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Linked

What would the flora on a methane world be like?

What would animal life on a methane world look like and how would it evolve?

What would the conditions on a methane world be like?

How would an intelligent race on a methane world achieve a fire equivalent?

Question:

How could an intelligent race on Titan (a planet like it, anyway) achieve space travel? It might be helpful to look at some of the linked questions for ideas.

Edit:

In response to the comments I am looking for chemical reactions and the force needed to escape the higher pressure and g's on Titan.

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  • $\begingroup$ What, exactly, are you looking for with this question? The chemicals needed to achieve lift? The shape of the vessel? The resources needed to overcome gravity? $\endgroup$ – Frostfyre Apr 15 '15 at 14:37
  • $\begingroup$ @Frostfyre How in general could a civilization on Titan overcome the many obstacles facing it to achieve space travel. Higher pressure (and consequently G's) as well as the chemical reactions required. $\endgroup$ – the_OTHER_DJMethaneMan Apr 15 '15 at 14:43
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    $\begingroup$ Titan has lower gravity than Earth, 0.138 g, and only about 1.5 times Earth atmospheric pressure. Space flight (assuming you can get the needed materials to build a rocket) would be easier than on Earth. You could extract oxygen from ice, and burn it with hydrogen or liquified atmospheric hydrocarbons. It'd also be easier to store cryogenic propellants on Titan than on Earth. $\endgroup$ – jamesqf Apr 15 '15 at 16:24
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    $\begingroup$ I disagree with the close votes; questions can be on-topic on multiple sites. This is also not a straightforward physics question per se; it is also heavily dependent on space exploration. Regardless, I don't see how this could be off-topic here. $\endgroup$ – HDE 226868 Apr 15 '15 at 21:21
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    $\begingroup$ I agree with HDE. Something being on topic somewhere else (which might be debatable anyway) does not stop it also being on topic here. $\endgroup$ – Tim B Apr 16 '15 at 9:21
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Important Factors, Assumptions

This answer is going to totally ignore all the groundwork needed before a species can even dream of space travel. We're going to assume some intelligent form of life evolves on Titan, and that they want to get off of their moon and explore all the things in their sky. (Which they wouldn't know about, because Titan's Atmosphere is opaque at many wavelengths.)

Titan has:

  • An escape velocity of 2.638 km/s (compared to 11.186 km/s for earth)
  • A mostly nitrogen with some methane (1.4%) atmosphere
  • A smattering of other chemicals (such as hydrogen, hydrocarbons, etc.)
  • Higher surface pressure of ~1.45 atm.
  • A Surface Temperature of ~94 K; that's cold. Cold enough to store liquid gasses.

Rocket Engines

Here are some demonstrated to work rocket engines they could use:

It should be noted that these are just a few rockets which are possible. There are many types of rocket these aliens could go for. The significantly lower escape velocity means that they have more options practically open to them.

Getting the liquid oxygen oxidizers, which many chemical rockets require, would be hard, but not prohibitively hard. They could decompose the water they have to make the hydrogen-oxygen rockets. Furthermore, they can store them on the surface without needing coolant. They could grab a bunch of air to power their steam rocket. This also ignores the other nifty rockets out there, such as light beam powered rocket or nuclear gas core rockets. There are other ideas, too, such as scramjets, which they may take advantage of to get to orbit.

Really, it seems the aliens in question would need to answer: what rockets do they feel comfortable with? They have options, and can easily choose between many of them. Sure, Titan itself presents problems, but they can be overcome.

What about that Atmosphere?

According to Robert Zubrin, if you found yourself on the surface of Titan, you could fly by attaching wings to your arms and flapping. Flying is not as energetically difficult as on Earth. You could easily have a craft get into the upper atmosphere and then use the engines to get into orbit or achieve escape velocity. So yes, you would not want to rocket your way from the surface to orbit, but you could easily fly up to a point where it would make sense to rocket out. You can hear about the Cassini-Huygens mission and some of the challenges presented by the atmosphere in this presentation by Elizabeth P. Turtle.

I suspect the thicker atmosphere mostly means that launch vehicles will simply fly up through most of the atmosphere, and then launch a payload into orbit.

Rocketry on Titan is Easy

The thicker atmosphere makes getting higher up easier, and the lower gravity makes escaping that atmosphere easier. You can synthesize oxidizers from the ice, or use one of many other rocket options to get out. The cold surface temperature even means that fuel containment tanks need not be cooled, and that's further energy savings!

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What about a railgun? They need refined metal and a source of electricity. https://en.wikipedia.org/wiki/Railgun. I would assume that you could build a longer track and adjust amperage to keep G forces survivable. The track might be more durable than on Earth. Earth has an oxygen rich atmosphere that is oxidative. A nitrogen/methane/ethane atmosphere would be reductive and therefore no rusting. However, the cold will make things more brittle. On the other hand a "room temperature" superconductor will be easier. There are superconductors at -135C, and Titan is already at -179C.

The railgun could work for satellites that do not necessarily need to move. Fine-scale placement could be provided by small solid or liquid thrusters.

The chemistry that works on Earth will work on Titan. So hydrogen + oxygen will produce water. However, the cold will slow reactions and make all metals more brittle. With little oxygen in the atmosphere things will not burn. Depending on how much methane is present one might be able to carry oxygen rather than hydrocarbons to make engines. So rocket could work, or something like a high altitude aircraft that carries a final payload that gets boosted into space.

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    $\begingroup$ This is a good, creative, solution to get up into space, but it has a small problem with "What do I do now?" The spacecraft is stuck without means to change direction, accelerate, slow down. Motive power needs to be on board the space craft. The OP also specifies chemical reactions. It's a good start, but can use some refinement $\endgroup$ – Paul TIKI Feb 22 '17 at 22:03
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Titan's surface is primarily made of ice, which is just oxygen and hydrogen. They could extract liquid oxygen from the ice. Titan is a typical methane world, so ice should not be hard to come by. And the boiling point of oxygen is only 10 degrees lower than the ambient temperature on Titan, so it could be stored in a basic home freezer. There are plenty of fuels on a methane world, you could even just use the atmosphere or liberated Hydrogen.

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