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Would certain types of flying be possible on planets like Venus, Titan (which is a moon, I know :P), or gas-giants?

I'm thinking on the aspects of these types of aircrafts: airships (that uses only enormous amount of air to float and fly), gliders (that uses only the wind to fly), planes with propellers, helicopters (they use similar ways to fly) and planes with jet engines.

Obviously, most of them wouldn't work on planet with no or very thin atmosphere like the Moon or Mercury, so I specified the question to those planets and moons which have dense and/or thick atmosphere. Also, by aircrafts I mean only those vehicles which are not able to leave the atmosphere - since those that can travel in space, must be able to travel within the atmosphere too. But vice versa, it's not true.

For example, gliding on Jupiter (or even on Venus) would be strongly possible, since the heavy storm in their atmosphere generate strong winds. But it obviously can't go to space, since there's no wind to throttle it in higher layers of the atmosphere.

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  • $\begingroup$ What's the question? :) If you're confident that heavier-than-air probes are viable, then maybe you should narrow this to what you don't know about, like gliders. $\endgroup$ – AlanSE Jul 31 '13 at 13:21
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    $\begingroup$ @AlanSE The question is that which of them are able and unable to fly on the mentioned type of planets & moons. Just a theoretic question. $\endgroup$ – Zoltán Schmidt Jul 31 '13 at 13:24
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I was actually just reading a great What If? article on this found here. Flight on other planets is possible. I think the included comic strip summarizes it wonderfully:

Some Description

As for each valid body in our solar system (barring Earth of course), I'm going to paraphrase a bit:

The Sun: Attempting flight on the sun is more or less useless as any vessel close enough to feel its atmosphere would be instantly vaporized.

Mars: The article goes into a lengthy discussion about simulation via X-Plane. X-Plane, as it turns out, can be made to closely simulate the conditions found on Mars. Unfortunately, as was also found, flight on Mars is possible but difficult. To achieve flight on Mars, you need to be going fast. The article states that a speed of mach 1 is required merely to achieve flight. Problem is, once you achieve flight, the inertia makes it nearly impossible to change course.

Venus: Venus is interesting. The atmosphere on Venus is 60 times denser than Earth's atmosphere. You could easily achieve flight at incredibly low speeds (a Cessna 172 Skyhawk, the aircraft the article is based around, could achieve flight at running speed). Problem is, the air on Venus is hot enough to melt lead. You can always get around this by flying in Venus's upper atmosphere. The upper atmosphere is rather earth-like and would be quite easy to fly a plane in. Only, you'd have to ensure no metal is exposed as sulfuric acid in the upper atmosphere introduces the threat of corrosion.

Jupiter: Flight on Jupiter is unrealistic. Jupiter's gravity is much too strong. The power required to maintain flight is about 3x that of Earth making flight there highly unrealistic.

Saturn: Weaker gravity and slightly denser atmosphere than Jupiter means an aircraft might fair better but ultimately would succumb to cold or high winds.

Uranus: Flight on Uranus could be sustained slightly longer but ultimately the aircraft would still succumb to the conditions found there.

Neptune: The temperature and turbulence make it impossible to achieve flight on Neptune. It's assumed your aircraft would quickly break apart in the atmosphere.

Titan: Titan is perhaps the best plan to attempt flight on. To quote the article:

"When it comes to flying, Titan might be better than Earth. Its atmosphere is thick but its gravity is light, giving it a surface pressure only 50% higher than Earth’s with air four times as dense. Its gravity-lower than that of the Moon-means that flying is easy."

Flight on Titan IS easy. A human could theoretically achieve flight with a wingsuit and mere muscle power. The problem is, Titan is cold, 72 Kelvin cold. Flight would require some major heating modifications but, barring the heat factor, Titan is the absolute best place to attempt flight in our solar system. It's even better than Earth. As an interesting note, Titan, thus far, has actually been too cold for even unmanned probes to explore. Again, quoting the article:

The batteries would help to keep themselves warm for a little while, but eventually the craft would run out of heat and crash. The Huygens probe, which descended with batteries nearly drained (taking fascinating pictures as it fell), succumbed to the cold after only a few hours on the surface. It had enough time to send back a single photo after landing—the only one we have from the surface of a body beyond Mars.

Earth: Earth's conditions are quite optimal for flying. Earth's gravity is 9.78 m/s². As a comparison, Jupiter's gravity is 24.79 m/s² and Titan's gravity is 1.352 m/s². Earth's atmosphere is, at sea level, 1 standard atmosphere or 101.3 kPa or 14.7 psi compared to Mars's average which is about 0.006 standard atmosphere or 600 Pa or 0.087 psi and Venus's average which is about 9.2 mPa or 1,330 psi. Takeoff speed for our Cessna 172 Skyhawk is 64 KIAS (Knots Indicated Air Speed) and the best rate of climb is 73 KIAS. Normal cruise speed in a Cessna 172 Skyhawk is 122 knots (140mph, 226 km/h). As a comparison, flight on mars would require speeds over Mach 1 which translates to 768 mph or 1,236 kph.

To summarize:

  • Sun: Instant vaporization.
  • Mars: Atmosphere's too thin to fly below mach 1, above mach 1 you essentially can't steer.
  • Venus's Lower Atmosphere: Flight is possible but the air's hot as lead. You'd melt.
  • Venus's Upper Atmosphere: Flight is possible but corrosion is a factor due to sulfuric acid so no exposed metal.
  • Jupiter: High gravity makes flight extremely unrealistic.
  • Saturn: Flight's possible but your aircraft might ultimately succumb to the cold and weather conditions.
  • Uranus: Same as Saturn but you MIGHT last a bit longer.
  • Neptune: Your aircraft would break apart quickly from the extreme turbulence.
  • Titan: Flight could be achieved with artificial wings and mere muscle power. Unfortunately, Titan's cold. To quote the XKCD article:

If humans put on artificial wings to fly, we might become Titan versions of the Icarus story—our wings could freeze, fall apart, and send us tumbling to our deaths.

Icarus on Titan

  • Earth: We know flight on Earth works due to firsthand knowledge. We don't have the most optimal conditions in our solar system, but the conditions here are still great for all types of manned aircraft.
  • Anywhere Else: No atmosphere, so you would crash ballisticly.

As a small note:

Titan is the absolute best environment for flight using a conventional aircraft if you don't factor in the cold. I imagine it would be much easier and less costly to attempt flight in Venus's upper atmosphere by protecting all exposed metal from corrosion than it would be to make major modifications to a conventional aircraft so that it and its pilot can withstand the extreme cold found on Titan.

Another Small Note: Mach 1 is measured relative to earth so 340.29 m / s. The speed of sound on Mars is different. The speed of sound is 226 m/s.

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    $\begingroup$ Jupiter may not have flight at pressures where you would survive, but flight is definitely possible, in fact as you lose altitude you will eventually float at an equilibrium position so an airship is a viable solution. $\endgroup$ – Rory Alsop Jul 31 '13 at 15:41
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    $\begingroup$ Oh wow, this is hilarious! =D however, there might be interesting to check the behaviour of helicopters (but most certainly it's similar to the Interplanetary Cessna since both use propellers), gliders and airships. For example, I'm quite sure that flying with Zeppelin must be possible on Jupiter since it's air density is way bigger. On the other hand, air pressure would destroy the balloon itself, I think. $\endgroup$ – Zoltán Schmidt Jul 31 '13 at 23:02
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    $\begingroup$ @ZoltánSchmidt The only problem is Jupiter's gravity is crazy high at more than twice that of Earth's. Something weighing 150 kg here would weigh 354.6 kg on Jupiter. Maybe a Zeppelin or balloon type aircraft could survive that but the conditions are less than optimal for winged aircraft and helicopters. $\endgroup$ – DanteTheEgregore Aug 1 '13 at 13:10
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    $\begingroup$ @ZachSmith In regards to Mars, do you mean Mach 1 relative to Mars's speed of sound or Earth's? $\endgroup$ – called2voyage Aug 1 '13 at 15:14
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    $\begingroup$ @called2voyage I actually added it thanks to your comment. Thank you for pointing that out! $\endgroup$ – DanteTheEgregore Aug 1 '13 at 15:54
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Venus would appear to be the most practical, not Titan (one HAS to factor the cold). Yes, it's so hot on Venus it melts lead at 621 degrees F. However, lead is a soft metal and it's heavy. We don't build aircraft out of lead. Aluminum melts at 1,218 degrees Fahrenheit (F) and Titanium melts at 3,200 degrees F. The Lockheed SR-71, flying at Mach 3+, was designed in the early 1960s with an aluminum structure and titanium skins to protect it from air molecule heat friction created at those speeds. One could build another "SR-71" type aircraft and fly on Venus albeit the more temperature sensitive materials would all need to be thermally insulated and some would require active cooling. On Titan, at 72 degrees Kelvin that's -330 degrees Fahrenheit and we just don't fly "normal" aircraft in that kind of cold. That's as cold as liquid nitrogen and the metal would become so brittle it would simply break from aerodynamic forces. However, the temperature in space is even colder at 2.7 degrees kelvin (-455 Fahrenheit) but there are no aerodynamic forces since it is a vacuum. We "fly" there all the time with spacecraft. Boeing just completed a record breaking 674 days in space with it's X-37 space plane. So, flying on Titan with a space plane similar to the X-37 may be practical after all.

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    $\begingroup$ This is hard to read. Can you format or clarify it a little? $\endgroup$ – Hohmannfan Apr 27 '17 at 21:05
  • $\begingroup$ Space is colder than Titan but vacuum is a good thermal insulator. Therefore, for practicar purposes Titan atmosphere would cold an aircraft a lot faster than space cools an spacecraft. $\endgroup$ – Pere May 27 '17 at 23:32

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