(Launch failure) Stratos III Rocket Launch

[Ultimate Steve]

 

The Delft Aerospace Rocket Engineering (DARE) team is comprised of mainly university students, and they have a history of building and flying really large rockets. This rocket, Stratos III, is 2 years in the making and aims to break the European student altitude record (which is 30-ish km IIRC). It is a hybrid rocket, with a recoverable capsule section.

They aim to launch soon-ish but the launch time has bounced around a lot, they have had to replace at least 2 faulty components today, and they are currently in a hold as they heat the oxidizer tank.

Best of luck to them!

 

 

 

 

Edited July 26, 2018 by Ultimate Steve

[Ultimate Steve]

12 minutes to liftoff!

[Mad Rocket Scientist]

That looks bad.

[4x4cheesecake]

oh man, that's sad

[Ultimate Steve]

Well, first failure I've seen live.  Although I would have preferred it to be something big and commercial instead of a student project that they were so attached to. Took them 2 years.

[James Kerman]

Condolences to the Delft team.  Space is hard.

[4x4cheesecake]

'An anomaly occured during launch...' at least they wrap it like a big institute^^

[.50calBMG]

Looked a bit like a fin failure or something. You can see something come off a few seconds before it brakes up.

Edited July 26, 2018 by .50calBMG

[Ultimate Steve]

It's looking like there were two separate booms, one big one and one break-aparty one. I initially thought the failure might be because of blowback (their oxidizer is also a monopropellant if heated enough, if the fire got to the oxidizer tank it would be bad) but it's looking to me like a combustion chamber failure followed by the top section of the rocket turning sideways into the airstream and breaking apart. If it was blowback the first boom would have probably caused disintegration due to the LOX tank's central location, but with the combustion chamber being strictly at one end it had a good chance of staying straight for a while following the failure.  The second event could also have been a secondary explosion caused by the oxidizer, like a blowback but not really. Actually, now that I think about it the secondary explosion was probably the flight termination system.

It was a bit hard to tell on the (infared?) camera, but there's a chance that could have been the sonic shock wave and the whole thing disintegrated at max Q, but the first event looked more like an explosion then a disintegration.

So if it was a combustion chamber failure, it could have been either an overpressure caused by a sudden valve opening, a crack in the propellant, or maybe something melting that wasn't supposed to, or a damaged casing that couldn't take normal operating pressure.

The engine did operate for the first several seconds of flight, apparently normally, though, so the failure likely wasn't present at the time of launch and likely manifested itself during the flight. Engines like this one have also been tested many times by DARE, so they have been known to work well. This gives the aerodynamics theory a bit more merit, as that would not have been a factor during ground tests.

I'd put my money on it being damage to the motor grain or casing somehow, causing the first explosion, then the FTS going off. I'd review the footage more, but right as I was recording the failure to analyze they took the stream down (I just needed 10 more seconds!)

 

 

Disclaimer: These are just guesses by a high school student who has no formal training in aerospace engineering.

[4x4cheesecake]

2 hours ago, Ultimate Steve said:

right as I was recording the failure to analyze they took the stream down (I just needed 10 more seconds!)

Someone else recorded the failure:

 

[4x4cheesecake]

So, I downloaded the video and extracted every single frame, I guess these are the 'key' frames:

Looks like some thing breaks apart. I guess, it is the same thing mentioned by .50calBMG, seems to be pretty dark (hot):

The first frame showing the anomaly regarding the combustion, in my opinion, it looks like a rapid change in the pressure difference between the atmosphere and the exhaust (exit pressure greater than ambient -> expanded exhaust), so maybe something went wrong with the nozzle?

This status keeps 'stable' for a few ms (~20 frames), than the exhaust/flame starts to expand even further:

Explosion or hyper sonic effects? I really don't know:

Right after the explosion/hyper sonic effect. The trajectory changed a lot, looks like the rocket already falls back to earth so the rocket probably lost a large amount of speed:

Desintegration of the rocket. Looks pretty 'clean' to me so probably the abort sequence to destroy the rocket:

I have uploaded all of the extracted frames (488) to dropbox, if anyone wants to take a closer look: https://www.dropbox.com/s/fx11r2vnv79kg4a/Stratos III launch failure.rar?dl=0

Edited July 26, 2018 by 4x4cheesecake

[Ultimate Steve]

Okay, the tram uploaded their own video and in the description they say that the first "Boom" was actually the camera refocusing, so it's a 1 boom failure now.

[4x4cheesecake]

I really hope they can nail down the issue so it will not happen again on the next try

Also, I'm quiet curious about the reason for the failure, so lets hope that they will share their findings.