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Right you are CONSO. I should have added that I was working on ISA more or less. My bad.
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I wonder if it's possible to insure payloads against disasters likeI wonder if it's possible to insure payloads against disasters like that? And if so, what the premium would be? that? And if so, what the premium would be? Don't know very much at all about rocketery but, if a test involving the live firing of the rocket is required, would it not be prudent to carry out this test before the valuable satellite is placed on top? :confused: |
Don't know very much at all about rocketery but, if a test involving the live firing of the rocket is required, would it not be prudent to carry out this test before the valuable satellite is placed on top? http://cdn.pprune.org/images/smilies/confused.gif |
In the bad old days of rocketry it was not uncommon to source at least two copies of parts for each satellite/interplanetary probe in case of such a mishap. I am taking a wild guess that now it is not so common, given the incredible expense and complexity of such a high capacity modern communication satellite.
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Some good information on this lies in the "forum" of NASASpaceFlight.com discussing this very practice. Bottom line is that early mating of the payload and rocket is cheaper, given that the launch was scheduled for this weekend. Alas.....
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Thank you tdracer and averow.
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Speaking of Saturn V's,here's an interesting article about a recent project to get re-acquainted with the Rocketdyne F-1 engine.
http://arstechnica.com/science/2013/...-back-to-life/ |
Originally Posted by MG23
(Post 9494658)
However, as I understand it, the in-flight failure was due to acceleration forces, which would be going in the opposite direction to bouyancy. They've put extra effort into checking every single strut since then. and I presume the second stage has been test-fired (and, hence, previously fuelled), like the first.
It's possible it's a related problem, but, from what I've read, the failure seemed to start around the umbilical attachments, which would make them a prime candidate. If it disconnected and started spraying liquid oxygen around, that would have been bad news. I've seen videos of a car driving round a roundabout with a helium baloon inside. It looks *really* weird when the baloon is pressed toward the *inside* of the roundabout (i.e onto the driver)... |
Originally Posted by deSitter
(Post 9494679)
There are three main explosive reports in the initial event 1) the initial tank rupture 2) a much larger report 3 seconds later, possibly from the RSO operating the self-destruct mechanism and 3) the report from the satellite stage toppling to the ground about 11 seconds after the first report.
-drl |
Thanks TWT, for the Saturn V article. I just had good read through it. The stats and figures are monsterous! I feel the same awe as I got when I found the same sort of info on the V2 weapon. I remember struggling to absorb the key facts such as 500 hp (if memory serves) being needed just to drive the fuel pump for the main engine. 500 hp is a good amount of power for a decent road car at the start of the 21st century and they were using this much just to drive a fuel pump in the 1940s. Magic.
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Speakingb of Saturn V's,here's an interesting article about a recent project to get re-acquainted with the Rocketdyne F-1 engine. |
SpaceX have been totally transparent with their launcher failures and are far and above any other organisation in this respect.
The previous helium tank failure was traced down to a 3 D 4" square area by interrogating strain gauge outputs and applying different filtration to the raw data to produce the result. This showed that the support struts could have suffered oxygen intergranular corrosion. This was proven when lab tests showed a number of the struts had a chemical imbalance that could lead to this type of weakening. The support struts were then manufactured in house. |
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I remember struggling to absorb the key facts such as 500 hp (if memory serves) being needed just to drive the fuel pump for the main engine. |
Back at the ranch History
:cool::8
The helium tank issue brought back some very old memories re the Saturn first stage- I’m talking 1963-64. Working at Boeing at a facility which had some large steam- accumulators to run steam ejectors to simulate 100K altitudes for early ramjets ( BOMARC ) gave us a facility which allowed us to simulate some parts of the S-1C first stage oxygen tankage system using the accumulators as a large air supply to evaluate the LOX tank pressurization system. The GOX ( gaseous oxygen ) in the fight bird used some bleed oxygen from the turbo pumps to maintain some pressure in the LOX tank to prevent pump cavitation . It was mounted on the top of the dome and fed by a approx 4 inch diameter tube running up the outside of the tank. The concern was the effects of impingement on the top dome of relatively high velocity oxygen. So we built an upside down 1/8 section of the dome ( like a ski ramp-) mounted the distributor upside down in the correct relative location. The flight design distributor was like a large 3-4 foot diameter trash can with half of the cylinder made of ‘ regimesh ‘ - sort of a multilayer screen to break up the flow and then run it with air and monitor with tufts and some instruments the impingement and internal pressures, etc. Each test run was about 30 seconds on condition. But we had various photo and instrumentation and flow measurement problems which with running certain specific flow rates required so we made several test runs. About the 5th or 6th run ( 30 seconds each ) the distributor exploded ! Luckily We had some high speed cameras focused on the distributor .As the Engineer in charge I ordered 3 copies of the film to be made ASAP. Examination of some of the parts indicated a fatigue failure ( high pressure, high flow and supersonic noise can do a lot of things ). The test was on a friday. I called the designers in New orleans and told them I had destroyed the distributor- after convincing them I was NOT joking- they hopped a plane to be in Seattle by Monday . Monday afternoon when I got the file, I was “ invited “ into the Seattle Program Directors office ( George Stoner ) to show the film and explain as best I could what happened. The film showed the beginning of a seam in the regimesh starting to unzip.[ NOTE- In normal flight the SIC stage runs for about 2 minutes and 40 seconds- our total test time on that unit was close to 3 minutes !! ] Getting together with the designers- I suggested three changes - adopted- 1) an intermediate dome in the distributor with many many 1/4-3/8 holes, 2) the above ( below in flight attitude ) cylinder not of regimesh but many many 3/8 holes and 3) a change to holes in the supply tube from slots. We fabricated such a design and ran and ran and ran it for three to four times the normal expected flight time with no problems other that some minor ‘ working” of fastener holes evidenced by smudges around the fasteners. As far as I know- that was the design that flew. SideNote - we used 4 inch diameter SS tubing - special run of about 30 feet. Leftover tubing from the initial build was sold to a local junkyard as no problems were anticipated. I chased the tubing down, bought it back to fabricate the new tube design ( about 3 -4 feet used for the tests ) . The remainder tubing was again sold. Junkyard sold several 3 foot sections as local clam guns - ( seattlelites know what they are ) :) |
Originally Posted by deSitter
(Post 9494679)
There are three main explosive reports in the initial event 1) the initial tank rupture 2) a much larger report 3 seconds later, possibly from the RSO operating the self-destruct mechanism and 3) the report from the satellite stage toppling to the ground about 11 seconds after the first report.
https://www.youtube.com/watch?v=maRTEzlSBLk |
Originally Posted by Loose rivets
(Post 9493827)
I can't stop frame the first part of the flash. The ball of fire is either not there or there.
I'm surprised at the location of the explosion, and equally surprised at the extent of what I assume is a flow of burning fuel from the top. The payload and second stage remained in place for seconds before toppling. Once it toppled, it fell to the ground where it created a blast and mushroom cloud of its own. I'm not so sure that there wasn't an explosion. There are a couple of fragments that were ejected with considerable velocity from the original (frame 1) blast point. That was a diamond shaped blast - as you might expect from a relatively small container rupturing under pressure. Or perhaps it was just shaped from obstacles around it. |
Originally Posted by .Scott
(Post 9498825)
The rocket was less than 1/3 full. So there was no fuel at the top. .
both 1st and second stages were fully fueled with RP-1, only the stage 2 LOX tank was still being loaded, reports suggest it was at ~80% at the time of the fire/explosion) |
only the stage 2 LOX tank was still being loaded, reports suggest it was at ~80% at the time of the fire/explosion) |
Most probably wanted to duplicate temperature effects and pressure effects of 2nd stage in relation to first stage- consider that in flight as first stage shuts down- momentary negative g would have some effects on valves and pressurization and fuel sloshing of 2nd stage LOX and fuel tanks. Without a detailed diagram of plumbing, valve types and sequencing one can only speculate. Liquid fueled missiles have been lost due to failures of certain valves needed to mitigate or stop flow effects of momentary negative g..
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Ambient, thanks for that - his audio is chopped off up front because the loud sound that predated the first explosion by 5 sec is not heard. That sound is key to the investigation.
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Ambient, the loud sound is heard right after the electronic chirp in the original video - this is gone from the sound-sync version.
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Originally Posted by Max Angle
(Post 9499294)
The reports said it was being fuelled for a static engine fire test, why was the second stage being fuelled I wonder? Perhaps something to do with structural considerations or just a test of fuelling process and equipment, it certainly won't have been fired in the test. Any ideas?
Part of this will be testing the RP-1 and LOX loading systems etc, with super-cooled fuel/LOX temp is everything so load times etc are very critical, if there is a bug in the ground systems, this is when you want to catch them. |
In the video, what is the small high-speed object approaching the point of explosion at 1.09 to 1.10? It is traversing from right to left and you can see it for a millisecond between the tops of the two lightening towers on the right. Just focus your sight between the two right towers at this point in the vid and not on the explosion.
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Here's one theory:
Was SpaceX rocket hit by a drone? Video appears to show an object flying into the launcher moments before it exploded Grainy video appeared to show small object flying over the SpaceX rocket SpaceX said an 'anomaly' had occurred while it was being loaded with fuel A massive explosion destroyed the rocket on Thursday - just two days before it was due to blast Facebook's first satellite into orbit By Daily Mail Reporter Published: 07:39 EST, 5 September 2016 |
That is the most stupid....
Can you not clearly see that dot is actually moving WAY too fast for a drone, it also moves _past_ the rocket! It is a fly or other insect, very close to the camera! |
Originally Posted by sandos
(Post 9500639)
It is a fly or other insect, very close to the camera!
Or, maybe not... :confused: Elon Musk is still trying to pinpoint the source of a huge chain of explosions that destroyed SpaceX's Falcon 9 rocket last week at Cape Canaveral. "Still working on the Falcon fireball investigation," Musk said on Twitter. "Turning out to be the most difficult and complex failure we have ever had in 14 years." The company said that the explosion happened in preparation for a test firing of its engines. Musk revealed Friday that the engines had not yet fired when the explosion took place, adding to the mystery of what caused the blast. "Important to note that this happened during a routine filling operation," Musk said. "Engines were not on and there was no apparent heat source." In a reply to a Twitter user's question, Musk said he had not ruled out the possibility that something hit the rocket and caused the fireball. The SpaceX CEO said he was focused on understanding a "quieter bang sound a few seconds before the fireball goes off." He said the sound may have come from the rocket or another unidentified source. |
An odd shadow and a white spot on a video seem to be focal points of further scrutiny in the investigation:
Implication of sabotage adds intrigue to SpaceX investigation By Christian Davenport September 30, 2016 The long-running feud between Elon Musk’s space company and its fierce competitor United Launch Alliance took a bizarre twist this month when a SpaceX employee visited its facilities at Cape Canaveral, Fla., and asked for access to the roof of one of ULA’s buildings. About two weeks earlier, one of SpaceX’s rockets blew up on a launchpad while it was awaiting an engine test. As part of the investigation, SpaceX officials had come across something suspicious they wanted to check out, according to three industry officials with knowledge of the episode. SpaceX had still images from video that appeared to show an odd shadow, then a white spot on the roof of a nearby building leased by ULA, a joint venture between Lockheed Martin and Boeing. The SpaceX representative explained to the ULA officials on site that it was trying to run down all possible leads in what was a cordial, not accusatory, encounter, according to the industry sources, who spoke on the condition of anonymity because of the ongoing investigation. The building, which had been used to refurbish rocket motors known as the SMARF, is just more than a mile away from the launchpad and has a clear line of sight to it. A representative from ULA ultimately denied the SpaceX employee access to the roof and instead called Air Force investigators, who inspected the roof and didn’t find anything connecting it to the rocket explosion, the officials said. |
Er, they’re right by the sea and seagulls are often white and like to perch on roofs. Would that not be as good an explanation as any for a white spot and shadow on a grainy video?
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US Air Force Investigators called in by a joint Lockheed and Boeing firm? That sounds neutral enough. I like the seagull option.
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US Air Force Investigators called in by a joint Lockheed and Boeing firm? That sounds neutral enough. I like the seagull option. |
As someone once said there's no such thing as bad publicity is there, good or bad, credible or not?
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I was visiting Peenemunde launch site and museum a couple of months ago ( Place where Wernher von Braun designed, manufactured and tested the V2s in late 1930- early 40's.) There I learnt that nearly 1/3 of the rockets fired were exploding on site at the beginning , mostly during the refueling process, and that later in the war a large number of rockets were lost due to sabotage..
Amazing to see how little has changed 70 years later... |
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Originally Posted by Needle Knocker
(Post 9493832)
I wonder if it's possible to insure payloads against disasters like that? And if so, what the premium would be?
Space insurers warn that current low rates are not sustainable - SpaceNews.com |
An update in this Washington Post article:
Elon Musk’s SpaceX says it has found cause of rocket explosion and plans to fly again Sunday By Christian Davenport January 2, 2017 Elon Musk’s SpaceX said Monday that it has discovered the cause of a September rocket explosion and plans to return to flight as soon as Sunday. The conclusions of the company’s investigation have yet to be approved by the Federal Aviation Administration, and the agency has yet to provide it a license to launch. But SpaceX’s statement means that it has confidence that federal agencies will approve its remedies for the problem and that it will soon receive the green light. SpaceX’s Falcon 9 rocket exploded while being fueled on a launchpad at Cape Canaveral Air Force Station ahead of an engine test firing on Sept. 1. No one was on board the rocket, and there were no injuries. But the blast touched off a massive fireball and caused extensive damage, including the loss of a commercial satellite. In its statement, SpaceX said it traced the cause to a pressure vessel in the second-stage liquid oxygen tank. The tank buckled, the company said, and supercooled liquid oxygen pooled in the lining. The fuel was ignited by breaking fibers or friction. The company said that in the short term, it plans to change the way it loads fuel. Eventually, it plans to change the design of the pressure vessels to prevent buckling. SpaceX led the investigation, which was overseen by the FAA, the Air Force, NASA and the National Transportation Safety Board. Shortly after the explosion, Musk had said it was “turning out to be the most difficult and complex failure we have had in 14 years” and asked the public for help. Over the past four months, the investigation took several bizarre twists and turns. Musk said there was a mysterious “bang sound” that may have come from “the rocket or something else” seconds before the explosion. And at one point, SpaceX officials asked for access to the roof of a nearby facility used by rival United Launch Alliance, implying sabotage. |
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