in my lie way back i the 1960's when space flight was ajust getting started.. My family was stationed in Orlando and My father would do security duty at the gate that was in fact Cape Kennedy.. and he had a friend of his who was a Range Safety officer.. From what my father told me the friend had to pull the plug twice on two seperate unmanned flights because of a similar type of event..

Luckily no one was injured..

But on a side note, everyone here remembers why they scrubbed the flight the night previous, right? If not there was a sailboat located down range in the range safety zone that had somehow gotten there.. Now imaigine if this had happened not at the 6 second mark but rather say 60-90 seconds down the line.. tht 143 foot long rocket would have ended up right where that boat probably would ahve been sitting..

I could see the lawsuit if that had happened..

But then stop and think about this.. The courts would have tossed the lawsuit out cause the mariner actually wandered into taht zone and parked himself in harms way..

I bet that guy now is thankful they scrubbed the launch the night before.. or else the worlds, "You sand my sailboat' would ahve been heard.. Oh wait, that's right, the mariner wouldn't be saying that, cause the rocket would have been on his boat.. the hard way.. (Ouch)

Oh well thank god the Game has an Abort switch too... at least now when we program it, we'll know what to do..

Space_Coyote

[Brotoro]

There are only two engines in the Antares first stage.

[J.Random]

Telemetry data has been released to Orbital and our engineers presented a very quick look assessment to the Accident Investigation Board at the end of the day. It appears the Antares vehicle had a nominal pre-launch and launch sequence with no issues noted. All systems appeared to be performing nominally until approximately T+15 seconds at which point the failure occurred. Evidence suggests the failure initiated in the first stage after which the vehicle lost its propulsive capability and fell back to the ground impacting near, but not on, the launch pad. Prior to impacting the ground, the rocket’s Flight Termination System was engaged by the designated official in the Wallops Range Control Center.

See what I've meant previously? Nominal, nominal, nominal... UNTIL.

[Camacha]

It surprises me that the launch site seems largely undamaged. I would have expected a little more damage.

Edited November 2, 2014 by Camacha

[sgt_flyer]

Well, the fireball burned most of the fuel / oxydizer in a few seconds - with most of the heat energy ascending due to convection - which wouldlimit heat damage. The launch pad itself use materials meant to withstand a rocket flame for a period much longer than the fireball's duration. (After all, you need sustained heat to melt something)

The gas expansion can occur relatively unimpeded around the rest of the structure, so apart from the windows who shattered due to the blast waves, most of the materials present can absorb and dissipate those waves.

That said, even if the other materials resisted to those blastwaves, i would not be surprised that they suffered from various cracks - so they'll need to inspect and repair / replace a lot of things. Had the explosion occured in a more enclosed space, the bouncing blastwaves might have done much more damage.

[Frybert]

[Nibb31]

Congratulations for being the 100th person to post the same bad joke.

[Camacha]

Well, the fireball burned most of the fuel / oxydizer in a few seconds - with most of the heat energy ascending due to convection - which wouldlimit heat damage.

I found a larger picture that reveals a bit more damage. The crater is still much more limited that I would expect.

Picture one.

Picture two.

Congratulations for being the 100th person to post the same bad joke.

Lighten up. Antares did!

[Kryten]

Orbital have put out a press release with some preliminary findings; it was 'probably' a turbopump failure, and they will 'likely' discontinue use of AJ-26 as a result. Given the time engine replacement and pad repair will take, they plan one or two launches of Cygnus on another rocket in the interim.

They've separately stated the other launchers they're looking at are from 2 US and one European operator, meaning they can't really be anybody other then spacex, ULA, and Arianespace.

Edited November 5, 2014 by Kryten

[sgt_flyer]

So, i would guess time did take it's toll on the old nk-33 components. (Even if they did thorough inspection (with x-rays and such) of those engines, i think it would be difficult to fully disassemble then reassemble it if some of the parts were welded during construction)

A shame that the old components will be shelved after that, but if they have the license, maybe aerojet can build new improved ones, (using today's advancements in metallurgy/3d printing to build a simplified / less expensive / more effective version of those.

[GoSlash27]

So, i would guess time did take it's toll on the old nk-33 components. (Even if they did thorough inspection (with x-rays and such) of those engines, i think it would be difficult to fully disassemble then reassemble it if some of the parts were welded during construction)

A shame that the old components will be shelved after that, but if they have the license, maybe aerojet can build new improved ones, (using today's advancements in metallurgy/3d printing to build a simplified / less expensive / more effective version of those.

The issue with these engines isn't their age or origin, it's their design. Even with modern metallurgy, the turbopump's only going to hold up when things are going well.

Best,

-Slashy

[Kryten]

The issue with these engines isn't their age or origin, it's their design. Even with modern metallurgy, the turbopump's only going to hold up when things are going well.

Best,

-Slashy

That doesn't make any sense; everything was going well, until something happened within the turbopump.

[sgt_flyer]

The issue with these engines isn't their age or origin, it's their design. Even with modern metallurgy, the turbopump's only going to hold up when things are going well.

Best,

-Slashy

Well, the nk-33 basic operating mode (oxygen rich staged cycle) is used in other russian kerolox rocket engines.

RD-170/171 for energia boosters/Zenit 1st stage | RD-180 for Atlas-III and atlas-V and RD-191 for angara. RD-171 and RD-180 have multiple combustion chambers and nozzles, but they are fed from a single turbine + turbopumps in oxygen rich mode.

There have been 0 rd-180 failures, and 3 rd-171 failures on rockets. So it could be said the principle of operation of the engine works

The NK-33s however, where truly cutting edge technology when they where built (it's not even a rocket engine company who made them - it was a turbojet engine company)

Aerojet changed some valves, added a gimbaling system, and rebranded them as AJ-26.

The fact remains, that the metals used in making the main components (Turbine, turbopumps, combustion chamber, nozzle) is more than 45 years old! And they where stored in a warehouse from 1969 until 1990.

So, of course aerojet checked those engines thoroughly (x-rays and such) to check for the smallest crack, but the fact remains that the metal of these engines was subjected to whatever conditions they encountered in their warehouse for at least 20 years. And metals can be affected by temperature changes, the oxygen from the air itself, even moisture if the warehouse was not hermetic - especially over such a long time. I'd say, it's even wonderful that those engines still works after all this time. (I doubt someone came down in the warehouse to put a new later of paint on the engines every few years ).

At least, if the problem really came from the aging of materials, it will be an interesting thing for metallurgy rocket scientists - they'll have real data on how rocket grade materials age over time - which could prove useful if they want to send automated ISRU bases on other planets years in advance of a manned mission.

[J.Random]

So, of course aerojet checked those engines thoroughly (x-rays and such) to check for the smallest crack

AFAIK, they also did a test burn. 40 seconds, no ka-boom. And I'm quite sure "x-rays and such" are done both before and after the test burn.

[Kryten]

AFAIK, they also did a test burn. 40 seconds, no ka-boom. And I'm quite sure "x-rays and such" are done both before and after the test burn.

Two AJ-26s did go kaboom during test burns, as did at least two of the NK-33A's done for the 2.1v.

[sgt_flyer]

Well, i wonder how much test burns approach a real launch condition - is it similar regarding to how much vibrations devellops into the rocket ? - get a pogo oscillation in the rocket, and you can damage the turbopumps very fast.

Edit : @Kryten - ouch - did not know how much went kaboom during the tests - that's not a very good ratio so far (given the number of avaible engines) - 3 booms on the 36 nk33 aerojet bought. (Which is even worsened statistically by the fact they use two of them at the same time as each would have the same possibility to fail)

Edited November 6, 2014 by sgt_flyer

[J.Random]

Two AJ-26s did go kaboom during test burns, as did at least two of the NK-33A's done for the 2.1v.

I don't really know if there were any issues with engines after successful burn test before. Were there?