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Rockets consume a lot of fuel and carry not eough payload. To reduce the fuel needed, why not send it in the mesosphere?

Imagine a big balloon, capable of carrying a small rocket to the mesosphere (or at least stratopause) where about 99.9% of the air is located under, so basically, its almost a vacuum.

We would drastically reduce air friction: the rocket would be smaller.

How big would the ballon need to be (we could reuse it)?

For 5 tons of payload, how much of liquid oxygen and liquid hydrogen would we need (as rocket fuel)? How about for 10 tons of payload?

Thank you for your help.

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This question asks for hard science. All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See the tag description for more information.

  • $\begingroup$ Balloons just...float away you can't control their course. They make for excellent targets since they can't be stealth. $\endgroup$ – Valerio Pastore Jun 30 '18 at 16:22
  • $\begingroup$ Shouldn’t this question be on the space exploration stack exchange? $\endgroup$ – yobddigi Jun 30 '18 at 19:23
  • $\begingroup$ Any question that asks about "real world stuff" is fair game here on WB.SE in an effort to understand how such things might be applied to a fictional world. $\endgroup$ – elemtilas Jun 30 '18 at 19:30
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    $\begingroup$ @elemtilas That is false. All other question requirements must till be met. $\endgroup$ – Aify Jun 30 '18 at 20:11
  • $\begingroup$ Most of the energy is expended in accelerating the vehicle and payload to orbital velocity. Only a small part is expended pushing the rocket out of the atmosphere. So the answer is, there would be a little saving on fuel, but nothing to write home about. Full explanation in XKCD What-If #58. $\endgroup$ – AlexP Jun 30 '18 at 21:24
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Achieving orbit is much more about velocity (gaining 16,000+ mph) than about altitude.

For vertical-launch rockets, a higher launch platform will save a few seconds' drag. The extra complexity is generally not worthwhile.

Horizontal-launch rockets (like Pegasus) spend longer in the atmosphere, so reducing atmospheric drag is worthwhile. Instead of a stationary launch site, they get a small extra velocity boost from their launch aircraft...since velocity is still more important than altitude if you want to make orbit. Note that no current horizontal-launch systems can handle 5 tons of payload.

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This question asks for hard science. All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See the tag description for more information.

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Using a balloon to launch a rocket is already a thing. Especially interesting here will be the democratization & commercialization of launching micro a/o nano satellites from a relatively cheaper platform.

Article

Using a dirigible HAPS may also be a way to go, as you can control the platform's motions in the way you can't with a balloon. Plus the station can be manned & manoeuvred more easily.

WP article

The first such launch was 70 years ago:

Rockoon

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This question asks for hard science. All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See the tag description for more information.

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You could have a rail system thousands of miles long, or a giant cannon, lifted miles high above at least part of the atmosphere by countless thousands of giant balloons, to accelerate a rocket to a good fraction of orbital velocity. Then the rocket would have to provide the rest of the acceleration and also circularize the orbit at the right altitude.

Such a system would be very expensive and would probably need a very high volume of launches to be worthwhile.

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This question asks for hard science. All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See the tag description for more information.

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Such a balloon rocket launch pad would probably be a very worthwhile and cost-effective endeavor somewhere like Venus, with a far thicker and denser atmosphere and with extremely difficult surface conditions. On Earth, not so much.

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