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Might want to rethink this GLONASS thing


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The iPhone 4S and 5 use GLONASS satellites, as well as the US ones. I wonder why they are not more accurate than regular GPS units as a result.

 

Because it's not really about accuracy - it's just more satellites to choose from, so more likely to have some in positions in the sky just right for a quick lock, and to maintain a good lock. At the end of the day you'd probably need better electronics in your GPS unit to get more accurate.

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What I don't understand is why their launch control didn't cut off the motor burn before impact. I read somewhere that one one of the motors had some sort of burn through that toasted the gimbal controls thus eliminating all guidance making it unstable.

 

Never had one of mine fail like THAT...of course mine aren't near as big lol.

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What I don't understand is why their launch control didn't cut off the motor burn before impact. I read somewhere that one one of the motors had some sort of burn through that toasted the gimbal controls thus eliminating all guidance making it unstable.

 

Never had one of mine fail like THAT...of course mine aren't near as big lol.

Forget which of many reports I read, but it was stated that they lockout the shutdown process for one of the rocket systems for something like 42 seconds in order to get the rocket clear of the launch site. Obviously it wouldn't work on a SFB system, but might on the mains. It did crash a distance away.

 

Doug 7rxc

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Now that I've looked up dimethlyhydrazine I think I understand why they didn't shut off the motors. Yeeeesh that's some nasty stuff so they probably wanted as much burned off as possible. Kind of a "move the crater as far away as possible" mentality. Can you imagine what the EPA would do if that happened in the states?

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What I don't understand is why their launch control didn't cut off the motor burn before impact. I read somewhere that one one of the motors had some sort of burn through that toasted the gimbal controls thus eliminating all guidance making it unstable.

 

The Russians don't have Range Safety. Their rockets shut themselves off if control is lost or there is some major fault, but only after some number of preprogrammed seconds (which usually means the rocket gets far away from the big expensive launch pad). As I understand it, there's no way for "ground control" to do anything to the rocket once it leaves the pad.

 

Russianspaceweb.com has reported that it is likely there was a fire in one of the six engine compartments, and that one of the engines gimballed "hard over" and the other five couldn't compensate. I'm very curious because the video shows the engine exhaust all over the place indicating the flight computer gimballing the remaining five furiously to regain control. At one point the rocket was rolling really fast too. If the gimbal simply failed and one engine was randomly slewing about, it would explain a great deal.

 

The rocket breakup is interesting because one of the six propellant tanks fastened to the first stage broke away just after the upper stage/payload shroud. I wonder if the fire was associated with that tank...

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Hey, this isn't rocket science!

 

What???

 

It is???

 

Oh, that's very different. Nevermind...

This reminds me of a line from Tom Lehrer's song about Werner Von Brown:

 

"Once the rockets go up, who cares where they come down,

that's not my department says Werner Von Brown."

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Found that article again... the part I mentioned was from another source mentioned above.

 

"According to RussianSpaceWeb.com:

 

Since the emergency cutoff of the first stage engines is blocked during the first 42 seconds of the flight to ensure that the rocket clears the launch complex, the vehicle continued flying with its propulsion system firing practically until the impact on the ground."

 

Hate loose ends. Lots more over there.

 

Doug 7rxc

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