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A SpaceX Falcon 9 rocket has exploded at Cape Canaveral

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Re: A SpaceX Falcon 9 rocket has exploded at Cape Canaveral

#431

Post by jessaustin »

jlebrech wrote: post #150
corv wrote: post #27

"This rocket was scheduled to launch the Amos-6 communication satellite, which among other functions included the capabilities for Facebook to spot-beam broadband for Facebook’s Internet.org initiative" Bad karma

a facebook satelite doesn't sound too good anyways.

It's hard to imagine that this sort of scheme is the best way to provide broadband to most parts of Africa. Why can't they just put microwave links on their cell towers? This is some sort of speculative play by FB to bypass local influences.

Re: A SpaceX Falcon 9 rocket has exploded at Cape Canaveral

#432

Post by TenOhms »

rsp1984 wrote: post #420
trothamel wrote: post #228

Here's good video of the test/failure: https://www.youtube.com/watch?v=_BgJEXQkjNQ#t=1m10s

Can somebody properly explain the different stages of the explosion? Obviously there's the first explosion but then after about 3.5 seconds there's a second, bigger one. What's exploding in the first boom and what in the second? Then, about 12 seconds in, the "nose" is falling down and causing a 3rd explosion. Why hasn't the nose "co-exploded" already with the 1st or 2nd explosion?

Just some wild guesses:

First explosion related to second stage (upper). Second explosion related to first stage's fuel igniting (I was expecting some much bigger, but likely there was already little oxygen left in that area and why it burned for so long. Third Explosion was the satellite's internal fuel (Hydrazine or something like it) detonating due to the fall damage and contact with the rest of the flame.

Re: A SpaceX Falcon 9 rocket has exploded at Cape Canaveral

#433

Post by peletiah »

Coincoin wrote: post #426
fudged71 wrote: post #267

Earlier quoted context omitted.

Imagine how stressful that job would be when astronauts are the payload!

Don't worry, unlike the space shuttle, rockets have escape mechanisms. In that specific case, the astronauts would probably have survived as the emergency rocket thingies would have fired and evacuated them far from the explosion before it could reach the capsule.

How are these triggered? Motion-sensors?

Re: A SpaceX Falcon 9 rocket has exploded at Cape Canaveral

#434

Post by throwanem »

npiazza83 wrote: post #415
throwanem wrote: post #412

Earlier quoted context omitted.

God forfend anyone should try to maintain a quality of discourse that encourages thoughtful people to stick around.

Its a difficult distinction to make. I don't think it unreasonable to expect some nuance on the part of moderators. My personal suggestion would be to remove subjective comments more readily in threads related to highly technical topics where there is MUCH to discuss related to the science or engineering of the piece but show some discretion in threads regarding topics which are inherently political or more subjectiv…

The HN moderation staff has a difficult job which they do exceedingly well, and in a thoroughly nuanced fashion. Were this otherwise, discourse here would differ little in quality from what, for example, Reddit provides in such abundance.

I appreciate you feel strongly that you can tell HN's moderators how to do their jobs even better. Consider the possibility that this may not be the case.

Re: A SpaceX Falcon 9 rocket has exploded at Cape Canaveral

#435

Post by mhermher »

manarth wrote: post #289
ChuckMcM wrote: post #212

This comes at a uniquely bad time. I was reading about the cash squeeze ( http://www.wsj.com/articles/elon-musk-faces-cash-squeeze-at-... ) and it struck me that any interruption at SpaceX would put further pressure on what Elon is trying to pull off. I really hope they can root cause this failure and get the flight schedule back up and running quickly.

I initially started this comment saying "I doubt that there's that much cash-flow between SpaceX and Tesla/Solar City", then thought I should at least google it first. What do you know? Turns out SpaceX invested $165M in Solar City last year [1]. [1] http://fortune.com/2015/08/07/this-is-why-elon-musks-spacex-...

Looks like it was in 2015 on a 1-year term. So it would already be paid off. However, the linked article is from Aug 2015, so they may have bought even more bonds after that point.

Re: A SpaceX Falcon 9 rocket has exploded at Cape Canaveral

#436

Post by dnautics »

trothamel wrote: post #228

Here's good video of the test/failure: https://www.youtube.com/watch?v=_BgJEXQkjNQ#t=1m10s

interesting highlights:

1:23 you can see the sat fairing fall from the stack, and then a secondary explosion when it hits the ground (presumably sat propellant)

3:24 second explosion with a fairly fast projectile coming out the top. Any clue as to what that is?

Re: A SpaceX Falcon 9 rocket has exploded at Cape Canaveral

#437

Post by hoorayimhelping »

rsp1984 wrote: post #420
trothamel wrote: post #228

Here's good video of the test/failure: https://www.youtube.com/watch?v=_BgJEXQkjNQ#t=1m10s

Can somebody properly explain the different stages of the explosion? Obviously there's the first explosion but then after about 3.5 seconds there's a second, bigger one. What's exploding in the first boom and what in the second? Then, about 12 seconds in, the "nose" is falling down and causing a 3rd explosion. Why hasn't the nose "co-exploded" already with the 1st or 2nd explosion?

The first explosion is the smaller second stage igniting. The second, bigger explosion is the first stage exploding. The first stage has most of the mass of the rocket in the form of propellant and is what SpaceX lands on the barge after it separates from the second stage. The second stage is smaller and lighter, and puts the satellite into low earth orbit, or into its transfer orbit in the case of higher orbits (eg geostationary orbit).

The 'nose' falling is payload and its protective fairing. The idea of a fairing is to protect the the satellite from aerodynamic, heat and acoustic stress. It explodes because the satellite has propellant in it - certainly for its rcs system for attitude adjustment and station keeping, and it might have a main engine to help it reach orbit.

http://www.spacex.com/falcon9

http://www.spacex.com/news/2013/04/12/fairing

Re: A SpaceX Falcon 9 rocket has exploded at Cape Canaveral

#438

Post by tmptmp »

rbanffy wrote: post #410
GarrisonPrime wrote: post #409

Earlier quoted context omitted.

As unforgiving as brain surgery. :)

On brain surgery, the worst case scenario is one dead person. Rockets tend to inflate the body count prodigiously.

On a slightly light-but-not-so-light note:

A brain surgery can result in worse still: like, surgeon performs a surgery, makes some mistake, the patient is alive and gets up and goes home, but due to the surgical damage caused becomes a serial killer.

So, strictly speaking a brain surgery can also result in a body count that is greater than 1.

Respectfully submitted.

Re: A SpaceX Falcon 9 rocket has exploded at Cape Canaveral

#439

Post by ChristianBundy »

ChuckMcM wrote: post #368
karma_vaccum123 wrote: post #311

Earlier quoted context omitted.

You can just say explosion, we're not at the Cape.

Which is a sub-class of anomaly :-) it is really hard to scrub Youtube videos, and I (like probably a zillion others) was looking for root cause indicators; things like where exactly on the fuselage does it start? What equipment is there? How energetic was the explosion (oxidizer only? mixed with propellant? Etc. There are at least 30 frames between 1:10 and 1:11 (maybe 60). There are many things to rule out, was it…

Yes, but using "anomaly" when describing an explosion on HM is masturbatory at best. Don't even get me started on the rest of your comment.

Re: A SpaceX Falcon 9 rocket has exploded at Cape Canaveral

#440

Post by izacus »

dTal wrote: post #155
mabbo wrote: post #109

Earlier quoted context omitted.

They do the tests to validate that this rocket won't turn into a cruise missile, headed for the nearest residential area. Not an impossible scenario. Lots of energy stored up in one of those rockets. Just like when we test software, they want to have everything as close to what they would expect on launch day as possible (2 days from now). All the stresses, the structure, etc. That means putting stage 2 and the paylo…

Nitpick: you're thinking of a ballistic missile. Cruise missiles are more like exploding fixed-wing drones. The V-1 flying bomb was a cruise missile, and the V-2 rocket was a ballistic missile.

Not sure what exactly are you nitpicking here - ballistic missiles have propulsion for a short time after lunch and afterwards continuing on a ballistic (hence the name) trajectory towards the targets. Cruise missiles have propulsion usually during most of the flight.

A rocket straying off course could either smash into city under full power (thus being a cruise missile) or have its propulsion cut off remotely beforehand (thus being a ballistic missile), depending on a scenario. What kind of a correction were you making?

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