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SpaceX Plans To Resume Launches In November (reuters.com)
An anonymous reader quotes a report from Reuters: SpaceX is aiming to resume flights in November following a launch pad fire that destroyed a Falcon 9 rocket and an Israeli communications satellite it was due to lift into orbit, the company's president said on Tuesday. The space services company suspended Falcon 9 flights while it investigates why the rocket burst into flames on Sept 1 as it was being fueled for a routine prelaunch test at Cape Canaveral Air Force Station in Florida. "We're anticipating being down for about three months, getting back to flight in the November timeframe," Gwynne Shotwell, president of Elon Musk's space company, said at a satellite industry conference in Paris. SpaceX previously said a nearly-completed second launch site in Florida, located at NASA's Kennedy Space Center (KSC), would be finished in November. The pad was last used to launch NASA's space shuttles five years ago.
Zero.
You seem awfully sure about that, there are .50 cal sniper rifles in civilian hands that can shoot through a window at 2500 meters.
There was a bang right before the explosion. What are the chances the rocket was shot at?
A bullet from a sniper rifle typically travels in excess of 1000 m/s, or about 3 times the speed of sound. So the "bang" would have come after the explosion.
There would have been two 'bangs' perceived by people at the site of the rocket, the sound of the bullet smacking into the rocket followed by the report of the rifle which could have been over two kilometres away if he was firing a .50 cal. Against a target the size of that rocket and with a fair idea of what the wind is like along the path of the bullet a good sniper could have made a 2000 m shot, possibly even a longer one. However, At 2000 m there is no guarantee the muzzle report would have been noticed at the site of the rocket, especially if the shooter made efforts to suppress the muzzle report. Having said all of this I think a sniper is the least likely suspect... Occam's razor...
The NASA spaceflight forum is up to about 136 *pages* of people debating theories on the subject. A lof of the more recent comments have focused on a particularity that only applies to SpaceX and not any other rocket in the world: their densified / superchilled LOX. The only other rockets to have ever used any sort of densified LOX have been the NK-33 variants, all of which have very short, very poor test/flight records - and their LOX wasn't as densified as SpaceX's. A unique risk of densified LOX is air liquefaction; it's colder than the boiling point of both oxygen and nitrogen - and nitrogen tends to boiloff first, or not form at all if the surface in contact with air isn't as cold as the densified LOX itself. You can see LOX forming straight from air by pouring liquid nitrogen into an uninsulated, thin-walled metal container (aka, a rocket) and letting it sit; droplets form on the side and slowly drip off.
Like is common with non-densified LOX, SpaceX has no insulation on its stages, apart from any frosts that form. And frosts do not form a rigid layer, nor are they a comparable insulation to foam. There is one type of propellant that has long faced challenges with air liquefaction: liquid hydrogen. And liquid hydrogen tanks are always insulated. In part it's to avoid the air liquefaction from drawing heat out of the hydrogen, but it's also in part for safety and to prevent liquid air from collecting in vents, in the interstage, etc and adding weight.
If there's LOX outside the tanks, that's a serious potential hazard. If there were leaked fuel vapours (for example, hydrazine from the payload, RP-1 from the stage, etc), or if it collected on top of an organic material on the strongback, or even with Falcon's paint itself, that's a major potential hazard for a serious, rapid deflagration.
Some of the other theories are internal. LOX contamination is a common one. Tank contamination is another. Another is failure of the COPV (the helium pressurant container). Another is a common bulkhead failure. I'm sure these things will all be debated endlessly until the actual investigation results come out.
It's neat to see the lengths people go to through to try to get data without access to the official investigation data. For example, they've brought in a seismologist who's been going over results from seismic stations in the area, looking at the S and P waves and what they could correspond to. Lots of people have been working on processing the video in different ways to try to bring out details. I myself am trying to get ahold of the raw video footage; I suspect it may have been interlaced as well as having a rolling shutter, but have been deinterlaced in all of the subsequent processing. If so, it may be possible to bring out a whole extra frame, plus limited details at sub-millisecond accuracy.
All just idle work of course; the real work is going on at SpaceX.
"I need swat, tactical, the guys with the flashlights on their guns, those guys with the big shield thingies"
What is scary is if Musk has already decided they will resume so quickly even if they have not determined the cause. With his own admission that they are struggling, I find it hard to believe they can conclude a proper root cause analysis so soon. I have performed much simpler root cause analysis on failures that we had pretty good idea what the cause was, and just to go through the process of properly validating and making sure nothing was missed took a good month. What Space-X is facing is much more difficult.
If they were to resume quickly without knowing the cause, another failure could be devastating to the company. I think he is just being his usual overly optimistic self on the timeline, and trying to tell investors what they want to hear.
Evil green Martians shot a small rock from the big gun mounted in the throat of great Maunt Pavonis volcano. They want to stop Earthmen from coming to Mars and distributing smallpox-infected blankets.
What is scary is if Musk has already decided they will resume so quickly even if they have not determined the cause.
Everything SpaceX does is always attributed to Musk. The actual article attributes the quote to Gwynne Shotwell, president of SpaceX.
She was speaking at a conference. Somebody asked when they'd be likely to start flying again, and she gave a best guess. This is not a firm commitment to fly whether or not they have found and fixed the problem, it's just a best guess about how long the process will take.
My personal best guess is that a failure review for a non-manned system takes about six months (after their June 2015 failure launches resumed in December, for example) so I think she is a little optimistic, but she probably would prefer to err on the side of optimism.
http://www.geoffreylandis.com
Huh?
In many cases that is correct. AMOS-6 happened not to be one of those, but....
Failure probabilities don't work that way. Every rocket family, and every individual model, tends to get safer as time goes along as problems are remedied and fixed. The cost for innovating (needed to bring costs down) is that you have to start over on that curve. But the more you launch, the more potential problems you fix and the lower the odds of a future failure. There's always a high degree of randomness, of course, but in general you find a problem, you fix the problem, and the rocket is a safer vehicle for it.
Do recall how terrible the Atlas and Delta families used to be in terms of reliability. Things blew up, they learned, and were remedied. Heck, in terms of families, Falcon 9 is almost like a whole family rather than a single rocket thusfar... some of the changes, like switching to densified LOX, are pretty dramatic changes. They're trying to evolve and optimize it very, very quickly. But of course, that faces the learning curve reset problems above.
(Also, on that note, I think it's a bit premature to talk about the spotless record of the Delta-IV heavy, given that it's only ever had 9 launches, vs. Falcon 9's 29 (if you count AMOS-6... which if you're going to count it in the failure category, you should count it toward the total as well).
Some aspects of the Falcon design were designed to speed up the learning curve - and seem to have worked. Namely, the engines seem to have become quite reliable; part of the reason for going with so many engines was not just so that you can keep going after an engine failure, but also so that you're mass producing the engines and going through ten per flight; you're going to retire the risk a lot faster when using something in such large numbers. On the other hand, there's only two stages/pairs of tanks per flight, two COPVs, etc, so the learning curve is going to be - and has been - slower. . Falcon Heavy will help speed it up, of course, since there's four separate cores, all built similarly.
For a totally new (and frequently evolved) branch, Falcon 9's reliability is quite high; there are mature systems in use today with reliability records no better. But everyone wants you to approach 100%. At some point, SpaceX is going to have to stop with working on the "development branch" and offer up a "stable release" - that is, get the same identical cores with a long safe launch record, and stop changing them. And I'm sure they know that. But they seem to have a higher priority that they want to get to first: evolving their rockets to the point where they feel they can change the world. Not just "cheaper than everyone else", but "immensely cheaper than everyone else".
It's a tall order. But I fully sympathize with it.
On the upside from a stability perspective, there's really not much more need for evolution on the F9 production side, now that they're regularly landing cores. Getting multi-mission reliability, however, that's going to be a new challenge.
"I need swat, tactical, the guys with the flashlights on their guns, those guys with the big shield thingies"
Not necessarily. Contrary to your statement that there's a "glut of launch systems", there's actually a serious shortage right now in launch vehicle production. There are far more companies with payloads than launch providers can manage for now. Additionally:
* The cheaper launch prices get, the higher that number will get.
* Not all first stages will be recovered
* None of the second stages will be recovered
* Even recovered launch stages don't have an infinite life, they're only targeted for a few dozen launches
* You have to ramp up inventory no matter what as the market grows.
* Falcon Heavy has four large cores
And so on. There still will be ample need for production. Reusability will mainly just keep SpaceX from having to expand their production too greatly, if they can make it reliable and affordable.
"I need swat, tactical, the guys with the flashlights on their guns, those guys with the big shield thingies"