# Tag Info

41

When will we send? We already did. In 1985 and 1986 the Soviet Union sent two Vega probes to Venus. Both included a robotic balloon (usually called aerobots). The two balloon aerobots were designed to float at 54 km from the surface, in the most active layer of the Venusian cloud system. The instrument pack had enough battery power for sixty hours of ...

31

Why are people so fascinated about Mars and not about Venus at all? The trivial answer - Mars is moderate place. A human could easily get around with a spacesuit, and it is trivial for robots and equipment to exist on Mars. Venus is a swirling hell. The "atmosphere" is a sea of incredibly hot, ultra-boiling, 800+ F° sulfuric acid (!!!) (Indeed, Venus is ...

25

Buoyancy is a big problem. To stay aloft, the average density of the balloon envelope, lifting gas and gondola must be <= the density of the surrounding atmosphere. The pressure inside a balloon must be equal to or slightly greater than the surrounding atmosphere, otherwise the balloon will collapse. If you look at the ideal gas law you'll see that see ...

24

First of all, LEO isn't just reaching 160 km, it's reaching there and moving at a very fast speed. In fact, 160 km would be a really poor orbit, you really need something more like 350 km to get anything practical done. As to your question, yes, it is theoretically possible. In fact, there have been a few amateur made rockets that have reached the Kármán ...

22

There are good reasons why balloons have not been used for launch systems. Fragility of the balloons The highly energetic nature of rocket launches Limited control over balloon trajectory Expense of Helium Flammability of Hydrogen. Balloons are inherently fragile. You have to have very thin, very light materials to make an effective high altitude balloon ...

18

Nearly all balloons that have been constructed have been for flights from the surface to altitude. That requires a structure that can survive tethered at the surface in a range of wind speeds in high-density air, then expand to several times their original size in order to maintain lift as the air density decreases. The minimum density ends up being ...

18

In order to stay within the scope of this question, I will reference one idea that I believe fits the criteria, although that might be disputable. I'll call the idea balloon-tether LAS, and it was published in a journal paper in 2012. The reason this idea is notable is that it started from a study of previously proposed LAS (Launch Assistance Systems), and ...

15

TLDR: "inflation" really isn't the issue, because the outside pressure and aerodynamic loads were so low. The Echo series were deliberately-leaky balloons that carried sublimating solids that would slowly provide a tiny amount of inflation pressure though-out the active parts of their missions. During the development process, there was much more concern ...

13

No, there is no space race to Mars. The original space race was to orbit, for entirely military reasons. Sputnik was simply a demonstration of "we can drop a nuke anywhere we want, any time". The second space race to the Moon was a publicity exercise. It served no military purpose, and it didn't serve any scientific purpose either. (Science builds off ...

11

Yes. However the largest high-altitude balloons in operation can only lift 8,000 pounds (3600 kg). Plot from NASA's Columbia Scientific Balloon Facility: So it would be a pretty small rocket. For comparison, the airplane-launched Pegasus XL weighs about 50,000 pounds (23000 kg).

11

You probably could, but it wouldn't help very much. The reason it's hard to get to orbit isn't that space is high up. It's hard to get to orbit because you have to go so fast. from XKCD What If? #58

11

To float something at 140,000 feet (> 42 km) requires an impossibly low density structure. At 40 km the density of air is less than 4 grams per cubic meter. Barely attainable with the lightest of balloons. The proposed added structures, engines etc make it quite impossible. As to making a balloon structure ascend to orbit, again impossible. The drag will ...

11

Yes, this was done during the EO-21 mission via a spacewalk from Mir in May 1996. The deployment was filmed (or videotaped) for use in a TV commercial. The balloon was not intended to be visible directly from the surface of the Earth. Additional info here.

10

No, altitude is not the hardest thing about getting to space, it's getting enough lateral velocity so that you literally miss the earth as you fall. A weather balloon would get you to 23 miles (37 kilometres). Geostationary orbit is 22,000 miles (35,000 km), almost one thousand times that. In fact no balloon could get you that high since the earth's ...

10

While it's theoretically possible to home-build something capable of attaining the needed 9.3+ km/s, it's not something that the average person can pull off. You'd need to be exceptionally talented and extremely wealthy. You'd also still need multiple flying stages, and a rather large rocket. It's implausible, but not impossible. Note that balloon ...

10

The question contains a misconception - wind is the movement of the atmosphere relative to the surface. So if you are at an altitude with no wind, you'll be stationary relative to the surface - the earth won't be rotating underneath you. However, if the objective is to go up, move around the world and come back close to where you started, you might be ...

10

The MAKS design was supposed to do this. There is much additional info about MAKS in the answers to this question and their sources: Seeking concept art or photo of MAKS on carrier plane

8

It would be quite easy. As you mentioned, the wind speed is roughly 300 km/hour, in the clouds, where Venus is the most hospitable. The same article mentions that oscillations of the atmosphere happen every 4.8 Earth days. Hot air balloons move at about the same speed as the wind around them. Thus, a hot air balloon should be able to circumnavigate Venus in ...

8

But would it be possible to create one that floated near space with almost no air pressure? Possibly, depending on what material(s) you use to make the balloon. If so how much could it lift? what are its limits? That depends entirely on how big the balloon is and what material you use to create it. A regular balloon uses internal gas pressure (...

8

In September of 2013, JAXA launched an $80,\!000\,\mathrm{m^3}$ zero-pressure Helium balloon from Hokkaido1. It reached a float altitude of $53.7\,\mathrm{km}$. From the ICAO 1993 Standard Atmosphere2, the density at that altitude is $6.62\times 10^{-4}\,\mathrm{kg/m^3}$. That same zero-pressure balloon would float at the same density at Mars. The altitude ...

7

You can get things to the edge of space with a balloon fairly easily (in fact quite a few people have done this as amateur science projects) but getting into a stable orbit is an entirely different matter as a low earth orbit requires a relative velocity of something like 7km/s. In fact for a conventional rocket the energy to achieve the altitude to get ...

7

So far, we have only two actual examples of balloons deployed into Venusian atmosphere, the two Vega program balloons from June 1985. They were identical in design, 3.4 m diameter helium filled balloons made of teflon cloth matrix coated with teflon film, each with a gondola suspended on a 13 m long tether. You can read more about them on Goddard Space ...

7

There is a standard clause included in all GPS receiver manuals regarding COCOM Limits. I cannot find the source of this clause, but since it is worded exactly the same in all the manuals I could find, I assumed it was probably derived directly from the regulation at some point: COCOM Limits The U.S. Department of Commerce requires that all ...

7

Here's a rough estimate. From the curves at top left of the plot in figure 1 in this paper, we can expect on average, per year per million km2 of earth surface, 4.5 meteors, weighing 31 grams ("log m" -- base 10, not base e, which would mean 7 grams). Heavier ones are rarer. Your 500 m diameter balloon's projected area is about 0.2 km2. So the average ...

6

I think it's possible that the airship can go hypersonic which is already a major achievement if it does. If they can reach Mach 12 then it could be combined with momentum exchange tether assist to get to orbit. That's still a big ask though. [ see also this paper For details of HASTOL system see this paper. I'm not so sure about accelerating to orbit ...

6

Venus' atmosphere is mostly CO2 which has a higher molar weight than N2 or O2 so a balloon filled with our atmosphere would be buoyant. Balloons filled with H2 or He even more so. But Uranus' atmosphere is mostly hydrogen and helium. Balloons that float would be harder. For a more thorough explanation of this problem, see pericynthion's excellent answer. ...

6

The winds are believed to be relatively constant, so the speed of the outpost relative to the surface should not be a factor. If there are major wind shears at that altitude, then the outpost has other problems. In fact, landing on something that naturally moves with the wind is easier than landing on a runway that is fixed relative to the wind. A runway ...

6

It has never been attempted, but there have been a few people to consider it. There actually was an extensive section on balloon launches in the Ansari X-Prize competition a decade ago. The most notable rocket to be designed was the da Vinci Project While this could work for suborbital, it is rather unlikely to work well for an orbital flight. The speed is ...

6

In tradition with the mentioned Jules Verne's Around the World in Eighty Days, this would take a fair deal of imagination to achieve, but yes. Let's see what our cheat sheet could look like: The length of one Venusian solar day is equal to 116 Earth solar days and 18 Earth hours, so 8 Venusian days translate to 22,416 Earth hours. Assuming we travel West to ...

6

Yes, some people are trying to do it: http://www.bloostar.com/ There are advantages to this solution, such as less drag during ascent (which is especially important for small launchers due to the square/cube law), and a better Isp due to lower pressure at launch. You might also reduce payload fairing mass. However, the mass of the launcher is severely ...

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