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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

#551

Post by rpgmaker »

dogma1138 wrote: post #185
wyager wrote: post #174

Earlier quoted context omitted.

Won't they just relaunch in a few months? Not sure what the rebuild timeline is.

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…

I admire Musk as much as the next guy but SpaceX has always seemed fraught in the QA department[1]. I'd be surprised if they can survive long enough to accomplish their Mars mission if they keep screwing up this often.

[1] Which also seems to be a problem at Tesla as of late.

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

#552

Post by rpgmaker »

Patrick_Devine wrote: post #154
artursapek wrote: post #51

Looks like they had a payload go with it. Sad. > "SpaceX confirm Amos-6 was aboard the Falcon 9 and was lost in the explosion." https://twitter.com/NASASpaceflight/status/77135388623807283...

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...

I don't think the USG will allow SpaceX to be acquired by a Chinese company.

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

#553

Post by cptskippy »

dogma1138 wrote: post #400
dragonwriter wrote: post #385

Earlier quoted context omitted.

> Long Answer: How was that not racist? Belief that the Israeli intelligence services are, in the modern era, more likely to engage in certain types of action against particular targets than, say, their French counterparts need not be based in any anti-Jewish sentiment. It can be based, e.g., on the degree to which Israeli intelligence services have been found to be doing certain things (e.g., carrying out operations…

>Belief that the Israeli intelligence services are, in the modern era, more likely to engage in certain types of action against particular targets than, say, their French counterparts need not be based in any anti-Jewish sentiment. You are either giving too much credit to the Israelis, or nearly not enough to the French. >It can be based, e.g., on the degree to which Israeli intelligence services have been found to b…

You can't just make-up new definitions for words to fit your narrative.

Distrust of a government does not correlate to racism against the people under it. And since there's no basis for comparison you have no way of knowing the level of distrust one has for any or all governments. Therefore you can't gauge if there is any bias in the level of mistrust for the Israeli government.

By your logic, anything other than blind acceptance of any and all actions by the Israeli government is likely racist in nature.

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

#554

Post by engi_nerd »

cwillu wrote: post #550
garaetjjte wrote: post #517

Earlier quoted context omitted.

It wasn't "You are asking me to do to much, so I'm going to follow the rules you instilled in me about what tasks are vehicle critical and what tasks can be dropped.", but "You are asking me to do to much, so I'm going to reboot". It also overcompensated throttle lag due to old documentation. http://www.doneyles.com/LM/Tales.html

Your reference confirms the parent's interpretation as well as yours: > During the braking phase, up to the time the landing radar locked onto the surface, the duty-cycle margin was over 15%. After the radar acquired, the extra computations involved in converting the body-referenced radar data to the navigation coordinate system lowered the margin to perhaps 13%. When a monitor display such as Verb 16 Noun 68 was add…

Admittedly, I was being a little terse.

I've read his reference before and my reaction to his reply to me was "Yeah, that's right, too."

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

#555

Post by rlanday »

dredmorbius wrote: post #494
rlanday wrote: post #285

Earlier quoted context omitted.

And one of the Shuttle failures was actually on landing

Interesting question of how you'd classify that. A design flaw (foam) under launch stress resulted in foam shedding and leading edge wing impacts damaging tiles and ensuring loss of the vehicle on reentry. I'd argue the failure was in design, triggered during launch, and manifested on reentry. But Columbia was doomed from seconds into flight.

The Falcon only has to solve the problem of getting the payload into orbit. The Shuttle had to both get payload into orbit and return its crew (and the Orbiter, and any return payload) safely to Earth (the Dragon capsule has to do this as well but the statistics given are for all Falcon launches). So as far as comparing the technical challenges involved with Falcon vs. the Shuttle, the Shuttle was solving a harder problem, which I think makes the numbers for the Shuttle look even better relative to the Falcon.

Harder at least as in there are extra steps that can go wrong (re-entry + landing), I suppose it’s debatable which was really a more difficult engineering project…

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

#556

Post by robryk »

ygra wrote: post #518
robryk wrote: post #429

Earlier quoted context omitted.

Nit: flight termination system does not cause the rocket to magically vanish. It will still continue on its current trajectory and impact Earth somewhere. It just causes the rocket to stop thrusting and, IIRC, disperses the fuel/oxidizer so that we don't end up with large quantities of fuel/oxidizer in a small area on ground.

Indeed, all it does is break up the rocket. Depending on when it happens during the launch we might still end up with a fireball near the ground (unlikely to be near anything inhabited, though, as there's a lot of free space around launch sites) or with a quickly disintegrating rocket because it's already at high speeds. There will still be debris, of course, but I guess the reasoning is that it's preferable to have…

Size of debris is not that important: lots of small pieces will cause a similar amount of damage as the same mass in a large piece.

Two important roles of flight termination are: 1. Cause the rocket to stop thrusting (and thus prevent it from thrusting out of range safety exclusion zone). 2. Cause the propellant tanks to be destroyed. This prevents the propellants from causing a large explosion on the ground (when the tanks hit the ground) in preference to a conflagration in the air.

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

#557

Post by mapt »

xenadu02 wrote: post #382
kuschku wrote: post #157

Earlier quoted context omitted.

> Of course SpaceX is so much cheaper than their competition that it may not matter, and reuse is about to make them cheaper still. They’re 2 million USD more expensive per launch for a mid-size satellite than the Ariane 5 is, so I’m not sure I understand what you mean.

No they aren't; SpaceX is charging around $62m and Arianespace charges $100-$130m for the same launch. The first few Falcon 9 launches were a lot cheaper, around $40m I think. I'm sure SpaceX would still be massively profitable at that price, but they're already over-booked so might as well raise prices to generate more capital since building rockets is an ahem capital intensive business. If SpaceX can re-use rocket…

$5M is rather low, and 10 launches rather high, for the time being. First-stage reuse would likely cut prices by 33-75% for the first decade; More than that is going to require a significant expansion of the satellite market, which takes time.

The best market prospect for cheap launch is probably the re-advent of LEO communication constellations, which will each require hundreds to thousands of satellites along tens of orbital planes (adding tens of launches to the global manifest per network).

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

#559

Post by greglindahl »

TheMagician0 wrote: post #558

Is this going to change the launch window (in 2018) for Red Dragon to Mars?? I guess it all depends on the reason for the launch failure. People on Metaculus are discussing about this- http://www.metaculus.com/questions/224/will-spacex-launch-fo...

Last accident, Falcon Heavy had a big delay. Apparently SpaceX pulled engineering resources off of FH to work on F9. Given that the 2018 launch window is narrow, it's quite likely that Red Dragon won't launch until the 2020 launch window.

p.s. are you involved with Metaculus in some way? All of your recent postings appear to mention metaculus.com.

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

#560

Post by T0T0R0 »

dalke wrote: post #345
T0T0R0 wrote: post #292

Earlier quoted context omitted.

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 o…

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