SpaceX And/Or Rocketry In General

robl
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RE: Scrubbed for today for

Quote:

Scrubbed for today for violation of the anvil cloud distance rule.
This means next attempt may be just about 24 hours from now.

The abort call came at just over 3 minutes before launch.

We must have been watching at the same time. Do you notice lots of buffering on the live feed?

archae86
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RE: Do you notice lots of

Quote:
Do you notice lots of buffering on the live feed?


I initially noticed not specially good picture resolution. I found that the "auto" resolution setting was at the lowest level (270p or close to that). I clicked for HD and the picture looked much more detailed. But some motions were oddly jerky (for example, when the things which looked like clamps opened away form the vehicle). Yet the countdown clock in the video image seemed to update regularly. It almost seemed that the video content was updating at a variable frame rate far below normal video?

I don't stream movies at all nor watch other internet video often, so don't know what to expect.

Mike Hewson
Mike Hewson
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I couldn't get on to the feed

I couldn't get on to the feed at all. :-(

Cheers. Mike.

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

archae86
archae86
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RE: I couldn't get on to

Quote:
I couldn't get on to the feed at all. :-(


When I first tried after robl posted it and advised there should be a count down clock, I saw the clock in some browsers, but not others. You might try another browser next time, Mike. Or not living down unda, or ...

Mike Hewson
Mike Hewson
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RE: RE: I couldn't get on

Quote:
Quote:
I couldn't get on to the feed at all. :-(

When I first tried after robl posted it and advised there should be a count down clock, I saw the clock in some browsers, but not others. You might try another browser next time, Mike. Or not living down unda, or ...


... not living on the edge of the local node's broadband reach ie. 4.5 km from the DSLAM port on 60+ year old twisted pair. They had to remove an inductive/HF choke from 1952 just to get a handshake. On a good day my service is rated at 4 ( out of 24 whatevers ). FWIW my daughter actually works for the ISP and got a techie gadget to have a special look/test. She just rolled her eyes ..... some form of aggressive quantum tunneling was my only remaining option* alas. :-)

If the price of copper goes up just another 10% it will be worthwhile to dig the line up myself ..... thus paying for a two-way sat link. :-)

Cheers, Mike.

* Or possibly some quantum effect has already been leveraged to achieve the 4 ...

( edit ) With the pretty good price of copper nowadays there has been more than a few instances of 'infrastructure theft' around and about. By the time the repair crew gets to some remote site to fix the outage, all they find is a scorched concrete plinth and nearby wheel tracks. One doesn't need much gear that won't be readily re-imbursed : an oxy-cutter, a light truck with a winch and a tarpaulin. Transformers are highly sought after. You need a good thickness of metal bar for grounding to pop the fuses.

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

robl
robl
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RE: But some motions were

Quote:
But some motions were oddly jerky (for example, when the things which looked like clamps opened away form the vehicle).

I noticed that also. My initial response was that the "left" clamp was not moving and stuck in place (big problem), but after the right one moved away from the vehicle then the left one moved.

I do stream movies occasionally and the streaming is smooth without buffering. I had to constantly click stop/start to keep the stream moving. I know that there were 50k viewers at one time but that is low compared to what it could be. They certainly should be able to handle this.

Mike Hewson
Mike Hewson
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RE: RE: But some motions

Quote:
Quote:
But some motions were oddly jerky (for example, when the things which looked like clamps opened away form the vehicle).

I noticed that also. My initial response was that the "left" clamp was not moving and stuck in place (big problem), but after the right one moved away from the vehicle then the left one moved.


Do you mean the claw/clamps up at the top of the gantry before it leans back ? The ones that grip the payload ?

If so then the one on the right with the usual camera view ( so actually the left sided one if you are looking at the rocket from the gantry ) has been going first in all the launches I have seen, and after about at least five seconds the other side then retracts. Both seem to jerk and wobble slightly several times during the retraction arc, as if the hinge is momentarily stuck and then suddenly releases.

Cheers, Mike.

( edit ) Apropos of nothing in particular : I've been researching the Minutemen missiles. These are solid fueled. They need to shut off very reliably to the instant in order to ballistically progress to target with high accuracy. But how do you throttle a solid fuel firecracker once lit ? Won't it burn until fuel exhausted ? Loading a fixed amount of fuel prohibits re-targeting.

The solution was brilliant and simple. At the predetermined moment, some bolts blow on vent covers up at the head end of the missile. The air rushing in at that Mach 20+ speed just blows the flame out ! Even if not, then any lingering combustion has no sealed surrounds to recoil against and thus produce forward thrust. Thus little or no pressure in the reaction chamber and so no go. Very clever and so obvious in retrospect. :-)

( edit ) Here is a genuinely spooky scenario from the Mutual Assured Destruction tactical cabinet. This was considered in the early 60's by US analysts before submarine launched & cruise missiles etc.

Suppose the Russians using some of their land based silo nukes did a pre-emptive strike on US continental silos. US satellites note in early flight which Russian silos were launched from and thus which still retain unsent salvos. The US waits until it is clear which of their silos are being descended upon. So by then the Russian missiles are in late stage of their journey indeed. When it is quite apparent to the US which silos will be shortly nuked, they launch from those silos alone, but only targeting the Russian ones as yet un-launched from.

The proposed nett effect of the exchange ( all going 'well' ) is that the USSR missiles were wasted hitting the recently vacated US silos, and the US missiles devastate any remaining unused USSR ones sitting in their holes. And the US still has very many nukes in hand. So this is scored as a credible US 'win'. All happening within about 3/4 of an hour. In reality it would require amazing timing finesse to succeed, with probably less than four minutes to re-target and launch hundreds of missiles. These retaliatory missiles would likely just pass say, 50,000 feet going upwards, when their silos get obliterated below them.

It boggles me to think that this type of 'logic' was entertained and in a upbeat manner as it were. When I was a mere toddler. It's a good thing we never found out if it would have worked.

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

robl
robl
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RE: RE: RE: But some

Quote:
Quote:
Quote:
But some motions were oddly jerky (for example, when the things which looked like clamps opened away form the vehicle).

I noticed that also. My initial response was that the "left" clamp was not moving and stuck in place (big problem), but after the right one moved away from the vehicle then the left one moved.


Do you mean the claw/clamps up at the top of the gantry before it leans back ? The ones that grip the payload ?


I believe we are talking about the same claw/clamps. I had not noticed that behavior before.

Quote:


If so then the one on the right with the usual camera view ( so actually the left sided one if you are looking at the rocket from the gantry ) has been going first in all the launches I have seen, and after about at least five seconds the other side then retracts. Both seem to jerk and wobble slightly several times during the retraction arc, as if the hinge is momentarily stuck and then suddenly releases.

Cheers, Mike.

( edit ) Apropos of nothing in particular : I've been researching the Minutemen missiles. These are solid fueled. They need to shut off very reliably to the instant in order to ballistically progress to target with high accuracy. But how do you throttle a solid fuel firecracker once lit ? Won't it burn until fuel exhausted ? Loading a fixed amount of fuel prohibits re-targeting.

The solution was brilliant and simple. At the predetermined moment, some bolts blow on vent covers up at the head end of the missile. The air rushing in at that Mach 20+ speed just blows the flame out ! Even if not, then any lingering combustion has no sealed surrounds to recoil against and thus produce forward thrust. Thus little or no pressure in the reaction chamber and so no go. Very clever and so obvious in retrospect. :-)


archae86
archae86
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Next launch opportunity is

Next launch opportunity is Tuesday 4:10 p.m. EDT. They are mentioning a significant chance of another weather wave-off.

MAGIC Quantum Mechanic
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