Build a better Kerbin

[sevenperforce]

In the vein of "beat Sputnik" and "1900s Space Race"...

We all know it is much easier to get to orbit from Kerbin than it is from Earth. Kerbin has roughly the same surface gravity as Earth, but is apparently far denser and thus less massive, so the escape velocity is a lot lower. 

But is there any way you could get a planet or planetary system even more conducive to early space access than Kerbin? 

Rules: The planet has to be habitable by humans: comparable surface gravity, comparable atmospheric pressure and temperature at the typical habitation regions, comparable oxygen partial pressure. It also has to have at least a moderate chance of forming naturally; no Kardeshev-II alien geoengineering. No weird physics, either.

What are the options? Perhaps you could have a world with less habitable surface space, but a higher rotation rate and bulge, so launching from the equator (even if the equator isn't as temperate as ours) gives you a nice boost. Maybe the atmosphere could be made of a collection of gases which are still okay for humans, but work better for an airbreathing engine. Perhaps you have a very low tidally locked moon with a strong common magnetic field, allowing transient magnetic gradients which can be ridden into orbit.

Ideas?

[fredinno]

47 minutes ago, sevenperforce said:

In the vein of "beat Sputnik" and "1900s Space Race"...

We all know it is much easier to get to orbit from Kerbin than it is from Earth. Kerbin has roughly the same surface gravity as Earth, but is apparently far denser and thus less massive, so the escape velocity is a lot lower. 

But is there any way you could get a planet or planetary system even more conducive to early space access than Kerbin? 

Rules: The planet has to be habitable by humans: comparable surface gravity, comparable atmospheric pressure and temperature at the typical habitation regions, comparable oxygen partial pressure. It also has to have at least a moderate chance of forming naturally; no Kardeshev-II alien geoengineering. No weird physics, either.

What are the options? Perhaps you could have a world with less habitable surface space, but a higher rotation rate and bulge, so launching from the equator (even if the equator isn't as temperate as ours) gives you a nice boost. Maybe the atmosphere could be made of a collection of gases which are still okay for humans, but work better for an airbreathing engine. Perhaps you have a very low tidally locked moon with a strong common magnetic field, allowing transient magnetic gradients which can be ridden into orbit.

Ideas?

Not much. Kerbin is already using about the same delta v to get off as Mars, which is pretty close to the edge of the 'small' end of being able to retain a habitable atmosphere. However, with a habitable atmosphere, it would go high above Kerbin in terms of Delta V requirements. Iron planets (increasing the density of a planet to reduce the circulation burn) won't help either, those are not conductive to Earth life, and can't hold water for long periods of time. A higher rotation rate would cause the oceans to bulge more in the equator, degating a lot of your gains from the increased rotation.

[KAL 9000]

A planet roughly the same gravity and atmospheric composition as Earth, with active plate tectonics and a strong magnetic field. Three moons orbit it, each about 1/2 the size of our own Moon. Tidal forces are thus roughly 1 1/2 times that of Earth's, keeping the core molten for longer. The core also has a higher proportion of radioactive elements, also keeping it warm for longer. This planet orbits in the habitable zone of a K-type star, and is very habitable. It rotates roughly every 18 hours, producing a significantly greater boost from the equator. It is slightly denser than Earth, and has a radius around 2/3 of Earth. Its Karman line is around 75 km. Atmospheric composition is: 65% Nitrogen, 34% Oxygen, 0.9% Argon, 0.1% trace gases (no poisons). With a greater percentage of Oxygen, jet engines work more efficiently. It's name: Let's see, random name, AHA! Jolton!

[Elthy]

I would like more Xenon in the atmosphere, that would make ion-engines way cheaper (on larger scales). Otherwise maybe a tiny bit smaller/lighter than earth, so you would need about 1km/s less Delta-V to get to orbit, which would make SSTOs way, way easier.

[fredinno]

3 hours ago, KAL 9000 said:

A planet roughly the same gravity and atmospheric composition as Earth, with active plate tectonics and a strong magnetic field. Three moons orbit it, each about 1/2 the size of our own Moon. Tidal forces are thus roughly 1 1/2 times that of Earth's, keeping the core molten for longer. The core also has a higher proportion of radioactive elements, also keeping it warm for longer. This planet orbits in the habitable zone of a K-type star, and is very habitable. It rotates roughly every 18 hours, producing a significantly greater boost from the equator. It is slightly denser than Earth, and has a radius around 2/3 of Earth. Its Karman line is around 75 km. Atmospheric composition is: 65% Nitrogen, 34% Oxygen, 0.9% Argon, 0.1% trace gases (no poisons). With a greater percentage of Oxygen, jet engines work more efficiently. It's name: Let's see, random name, AHA! Jolton!

The increased O2 would make fires too common. Also, the 3 moons would be unstable and sling each other out. I can see it happening if they were asteroid sized...

[KAL 9000]

1 hour ago, fredinno said:

The increased O2 would make fires too common. Also, the 3 moons would be unstable and sling each other out. I can see it happening if they were asteroid sized...

Then why don't the Galileian moons sling each other out?

[fredinno]

7 minutes ago, KAL 9000 said:

Then why don't the Galileian moons sling each other out?

3 are locked in gravitational resonance, and those moons are a lot smaller in comparison to Jupiter, and have a lot more SOI to spread out. Luna would already sling any moon out from Earth Orbit over time unless it was at a trojan point (which also has size limitations)

[sevenperforce]

Here's a thought. 

Triton-Neptune setup, with the primary ice giant (we'll call it Theron) having a very strong quadruple magnetic field, and the dense secondary (we'll call it Fiora) having a high spin rate and a highly inclined axis of rotation, such that each of its poles sweep through Theron each orbit. It also has a strong magnetic field due to its high spin and heavy, hot core. Its orbital plane isn't quite aligned with Theron's magnetic equator. 

Thus, every dozen orbits or so, one of Fiora's magnetic poles will momentarily line up perfectly with one of Theron's magnetic poles, locking together. The solar wind would flow between in a brilliant aurora, and if you were in the right place at the right time with a large electromagnetic gyrostabilized platform, you could ride the magnetic gradient straight into space. 

[NFUN]

3 hours ago, fredinno said:

The increased O2 would make fires too common. Also, the 3 moons would be unstable and sling each other out. I can see it happening if they were asteroid sized...

So what if fires are common? Man doesn't have to develop on it, it just has to be habitable. Though the atmosphere might have to be less dense, depending on how strictly one looks at the rules.

[fredinno]

35 minutes ago, sevenperforce said:

Here's a thought. 

Triton-Neptune setup, with the primary ice giant (we'll call it Theron) having a very strong quadruple magnetic field, and the dense secondary (we'll call it Fiora) having a high spin rate and a highly inclined axis of rotation, such that each of its poles sweep through Theron each orbit. It also has a strong magnetic field due to its high spin and heavy, hot core. Its orbital plane isn't quite aligned with Theron's magnetic equator. 

Thus, every dozen orbits or so, one of Fiora's magnetic poles will momentarily line up perfectly with one of Theron's magnetic poles, locking together. The solar wind would flow between in a brilliant aurora, and if you were in the right place at the right time with a large electromagnetic gyrostabilized platform, you could ride the magnetic gradient straight into space. 

Such a moon would quickly lose energy and become tidally locked. All moons do.

12 minutes ago, NFUN said:

So what if fires are common? Man doesn't have to develop on it, it just has to be habitable. Though the atmosphere might have to be less dense, depending on how strictly one looks at the rules.

https://www.quora.com/What-would-happen-if-the-amount-of-oxygen-in-Earths-atmosphere-was-doubled-instantly

• Paper airplanes now fly further. With all that extra air, the air pressure near the surface increases significantly. Gliders, parachutists, birds and paper-plane hobbyists enjoy greatly improved performance.
• Everyone gets better gas mileage. Oxygen-enriched air improves engine performance by producing hotter reactions and reducing the proportion of nitrogen, which reduces heat transfer (Page on Energy.gov)
• Higher elevation Biomes become inhabited by more vertebrates. Areas such as the high Himalayas or high Andes are no longer off-limits to animals without special adaptations to increase their levels of hemoglobin.
• Insects of unusual size. Many insects rely on gaseous diffusion to for respiration, therefore the maximum body size depends on the proportion of oxygen gas in the atmosphere. Most bugs get bigger, some smaller (see Atmospheric oxygen level and the evolution of insect body size)
• Everyone feels more alert, active, and happier. All that fresh oxygen improve our cognition, alertness, and physical performance. As a result, most athletic records would likely be broken by oxygen-enriched athletes.
• We get sick less often. Neutrophils, soldiers of the immune system, destroy bacteria by using NADP oxidase to pump ions into, and disrupt, intruding cell's membranes causing rupture. More oxygen, more oxidase. (Page on Nih.gov)
• We die younger. Free radicals (i.e.  O2-) are thought to exacerbate the aging process through Oxidative stress, which interferes in numerous cellular processes: protein production, DNA replication, intercellular communication, and are also thought to contribute to MS, Alzheimers, Parkinsons, and a host of other ailments.
• Plants are less effective at photosynthesis.

[NFUN]

So, nothing that makes in inhabitable. My point about making the atmosphere less dense was:

8 hours ago, sevenperforce said:

Rules: The planet has to be habitable by humans: comparable surface gravity, comparable atmospheric pressure and temperature at the typical habitation regions, comparable oxygen partial pressure.

I'd say that a breathable atmosphere would have a comparable oxygen partial pressure, but others might argue against it.

[sevenperforce]

11 hours ago, fredinno said:

12 hours ago, sevenperforce said:

Here's a thought. 

Triton-Neptune setup, with the primary ice giant (we'll call it Theron) having a very strong quadruple magnetic field, and the dense secondary (we'll call it Fiora) having a high spin rate and a highly inclined axis of rotation, such that each of its poles sweep through Theron each orbit. It also has a strong magnetic field due to its high spin and heavy, hot core. Its orbital plane isn't quite aligned with Theron's magnetic equator. 

Thus, every dozen orbits or so, one of Fiora's magnetic poles will momentarily line up perfectly with one of Theron's magnetic poles, locking together. The solar wind would flow between in a brilliant aurora, and if you were in the right place at the right time with a large electromagnetic gyrostabilized platform, you could ride the magnetic gradient straight into space. 

Such a moon would quickly lose energy and become tidally locked. All moons do.

Not if it was fairly dense, with an axis of rotation in line with its orbital plane. That's a lot of angular momentum.

I'm more unsure whether field coupling could produce strong enough magnetic gradients to use for lift.

Other ideas....

A planet with a very high rate of spin would likely have an equatorial ocean, making water-based launches a necessity.

Then there would be fun stuff like a smaller planet with lots of geologic activity where you could ride periodic volcanic eruptions into orbit...

[KAL 9000]

2 hours ago, sevenperforce said:

Then there would be fun stuff like a smaller planet with lots of geologic activity where you could ride periodic volcanic eruptions into orbit...

I can just imagine Jeb riding that into space... "Yee-Haw!"

[fredinno]

5 hours ago, sevenperforce said:

Not if it was fairly dense, with an axis of rotation in line with its orbital plane. That's a lot of angular momentum.

I'm more unsure whether field coupling could produce strong enough magnetic gradients to use for lift.

Other ideas....

A planet with a very high rate of spin would likely have an equatorial ocean, making water-based launches a necessity.

Then there would be fun stuff like a smaller planet with lots of geologic activity where you could ride periodic volcanic eruptions into orbit...

No, if there's anythng i've learned from the alt. solar system thread, it's that EVERYTHING orbiting a planet gets tidally locked over geological timescales.

[sevenperforce]

5 minutes ago, fredinno said:

No, if there's anythng i've learned from the alt. solar system thread, it's that EVERYTHING orbiting a planet gets tidally locked over geological timescales.

Not necessarily. Orbital resonances are possible. In this particular case you'd probably have a resonant precession. 

[GeneralVeers]

Simplicity incoming:

How about a planet with a mountain a hundred miles high? Lower gravity and near-zero air pressure. Makes the perfect launch site!

(Kerbonauts all over this forum are probably already familiar with the fact that a mission to Eve is much easier if you use its highest elevation as the landing site.....)

[sevenperforce]

1 minute ago, GeneralVeers said:

Simplicity incoming:

How about a planet with a mountain a hundred miles high? Lower gravity and near-zero air pressure. Makes the perfect launch site!

(Kerbonauts all over this forum are probably already familiar with the fact that a mission to Eve is much easier if you use its highest elevation as the landing site.....)

I was thinking of how a world with very, very high prominences could form...

[GeneralVeers]

Earth has Mount Everest. Which is tiny compared to the planet it sits on.

"Very, very high" is entirely relative here. We don't know how high a mountain on Earth could get; it could happen, maybe it simply hasn't happened yet.......

[sevenperforce]

7 minutes ago, GeneralVeers said:

Earth has Mount Everest. Which is tiny compared to the planet it sits on.

"Very, very high" is entirely relative here. We don't know how high a mountain on Earth could get; it could happen, maybe it simply hasn't happened yet.......

IIRC it has to do with a complex relationship between the angle of repose for sedimentary rock, the buoyancy of the continental plates, and so forth...

More likely: a world where the poles have some sort of crystalline extrusion process that produces hollow, pyramidal structures reaching into space.

[peadar1987]

A planet smaller than earth with a very thick crust, so very tall mountains could be supported. An atmosphere rich in oxygen, so you can maintain a high enough partial pressure for breathing with a less dense atmosphere. A 40-50-km high mountain at the equator, poking above most of the atmosphere. Launch to orbit with a railgun and a small kick motor.

[sevenperforce]

I like the idea of a planet with less hospitable zones more suited to launch....

[fredinno]

3 hours ago, sevenperforce said:

Not necessarily. Orbital resonances are possible. In this particular case you'd probably have a resonant precession. 

That's not enough to prevent tidal locking. You need a huge amount of energy to keep a moon spinning.

3 hours ago, GeneralVeers said:

Simplicity incoming:

How about a planet with a mountain a hundred miles high? Lower gravity and near-zero air pressure. Makes the perfect launch site!

(Kerbonauts all over this forum are probably already familiar with the fact that a mission to Eve is much easier if you use its highest elevation as the landing site.....)

Like Mars' Tharsis Volcanoes? Pretty sure that needed a lack of tectonic plates to form... pretty bad for life on the long term.
http://www.dailygalaxy.com/my_weblog/2014/05/without-plate-tectonics-life-on-earth-might-never-have-gained-a-foothold-harvard-smithsonian-center-.html

[GeneralVeers]

On further reflection, you don't "need" a hundred-mile-tall mountain for a good launch site. Mount Everest as it is would be great. Well, if not for the fact that it's considered an international landmark and a lot of people would be pretty unhappy if a bunch of little green aliens bulldozed the peak flat and put a launch pad on it.......

[kerbiloid]

On 06.03.2016 at 9:46 PM, sevenperforce said:

No weird physics, either.

Kerbin, a 600 km planet with 9.81 m/s² gravity... If this physics is not enough weird... OK, OK...

On 07.03.2016 at 6:06 AM, fredinno said:

Everyone feels more alert, active, and happier. All that fresh oxygen improve our cognition, alertness, and physical performance. As a result, most athletic records would likely be broken by oxygen-enriched athletes.

Probably vice versa: all feel unhappy.
Because they are already just at the ceiling of the oxygen consumption and any lesser concentration means a depression, while any greater concentration means an intoxication.
Better there would be 17% of oxygen. Then any pot with ficus will give them a real euphoria because it means 1% of oxygen more!

On 07.03.2016 at 6:06 AM, fredinno said:

Insects of unusual size.

Yes, and giant spiders with kilometers of web providing a ready-to-use space elevator.

(Similar to Brian Aldiss's "Hothouse / The Long Afternoon of Earth")

14 hours ago, GeneralVeers said:

How about a planet with a mountain a hundred miles high

A planet with a mountain a hundred miles high is called "an asteroid". It's this mountain itself.
On any other planet a mountain height (as well as a pit depth) is very limited by gravity
Height_max ~= 3 * YieldPointOfRock / DensityOfRock * GravityAcceleration, So, no mountains higher or pits deeper than ~30 km.

 

Back to the theme.
A tidally-locked Mars-sized planet revolving round a (super-jupiter / brown dwarf) exactly at the Roche limit.
Yes, it is being destroyed, but so what? All we need — to live there several thousand years, then we find another such planet.

On its sub-Jupiter hemisphere there is zero gravity and stones are flying up to the sky.
So, to launch something into space you need just to put this thing on a railcar, bring to the sub-jupiter side and release from the ropes.
Of course the railcar would be attached to the railway to stay on the planet itself.

Rich with water ice (at least — was, at least — on the outer side), that's obvious.

On the outer side there is a crater or cleft (yes, this planet is a poor, poor thing): 10-30 km deep.
Humans and NPC live inside this cleft / crater. Its bottom level keeps a normal air pressure, they can breathe without spacesuits.
Also it's warm there: because this planet is being destoyed by the tidal force, so to get enough heat is not a problem.
(Idea of a habitated cleft is stolen from W.H.Hodgson's "The Night Land")

There is no significant air above the edge of the cleft/crater., so no atmo drag there.
I.e. living beings are living in an air blob inside a well, on its bottom.
It's a small and homey habitat 10-20 kilometers in diameter, with lakes and gardens (or at least with algae tanks).
This is a flat location easily being mapped for navigation or game purposes — a sandbox.

All industry is placed inside rocks around this location and all pollution exhaust is thrown away right into space, keeping this oasis green and happy.
There is a an elevator on the side of the well — to get out of there, and a circumplanetary railway Which is also used as a launchpad (see above).
 

The sub-Jupiter hemisphere is something like this, but more optimistic

Edited March 8, 2016 by kerbiloid

[GeneralVeers]

1 minute ago, kerbiloid said:

A planet with a mountain a hundred miles high is called "an asteroid". It's this mountain itself.

On any other planet a mountain height (as well as a pit depth) is very limited by gravity
Height_max ~= 3 * YieldPointOfRock / DensityOfRock * GravityAcceleration, So, no mountains higher or pits deeper than ~30 km.

Seeing as how the game already violates the laws of physics wholesale (its crowning fail being a star that needs to be a hundred times more massive for fusion to even be possible!) I think we can take a few liberties.