If this needs to be said, i think its not clear to everyone... being "in space" is not what causes weightlessness. "Falling" towards your local gravitational source does it. This includes orbiting.
If the balloon malfunctions, they can feel weightlessness until they reach terminal velocity. The problem is they're also going to experience a pretty large acceleration when reaching the surface.
“The sensation of weightlessness is achieved by reducing thrust and lowering the nose to maintain a neutral, or "zero lift", configuration such that the aircraft follows a ballistic trajectory, with engine thrust exactly compensating for drag”
Falling. Falling towards a planet, star, or galactic core is all pretty much the same. Tidal forces will be a bit different, but those aren't on a feelable scale with most objects.
OK, but as a poor earthling who's never experienced low gravity... surely the force of gravity affects the feeling of "falling" even if you're not in an orbit around some nearby planet sized thing? Does that feel substantially different than, say, falling down an elevator shaft on earth?
"the feeling of falling" -- That's called weightlessness, free-fall, and zero-gee. Being in interplanetary space, being in earth orbit, being in the parabolic Vomit Comet, being in a drop tower capsule, being in an elevator compartment falling down a shaft, stepping off a diving board, there's no difference in the 'feeling'.
The opposite of falling is accelerating, and you feel acceleration. A rocket rocketing in an empty universe would feel the same as a rocket rocketing in orbit would feel the same as a rocket just sitting around on Earth. Wait, that last one's different...
We happen to live most of lives in a somewhat exceptional case of constant acceleration (with respect to falling). The ground below our feet has gotten us pretty used to acceleration. But, if you jump, you'll feel like falling too!
Hmm, makes me wonder what percentage weight you would feel at, say, the height of the ISS if you were fixed in a relative location to the Earth (not orbiting at all).
Considering the same question for geostationary orbits had me confused for a moment and then I realised we are not in a fixed location relative to the Earth, thanks to the Earth's spin. I wonder what extra percentage weight we would feel if it weren't spinning.
F = g(m2*m2)/d^2. Earth surface gravity using Earth's radius as d; iss using that radius plus orbital height of 408km. Earth's surface gravity = 9.81m/s2, ISS gravity = 8.66m/s2.
So the answer is, if you could hold the ISS stationary without falling, people in it would feel almost as much gravity. You would have to go much higher than the ISS to feel weightless without orbiting/falling.
Assuming people feel weightless at 1m/s2 or less, you can solve for that! And the answer is 13,600 km.
Thanks to all the replies about the (very small) extra weight at the height of the ISS.
As for the centrifugal force from the Earth's rotation, Wikipedia puts it at about 0.3% (which, added to the effect of the Earth's bulge, means you feel a total of 0.5% less weight at the equator than at the poles).
At the ISS, the extra distance from the center of the earth is minimal compared to the radius of the earth itself. Therefore, there wouldn't be a great difference.
Gravity is proportional to 1/r^2 (r being distance), so you could take a stab at computing your ISS question with that info.
The centripetal force question is a little more challenging, but still in the realm of algebra. The complicated part is setting up the problem and understanding where the forces are coming from and if/how they cancel each other.
Since the inverse square law applies and you're only 100 miles away from a planet 25,000 miles in circumference, I think it would be in the high 90's percentage of your weight on earth.
You have to get pretty far away to experience true "weightlessness".
I've been part of a space industry non-profit that partners with the Government of Canada to put experiments run by students on planes that do "parabolic flights" to simulate "weightlessness" while falling. Around when I first started, I proposed writing the term "zero gravity" on a webpage we were updating. But as my supervisor adamantly noted at the time, that would have been inaccurate.
The convention was to never use the term "zero gravity," since using that term would perpetuate a common misunderstanding. Instead, we've used the term "microgravity" in its place—which makes sense, as there are still small gravitational forces acting on every object in space.
Gravity is the attraction of two objects. Space (which is nothingness) has no gravity. Where you are located in space might have gravitational pull relative to an object.
fair point, but 100k up hopefully it's a lot smaller. maybe you could pull harder on the rope from the ground as well to balance it somewhat. but yes, you won't be weightless the whole way.
It won't change any minds among the flerfers. Commercial airline flights regularly go to 40,000 feet. You can see the curvature of the earth just fine at 40k feet.
It's clearer at 100k feet, but if you're intent on not seeing it then you still won't see it.
I have doubts that even orbit would change their minds. They've already gone through contortions about why it's night in some places when it's day in others. I am quite certain they're up to the task of explaining why they're over America now and then Africa, previously out of sight, a few minutes later.
It's just not worth arguing with those on intent on being stupid. They can simply say "no" and no power of evidence or logic can force them to do otherwise.
Where is Ocean gate was charged with dealing with pressures above one atmosphere, this company will have to deal with pressures between zero and one atmospheres. Probably the same outcome will occur at some point.
I’m not OP, but the startup ethos of the last few decades has been to move fast and break things, fake it til you make it, and generally operate on the bleeding edge to deliver incredible products (and, occasionally non-credible, cough Theranos).
My concern would be that the team would cut safety corners until the probability of success just barely rises above some threshold, rather than engineering everything to have as low a risk as is feasible. Is 0-1atm easier than 1-infinity atm? Yes, but that just means you can cut more corners.
I buy it. OP's comment struck me as interesting, because the "above 1atm" value turns out to be about 300atm; designing a pressure vessel to sustain a 300atm pressure difference is much more challenging than one to withstand 1atm, which is the case for these balloons. If we assume relative cost cutting due to cultural concerns, then the analogy makes sense.
I’d recommend the documentary BLAST! (https://m.imdb.com/title/tt1190065/) for a look at the scientific side of stratospheric ballooning, which personally would put me off wanting to ride in one.
I'd love to see a version of this where each passenger is in a glider, allowing a long distance controlled decent to a new destination. Maybe even use reusable balloons filled with hydrogen, that can be depleted with a fuel cell to create enough ballast, and electricity to do a controlled decent.
There's so little air up there that the gliders would go supersonic rather quickly until they got into denser air. This would mean you'd need low aspect dart like wings so they don't get ripped off but that means the landing performance would be abysmal. You'd have landing speeds nearing 200kts (as opposed to ~50kts for a normal glider). Since kinetic energy is the square of speed, any fuck up would be very fatal at those speeds.
The U2 was famous for this issue, the pilots were flying on a knife edge because a stall (a less aggressive situation that deploying from a static balloon) would mean the plane starts accelerating well beyond it's structural limit before you can do anything about it.
Yeah, I was thinking about that...you'd likely need wings that could be pulled in close at higher speeds/altitudes or to not go quite as high. I would be happy for the later...just get rid energy needs of gaining altitude in a glider.
Funny enough, this was a thing in Pandora's Star. There's a weird chapter where the author gets bored and describes this exotic glider extreme sport where people ride variable geometry winged gliders through mega storms on another planet.
> That price seems crazy to me. It's "just a balloon" I don't see what their hard costs are that make this more than the cost of a commercial flight.
Answer: exclusivity.
---
Or to explain the topic in economic terms: with their offering, these companies offer a given supply for balloon rides into the stratosphere. On the other hand, for a given price for such a ride, a demand to buy it for this price. What a company wants to optimize is
(number of sales for a given price) * price.
Since the supply is currently rather limited, the price can be set to a very high value to optimize this function.
> That price seems crazy to me. It's "just a balloon" I don't see what their hard costs are that make this more than the cost of a commercial flight.
They need to make back the cost of R&D. IE, based on how much it costs to design and certify the balloon, the first flight might operate at a loss. They will need to perform X successful flights before they break even on the cost of R&D.
IE, it might cost $10,000 to pay the staff on the balloon ride, but the vessel itself might cost 10 million to design. It might use $200,000 worth of parts, but the factory cost $20 million to build. Those costs need to be amortized by paying passengers.
Almost no prices are set based on cost to produce. When you shop for eggs, do you care if the producer’s costs were higher or lower than normal? Essentially all prices are based on the value people receive from the good.
That is a new development and the massive shift away from cost plus pricing to value based pricing is a big part of the financial squeeze of the lower and middle classes.
Simultaneously, from all sides sellers are now constantly testing the elasticity of consumer budgets to maximize profit until they exclude the bottom x%, it's a huge financial strain for the poorest among us.
Cost plus was never a pricing model differentiated goods. Human psychology just doesn’t work that way; nobody says “having a nice reliable car is worth $20k to me, but I’ll pay $30k because their cost to produce is high”.
That’s kind of the whole point of the capitalist / consumerist model: first movers take high risks with investment and can reap outsized returns if successful, while success breeds competition from new entrants who have a proven market and a product to copy. The expansion of the market means more price competition, driving prices and returns down.
I’m not saying it always works like that, just that it generally does.
> Ticket prices range from $50,000 per seat with World View to around $184,000 with Zephalto. Space Perspective sells tickets to its experience for $125,000 per seat. That’s all assuming commercial service gets off the ground.
This suddenly makes paying for a 0g flight a steal.
This is a local startup in my hometown, I have been following them for 4 years or so, and have met the founders on several occasions. Decided to pull the trigger on a reservation for a seat for ~2028 flight. Excited to keep tabs on their progress.
I tried to find out how these balloons intend to navigate and descend. I read that World View completed a parachute test earlier this year but I'm not sure if that's intended during normal operation or during an emergency. Details of how each of these companies intend to operate is thin on the ground.
100k feet in altitude may not be quite high enough to get that 'in space' feel. I think you can see the curvature of the earth and the sky above you is dark / blackish.
If this needs to be said, i think its not clear to everyone... being "in space" is not what causes weightlessness. "Falling" towards your local gravitational source does it. This includes orbiting.