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This is probably a tremendously dumb question, but what are the major impediments to literally sticking a big freaking balloon to the top of a rocket and floati

This is probably a tremendously dumb question, but what are the major impediments to literally sticking a big freaking balloon to the top of a rocket and floating it up much of the way?

Analemma_ 10y ago
It wouldn't save you nearly as much fuel as you'd think. The majority of the delta-V (fuel) to get something into orbit is for pushing it sideways, not pushing it up - you need about 8 km/s of sideways speed to get into even a low orbit, and that's where the the fuel is going. When you see balloons lifting cameras (or people) out of the atmosphere, they're going to space, but not to orbit - they fall straight back to Earth as soon as the rope is cut, even though they might be at the same altitude as the ISS which does not fall. xkcd had a helpful explanation about the vertical/horizontal mistake that is often made when thinking about space travel: https://what-if.xkcd.com/58/ https://what-if.xkcd.com/58/
blater 10y ago
Why bother with the rocket? It sounds mad, but you can actually just send the balloon. to orbit... http://www.jpaerospace.com/atohandout.pdf http://www.jpaerospace.com/atohandout.pdf
- andrewflnr 10y ago
  Well, with some help from "hybrid electric/chemical propulsion". Also, hydrogen. Yikes.
- mrfusion 10y ago
  Why do they need the space station part?
  - blater 10y ago
    Because the orbital ship is structurally unable to cope with higher atmospheric density so must be assembled and maintained at altitude and never go below the height of the station. There's a few challenges there...
- rtkwe 10y ago
  It's a neat idea but I'm not sure the materials science is there. Right now out best balloon material leaks a fair amount of helium over time. Then there's trying to make a ship that's large enough to carry enough helium to float itself up there then rigid enough to survive the extreme velocities to fly up. Seems like there's a huge gap there that might just not be possible to cross.

This is probably a tremendously dumb question, but what are the major impediments to literally sticking a big freaking balloon to the top of a rocket and floating it up much of the way?

Analemma_ 10y ago

It wouldn't save you nearly as much fuel as you'd think. The majority of the delta-V (fuel) to get something into orbit is for pushing it sideways, not pushing it up - you need about 8 km/s of sideways speed to get into even a low orbit, and that's where the the fuel is going. When you see balloons lifting cameras (or people) out of the atmosphere, they're going to space, but not to orbit - they fall straight back to Earth as soon as the rope is cut, even though they might be at the same altitude as the ISS which does not fall. xkcd had a helpful explanation about the vertical/horizontal mistake that is often made when thinking about space travel: https://what-if.xkcd.com/58/ https://what-if.xkcd.com/58/

blater 10y ago

Why bother with the rocket? It sounds mad, but you can actually just send the balloon. to orbit... http://www.jpaerospace.com/atohandout.pdf http://www.jpaerospace.com/atohandout.pdf

andrewflnr 10y ago
Well, with some help from "hybrid electric/chemical propulsion". Also, hydrogen. Yikes.
mrfusion 10y ago
Why do they need the space station part?
- blater 10y ago
  Because the orbital ship is structurally unable to cope with higher atmospheric density so must be assembled and maintained at altitude and never go below the height of the station. There's a few challenges there...
rtkwe 10y ago
It's a neat idea but I'm not sure the materials science is there. Right now out best balloon material leaks a fair amount of helium over time. Then there's trying to make a ship that's large enough to carry enough helium to float itself up there then rigid enough to survive the extreme velocities to fly up. Seems like there's a huge gap there that might just not be possible to cross.