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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

#341

Post by Tloewald »

wfunction wrote: post #317
lobster_johnson wrote: post #299

Earlier quoted context omitted.

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...

How good is the photo quality? Is it close to entry-level DSLRs'?

It's shockingly good for what it is, which is why the camera was sold out for six months and still commands pretty much its original retail price nearly a year after release.

Its big weakness is autofocus speed (making it useless for birders, etc.)

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

#342

Post by mejari »

anigbrowl wrote: post #240
Patrick_Devine wrote: post #154

Earlier quoted context omitted.

This disaster may have bigger implications for Spacecom. They were in the middle of being acquired by Beijing Xinwei and the successful launch of Amos 6 was supposed to be a factor in closing the deal[1]. I have no idea what blowing up on the pad means for the merger. 1. http://www.satellitetoday.com/technology/2016/08/24/spacecom...

It's irrational to argue that you would pull out of a merger because a 3rd party's rocket failure delayed a launch. Contracts almost invariably include escape clauses to avoid liability for matters that are outside the control of the parties. If the launch was already scheduled at the time of the merger agreement (which seems likely, a rocket launch is not the sort of thing you arrange at the last minute) then Beijin…

The failure of the launch changes the real world situation. It's not irrational to argue that such a change also changes the pros/cons of a merger. The fact that it was related to a 3rd party is irrelevant.

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

#343

Post by angryspacesheep »

Tuna-Fish wrote: post #148
mikro2nd wrote: post #79

Earlier quoted context omitted.

Interested to know more about the fuels... when I searched for info about Falcon-9 fueling a week or two ago (having briefly conceived of a semi-idle interest in rocket propellants) I read it was RP-1 plus oxidiser - so basically "just" high-spec kerosene. That doesn't jibe with supercooling in my mind... Please enlighten us further.

They chill the fuel and oxidizer to slush, just above their freezing point, to fit more of it into the same volume and save on structure.

How many Falcon 9s have been launched using this fueling method?

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

#345

Post by dalke »

T0T0R0 wrote: post #292
dogma1138 wrote: post #169

Earlier quoted context omitted.

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.

Phlarp's original comment was about 'a "Range Safety Officer" on the ground whose entire job is to determine if and when to deploy this self destruct system.'

The text I quoted implies there is an onboard flight termination system, even if there is no Range Safety Officer who can send external commands.

FWIW, a part from an exploded rocket, like the engine, could still destroy a school bus filled with children. The odds are very hard to estimate, and made more complicated in that there are few failure modes where a rocket failure halfway across a continent, at supersonic speeds, would reach the ground without breaking long before.

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

#346

Post by AnimalMuppet »

ProAm wrote: post #204
dogma1138 wrote: post #185

Earlier quoted context omitted.

It takes years to build a satellite, the bus, and every component is purposely built each component and the satellite itself goes through months of testing and even if they could build one within 6 months all of the contracts would expire by then which will require Spacecom to open the bids again. All of the contracts were based on AMOS-6 being operational by a given date, AMOS-6 has been "under construction" for pro…

That's why you always build two.

For things like the Mars Rover, they built two so that if something goes wrong, they have one in the warehouse that they can experiment with before they try to remotely repair the one on Mars. I don't know if people do that for Earth-orbit satellites, though.

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

#347

Post by objclxt »

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

> but how hard will it be to just fly a drone there with some kind of projectile?

It's a massive long metal tube full of extremely flammable things...what seems more likely: drone with projectile entering a highly restricted piece of airspace, or as rockets are want to do, it blew up by itself.

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

#348

Post by rohit89 »

ygra wrote: post #56
artursapek wrote: post #50

My mind goes to the debugging stage after the dust has settled... how would a rocket scientist determine the cause of a RUD like this?

About the same as you debug an issue from having just a tracelog. The rocket and pad equipment have quite a few sensors that record information, so you have quite a lot of data afterwards to spot anomalies (you could also compare to previous successful launches / static fires to spot them). Admittedly, that doesn't really explain how they figure out some stuff, e.g. with CRS-7 the problem was with a strut holding a h…

They probably brainstorm through all the possible scenarios that could have caused a particular condition and then see if the data matches and they can prove it as best they can.

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

#349

Post by phonon »

frandroid wrote: post #331
phonon wrote: post #279

Earlier quoted context omitted.

Well, in this case it looks like it is $0 :-( https://twitter.com/pbdes/status/771409425475174400 https://twitter.com/pbdes/with_replies

He says it was covered under marine cargo insurance.

Yes, looks like.

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

#350

Post by dalke »

twic wrote: post #333
dalke wrote: post #168

Earlier quoted context omitted.

"Over-reliance on unit testing"? I have a somewhat different read from the inquiry board report, which says it was a "systematic software design error." Yes, inadequate testing, and a belief the working code for Ariane 4 meant it was validated for Ariane 5 were certainly contributory, but I think it's unfair to single out an over-reliance on unit testing. The board argues that there was a bias towards believing the s…

You have quite fairly picked me up on a cheeky exaggeration. Lots of things had to go wrong to cause the Ariane 5 failure - including bad handling of overflow, as you mention. But to my mind, the universal last line of defence against any kind of mistake is an integration test: put all of the parts of the system together, feed them real input, and verify that you get correct output. Arianespace did not do that. Well,…

That means there was an under-reliance on system testing, which I agree with. It doesn't imply there was an over-reliance on unit testing any more than it implies there was an over-reliance on analysis or over-reliance on the expectation of developing bug-free software.
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