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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

#291

Post by mandevil »

fudged71 wrote: post #267
Phlarp wrote: post #125

Earlier quoted context omitted.

For more context, all (edit: American!) rockets for decades have had onboard self destruct systems and a "Range Safety Officer" on the ground whose entire job is to determine if and when to deploy this self destruct system. The cruise missile scenario is highly unlikely as the rocket itself would be destroyed soon after leaving its intended trajectory.

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

There were no self-destruct systems on the shuttle orbiter, though there were on the solid rocket boosters and external fuel tank. They were used only once, on the Space Shuttle Challenger after the orbiter broke up, but the SRB's were still burning in an uncontrolled manner.

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

#292

Post by T0T0R0 »

dogma1138 wrote: post #169
dalke wrote: post #143

Earlier quoted context omitted.

That links to http://www.thespacereview.com/article/2323/1 where one of the comments is: > Like Russian vehicles, there is no flight termination system that receives ground commands onboard Chinese launch vehicles. Only US and ESA launch sites have such a system. Correction, Falcon 1 did not have such a system for launching on Kwaj.

That's because usually the US and ESA/France launch from densely populated areas. The launch pad at the Kennedy Space Center/CC is effectively about 50 mile from downtown Orlando, Baikonur is in the middle of nowhere.

Okay, rockets that can go very high, can still crash very far away.

An unpredictable, malfunctioning rocket could still million-to-one itself onto a school bus filled with children, halfway across a continent.

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

#293

Post by manarth »

dogma1138 wrote: post #176
brianwawok wrote: post #159

Earlier quoted context omitted.

So you would rather pay $600 million per launch with 95% chance of success vs $200 million per launch with 93% chance of success? There is no such thing a 100% chance of success, everyone has a chance of failure. I would not put ESA more than a few % more reliable. Math says your satellite would need to be really expensive for the price difference to be worth it.

Depending on the cost of failure, however for virtually every mission the 600M$ is a winner this is a no-brainer. That "little" difference has huge huge economic repercussions, cost of insurance, ease of financing, and many other things. Not to mention that a satellite going boom can kill an operator if it doesn't have a backup. This isn't an insurance case where you get your money and try again the week after, build…

The satellite build costs $200m.

Launch 1 costs $600m: total cost, $800m.

Launch 2 costs $200m: you can build 2 spare satellites for the same cost (assuming you don't pay for the launches that go boom; and even if you do, that still gives you one spare satellite).

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

#294

Post by nkrisc »

zzleeper wrote: post #287
TheGuyWhoCodes wrote: post #283

Earlier quoted context omitted.

There is something flying just above when the explosion starts, probably a bird, but how hard will it be to just fly a drone there with some kind of projectile? [Edit] Pre and Post explosion: http://imgur.com/a/IIzg2

Looks way too fast and round for a bird.. but yeah it's clearly there

It's probably a bug in the foreground of the camera. You can see the same thing at around 1:06 in the bottom half of the frame before it explodes.

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

#295

Post by ww520 »

julianpye wrote: post #75

http://www.spaceflightinsider.com/organizations/space-explor... This article has some information on the new characteristics: - Although considered to be an iterative upgrade from the Falcon 9 v1.1 that preceded it, the modifications to the Full Thrust version have increased the vehicle’s published liftoff capabilities by as much as 30 percent. - A key component of this performance increase is the use of “densified”…

Interesting on the fuel. Oxygen's boiling point is at -297F (turned into liquid) and its freezing point is at -362F (turned into solid). Lowering the temperature to -340F would be solidifying the liquid oxygen but not quite yet. I guess at that point the volume has reduced, enabling the packing of more LO into the container.

Having an additional phase change doubles the risk factor along the whole pipeline that it flows through, the container, the valves, the pipes, the chambers, whatever. Liquid to gas can be dissipated quickly. How bad can uncontrolled solid to liquid expansion be?

Edit: uncontrolled liquid to gas venting is equally volatile and dangerous.

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

#296

Post by giarc »

TheGuyWhoCodes wrote: post #283
trothamel wrote: post #228

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

There is something flying just above when the explosion starts, probably a bird, but how hard will it be to just fly a drone there with some kind of projectile? [Edit] Pre and Post explosion: http://imgur.com/a/IIzg2

Given the distance between the camera and the rocket, it still could be a bird.

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

#297

Post by jychang »

daeken wrote: post #266
anigbrowl wrote: post #258

Earlier quoted context omitted.

That's quite a lens, assuming the sound is correctly synchronized with the image.

That's my thought. I counted about 12 seconds between initial explosion and the sound hitting the camera, which puts it at roughly 2.88km away. Edit: Helps if I multiply properly. 12 seconds * 340m/s == 4080m.

Ok, the Falcon 9 1.2 [1] is 70m tall [2], and the rocket fills up about 80% of the vertical frame [3].

Using the "Image = FL * Obj / distance" equation, we get:

.8 * 24mm = x * 70m/4080m

Where x is the focal length of the lens assuming a full frame camera.

This comes out to a x = 1119mm equivalent focal length. If you have a crop sensor, this isn't too hard to obtain. I'd be amused if the video was taken with a Canon EF 1200mm lens or something, but the probability of that is 0.

[1] https://en.wikipedia.org/wiki/Amos-6

[2] https://en.wikipedia.org/wiki/Falcon_9_Full_Thrust

[3] https://www.youtube.com/watch?v=_BgJEXQkjNQ#t=1m10s

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

#298

Post by samwillis »

TheGuyWhoCodes wrote: post #283
trothamel wrote: post #228

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

There is something flying just above when the explosion starts, probably a bird, but how hard will it be to just fly a drone there with some kind of projectile? [Edit] Pre and Post explosion: http://imgur.com/a/IIzg2

The camera is over 4km away, I think its something flying past much closer to the camera.

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

#299

Post by lobster_johnson »

anigbrowl wrote: post #258
trothamel wrote: post #228

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

That's quite a lens, assuming the sound is correctly synchronized with the image.

You can get cheap consumer cameras now with pretty absurd zooms. The $600 Nikon P900 [1] has an 83x optical zoom lens, giving it the 35mm-equivalent focal length of 24-2000mm: https://www.youtube.com/watch?v=4SC_2yD6wKk.

[1] https://www.bhphotovideo.com/c/product/1127274-REG/nikon_264...

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

#300

Post by mandevil »

_puk wrote: post #239
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…

Could they not have mocked the payload?

Mocking a six ton payload is actually fairly expensive, to get the cg, vibration etc. right. A lot more difficult than payload = mock(satellite); NASA did it for the Hubble but so the ground crew could practice operations and not drop the billion dollar space observatory, not to try and save some money if something blew up during testing.
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