MWC: Google Talks Projects Titan, Loon And Becoming An MVNO

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ZolaIII

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Google could actually perfect balloons & use them to place real satellites. This would actually provide much to everyone (who need to lunch satellite) as it would significantly cut cost & wile also staying green. This is not new idea.
 

alextheblue

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The drones are very interesting. However looking at a picture of one almost makes me want someone to shoot it down with a homemade remote piloted drone. I mean it just screams expensive sitting duck. I can't help but to feel that would be incredibly hilarious to read about... at least once. Same with the Amazon drones. "What do you mean my package was 'intercepted'?"
 

Calvin Huang

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They're called atmospheric satellites.

Also, Loon balloons only reach 32 km up, which is 68 km short of space and 268 km short of the lowest satellite orbits. And even if a balloon could deliver a satellite to the right altitude, it wouldn't have anywhere near the 7.8 km/s orbital velocity required to stay up there. So as soon as the satellite gets released, it would just fall back to Earth and burn up.
 

genz

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Calvin, you attach a horizontally firing rocket to the ballon. At the gravity level present at 100km, and the complete lack of atmosphere you could use a relatively small one, as we all know 90% of the fuel of every rocket we've ever put in space has been spent escaping earths atmoshpere.
 

Calvin Huang

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That would be possible theoretically. But you're overestimating the change in gravity and air density at those altitudes.

At 2000km, gravitational acceleration is still over half of what it is at sea level. Satellites aren't really trying to escape Earth gravity. They're in continuous free fall in fact. They just move at such a speed (over 7km/s ~= 15,658 mph) that they continuously fall beyond the curvature of Earth, balancing their inertia with gravity so that they don't drop in altitude and also don't fly off into space.

At 100km, the air density is much, much lower, but it's still over 4x as much as at actual satellite orbits. So it's still questionable that we can economically launch satellites with balloons, if we could even make them big enough to carry full-sized satellites + rockets and get them up to 100km.

In terms of fuel savings, the Saturn V used 38% of its fuel to get to 67km. But launching from that height wouldn't necessarily save you 38% of your fuel costs because a balloon's ascent adds very little to the inertia of your vehicle. In regular launches, that vertical inertia is built up by each stage of the rocket and then finally topped off and converted to horizontal orbital inertia by the final stage.

On top of that, you have to deal with the cost of expensive helium gas or use highly flammable hydrogen gas to inflate the balloon, which would have to be massive. And then there's the unpredictability of wind that may blow your balloon off-course.
 
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