'low thrust alarm'
should've used 'John Holmes Mode'.
SpaceX yesterday failed once again to get the SES-9 satellite aloft atop a Falcon 9 rocket, after the lifter's computers shut down the engines shortly after motor ignition. The Falcon 9's motors ignite We have ignition and lift.... The Falcon 9 engines shut down ...oh, no we don't The launch was first delayed by a boat …
This is the second payload to use the Falcon 9 FT (aka Falcon 9 v1.2) stick. The first was Flight 20 - the Orbcomm-OG2 launch late last year, which was also the F9 first stage that did the neat return to landing site trick after stage separation. The reason you might have been confused is that SES-9 was originally slated to be the first FT launch, but they switched it round with the lighter Orbcomm birds. This was so that a second stage test could be done after the Orbcomms were away (specifically a relight of the second stage Merlin to boost to a higher orbit, which SES-9 needs and Orbcomm-OG2 didn't).
Yup. Once the SRBs were lit, it was no longer a case of "are we going?" but one of "which direction are we going?"
And if the range safety officer pressed their button, it would be been going in all directions all at once, very quickly!
It's a real shame that boat got in the way. I hope it was identified and the owner given a thorough explanation of the rules of the sea and how waters can be closed when needed. They literally are a waste of oxygen.
I hope it was identified and the owner given a thorough explanation of the rules of the sea and how waters can be closed when needed.
Some waters can be restricted, not all. I would imagine the danger area extends into international waters. The other issue is in disseminating the information regarding restricted zones to all craft. How would you inform the skipper of a sailboat inbound from Jamaica - bearing in mind that he is not required to keep any sort of radio watch, and even if he does it will probably be on a VHF channel which will be out of range of coastal stations until he is quite close to shore.
The only practical way is via a good radar watch and helicopter intercepts - in which case blame the radar operators instead of the vessel's captain (though small vessels won't show up on long-range radar).
"The other issue is in disseminating the information regarding restricted zones to all craft. How would you inform the skipper of a sailboat inbound from Jamaica - bearing in mind that he is not required to keep any sort of radio watch,"
Well, if they can't be bothered to pay attention to charts like this and the abundant warning notices and information therein, then they shouldn't be entirely surprised if on launch day some extremely grumpy coastguards turn up or bits of rocket start landing on their boat.
It has been said that in the days of the Shuttle, the range safety officers made the point of not mixing with the astronauts in case they had to terminate a shuttle flight and kill the astronauts.
The shuttle had no effective escape system. Only the first test flights did the Shuttle have ejection seats, and that was just for the two pilots.
which is why the SRBs were only lit at T-0, when you commited to launch. the Shuttle launch aborted 5 times I think within the final countdown sequence when all 3 main engines were lit (which happens at T-6seconds) ramping upto launch thrust, the closest they got to launch and aborted was within 2 seconds,literally a 5..4..3..2..abort, any closer might have got interesting. but it was an automated launch sequence abort and should have been possible right up to the command to fire the pyrotechnics at T-0
once the SRBs were lit, then you were going somewhere,and although the ability to stop them firing is seen as one of their main disadvantages,abeit taken against the quantity of thrust they produce,theres generally not alot you can do within the first 2mins of any rocket launch flight, where stopping a main chunk of thrust is really the better option, than just keeping going.
you stop the SRBs on the Shuttle during launch, and it would simply have crashed instead and you are still strapped to a gigantic aluminium tank of combustive fuel,the SRBs really arent the problem in that kind of setup.
At least the Falcon can shutdown its engines, unlike some other rockets *cough*Shuttle*cough*
Shuttle flights STS-41-D, STS-51-F, STS-51, STS-55, and STS-68 all went through successful pad aborts, shutting down their SSMEs without flying.
Yes, the shuttle was committed to flight once the SRBs lit, but the launch sequence lit and tested the liquid fueled main engines 6.6 seconds before the solid-fueled boosters lit. The process was called, "Redundant Set Launch Sequencer Abort."
Agreed... 'failing safe' is good.
As is getting a major part of the rocket back on the ground (for re-use).
It's progress, however, it certainly highlights what must be 'fundamental difficulties' in harnessing rocketry for use as a mundane form of transport.
It's been 70 years since this type of rocket began to fly, with billions and the best brains invested into this technology... and it's still problematic.
Thankfully it has paid off, delivering global communications that we now take for granted...
... but my goodness, my hopes are high for the Skylon project.
Let's hope that it delivers that 'next generation' of space flight that we've all been waiting for, providing genuinely repetitive 'take off and land' operations, in a broad weather spectrum.
Just another 4 or 5 years until the first test flights.
I can hardly wait :)
Closer to 90 years, I think, but YES. Part of the problem might be that, compared to, say, cars, rockets aren't exactly produced in really large numbers.* Mass production tends to shake out the bugs. On the other hand, when a rocket malfunctions you can't simply pull over and look under the hood...
*contrary to comrade Nikita Sergeyewich Khrushchev's claims that the soviet union had factories that churned out rockets 'like sausages'
There was a boat in the ocean down range from the launch pad. Had there been a problem after launch, it is possible that the SpaceX might have fallen on the boat so they had to wait for the boat to move.
This delay cause temperatures to rise.
it appears there may be a issues with the latter, specifically keeping it at the right temperature.
That's the funny thing about liquid oxygen, it has an annoying habit of becoming gaseous oxygen. Still, any launch that can "get off at Edge Hill", so to speak, has to be admired. I've had less sensitive lovers than a Falcon 9.
Controlling the cryogenic temperature is a balance between controlling the vapour space pressure and the incoming ambient energy to the liquid. If your vessel insulation cannot cope then you have to start venting vapour and losing oxidant. Fundamental decisions will have been made regarding vessel insulation effectiveness and time on the pad at design time. It's all part of the learning curve...
The FT uses super chilled LOX, which is denser than normal LOX, they get more performance that way. But the down side is you can not hold for any real length of time as it warms up and becomes less dense long before you get boil off. SpaceX do not even start loading the LOX and the RP-1 (which is also super chilled) until T - 35 minutes so it does not get the chance to warm up before launch.
Like most things rockets, everything has a trade off, in this case, extra performance against hold / recycle times.
If you thought rocket science is hard, try rocket engineering!
I have to agree with the Chinese approach, especially when the barge is in international waters and not subject to US jurisdiction (i.e. the US can't chase them off)
Launch and let the rockets fall where they may.
I wonder if Musk can sue them for damages?
Why are you assuming that the boat's skipper knew anything about the launch or the need to stay clear of the area he was in? If you were the skipper of a yacht heading toward, say, China and had been at sea for the past 4 weeks, with only the usual VHF transceiver and shortwave receiver on board, please explain how you would find out about any temporary danger areas caused by a twice-delayed rocket launch.
"They should know the risks"
Why should they know the risks? There are NOTAMS issued that pilots must read before a flight to check for restricted airspace along their planned and alternate routes, but there is no such thing available to mariners because it would be impractical, due to the fact that the restriction may only have become necessary a few days before coming into force, and ships can be at sea without effective communications for a lot longer than that.
But on rockets with mixture of liquid fuelled engines and solid boosters, they start the liquid fuelled engines first, and make sure they are working, before lighting the unstoppable solids. So the Shuttle, or anything else with solid boosters, can abort in exactly the same way as this did.
" So the Shuttle, or anything else with solid boosters, can abort in exactly the same way as this did."
Shuttle had an "interesting" launch mode.
Light the main engines. The kick would make the entire stack swing. When it swung back (about 3 seconds) the SRBs would be lit simultaneously.
At that point it was impossible to hold it down. The launch clamps couldn't hold the entire thrust back. For that matter they couldn't hold back the thrust of _one_ lit SRB (and in any case the pad's underpinnings couldn't withstand the erosion of one being run to completion whilst being held there)
The single biggest risk of any shuttle launch was one of the SRBs either not lighting, them not lighting simultaneously or any form of asymetric thrust out of them. At that point the chinese village incident would seem minor.
The thing really was a rube-goldberg (heath robinson) clusterfuck of epic proportions and the miracle is that more people weren't killed along the way.
Assuming the commentators on last week's ESA launch knew what they were talking about with the Rokot launch, it isn't possible to abort that once it's got close to being lit, either (launch broadcast 55'30").
Which is slightly worrying, given that it was based on an ICBM. No last minute reprieve there then!.
The thing about nuke-tipped ICBMs is that they're designed to hit their targets reliably, which means designing them to be hard to misdirect (amongst other things).
From what I've heard - an ex boss of mine had inside information (nothing he told me sounded like it was sensitive information, mind you) - once the things are launched, they're built to do nothing but hit the specified target and don't listen for further instructions in part to ensure that the target can't misdirect them that way (the implication being that they simply don't have radio receivers at all). Any encryption scheme is vulnerable to attack and let's face it, if you thought your enemy's ICBMs could be re-targetted or disarmed by remote control after launching, you'd put an awful lot of effort into trying to acquire the ability to do so yourself.
AFAIK the safeguard mechanisms in ICBMs etc. are designed in a way that the last 'switch' to arm the warhead is triggered by the acceleration at launch (pretty hard to fake that). There are a lot of other safeguards as well - there have been incidents where the rocket blew up in the silo during launch drills or maintenance and the warhead did a littlie ballistic hop without detonating.
(I guarded nuclear weapons (grenades for field artillery) for some 9 months in my youth and it kinda got me interested in the subject. And I've always liked rockets anyway.)
[MODE=CLEESE_HOLDING_DEAD_PARROT] Held for a boat downrange?????
Where in the constitution does it say "Ye peeple shalle be free to goe abowt theyr lives and shalle e'en tayke to ye sees in bowts withowt being clonked on ye bonce wyth sundrie rocket parts?"
Nanny state. Wouldn't have happened in my day. Fought on the beaches etc etc.
Rather than blaming the captain of the vessel (who would not necessarily have been expected to know of the restriction), perhaps people should be questioning why the presence of a vessel which would be unlikely to have been moving as fast as 20kts was not discovered until literally the last minute?
They were probably monitoring the boat as it approached the edge of the 'no-sail' zone, expecting it to hove-to just out side and wait for the zone to expire, but only called 'range red' when it did not stop and sailed into the zone and did not acknowledge the repeated calls on VHF by the coast guard.
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