back to article Flying saucer with 'stadium-sized' orb to INVADE Earth's skies

NASA's forthcoming flight of the Low Density Supersonic Decelerator (LDSD) – a flying saucer-esque test platform for technologies intended to one day safely deposit larger payloads on the surface of Mars – will be lifted by a helium-filled balloon so large you could "fit a professional football stadium inside it". This …

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fun at parties

Accordingly, we now know how many swimming pools there are to an official NASA professional football stadium, which is handy fact to have to hand during lulls in dinner party conversation.

shirley "fit a professional football stadium inside it" suggests that all we have is a upper bound for Swimming_pool.Football_stadium-1.

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Coat

Re: fun at parties

and now we also know how many Bulgarian airbags fit into the swimming pool :)

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Re: fun at parties

Olympic swimming pools comes as an area with a minimum depth so its not really a good thing to use as a volume and surely a US football stadium would have similar problems but with the added problem of much higher audience density.

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Boffin

Re: fun at parties

"much higher audience density."

Has anyone measured the density of a football fan?

How many will it take to create a singularity?

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Re: density of a football fan

"How many will it take to create a singularity?"

It happened during Superbowl XIII.

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Football or football?

Presumably NASA refers to the American aberration of the game. How many US football stadia to one UK football stadium?

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Happy

Re: Football or football?

UK football stadiums are quite a bit smaller. Wembley fits between the 11th and 12th largest stadiums in the US and seats about 20,000 fewer than the largest in the US.

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Re: Football or football?

Wembley seats about 15-20 thousand less than some of the bigger _university_ feetball stadia. The Big House, at the University of Michigan, has held well in excess of 116,000. (Officially, the name is 'Michigan Stadium'. No-one calls it that. It's supposed to go 109,900.) If you believe https://en.wikipedia.org/wiki/List_of_stadiums_by_capacity then Wembley is _way_ down the list, and most of the stadia above it are uni stadia. That list has Ben Hill Griffin, a.k.a. The Swamp, at the University of Florida, one rung below Wembley. I _know_ that they've crammed more than 95,000 into The Swamp, especially when Florida State or Alabama is the visiting team. (Yes, it's really called The Swamp. UF are the Gators, after all, and where do gators live?)

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So ....

.. it's about 1.7 GBags (Giga Bulgarian airbags).

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Boffin

Re: So ....

And the payload delivery capability will be upped from 357.14 Jubs to 476.19 Jubs or even 714.29 Jubs

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Trollface

Re: So ....

Yes, but is that a simple division of volumes or does it take into account that those airbags wouldn't tesselate perfectly...?

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Re: So ....

If you, as has been noted in the article, wrap them in clingfilm, tesselation will be close enough to perfect for practical porpoises.

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Re: So ....

who cleans up the 2 acres of sammy wrap?

Illegal aliens would do it at $5/hr, but real aliens might not.

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Re: So ....

...close enough to perfect for practical porpoises.

Arrrgh... I sense a fellow Homestuck fan, methinks... well either that or f### you, autocorrect!

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Re: So ....

I was wondering who was going to think of the children.

So hw may swimming pools fill a garbage patch and can we rely on NASA to put them in the skies around Hawaii so that few of them will drift into the Atlantic?

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Fantastic Design

It makes my Monday happier to imagine some engineers developing this thing, working long nights and lots of telecommute work from the pub. During one of those pub sessions somebody leans back and says 'let's put some window shaped panels on this thing, and some porthole looking things too. When it is seen by civilians we will have singlehandedly started an entire generation of UFO stories. We could even prime it all by uploading images of 15th century paintings of Ezekiel's 'wheel in a wheel' UFO's from the Bible because that's exactly what this thing looks like. It'll be fucking hilarious.'

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Re: Fantastic Design

I thought it looked a bit like a high-tech ark.

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Waste of Helium?

On a very boring and serious note... what a really big waste of helium!

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Meh

Re: Waste of Helium?

Perhaps not "waste" (this description I reserve for birthday balloons) but I agree with the sentiment. It is bloody expensive in terms of natural resources used. Especially since US no longer wishes to maintain helium reserves.

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Re: Waste of Helium?

Yeah, well Hydrogen wasn't on sale.

Helium isn't nearly as rare as you think. We had absolutely no trouble procuring the enormous quantities of He3 for the cooling system in our new mirror production facility. It is blindingly expensive, sure, but there's as much of it as you want if you're willing to pay.

The entire market is skewed by long term surplus that makes obtaining more He a loser. Surplus anything held for long periods of time increases pricing, not decrease it like people think. The problem is that although surplus is held 'in reserve' you still have to figure it into overall availability because whoever is holding the surplus can dump it, either into the market, or into the garbage, at any time. You've got a massive uncertainty variable there that drives prices up and up because the market wants to get as much as possible out of each trade so that when something is done with the surplus they'll have made lots of money and can move out with minimal losses. The same uncertainty variable discourages people from obtaining more.

There are many things in the world that are truly rare, but He isn't one of them. It's an artificially capped market specifically designed to maximize pricing. Yes, manipulating markets sucks, but the added costs aren't the most damaging part of all that. What really causes BIG problems is that people think the resource is being wasted. I'm not saying you're dumb or ignorant or anything of the sort, but you have been mislead about the rarity of He. That causes blowback at places like NASA, ESA, CERN and other heavy science institutions.

If you want to see Helium being wasted come on down to Waterford, VA in October for Don Jefe day where we tie a Helium filled weather balloon to a giant piñata shaped like the Trojan Rabbit from Monty Python's Holy Grail and attempt to shoot it down using nothing but an analog watch, a transit and the balloon's position relative to Venus to calculate positioning for the servo controlled cannon emplacement. It's great fun.

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Re: Waste of Helium?

Agree with the comments about true wasting on birthday balloons and the like, I guess when being used for research at science institutions it merits the use of (maybe not such a rare) resource. I blame Brian Cox for making me believe it so rare :-)

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Coat

Re: Waste of Helium?

@Don Jefe,

Interesting, thanks for the explanation. I guess I need to educate myself a little on He availability, I had no idea that its market is massively skewed.

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Re: Waste of Helium?

Since the balloon is not a part of a factory complex or any other cooling system and hydrogen would prvide much more lift per stadium, why isn't hyrogen the gas of choice?

Doesn't NASA have the capabilities needed to design an hydrogen balloon?

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Re: Waste of Helium?

Hydrogen just happens to work as a lifting gas, but it sucks in application. Lifting performance over He is marginal, and you've got to deal with a volatile gas. If you're filling an extremely large envelope, as in this case, safety becomes an enormous issue. Doing it safely adds a lot of complication and expense and there just isn't that much of a performance gain.

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Re: Waste of Helium?

@Don Jefe

I thought He-3 was actually limited by what the DOE releases and read somewhere that that was around 10,000L per year, which was why I was a bit surprised you snarfed up 19,000L of the stuff!

Note that I am not saying that regular Helium is as limited but it was my understanding that He-3 was a different matter altogether.

None of that is to say that the government isn't artificially manipulating the market for gain but, again, it was my understanding that demand was outstripping supply and so the artificial limitation was enforced to ensure ongoing supplies.

Of course, that has the side-effect of people who really need it (research institutes) being unable to afford it!

Enlightenment requested : )

(please)

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Sourdough, salame, cheese, lettuce, ham, mustard, ...

It's a technological marvel but now all I can think about now is 963,000 cubic meters of sandwich.

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or in imperial units....

Six and a bit R101s.

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Flame

A rocket launched from a balloon?

Where have I seen stories about that very same thing recently?

Look like NASA have a set quite a high bar for the Reg SPB

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Re: A rocket launched from a balloon?

Ditto - was wondering where Lester should be submitting his ballocket design theft complaint to.

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'a "balloon-like" pressure vessel...

'...dubbed the "Supersonic Inflatable Aerodynamic Decelerator (SIAD) – will then inflate around the LDSD, "to slow the test article to a speed where it becomes safe to deploy a supersonic parachute".'

Sounds rather like the Ballute used in the aerobraking manoeuvre done by the Alexei Leonov in Jupiter's atmosphere in the film 2010.

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Trollface

Re: 'a "balloon-like" pressure vessel...

Wow, so Hollywood's going to sue NASA for copyright infringement. Nice.

"Your honour, the defendants plainly made a real aerobraking device which clearly infringed on the entirely fictional aerobraking device we used in our film, 2010. We call out for justice... and a hundred million, squillion bazillion dollars. Thank you, m'lud."

Don't laugh, there's a Hollywood lawyer writing up his brief as we speak...

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