Why not use some kind of inflatable to get a spacecraft up near

Because what ever your trying to lift into space cannot be lifted by a large helium balloon. It weighs thousands of tons.

>>7726202
Nah... The Hubble telescope, for example, only weighed like 12 tons.

Sure, the shuttle and the boosters and all that fuel weigh a lot more than that, but you don't need all that weight if you just float stuff most of the way up.

>>7726206
24,000lbs is still a lot of weight to lift with a helium balloon. And besides, to get the telescope out of our orbit you would need thrusters which would add to the weight even more.

You don't think NASA engineers have though of this lol?

>>7726211
Plain old Goodyear blimps weigh almost that much...

I'm sure it's not a new idea, but the question is what keeps it from being a valid idea. Clearly, something is wrong with it, because no one does it, but just the amount being lifted can't be the only problem.

>>7726178
>if you just float stuff most of the way up.
?
Floating it up fucking 80,000 feet hardly shaves anything off.

And the giant balloon needed to carry a million pounds up that high, would cost more than your rocket.

>>7726221
Good year blimps aren't trying to go to the edge of the atmosphere m8

>>7726230
What's the difference? Lighter than air is lighter than air.

>>7726224
A million pounds is ridiculous. The entire space shuttle only weighs 165000 pounds.

>>7726233
Well for one thing there's less oxygen as you get higher up in the atmosphere so it's harder for the blimp to gain altitude.

What if we made a balloon that was filled with a vaccuum, or just electrons? Wouldn't it rapidly float up past the atmosphere since it would have a density less than space?

>>7726257
An object filled with vacuum or near-vacuum is incredibly hard to create and incredibly unstable.

>>7726257
>vacuum
>filled

bad quality bait

>>7726239
and the external fuel tank weighed like 2 million pounds when fueled

>>7726233

Jesus h christ fucking stop.

Why not just build a huge international spaceport at the top of mt Everest? Would the fuel savings even be appreciable?

>>7726178
Look up "xkcd orbital speed", the fuel is used for speed, barely for altitude.

>>7726627
Or, as elon musk said: 9 units of fuel to go to space, 900 to orbit. Less than a percent more fuel and you won't have to build a balloon.

>>7726635
(Less than a percent because those numbers were to GTO)

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>>7726369
The International Space Station is about 250 miles above the Earth. Everest is about 5.5 miles tall. Launching from there would be of little help. It's also about 28 degrees north of the equator so it loses a good bit of the extra help it otherwise would get from being close to the equator.

>>7726178

Getting high up in the air is of no help in getting to orbit. Going into orbit is about moving fast, not getting high up. A rocket launchedfrom the upper atmosphere wood have to be almost the same size, and the balloon needed to carry it there would have to be far bigger than anything we could actually build - much hated than just making a slightly larger rocket.

Look up "Newton's Cannon" for a thought experiment explaining what an orbit actually is, and this will all make sense.

>>7726257
We don't have the materials yet. It's currently not possible to create something light enough to contain vacuum and still have it float.

>>7726178
Orbital speed is 8km/s. Launch delta-V is about 9.5km/s. The moment you detach from the ballon you need to fight the gravity drag, so you won't save up the whole 1.5km/s, only maybe half of it.

So, you reduce your rocket requirements from 9.5km/s to some 8.75km/s. Shaving off maybe 750m/s and increasing the complexity of the launch system immensely.

You'd be better off developing a jet-powered nacelle, a kind of minimal airplane with powerful turbojets. You'll get some 1km/s and a proper pitch, inclination and you get above the thickest atmosphere on the cheap.

>>7726178
LEO is much further than where the atmosphere ends. It was once a good idea for sub-orbital flight but now are engines are good enough that we may as well just blast straight there.

>>7726224
>Floating it up fucking 80,000 feet hardly shaves anything off.
It shaves off a lot of air resistance and thus need for heat protection and thus weight of the system. Moreover it shaves off a lot of high vibration thrust time.

Just use like, big fans.

>>7726754
It still doesn't shave much of delta-V and increases launch complexity. Plus the highest dynamic pressure occurs around 50km anyway, due to achieved speed; you won't save all that much by going some 20km up before launch.

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>>7726239
>A million pounds is ridiculous. The entire space shuttle only weighs 165000 pounds.
>Saturn V: 6,6 million pounds
>Arianne 5: 1,7 million pounds
>Space Shuttle Stack: 4,4 million pounds
gee, Billy, it's like you actually need to lift EVERYTHING from the ground, and not only the payload you actually take to orbit
who woulda thought

>>7726762
This. The closer it gets to space, the less air you have pushing down on your from gravity, and the better your fans will work.

>>7726764
It does not have to shave off much in order to be useful. For each kg you save you will also save a few kg fuel which in turn saves even more fuel.

I didn't talk about dynamic pressure but about vibrations. That is different.

NASA did explore this many, many years ago. From shaky memory here the idea was to use 3 huge ballons tethered to each corner of a triangle and then launch the rocket through the centre of the triangle once the system had reached maximum altitude. I am not sure that adds too much complexity to something that already is very complex.

Another early NASA idea which I will admit is complex, was to launch rockets sideways along a track that started horizontally and then turned upwards along a mountain side. The idea was that you could use electric initial start and a first stage that would be easily recovered. It was a little bit like the rail launch idea og Sänger's silverbird.
https://youtu.be/ZVGsJIc5I8U

KSP has a balloon mod. You could try comparing delivery systems and see for yourself. Real science m8.

>>7726768
kecked

does anyone know how much they could save on fuel/weight if they used a magic balloon to bring the shuttle to near orbit

>>7726776
Connect that with Real Solar System and Deadly Reentry.

4km/s to LKO doesn't really compare to 9km/s to LEO.

>>7726178
Because the problem isn't escaping Earth's gravity, but actually accelerating the rocket to a high enough speed that it orbits the Earth instead of just falling back down.

>>7726754
Heat protection is needed mostly for the return process, dummy.

>>7727208
>dummy
assuming you want to bring it down. Making first stage recoverable is getting there, making further stages recoverable is a totally different ballgame all together. And in the case of Apollo the reentry heat shield was on the underside of the command module.

Not for sensitive equipment obviously.... How about a supergun / rocket combination?
The supergun comprises multiple explosions triggered sequentially along the barrell providing ever increasing velocity, the rocket exits the gun and a solid fuel motor fires 'a la trident' style...

The advantage in cost comes from the reusability of the gun and the ground based xplosive propulsion

>>7727358
>How about a supergun / rocket combination?
it's like you're mentally incapable of typing even a single word into google
https://en.wikipedia.org/wiki/Space_gun

I saw on a hard sci bi board that lasers can be used today if someone invested billions in it. the laser combusts atmosphere in a concave pusher plate. when the atmosphere has become too thin to keep doing this the laser ablates part of the push plate and then orbit. i think it was something like 90% of its mass would make it into orbit. i think a reasonable proposed estimate that a craft could carry thousands of tons of cargo.

>>7726178
the air force actually did this, launching a balloon that that launched a rocket (straight up thru the balloon destroying it) into space.

the program was eventually axed. a balloon can't lift heavy payloads very high because you are limited by the atmospheric density with respect to your payload, which falls of exponentially. on top of this, a balloon is super fucking unstable with respect to weather conditions especially wind. just the slightest breeze and you are pushing your rocket WAY off course before you even begin the launch proper.

>>7726178
This doesn't seem like such a bad idea. Build a HUGE reusable blimp and get the rocket to a decent altitude without using a drop of fuel, then use the blimp as a high altitude launch platform, saving fuel.
What's wrong with this idea?

>>7726257
>>7726270
>>7726286
>>7726702
Stop /sci/
My brain
Its melting

>>7729050
That's theoretically viable, but yeah, the material science isn't there yet, nor anytime soon. We have some lightweight materials of great tensile strength for stretching, but nothing as good for compressive loads, not even on the horizon.

>>7726775
Yes, all these ideas look good on paper, then you start getting into technical details, like implementing all of the launchpad infrastructure into a rail, or preventing the rocket from swaying in the wind, or what if the engines fail to ignite properly and you need to perform abort, and suddenly you see the benefits don't outweigh the costs, and that simply adding several more tons of fuel capacity to the first stage tank or strapping an extra pair of SRBs gives exactly the same benefits at 10% the headaches.

These aren't bad ideas. It's just that they aren't good enough to be worth the effort and risk.

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Instead of this or a space elevator, why not a loosely coupled chain of tensegrity spheres? Spheres at the highest altitude could be made to spin and slingshot payloads and/or rockets into space.

>>7726270
What is that material that naturally forms into balls which contain a near vacuum?

>>7726233
The air gets less dense as you go higher, meaning at some point you're not lighter than the air anymore and won't rise.

>>7729086
If the rocket is carried in a ballon the ballon follows the wind and there is practically no net wind force excerted on the rocket and it should therefore not sway. A rocket on a launch pad is on the other hand subject to all sorts of winds and near the ground there is a lot more turbulence than just a few tens of metres further up.

Abort is always a hassle, however if you are suspended by a ballon an abort means you just don't blow the explosive bolts so you get a lot more time to recover and if crewed get the crew to safety. As a bonus you need no escape rocket as you did with Apollo and you get to save the crew unlike the Space Shuttle.

And speaking of complexity how on Earth is the Space Shuttle not a boondongle of complexity? Solid fuel boosters that destroy a shuttle, Shuttle placed strongly off axis to the main fuel tank, fragile tiles and more are each far worse astronaut killing misfeatures.

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airshipcenter.com

>>7726257
>What if we made a balloon that was filled with a vaccuum, or just electrons?
>balloon filled with electrons
Okay, the thread is stupid in general, but this particular idea intrigues me.

Obviously, it's possible to make something along these lines. I'm having trouble coming up with solid reasons why it would be impractical.

>>7729503
Outside pressure would crush the structure unless it was made incredibly strong from materials like steel, which would make if very heavy, which would defeat the purpose.

>>7726178
>use an inflatable
>to get to the edge of space

>edge has very little air density
>need to get air lighter than that in the ballon
>possible

OP kill urself

why don't we just reverse the charge in the electrons of the space shuttle? that way it will be repelled by the earth's gravity, sort of like an anti-gravity coating around the shuttle causing it to float up like a balloon.

>>7729536
>what is the space shuttle made of

>>7729544
Muons...

>>7729544
I am thinking of gravity like a magnet, there has to be a way it can repel objects instead of pulling them.

Like how two magnets with same poles repel each other.

Why dont we just create a ladder to heaven

>>7729574
Why don't we just play a song

>>7729560
Good luck with your electronics and humans

>>7726257
A balloon filled with nothing but electrons is a giant ball of utter planetary devastation. The contained charge would be massive.

>>7729513
>>balloon filled with electrons
>Outside pressure would crush the structure
Come on, man. Read what you're replying to.

>>7729592
The contained charge would be just enough for the repulsion between electrons to prevent the collapse of the balloon.

The potential (durhurhur) problems I see are:
- the balloon wall has to be a sufficiently good insulator
- the material of the balloon wall can't ionize
- the balloon wall must not be excessively heavy

...but I don't see any immediately obvious dealbreakers, without doing an in-depth analysis.

>>7729513
Graphene blimps when

Why not just sit on top of a + magnet then put that on top of another + magnet?

>>7729658
Replying to myself.

I think I see the problem: the overall vehicle can't have a high net charge in the atmosphere. It would repel electrons from the air, and attract positive ions. The attraction of the electrons to the air outside would increase the pressure from outside, and the effective mass of the vehicle.

I'm not sure exactly how it would work out, but clearly it's not a superior way of producing lift, compared to neutral gas inflation.

You might do an electron balloon of sorts in a vacuum, but not to get lift in an atmosphere.

>>7726211
They're probably too busy sucking cock. Fucking engineers, can't even prove infinite primes.

There is literally nothing wrong with using blimps.

>>7729672
A contained shute with an elevator magnet, charging a gaining positive output, with a platformed divergent polarity on a fixed track. Hmmm. I wonder how dense the insulation radius would have to be to keep it from caving in on itself. How many years and how much of Earth's concrete would it take to cast this barrel elevator? It would undoubtedly be a Pyramidic undertaking even with our modern construction capabilities. Interesting enough to have someone begin the physical calculations.

Something like a hyperfortified blast chamber, using anti-matter annihilation, with programmed magnet assist elevator may indeed save a tank or 2 off the launch sequence.

Does anti-matter annihilation devour everything within spherical radius?
Can pinball launch be effectively utilized?
Is op a faggot?

>>7729379
as opposed to OP, who remains dense regardless of position

>>7730946
Kek

>fuel is heavy
Why not use a giant hydrogen balloon, then burn the hydrogen stored in the balloon?

Space elevators will be more viable once carbon nano tubes can be mass produced.

>>7726178
>Or maybe just attach some big helium-blimp-tank-things to the sides

You do understand how incredibly expensive it would be to purchase all that helium needed just to get several hundred tons of propellant/equipment up into the upper stratosphere?

>>7726257

>getting high

A nuclear verne gun could put hundreds of thousands of tons of bulk materials into orbit

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>>7726221
>something is wrong with it,
>because no one does it
plantostart com/5-start-up-innovation-killers/

>>7726627
This.

>>7726221
Basically, the answer is
>Balloon lift drastically reduces the higher you go, because the air around you is less dense and so you displace much less mass, meaning you need a MUCH bigger balloon than you think
>Going to the edge of space barely saves you any trouble in the first place, because most of the fuel is spent getting the rocket up to the 8 kilometers per second of horizontal speed needed to maintain low earth orbit, not in lifting yourself the few hundred km upwards.
>The balloon adds a lot of things that could go wrong, including the possibility that your rocket will fall on somebody

>>7726635
>>7726627
>9 units of fuel to go to space, 900 to orbit.
Not really true, though.

If you're going to orbit, you'll spend about half your fuel just getting to space. Furthermore, getting from the ground to space poses much of the technical challenge. Once you get to space, there's no weather, no wind, no wind-shear, no moisture, no oxygen atmosphere for things to catch fire, no drag, no dynamic pressure, no conduction heating of cryogenic propellant, no backpressure at the engine nozzle, and no ground to crash into if you have some irregularity of initial thrust. Space is the ideal environment for a rocket, all of those challenges have been overcome once you're there.

While barely getting into space without much payload is considerably easier than going to orbit, carrying a big payload to space is most of the challenge of going to orbit.

Note that Blue Origin did take a substantial payload to space on their rocket, and separated the rocket from it, just like staging. They could put an upper stage on it, although the payload would be quite small. Their orbital plan is to build a considerably larger version, with fuel (methane) that has higher density impulse.

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>>7728949
Going up isn't the hard part. It's going sideways, fast.

>>7730798
I like this meme.

it's been done
https://www.youtube.com/watch?v=HRgvUVFB-CU

>>7726178
Because going to space isn't about going up, it's about going fast enough.

>>7730973
They're planning on doing that for solar generator balloons.

>>7732235
And liquidise the entire payload in the process

>>7726257
A balloon with a vacuum has only slightly more buoyancy than one filled with helium. It makes basically no difference.

>>7732633
>>7732495

Gravity drag (the lost thrust created by working against the vehicle's weight) and atmospheric drag add something like 1.5 to 2 km/s of delta-V over the 7.8 km/s of LEO.

Because fuel needed grows exponentially with delta-V, that extra 2 km/s actually does account for a majority of the fuel.

You need horizontal velocity to stay up there.

>>7732886
solar generator balloons are a meme

>>7732439
you are absolutely wrong.

Delta-v for passing the Karman line, IE reaching space, is 1.4km/s. At an absolute minimum.
https://en.wikipedia.org/wiki/Sub-orbital_spaceflight#Speed.2C_range.2C_altitude

Delta-v for reaching low Earth orbit is 10.6km/s at a minimum.
https://en.wikipedia.org/wiki/Low_Earth_orbit

Simply reaching space is NOT "most of the challenge".

>>7733257
>liquidise
Not a problem if the payload is fuel or bulk material.

>>7732212
>purchase all that helium
Use hydrogen instead, it is not as if the rocket is loaded with enormous amounts of the stuff anyway.

>>7726726
>increasing the complexity of the launch system immensely
Immensely? OK; how?

SPACE IS ABOUT SPEED NOT ALTITUDE
FOR FUCKS SAKE

>>7735602
Pure rocket launch system requirements:
>Rocket assembly

Rocket+balloon launch system requirements:
>Rocket assembly
>Balloon assembly

>>7726257
Helium is 86% less dense than air, whereas a perfect vacuum would be 100% less dense.

So a vacuum would have only 16% more lifting capacity than helium, but at the cost of requiring an incredibly heavy structure to maintain the vacuum that more than offsets the gain. I doubt such a thing could even be made light enough to lift itself.

>>7735816
>immenseley not documented
Moreover you have to also factor in the advantages listed above when you sum up the complexity.

Also rocket assembly is compunded into first stage, second stage, third stage, service module, command module, escape rocket etc if you want to be precise.

Oh and did you know Apollo had ballons? Those were for landing or that added complexity, you choose.

>>7735657
This, most of /sci/ is fucking retarded.

>>7729522

>filling balloons with air

Kill yourself