"It was important to the film to have fairly realistic balloon simulations. The balloons behave in a realistic way, although the notion of being able to fly a hosue with balloons is pretty preposterous. We're not physicists but one of our technical directors calculated that it would take on the order of 20 to 30 million balloons to actually life Carl's house. We ended up using [...] 20,622 when it actually lifts off."
So I can accept that, scientifically, a few tens of thousands of ordinary helium balloons won't lift a house. But think back-- who won NASA's "Mission Madness" in a slightly controversial upset? Indeed, it was the Superpressure Balloon, SPB.
And just how much can an SPB lift? While the SPB is expected to carry 'over 1000 pounds for up to 100 days'. Even better, looking up SPB leads to the more relevant existing NASA/Wallops long distance balloons (LDB) that can support up to 8,000 pounds.
It was a tiny house in "Up", so let's make it a pair of simple 10x10 rooms, one of top of each other. Anecdotal figures support a house being 120 pounds per square foot (sources). That's going to be about 24,000 pounds, plus furniture (est: another ton, easily) and weight of 1 old guy and a junior (est: neglible).
So three LPBs could loft the house and contents. But wait, Wallops balloons are designed for long duration and high altitude-- at least 33km up. After all, the point of science balloons is to get above the atmosphere, to where the density is 0.02 percent of less that at sea level. In the movie, most of the flight is low altitude, skyscraper level! The atmosphere is much denser near the surface and thus the LDB's lift much higher.
So I suggest that "Up" could happen with a small house, using a single LDB, as show in the image mashup below.
(Image sources: Pixar "Up" image and NASA "Aloft" image)
Finally, I close this analysis with a bit of conspiracy. The Pixar
film is called "Up", and the NASA-chosen feature picture for the SPB is
called Aloft. More than coincidence? You decide*
Alex, the daytime astronomer
* Yes, it's just coincidence. This is a science column, after all.
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