Looking at ORB-3 Antares Telemetry

1. I think this is a pretty good indicator that the failure did not originate with the engines. if they had been failing, the telemetry should not have shown them to be performing nominally.

   this indicates, to me anyway, some failure in the fuel or oxidizer lines.

   well, we’ll see what happens when they analyze the telemetry. it could be something not-obvious.

   1. Doug: what does the oxidizer line look like? I mean how big is it, what are the pressures involved? I suppose there is an entire system that channels cold liquids from tanks, adjusts pressures as needed, and feeds them to the engines?

      1. Unfortunately, there’s very little information about those systems that are freely available. I don’t know the details of the Antares design, and I’m not sure who would know, or if they would be able to tell you. probably the best place to go for discussion of such details is the NSF forums.

         http://forum.nasaspacefligh…

         my impression that the engines aren’t to blame for the launch failure is based on the trailing flame that was going down the side of the rocket during launch, the good telemetry from the engines up to the point of loss of thrust, and from reading on articles and forms like the link i posted above.

         1. The ‘trailing flame’ was just plume-illuminated vapour from the ice on the side of the LOX tanks.

         2. Here is a picture of one. “Modification and Verification Testing of a russian Nk-33 Rocket Engine for Reusable and Restartable Applications”, J. Hulka, et al isn’t a bad read It goes into a little depth regarding Aerojet’s modifications for the use on the K-1.

            1. thanks, that IS a great bit of information! though the original question was about the location, size, and pressures within the fuel and oxidizer lines.

2. I hope and right now I think it was a kerosene rupture. This looks like an air burst. Like they do at air shows to look like bombs exploding. A huge amount of kerosene was released and mixes with air and the exhaust sets it off. Line, fitting. If LOX, nothing to burn. If both, LOX would provide a bigger explosion. A combustion chamber or turbo pump would do both. But where are the engines? They are big and do not burn easy. Maybe one could explode, not both. They could have destucted them.
   After more rsearch, there was an air burst, but a bright white explosion happened first. This would be a mixture of LOX and Kerosene. A turbo pump rupture would fit. I don’t see how both engines could blow at the same time. If there is a pressure regulator and pressure got too high, that could blow both engines maybe. Too bad NASA did not show
   all of the camera views, like they always have done before.

   1. Maybe, but the colour change in the engine plume suggested oxygen starvation rather than fuel starvation.

   2. I would suggest the flare of the plume was the injector failing with the secondary explosion being the pump overspeed due to lack of resistance. cant wait to see timeline with Pc and pump speed.

3. “All systems appeared to be performing nominally until approximately T+15 seconds at which point the failure occurred.”

   I don’t think the above rules out a sudden failure in the engine since they’re only calling it “the failure”. It looked from the video I saw that the exhaust went fuel rich, based on the color of the engine exhaust. This engine uses a single shaft turbopump with the turbine, oxidizer pump, and fuel pump all on the same shaft. So I would think the a fuel rich condition might be caused by failure of the O2 tank, O2 regulator, O2 feed line to the engine, engine turbopump, engine O2 plumbing, or the engine O2 injector.

   1. we actually didn’t see anything in the video to indicate engine failure, or any failure at all for that matter – until the RSO blew it up! I think this may have been a process failure

      1. the destruct command was sent only when the rocket had already fallen out of the sky. it was already on or very near to the ground.

         1. No, you can see they exploded the rocket right when it was fixing to go higher. It was slowing down a little just because it had so much cargo on board. Sometimes when they launch it might go a little slow at first but to just blow it up when it is trying to get into space is ridiculous!

            1. incorrect. the explosion you see at about 10 seconds in the flight was the failure on the first stage, not the detonation of the second stage, which occurred about 20 seconds in the flight, when the rocket had already fallen back to the ground.

4. The statement didn’t say anything that we didn’t already know but I wasn’t expecting it to. However, it does confirm what most armchair experts were saying.

   1. I read that as saying that it could be any number of things related to the flow of O2 to the combustion chamber. Some of those would be inside the AJ26 engines, some would not.

   2. What I’m a little concerned about is, if it is shown to be the lines that failed, blame (especially the political) is going to shift from Russian to Ukrainian (Yuzhnoye SDO) — a/p Wikipedia:

      “The core provided by Yuzhnoye includes propellant tanks, pressurization tanks, valves, sensors, feed lines, tubing, wiring and other associated hardware.”

      It’s a similar, but separate can o’ worms that someone is going to exploit. And still just as ugly.

5. Well, thanks Orbital for clearing that up…

   “Evidence suggests the failure initiated in the first stage after which the vehicle lost its propulsive capability and fell back to the ground”

6. Orbital will pick a new Russian engine and do another rename Taurus II to Antares to Antareski.

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