In videos of the SpaceX CRS-7 explosion I've seen, it looks like the explosion vaporized the rocket, since no wreckage/debris made it more than a few feet downward -- tiny little things!

But the vaporization temp for aluminum is over 10,000 °C. RP-1 rocket fuel is kerosene, basically. So that doesn't seem to be sufficient to vaporize aliminium.

Also, I looked at many rockets exploding and the flames are always orange (kerosene). The SpaceX explosion is colorless. I also could not find any rocket explosions wherein NOTHING was left. So what happened in this incident?

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    $\begingroup$ This is not a question, unfortunately. Similarly, this question is also too opinion-based. Objectively, if you think SpaceX is faking their crashes, you might as well think that the moon landings were faked. Maybe with a heavy overhaul this could be put on Skeptics.SE $\endgroup$ May 14, 2018 at 20:51
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    $\begingroup$ I'm voting to close this question as off-topic because this is errant nonsense. $\endgroup$ May 14, 2018 at 23:37
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    $\begingroup$ Stop drinking the koolaid, Allancw. A conspiracy this large would have seen the light of day in, well, a day or so. There are several thousand employees at SpaceX alone, several thousand more at NASA, and several thousand more at SpaceX's commercial customers. SpaceX is not faking its successes or its failures. You can ask legitimate questions here such as "Why do the SpaceX rockets have plumes shooting upwards?" OTOH, we do not tolerate errant nonsense here. Skeptics.SE does (to some extent). $\endgroup$ May 14, 2018 at 23:48
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    $\begingroup$ I'm voting to re-open considering the revision; removing down vote as well. $\endgroup$
    – uhoh
    May 19, 2018 at 2:04
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    $\begingroup$ @RussellBorogove In the case of CRS-7, the rocket did not break up completely, the capsule transmitted telemetry until it impacted the ocean.... so the edit somewhat invalidates the premise of the question (nothing at all comes down). It seems quite hard to make this question reasonable. Sceptics.SE might be better suited for it. $\endgroup$
    – Polygnome
    May 23, 2018 at 15:48

1 Answer 1


I don't have a definitive answer for the appearance of the explosion in this incident, but a few things are worth noting:

Note the appearance of the first-stage engine plumes at 2:22. Rather than the bright dense yellow column seen at liftoff, the low atmospheric pressure at the rocket's altitude allows the exhaust stream to rapidly expand into a relatively faint, tenuous cloud. The rocket is still producing about the same amount of thrust (maybe somewhat less than at liftoff to control g-loading on the structure), but the exhaust looks completely different from kerosene/LOX combustion at sea level.

The incident occurred when a small high-pressure helium tank contained within the second-stage liquid oxygen tank broke loose, overpressurizing and rupturing the tank, as described in this Q/A. I assume the initial white cloud at around 2:30 is just oxygen release.

Once the second stage starts to come apart, kerosene is released as well, and you can see characteristic yellow-orange kerosene flame inside the white cloud at about 2:32 in the video.

You can see small pieces of the upper stage falling away from the rocket between 2:32 and 2:36 until the rocket comes apart completely. Two things to keep in mind here: one, the first stage is near the end of its burn here, and so largely empty of fuel; two, to get good combustion between kerosene and oxygen, you have to thoroughly mix the two. Starting with two separate "balls" of liquid venting into extremely thin air, you won't get good mixing; any combustion that does occur where the clouds meet will tend to spread the kerosene and oxygen further away from each other, so the majority of the remaining first-stage propellants just won't get burned here. That's why you don't see a large orange fireball here -- again, other rocket explosions you're comparing this to are probably low-altitude incidents, where atmospheric pressure is keeping the propellants from dispersing quickly. Additionally, according to the Q/A linked above, the flight termination system was activated, "unzipping" the tanks in a way that was intended specifically to minimize the force of an explosion.

At 2:38 you see several distinct pieces of the rocket. To me it looks like possibly 1/4 of the entire skin of the rocket is visible in pieces at that point -- remember that a rocket like Falcon 9 is basically a thin metal skin wrapped around fuel, not a solid piece of metal. So the big open question for me is where the rest of the metal went, but if it was being ripped into small pieces at about 2:37, those pieces could easily have gone out of frame while concealed in the vapor cloud.

Finally, I'm going to address the way your question here was initially framed. On this site we get a fair number of conspiracy theorists -- mostly moon landing deniers, but a few other kinds as well. I can't speak for the other regulars on the site, but they make me very angry; they waste our time and mental effort, and for the most part they aren't interested in truth as much as they're interested in propping up a paranoid world view. I'm happy to address any question posed in the frame of "I don't understand some phenomenon", but the same essential question framed as "This phenomenon proves some conspiracy theory" will never find a good reception here.

In this case, the idea that SpaceX would fake a launch accident simply makes no sense at all. They are still a young company trying to build a reputation for reliability; losing a rocket with a NASA payload hurts them very badly. Hundreds or thousands of people saw a rocket lift off, bound for the International Space Station. That rocket's payload never reached its destination, but it must have gone somewhere. In general, the simplest explanation for a phenomenon is, most likely, the correct one, while extraordinary claims require extraordinary evidence. "The rocket exploded as rockets sometimes do" is a very simple explanation, and "SpaceX faked a lost rocket" requires an awful lot of justification.

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    $\begingroup$ +1, space program deniers are calling me and all my former colleagues liars, and I take that very personally indeed. $\endgroup$ May 23, 2018 at 17:54
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    $\begingroup$ I wouldn't want to jump in and unnecessarily edit such a solid answer. But one additional thought that occurred to me on the topic of debris -- the asker may want to recall that the rocket is 230' tall, and being viewed from a camera many miles away. That we can see the rocket doesn't mean we can see the parts of the rocket when it comes a part at that distance. $\endgroup$
    – Saiboogu
    May 23, 2018 at 18:44
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    $\begingroup$ We can see lots of debris at 2:37-2:40. $\endgroup$
    – Hobbes
    May 24, 2018 at 11:19
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    $\begingroup$ There was enough debris to show up on radar: youtube.com/watch?v=nIOoZ9pz0r4 $\endgroup$
    – Hobbes
    May 24, 2018 at 11:24

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