Posts by Mike Hewson

11) Message boards : Cafe Einstein : SpaceX Dragon scheduled for 12/19 (Message 142172)
Posted 13 days ago by Profile Mike Hewson
Aha. This is definitely in the anti-intuitive category :

Inside the upper stage liquid oxygen tank, a steel strut about two feet long and an inch wide at its thickest point appears to have snapped, Musk said. "One of those struts appears to have failed, and as a result was unable to hold the helium bottle down. So the helium bottle was shot to the top of the tank at high speed."

So there is a bottle within a bottle as it were. The helium tank is normally sited within the lower/aft part of the oxygen tank. The helium tank has less dense contents than the surrounding liquid oxygen. Normally the tendency for the helium tank to rise ( go forward/up ) is balanced by the strut mentioned. This strut acts like a seafloor anchor holding down a buoyant craft. This will be true when the rocket is sitting on the ground in its normal 'up' position : one gee worth of acceleration times the density difference b/w helium and oxygen. But with the whole craft going upwards under rocket power that rises 3.2 times. The strut breaks, the helium tank goes up ( like a submarine rapidly rising to breach the ocean surface ), hits the inside top of the oxygen tank, the helium tank is breached, the helium spills and mixes into the liquid oxygen causing a rapid pressure rise in the oxygen tank ( too fast for relief mechanisms to kick in ), the oxygen tank now breaches, like a Coke bottle with way to much fizz it will continue to splurge the oxygen out, and it all goes to the crapper from there ....

Yup, I'd call that a new variant in the rocket industry failure mode roll call. AFAIK.

Cheers, Mike.

( edit ) The normal mode here is a controlled bleed of the helium from its tank into the surrounding liquid oxygen. The helium gas rises to the top and pushes down on the oxygen to facilitate its fast transfer via tubes & pumps to the second stage rocket engine. You want to keep the input pressure to the turbo well up to stop cavitation ( pumping of nothing ) and thus engine failure.

( edit ) So assuming this is confirmed as the cause then the fix is straight forward at least : make and test a stronger strut(s).

( edit ) And a ground hold-down test will not give that 3.2g ......

( edit ) Plus the above failure takes a much shorter time to happen than to describe ! :-)
12) Message boards : Science : The Square Kilometre Array: radio silence in Western Australia for most powerful telescope in history (Message 142148)
Posted 15 days ago by Profile Mike Hewson
I chuckled about the "Does the RQZ make a difference to future shed design (that is, open side away from the MRO)?"

You could do all the welding you like in a Faraday cage!

I was so disappointed when our cheap**** government knocked back the terrific LIGO offer in 2011. More power to India though, clearly more forward thinking there. With one thing and another we were pretty well going to get it for nix over the course of the funding agreement - a mere $30M per year for a decade IIRC. It would have been a great boon to science DownUnda. So this SKA has cheered me up ! :-)

Cheers, Mike.

( edit ) This is why countries like Australia really do need benign dictators such as I could be. Science funding .... no problem .... I just can't figure out why I haven't yet been offered this role .... :-) :-)
13) Message boards : Cafe Einstein : SpaceX Dragon scheduled for 12/19 (Message 142135)
Posted 16 days ago by Profile Mike Hewson
I'd be extremely delighted to own a Telsa Model S P90D. The centre of gravity is quite low with the batteries in the base of the chassis and of course it is near perfectly mid-balanced ( fore to aft ). It has received a safety rating ( ANCAP ) higher than anything previously tested.

What I wouldn't be delighted with is having to pay for it. DownUnda the P85D brand new and going crazy with all the mods ( including Lucridous Speed Upgrade ) is $226K AUD all up. Notably Tesla guarantee a resale trade-in value of 50% after three years ( well kept, undamaged etc ). I find that quite interesting as many high end performance and/or luxury cars lose 30% just by driving it off the lot on day 1.

Cheers, Mike.
14) Message boards : Science : The Square Kilometre Array: radio silence in Western Australia for most powerful telescope in history (Message 142134)
Posted 16 days ago by Profile Mike Hewson
Just let it be known that the site receives radiation from outer space, and it will be clear for 100 miles around.

LOL! :-)

Cheers, Mike.
15) Message boards : Science : The Square Kilometre Array: radio silence in Western Australia for most powerful telescope in history (Message 142130)
Posted 16 days ago by Profile Mike Hewson
It occurs to me that a restricted fly zone of some suitable radius and to height over the site's centre would also be of great merit too. Especially light planes going low, as the magnetos do pack a wallop of current bursts that would be an extreme broadband nuisance. Not to mention all the radio stuff, radar transponders especially. I fear it could be a worry as the array would be well liked to have a look at overhead by sightseers, lovely geometry etc.

Currently such zones are only associated with military air facilities, plus the usual spaces around civilian air traffic controlled airports. But of note is that there is much civilian traffic of importance in Western Australia ( unrelated to tourism ) for routine purposes. It's a very big space and the lighter modes of air travel is very handy way to get around.

Cheers, Mike.
16) Message boards : Science : The Square Kilometre Array: radio silence in Western Australia for most powerful telescope in history (Message 142117)
Posted 17 days ago by Profile Mike Hewson
I am more inclined to go with "beef on the barbie". :P

Not mutually exclusive really. Drop them with a snake. The cooking will destroy the venom .... :-)

Oooops. Didn't think that through very well ( like most Aussie solutions). On second thoughts : you'd get a ton of scavengers turning up looking for a free feed ( like most Aussie BBQ's ). The whatya do about the goannas mate? Of course the pastoralists ( who own the cattle ) may object. Free for all punch up in no time ..... not forgetting the camels too.

Cheers, Mike.
17) Message boards : Science : The Square Kilometre Array: radio silence in Western Australia for most powerful telescope in history (Message 142115)
Posted 17 days ago by Profile Mike Hewson
....use an algorithm to reduce that data down to a smaller magnitude that you can then process further on a super computer ...

Yes. Indeed. Hmmm ... now is anyone actually doing that already now? Let me think .... I wonder who that might be .... :-)

I note the concern about cows knocking up the hardware when the SKA becomes rather larger than now. I have a unique Australian solution : we have no shortage of really deadly snakes, just breed up a large number and drop them in! :-)

Cheers, Mike.
18) Message boards : Cafe Einstein : Cafe Einstein - LPTPW 16 - I found K-9; now, where's Romana? (Message 142101)
Posted 18 days ago by Profile Mike Hewson
In the Upper Carpathians perhaps ?

Cheers, Mike.
19) Message boards : Cafe Einstein : Seti Refuge Bar & Bistro Wing of Cafe Einstein (Message 142099)
Posted 18 days ago by Profile Mike Hewson

@ Zalster : I dread to guess what you have requested there, but I'll go for spicy and Indian?
Cheers, Mike.


Spicy maybe (very mild), Indian no, lol...Mexican

It's actually huevos con chorizo or Scrambled eggs with beef spiced sausage served with flour tortillas. This pic also has some beans on the side. Used to eat it every day when I was growing up.

Ah. Mexican. That explains it. We had that once but OH&S requirements ( multi-megalitre water dousing system, asbestos suits ) ruled it out. Just too many flare ups, patrons exploding into balls of flame. Bad for business. We said 'no reason' but that wore thin after a while. But we're having a consultant look into serving it within a hypoxic booth. Tests are continuing ..... on the upside SpaceX is helping to fund our research.

Cheers, Mike.
20) Message boards : Cafe Einstein : Cafe Einstein - LPTPW 16 - I found K-9; now, where's Romana? (Message 142097)
Posted 18 days ago by Profile Mike Hewson
There is only one logical conclusion : Mr Dixon came from Pluto, has lived amongst us ( probably for the purpose of observing the Illuminati ), and unwisely has left a clue as to his true origins. I profess this, so you must disprove ! My evidence is that you lack evidence .... the USAF has denied it, so it must be true .... pathoplasticity rules .... :-)

Cheers, Mike.


LOL ! I was thinking along similar lines.

I do hope Bill that you are also on The Protected List, as I am, for when Saurian Renewal Day comes.

[ HINT : If you spend your life not mocking lizards then you will have some chance . But don't mention the dinosaurs, it's a kind of embarrassment in the family thing. Let's face it : they blew it big time, sort of a Breaking Bad but without the meth. ]

Cheers, Mike.

( edit ) Yeah the dinos really got carried away. All that top-of-the-ecosystem stuff, the big things eating the smaller things and that. They had millions of years to come up with the opposable thumb, space flight, pizza, asteroid missile defences and Nintendo. So what did they do ? Blood lust. Rampage. Always the rampaging ....


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This material is based upon work supported by the National Science Foundation (NSF) under Grants PHY-1104902, PHY-1104617 and PHY-1105572 and by the Max Planck Gesellschaft (MPG). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the investigators and do not necessarily reflect the views of the NSF or the MPG.

Copyright © 2015 Bruce Allen