Open thread, Oct. 12 - Oct. 18, 2015

MrMind

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If it's worth saying, but not worth its own post (even in Discussion), then it goes here.

Notes for future OT posters:

1. Please add the 'open_thread' tag.

2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)

3. Open Threads should be posted in Discussion, and not Main.

4. Open Threads should start on Monday, and end on Sunday.

Thank you. I'm also interested in planets with less mass/lower escape velocity and non-chemical fuel methods. Atomic or nuclear fuel? Laser launch?

The smallest planet you can probably maintain an atmosphere on for gigayears of time is probably half to a third of an earth mass (barring the effects of geology). That gives you an escape velocity between 70 and 80 % that of here given similar composition and no thousand km thick hot ice layers or anything.

EDIT: If you assume an escape velocity of Earth's and a specific impulse similar to a Merlin engine and ignore all gravity drag and atmosphere, using the rocket equation an SSTO to LEO requires a fuel to payload+structure mass ratio of at least 12.0.... (read more)

0MrMind11y

Giant capacitor plates and you suddenly remove the insulation?

2polymathwannabe11y

Assuming an advanced civilization, the main limiting factor for the viable commercial use of nuclear energy would be the abundance of radioactive elements in the planet. During the formation of the planet, its mass will have an effect on which elements get captured. Unfortunately, Wikipedia isn't helpful on the specifics of planet mass vs. planet composition, but we know it depends on the composition of the protoplanetary nebula, which depends on the type of star. Too many factors.