World Missile and Space Launch Vehicle Failures

[R7]

In most rocket failures the detonation is caused by propellant touching hot engine parts, although RP-1 and LOX do form a highly explosive gel when mixed.

In most rocket failures there's hardly any detonations at all, except for the FTS explosive charges. Propellant detonation requires them ending up premixed at ignitable ratio and an energy spike (spark) or deflagration-to-detonation transition (which is easier said than done, just ask PDE-developers).

[Davd]

No, the  cloud is the LH2 condensing water vapor in the air.  The same effect would happen if there was no LOX onboard.

I know that; the hydrogen would still form water vapor from coming into contact with the oxygen in the surrounding atmosphere.

LH2 tank ruptured and LH2 spill down the sides of the vehicle.

Which is pretty obvious. Somehow I was a little bit doubtful of Art's claim that that was the Atlas's LOX spilling.

Also during AC-1's ascent, there's a visible trail of LOX streaming from the Centaur. Not sure if this was intentional or not, but it does remind one of Atlas 3D where the drain valves failed to close at liftoff.

in most rocket failures there's hardly any detonations at all, except for the FTS explosive charges

I did mean deflagration, that was just a poor choice of words. Pay it no heed. Deflagration is what happens if you threw a lit match into a paper cup filled with gasoline. Detonation is what happens inside a car engine (after the gas and air are mixed and ignited).

[Jim]

I know that; the hydrogen would still form water vapor from coming into contact with the oxygen in the surrounding atmosphere.

No, the visible vapor isn't from the combustion of the H2.  It is from the cold of the LH2 condensing atmospheric water into the white visible vapor.  It happens with any cryogenic fluid released into ambient air.

[R7]

Detonation is what happens inside a car engine (after the gas and air are mixed and ignited).

No. (Sorry  Detonation is not supposed to happen in car engines, things are tuned/timed to avoid that. Some times things go wrong and it can happen, it's called the engine knocking, and it destroys the engine quickly.

Please take no offense, it's just me being the pedantic wiserear  Detonation and deflagration are just so well defined that easy to keep them apart. Muddy waters start when using words like "explosion" where definitions become less scientific and more opinion-based. Then again whether things deflagrate rapidly or detonate when they aren't supposed to do either it's usually a bad day anyway...

[Art LeBrun]

No, the  cloud is the LH2 condensing water vapor in the air.  The same effect would happen if there was no LOX onboard.

I know that; the hydrogen would still form water vapor from coming into contact with the oxygen in the surrounding atmosphere.

LH2 tank ruptured and LH2 spill down the sides of the vehicle.

Also during AC-1's ascent, there's a visible trail of LOX streaming from the Centaur. Not sure if this was intentional or not, but it does remind one of Atlas 3D where the drain valves failed to close at liftoff.

I believe the temporary venting was hydrogen. It stopped about 8 seconds prior to the weathershield failure.

[Davd]

I believe the temporary venting was hydrogen. It stopped about 8 seconds prior to the weathershield failure.

Ok makes sense since it's coming from the top of the Centaur where the hydrogen tank is. I now just remembered that this same effect can be seen on Saturn launches.

But enough about AC-1 (at least until Jim posts the accident report he claims to have). Moving onto the next subject in this thread, Atlas 3D which had a nothing short of spectacular failure yet no accident reports have turned up.

Oddly, the official Atlas launch summary lists seem to imply that 3D failed because of the LOX valve not closing at liftoff instead of the (extremely obvious) launcher arm hangup at liftoff.

[Art LeBrun]

Here is a GD/A report I received recently on 3D and 7D. Not scanned from a GD/A document but I assume the wording is accurate.

It seems the B-2 thrust decay accounted for the "lurching" of 3D and not a launcher arm failure. I understand it looks abrupt like a sudden release but this is what I have for the moment. There is a dark stream in the B-2 exhaust which I do not understand. Obviously you need to discount the turbine exhaust just to the outside of B-2.

[Davd]

It seems the B-2 thrust decay accounted for the "lurching" of 3D and not a launcher arm failure.

It would seem that the engine already had some sort of problem that was exacerbated by the LOX spilling and causing an explosion.

There is a dark stream in the B-2 exhaust which I do not understand. Obviously you need to discount the turbine exhaust just to the outside of B-2.

There are a number of things that might cause that. Maybe the fuel/oxidizer mix in the engine was off from its normal value. Also you can seen from the video that there's a fire building up in the thrust section during ascent prior to the explosion @ T+28 seconds. That could have been the result of the liftoff damage or due to whatever problem caused the initial B2 malfunction.

As for 7D, on rewatching the video on Critical Past closely, I see it now. The launcher arm doesn't retract fully at liftoff.

[Art LeBrun]

Atlas Incidents in Images

Image 1 shows Atlas 6D in flight from VAFB January 26, 1960. Note that the two nacelle doors have not closed. No word of effect on flight.

Image 2 shows Atlas-Agena carrying first SAMOS recon satellite aloft on October 11, 1960. Note one Atlas nacelle door is only partially closed. The notable part of the image is the escaping Agena stage attitude control gas from the left side of the interstage. The happened during an umbilical disconnect which tore off part of the plate on the vehicle. Without the attitude control gas the Agena burn was unsuccessful in achieving orbit. There are multiple launch images showing the gas loss.

[Davd]

Atlas Incidents in Images

Image 1 shows Atlas 6D in flight from VAFB January 26, 1960. Note that the two nacelle doors have not closed. No word of effect on flight.

Image 2 shows Atlas-Agena carrying first SAMOS recon satellite aloft on October 11, 1960. Note one Atlas nacelle door is only partially closed. The notable part of the image is the escaping Agena stage attitude control gas from the left side of the interstage. The happened during an umbilical disconnect which tore off part of the plate on the vehicle. Without the attitude control gas the Agena burn was unsuccessful in achieving orbit. There are multiple launch images showing the gas loss.

As 6D and 57D both performed normally during flight, it does not appear that the nacelle doors affected anything.

Also Atlas 131D (Midas 6's booster) suffered liftoff damage similar to 7D however instead of causing pressurization gas to escape, the hydraulic fluid was lost leading to eventual loss of control and RSO destruct.

[kevin-rf]

Nice article on the space review concerning some failures, with root causes.

Launch failures: what’s changed?
http://www.thespacereview.com/article/2256/1

[Art LeBrun]

Nice article on the space review concerning some failures, with root causes.

Launch failures: what’s changed?
http://www.thespacereview.com/article/2256/1

Usually Wayne Eleazer gives dates and missiles with his failure reports but the three Atlas Ds have no such reference. My limited records indicate no such episodes of 3 Atlas D exploding on Cape pads much less the same pad. However, I am intrigued by the separate turbine exhaust duct so I will research that and see if it is visible in photos.

[libra]

Bringing back this oldie... my own little contribution to that topic, now published at The space review.

https://www.thespacereview.com/article/4085/1

Ariane, earthquake, cloth, and the Murphy law. A monument of absurdness - one can only laugh or just shake his head in disbelief.  Such bad luck, for everybody involved.

Yet, it could have been worse

(Samuel L. Jackson memorable -and very unfortunate - quote from Jurassic Park)

[Vahe231991]

I found this video from Youtube showing the first launch of the CZ-3B in February 1996, which ended in failure.

[WallE]

re: Atlas 3D. The dark stream in the B-2 exhaust was the engine running fuel rich from the LOX loss which would produce a lot of soot. AFAIK the actual cause of the explosion at T+26 seconds was LOX ducting rupture from loss of pressure to the propellant feed system--the video clearly shows that the explosion originates in the central thrust section and not outboard where the B-2 engine is. There were other Atlas launches and static firing tests which showed the very bad things that resulted from rupture of LOX ducting in the thrust section.

After the booster section was blasted off the missile slowly fell to earth, a trail of fire coming out of the fuel staging disconnect valve and the sustainer and verniers inexplicably kept going albeit with a major drop in performance since most of the propellant in the tanks was rapidly spilling out from everything ripped open and finally the range safety officer put the poor thing out of its misery after letting it go as long as he could to collect the maximum amount of T/M data.

We do not have an actual postflight report for 3D however other docs (including some posted in this thread) and film footage lets us more or less piece together the sequence of events.

As for SAMOS 1, its guidance pulse beacon failed in flight, preventing transmission of discreet guidance commands or programmed engine cutoffs. SECO and VECO were done by backup commands issued by the Atlas programmer but the Agena gas loss caused failure of the mission. The guidance system on 57D was not telemetered but it was thought that the beacon failed either due to in-flight vibration levels or RF interference due to the payload/vehicle combination causing loss of lock with the ground guidance.

[Jim]

re: Atlas 3D. The dark stream in the B-2 exhaust was the engine running fuel rich from the LOX loss which would produce a lot of soot. AFAIK the actual cause of the explosion at T+26 seconds was LOX ducting rupture from loss of pressure to the propellant feed system--the video clearly shows that the explosion originates in the central thrust section and not outboard where the B-2 engine is. There were other Atlas launches and static firing tests which showed the very bad things that resulted from rupture of LOX ducting in the thrust section.

After the booster section was blasted off the missile slowly fell to earth, a trail of fire coming out of the fuel staging disconnect valve and the sustainer and verniers inexplicably kept going albeit with a major drop in performance since most of the propellant in the tanks was rapidly spilling out from everything ripped open and finally the range safety officer put the poor thing out of its misery after letting it go as long as he could to collect the maximum amount of T/M data.

We do not have an actual postflight report for 3D however other docs (including some posted in this thread) and film footage lets us more or less piece together the sequence of events.

I have the Flight Test Summary.  The airborne LOX F/D failed to close.

[WallE]

That's a well-established fact though. The acutator shaft on the LOX fill and drain valve broke so it didn't close at launch and some RP-1 also got spilled and exploded on the pad because the launch crew forgot to purge the ground portion of the fuel fill and drain line prior to the launch and it still had RP-1 in it (this did some minor damage to LC-13 but none to the missile). The acutator shafts were changed from aluminum to stronger steel on Atlas 25D onward. While docs I've seen do not elaborate on the cause of the thrust section explosion, it seems safe to assume the LOX loss caused turbopump unloading, overspeed, and ducting rupture.

There were occasional episodes on Atlas launches of late nacelle door closures; on SAMOS 1 the B-2 nacelle door did not close until the vehicle was at a height of 30 feet off the pad perhaps due to liftoff-induced vibration.

[WallE]

Thor 401, most famous for falling on an occupied trailer park was one of the stranger failed launches ever as the vehicle was blown off course by wind, a highly original failure mode. The Thor-Agena D vehicle was carrying MPRV, a package of scientific test equipment that included an experimental fuel cell and a subsatellite. After liftoff from VAFB's Pad 5 at 1:00 PM local time on September 2, 1965, the booster began to veer off its flight path. The Range Safety officer was talked out of destroying it by the launch controller as he wanted to give it more chance to go back on course, but ultimately it crossed the safety limit and was blown up at T+60 seconds at an altitude of 6 miles. Some debris and burning propellant started brush fires where it landed, but a large chunk of tank section fell on a trailer with a woman and two small children inside, who were unharmed.

Postflight investigation determined upper level winds to have pushed the Thor off-course and that the payload fairing, longer than the one used for CORONA launches, was a contributing factor. As a result, the flight path for Thor-Agena launches would be changed to include a dog leg trajectory to better ensure it would be out over the ocean. The experimental fuel cell miraculously survived falling over 30,000 feet to the ground and was operational after replacement of some damaged components.

Overall 1965 was a successful year for Thor/Delta launches with only two failures in 36 vehicles flown, the other being OSO C one week before MPRV which failed to orbit due to a mishap during third stage separation.

[Blackstar]

https://www.thespacereview.com/article/2088/1

[catdlr]

https://www.thespacereview.com/article/2088/1

YES!