A Scifi Artificial Gravity Alternative....

[Spacescifi]

 

Hover above a planet.

Feel the gravity.

The altitude the ISS orbits at has a gravity about 96% percent of 1g, so you could walk around your hovering spaceship and barely notice any difference.

The ISS is falling away at just the right speed to not actually escape into deep space, so they are weightless.

To actually use this gravity hack technique though, you would either need an impossibly hot high thrust exhaust and a lightweight rocket to do this for extended amount of time, or some fictional propulsion or antigravity system. Either way, it allows you to enjoy gravity from ANY planet without ever landing. Thus places like Uranus could be useful, if only for a gravity rest stop after hours of weightless warp flight ( hour per LY sounds reasonable).

Nifty.

Edited October 25, 2019 by Spacescifi

[Codraroll]

Or alternatively, use a helicopter.

You didn't specify how far above a planet you should hover?

[Spacescifi]

7 minutes ago, Codraroll said:

Or alternatively, use a helicopter.

You didn't specify how far above a planet you should hover?

 

You can hover out however far you want, especially if you're using antigravity repulsors.

Beware that going out to far has diminishing returns on gravity.

[Rakaydos]

Orbital Rings are useful for this.

 

Orbital rings are suspended by a stream of pellets/particals/plasma that are deflected by the ring to counteract the force of gravity. Unlike a space fountain, however, this stream of... let's call it "working mass", never touches the ground below. Instead, it travels along the inside of the ring (at superorbital velocities, to generate the nessisary outward pressure) and pushes off the OPPOSITE side of the ring.

This is unstable, with small inequalities gradually causing the ring to go off center and strike the planet, but it can also be far closer to a planet than a standard space elevator- it is reasonable (albet not trivial) to tether the ring to the surface from multiple directions, for stability. The ring itself, as opposed to the working mass, is stationary relative to the surface.

[Guest]

In a gas giant, you can use a fusion torch. Since you'll be flying around in hydrogen, it's just a matter of sucking it in and fusing some of it. Of course, this assumes you've got fusion power. You can theoretically do it from any planet (most of the thrust will come from heating air around you), but you'll have to maintain a steady supply of hydrogen if it's not a significant part of the atmosphere.

Another idea is to do it with a star. This is called a statite, and is basically a giant solar sail hanging above the star. Make it big enough and it could support a large colony. Of course, any people living on the upper surface will need their own lighting, since the star will be below them (mirrors can help that).

[magnemoe]

Why don't just use spin. its idiotic simple no upkeep after spin up and  will fail pretty safe as in two parts connected with an tether will get 50 m/s dv in outward direction. 

[kerbiloid]

1 minute ago, magnemoe said:

Why don't just use spin

And that's a good idea. Let's spin the planet, so centrifugal force will press the humans to the ceiling of cave habitats at 1 g artificial gravity, radial out.

[Spacescifi]

17 minutes ago, magnemoe said:

Why don't just use spin. its idiotic simple no upkeep after spin up and  will fail pretty safe as in two parts connected with an tether will get 50 m/s dv in outward direction. 

 

Why?

Because being in low geostationary altitude is awesome!

The Earth would rotate beneath you, so you could travel to places MUCH faster. Just wait for a few hours and drop in.

Use engines to straighten up your fall a bit and air will do the rest. Land. Done.

Reentry is a thing of the past, unless you decide to go orbital velocity anyway.

You don't have to, since my hyperdrive drops you out in low orbit velocity of the planet you wanna visit.

[Bill Phil]

Or you can use hyperdense matter to create a disk of high mass. Set up a tower to support an elevator with the crew quarters. Then find some way of accelerating the mass. I can’t remember who but someone called this a “balanced drive.” You use the elevator to set the local gravity to a level so that it balances with the ship’s acceleration, thus high accelerations are possible without turning the crew into paste.

[Nuke]

On 10/25/2019 at 9:23 AM, Spacescifi said:

 

You can hover out however far you want, especially if you're using antigravity repulsors.

Beware that going out to far has diminishing returns on gravity.

i think that if a ship has an anti gravity device of some sorts, it would produce a field of null gravity which would simply ignore gravity for the ship and everyone on it. a centrifuge would still be possible in this situation as its not real gravity. this is kind of boring though. 

the other possibility is that your ship creates a field which cancels out other gravity sources by providing equal and opposite gravity. thus the ship itself would have equivalent to earth gravity but as a repulsive force. in this configuration you could simply make a spherical ship, stick the gravity field generator in the middle and have earth like gravity at the hull. you couldn't use this as a direct means of propulsion as you can only create a positive or negative gravity field in various magnitudes and it would be spherical radiating outward from the emitter in all directions.  you still need to be within strong enough of a gravity field to push off of. you could use it to amplify or invert the effects of gravity assists though, and since gravity is everywhere, travel would sort of be like hot air ballooning or sailing. 

Edited October 27, 2019 by Nuke

[Ultimate Steve]

On 10/25/2019 at 2:45 PM, Dragon01 said:

In a gas giant, you can use a fusion torch. Since you'll be flying around in hydrogen, it's just a matter of sucking it in and fusing some of it. Of course, this assumes you've got fusion power

Unrelated question. Is there a possible atmospheric combination where if you detonated an atomic bomb the atmosphere would undergo one massive catastrophic fusion reaction?

[Spacescifi]

44 minutes ago, Ultimate Steve said:

Unrelated question. Is there a possible atmospheric combination where if you detonated an atomic bomb the atmosphere would undergo one massive catastrophic fusion reaction?

 

No.

If you had an atmosphere with a lot more oxygen or some other flammable gas you could have greater explosions and shockwaves for miles, but that's the only way I can think of. It's not a nuclear chain reaction either way.

That is just combustion.

Edited October 27, 2019 by Spacescifi

[kerbiloid]

3 hours ago, Ultimate Steve said:

Unrelated question. Is there a possible atmospheric combination where if you detonated an atomic bomb the atmosphere would undergo one massive catastrophic fusion reaction?

A rephrasing:
"Is there any critical density of pure deuterium-tritium atmosphere when a fusion reaction can extend to distances comparable to the planetary size?"
and also
"Is the size of ⁶LiD hydrogen bomb limited?"

> Is there a uranium sky surrounding the atmosphere? [y/n]

[tomf]

On 10/27/2019 at 2:06 AM, Ultimate Steve said:

Unrelated question. Is there a possible atmospheric combination where if you detonated an atomic bomb the atmosphere would undergo one massive catastrophic fusion reaction?

They worried enough about this before the first trinity test that they did the calculations

https://blogs.scientificamerican.com/cross-check/bethe-teller-trinity-and-the-end-of-earth/

The answer turned out to be very comfortably no though.

[KerikBalm]

If you have such a drive, you don't need a planet. Apply thrust at about 10kN per ton, experience about 1g on the ship...

Its real simple.

Want to go from earth to Triton?

Once in LEO, thrust at 1g continuously, at the halfway mark, briefly cut engines, flip 180, and burn at 1g again.

1G "artificial gravity" the whole trip, and the trip is super fast.

This is nothing new in SciFi, ships with this kind of propulsion ate called "torchships".

[kerbiloid]

Plan A.
If have a Planck-scale teleporter, we can teleport the whole ship forward for several Plancks producing 1g acceleration, then teleport it back at once to stay on place. Probably.

Plan B.
If produce enough high density of magnetic field inside a spherical volume, we may have a ball of light making our ship/station enough heavy to have 1 g on the sphere surface.
Then we can release it from one side for propulsion.

Plan C.
If locally change a gravitational constant, we can make a toroidal mini-planet for our mansion, fill the torus hole with water to have an underground  zero-g pool, cover it with floor (from both sides) and have an eritrocite-shape mini-planet with flat ground from both sides, to build a palace/castle/mansion for our pocket homeworld.

[Zeiss Ikon]

On 10/25/2019 at 6:28 PM, Bill Phil said:

Or you can use hyperdense matter to create a disk of high mass. Set up a tower to support an elevator with the crew quarters. Then find some way of accelerating the mass. I can’t remember who but someone called this a “balanced drive.” You use the elevator to set the local gravity to a level so that it balances with the ship’s acceleration, thus high accelerations are possible without turning the crew into paste.

That would be Charles Sheffield in the stories that were collected as The McAndrew Chronicles.  Combine a biggish disk of neutronium (spun at some impossible rate to keep it flattish), an elevator that can move the crew cabin closer or further from the neutronium, to always maintain 1G in the cabin, and Zero Point Energy based drives that can push the entire object (final mass like a large asteroid, maybe?) at 50-100 G continuously.  Please don't attempt to land on a planet or moon...

[Dirkidirk]

big wheel, big spin, 1G.

Spoiler

a more "fun" alternative (If you call nausea fun), is having a chair, tie it with a string to a counter weight, and spin.