The Martian movie's rocket failure scene

[SlabGizor117]

So, me and my dad talk alot about ksp, orbital mechanics, rockets, etc. so The Martian was a really fun movie to watch for us and talk about, but we had a bit of an "argument" over what happened in the rocket failure. As I remember, and I don't hold my memory to be reliable as I can't find any clips of it, something turned to liquid in the high G-forces, sloshed around, and threw the rocket off balance. Here's where are opinions differ:

I'm of the opinion that the rocket veered off course and broke apart due to aerodynamic forces, considering there was no explosion or anything said about my dad's theory.

My dad said that they blew the rocket up themselves to keep the rocket, if it veered off course, from actually going off course from flipping all over the place and the engines going everywhere. He explained that with every launch because of the tight path the rocket has to follow(Even over the Atlantic NASA and shipping companies are fighting over where the rocket should go to stay out of each others' way), if something like that happens, as soon as they get the telemetry back that it's having stabilization problems, they self destruct it so they don't have a bigger problem of it landing in an unexpected place. Basically, someone's got their finger hovering over the big red button waiting till something goes wrong.

So, what do you think? There was no explosion that I remember, all it did was break apart. And, right before it did, somebody said there was a wobble and it was veering and then it breaks apart. Then it goes back to all the directors with them wide-eyed and slack-jawed, and not a word said about purposely self-destructing it, as well as the fact that there was nothing said about that in the press meeting.

So what do you think?

[Yukon0009]

In the book, hm, let's see... The Iris probe goes kaput because of the protein cubes I believe.

The harmless shimmy, caused by a minor fuel mixture imbalance, rattled the payload. Iris, mounted firmly within the aeroshell, held firm. The protein cubes inside Iris did not. At the microscopic level, the protein cubes were solid food particles suspended in thick vegetable oil. The food particles compressed to less than half their original size , but hte oil was barely affected. This changed the volume ration of solid-liquid dramaticly, this process transfomed the protein cubes from a steady solid to a flowing sludge. Stored in a compartment with no leftover space, the now-compressed sludge had room to slosh. It caused an imbalanced load, forcing the sludge towards tthe edge of the compartment.

[SlabGizor117]

So I was pretty much right What about the actual failure? Self destruct or break-apart?

[Yukon0009]

Break apart. The book mentions that the 300 kilos of sludge crashed to the back, causing the probe to break off from the aeroshell.

[Dman979]

It wasn't self destruct, because there was a loss of telemetry to the probe, then the rocket. They also tried to get it to limp to orbit, which they wouldn't have done if it had self-destructed.

[monstah]

In the book they go on to mention that the sudden liquid impact happens on a stage separation, and breaks one of five struts inside the fairing. The other four should have held, but since the ship was rushed, one of them wasn't up to the task and broke, and then the remaining three couldn't do the job. Payload was loose inside the fairing, causing off-balance thrust, and the ship started spinning uncontrollably.

Moral of the story: if it isn't obvious yet, MOAR STRUTS.

[briansun1]

The movie does say that it was caused by the protein cubes liquefying and sloshing around. It's the part where the Director and Kapoor are being interviewed by the news guy about the probe. I also kind of doubt that spacecraft have a self destruct button. It's just extra weight that you have to take up to space.

[Yukon0009]

Yeah, considering they had about a few weeks to make a Mars probe (!) there probably wasn't enough space for a self destruct.

[Dman979]

No, they just built the probe. The booster was already made, they stole it from the eagle eye team.

Most boosters/launch vehicles contain some sort of remote-controlled self-destruct system. According to NASA,

Every major vehicle flown from the Cape Canaveral area has carried an explosive destruct system that could be armed and fired by the range safety officer.

I don't think that Iris would be any different. However, I do not think that it was destroyed by the RSO.

[lajoswinkler]

We already have a thread about this movie, and we certainly don't need a new thread with its title being the spoiler. Come on.

[SlabGizor117]

Oh, so everything I said was right... XD I wasn't expecting to be completely accurate, but thanks guys, now I'll go rub it in my dad's face

- - - Updated - - -

Oh, I just saw that post. Sorry for the spoilers, I forgot about that

[NovaSilisko]

I haven't seen the film but apparently this was the footage used:

(Go to 1:50)

In this case, the main engine cut out prematurely, removing its thrust vectoring capability and thus making the vehicle unable to correct for deviations. At that point, it began to tip out of being pointed into the wind and, as anyone who's ever played using FAR knows, that is A Bad Thing.

Edited October 23, 2015 by NovaSilisko

[Whirligig Girl]

The movie does say that it was caused by the protein cubes liquefying and sloshing around. It's the part where the Director and Kapoor are being interviewed by the news guy about the probe. I also kind of doubt that spacecraft have a self destruct button. It's just extra weight that you have to take up to space.

Real rocket launch vehicles do have self destruct buttons, but only as a safety measure on the ground. When you're flying across the atlantic ocean, there's not much point in self-destructing. Self-destruct is, as far as I know, meant for right-after-launch aborts where you don't want the rocket to come slamming down onto the launchpad. Destroying a rocket because it is drifting off course in high altitude and speed flight would be stupid, because then you would have no hope of trying to get it to work and there would be no benefit from the destruction.

[GoSlash27]

A lot of the early launch vehicles (and some current ones) have an automatic self- destruct system built into the launch vehicle because human reaction and communications are unreliable.

The self- destruct is disarmed until a certain altitude is reached (protecting the launch complex), but once it is armed it will self- destruct under adverse conditions unless specifically commanded not to.

The book is a little vague on exactly how the launcher explodes, but IRL if there's no fire or burn- through then the explosion is due to the auto self destruct, *not* structural failure.

So my read is that you and your dad are *both* correct. The shifting load and structural failure caused the rocket to tumble, but the launcher's self- destruct system would have blown it up.

Best,

-Slashy

[SlabGizor117]

Thanks for the replies, It turns out, slashy, you're right, sort of... but not in the movie The real footage shows a failure of engines causing it to tumble and break apart and about 8 seconds after it is self destructed, although I'm very much of the opinion based on the evidence everyone has talked about, I would say in the movie it was solely a break-apart. As for what gregrox said, They very much have a reason to self destruct even in the atlantic, because from the conversation me and my dad had, NASA and the shipping companies are pushing back and forth about launch corridors, where NASA says,

"Well can we go this way?"

"No that's right over a major shipping lane, move it over X degrees"

"That's gonna cost too much fuel to correct our orbit to launch that far off. How about here?"

etc. So, the shipping companies have to clear that launch corridor, and when you have a rocket going out of control, there's no telling where it's gonna go, so you definitely are gonna just blow it up. That said, of course nobody is gonna blow the thing up for just drifting. As said in the movie, the rocket was unstable and wobbling, and also in the footage you could see it was completely tumbling out of control. There's no way you're gonna get out of that, so you wanna blow it up as soon as you can before the debris starts falling on populated areas.

[NovaSilisko]

Wikipedia has a good (if american-centric) overview of range-safety: https://en.wikipedia.org/wiki/Range_safety

The gist of it being: If something is putting the launch vehicle at risk of deviating from its flight corridor, blow it. Only in rare cases does the guidance get a chance to perform corrections. You do not want to risk an entire rocket smashing into anything important, so you instead convert it into as many small pieces as possible before it can do so. Sometimes the rockets take care of this themselves (see: CRS-7), sometimes they don't (See: Challenger's solid rocket boosters, those boosters were built very heavily, and survived the breakup of the rest of the stack)

The late Conestoga rocket provides an excellent example of why rockets need a robust self destruct function:

[cantab]

Wikipedia has a good (if american-centric) overview of range-safety: https://en.wikipedia.org/wiki/Range_safety

The gist of it being: If something is putting the launch vehicle at risk of deviating from its flight corridor, blow it. Only in rare cases does the guidance get a chance to perform corrections. You do not want to risk an entire rocket smashing into anything important, so you instead convert it into as many small pieces as possible before it can do so. Sometimes the rockets take care of this themselves (see: CRS-7), sometimes they don't (See: Challenger's solid rocket boosters, those boosters were built very heavily, and survived the breakup of the rest of the stack)

The late Conestoga rocket provides an excellent example of why rockets need a robust self destruct function:

https://upload.wikimedia.org/wikipedia/commons/3/34/Conestoga_rocket_failure_23_October_1995.jpg

This all applies in normal operation. The launch in Martian was emphatically not normal operation. If that launch failed, NASA's expectation was that somebody was definitely going to die. I feel confident saying that in that kind of situation Range Safety would not be pushing the destruct button unless not doing so would definitely kill someone else.