For Questions That Don't Merit Their Own Thread

[magnemoe]

22 hours ago, kerbiloid said:

As a bird has a lot of air bubbles inside to make it light, it would be probably thinking about everything but flight, due to the unpleasant feelings and maybe barotrauma.

2 times denser = 2 atm of pressure, so like a diver at 10 m depth.

the air bubbles is air sacks connected to the lungs, part of their purpose is to give more oxygen to the lungs, other part is just being light weight tubes. 
Higher pressure is no issue lots of birds dive to catch fish, other fly at many kilometers attitude. 

An higher air pressure will make flight easier, yes max speed would also be a bit slower because more air resistance. 

[KG3]

Has anyone ever tried to depict a sunrise from the surface of a neutron star?  I know it would be difficult to stand on the surface of a neutron star and there are a bunch of reasons why there aren't many stories that take place on neutron stars so there probably isn't any reason to visualize this like they did with the black hole in the movie Interstellar.  I realize the neutron star would have to be rotating very slowly (for a neutron star) and the "sun" would be orbiting around it instead of vice versa and at a distance where it wasn't dumping its outer surface onto the neutron star because that would just be a nuisance.   

[DDE]

What is the closest historical equivalent to the Mainsail?

[OrbitsR4Sissies]

1 hour ago, DDE said:

What is the closest historical equivalent to the Mainsail?

The Mainsail is KSP's functional (but not cosmetic) counterpart to the Rocketdyne F-1 engine, which powered the Saturn V moon rocket.

With Making History's introduction, the Kerbodyne KE-1 "Mastodon" is slightly less powerful than the Mainsail  but has better ISP, and is cosmetically most like the F-1.

[DDE]

6 hours ago, OrbitsR4Sissies said:

The Mainsail is KSP's functional (but not cosmetic) counterpart to the Rocketdyne F-1 engine, which powered the Saturn V moon rocket.

...Except that the game has the F-1, in the form of the Boar in the Twin Boar.

[OrbitsR4Sissies]

On 11/8/2019 at 2:49 PM, DDE said:

...Except that the game has the F-1, in the form of the Boar in the Twin Boar.

The question seemed to be asking about engines that aren’t the peculiar tank+engine clusters that KSP offers. So my comparison is more appropriate, at least in appearance. The Twin Boar itself isn’t a single engine in appearance.

That said, the Twin-Boar’s shape and two engine appearance is more comparable to the SM-65 Atlas rocket (with no center sustainer engine or half-stage).

The power of the Twin Boar is more comparable with the Rhino, and both of those are superior against a single Mastodon or Mainsail, if I am reading the wiki correctly. 

[DDE]

45 minutes ago, OrbitsR4Sissies said:

The question seemed to be asking about engines that aren’t the peculiar tank+engine clusters that KSP offers. So my comparison is more appropriate, at least in appearance. The Twin Boar itself isn’t a single engine in appearance.

That said, the Twin-Boar’s shape and two engine appearance is more comparable to the SM-65 Atlas rocket (with no center sustainer engine or half-stage).

The power of the Twin Boar is more comparable with the Rhino, and both of those are superior against a single Mastodon or Mainsail, if I am reading the wiki correctly. 

Yeah, the problem is that I run Restock and their detailed single Boar is unmistakably an F-1, so I'm coming in very biased.

[kerbiloid]

Not a question, just a just found link.

http://cyberneticzoo.com/teleoperators/1961-humpty-dumpty-space-tug-douglas-american/

[magnemoe]

On 11/11/2019 at 8:06 PM, kerbiloid said:

Not a question, just a just found link.

http://cyberneticzoo.com/teleoperators/1961-humpty-dumpty-space-tug-douglas-american/

How does you control all the mechanical arms? 
Yes you probably want two of them, more like legs however to attach to station or other stuff. 
And you don't want an rotating hatch, you rotate the entire cabin. 

Also gloves + Arms + life support is most of an spacesuit anyway. You need to be able to bend your arms well and gloves who are and usable as possible. 

You have this suit from freefall 

Upper body is solid, lower body is just an sack or more likely an long narrow skirt with an bottom plate.

Yes Florence can not use standard spacesuit pants anyway and this was the simplest option. 
Like the magnetic wheel scooter, would that work in real life? 

[kerbiloid]

6 hours ago, magnemoe said:

How does you control all the mechanical arms? 

(Just in case: I was not developing space capsules in 1961, so I redirect your questions to the project author.)

6 hours ago, magnemoe said:

Yes you probably want two of them, more like legs however to attach to station or other stuff. 

Probably, the capsule is for EVA building objectives on the truss-based external structures.

So, there are two pairs of "attachment arms" below. To hold with one pair the truss he is currently on and to grab the truss he is going to go to.
Also, that's why the top of the capsule can rotate. You get from one truss to the next one, turn back the capsule cabin and continue working on the same place.

Three upper arms are for working purposes. Say, to hold something with two arms and to use a tool by the third one.
The small arms are for accurate operations with human arms.

6 hours ago, magnemoe said:

Also gloves + Arms + life support is most of an spacesuit anyway.

Of course, and the life support should be there in the capsule in any case.

So, this capsule is just a much more advanced predecessor of the modern projects.

Spoiler

 

[DDE]

14 hours ago, magnemoe said:

You have this suit from freefall 

Upper body is solid, lower body is just an sack or more likely an long narrow skirt with an bottom plate.

Well, Orlan's legs aren't designed to be flexible, so... more real than some would think?

[magnemoe]

5 hours ago, DDE said:

Well, Orlan's legs aren't designed to be flexible, so... more real than some would think?

Think Orlan have some flex but not something you would want to walk in, this also has some as in you can use your legs for leverage if connected to something. 
Main problem is to get male astronauts to wear an skirt, that will be hard to sell
Flo has digtigrade legs and an tail so its prefect for her, her species has 20 something members so not something you can buy off the shelf. 
I guess it has an base plate for the feet so it would work like other suits connected to an cadarm, might have an quick connector at bottom too as its obvious you can not even try to walk. 

[DDE]

58 minutes ago, magnemoe said:

Main problem is to get male astronauts to wear an skirt, that will be hard to sell

Would it?

[kerbiloid]

10 hours ago, magnemoe said:

Main problem is to get male astronauts to wear an skirt, that will be hard to sell

The emergency breathing balloon is included.

Spoiler

 

[mikegarrison]

You may have to click on the image a few times to see it full size, or go here: https://www.smbc-comics.com/comic/space-3

From the second panel: "What's the best reason to go to Mars?" "Weird rich people want to." "That may not be sustainable."

Edited November 15, 2019 by mikegarrison

[HaplessBystander]

Hello, I wanted to ask about the idea of constant acceleration space ships with rotating habitat sections (like The Hermes from The Martian). How fast would it be possible to accelerate such a ship before the vector of the two forces starts to mess with the crew's perception of gravity? Clearly it would be a small acceleration (the Hermes accelerates at two millimeters per second per second), but how small?

It would seem the answer depends on just how little linear acceleration it is possible to perceive. My current understanding is that accelerations greater than one centimeter per second per second may be perceptible to some people and accelerations greater than ten centimeters per second per second will be perceptible to most people. So, if you want to make sure the crew is comfortable you should stick to the lower end of that range, maybe two centimeters per second per second. 

Is that right? Or is that acceleration rate already too high?

Edited November 22, 2019 by HaplessBystander

[kerbiloid]

There is a solution.
Hang the gravity modules on hinges.

Spoiler

 

[magnemoe]

3 hours ago, kerbiloid said:

There is a solution.
Hang the gravity modules on hinges.

  Hide contents

 

That is an pretty good idea and seen this on some scifi ships.

The downside is that limits the size of the crew modules more than an ring. 

We has this ksp mod part as an reference, yes you would lay the module flat instead, but you would get issues with the floor at the sides not feeling flat. 

[kerbiloid]

29 minutes ago, magnemoe said:

The downside is that limits the size of the crew modules more than an ring. 

The ring anyway should contain a lot of technical stuff, so be splitted into sectors.
As well, it should be splitted into sectors for the safety reasons: to hold the air if some place starts leaking, and to limit the permanent CoM displacement when people and goods are moving from sector to sector.

The radial scheme provides this by design, and also it's possible to place the radially moving counterweights between the modules to keep CoM stable.

Though, I can't fully agree with the depicted radial scheme (iirc, it's from the Nertea's station mod).
The radial habitat should not be radial, as the artificial gravity will vary from floor to floor, and very significantly (compare the rotation radii of the floors).
And as we can see, the 1 g floor area will be the least possible (compare the module width to the full circle length).

This scheme is appropriate in two cases:

1) A high-thrust (~1 g) space ship, when the modules get either radial (when drifting) or axial (when accelerating).
2) An on-ground habitat on a low-g celestial body. Then the modules hang down in the natural gravity, but spread out on rotation.

***

In case of an orbital station smaller than a kilometer in size, and as well in case of a low-thrust spaceship, the rotating habitat should be a bunch of parallel cylinders (like in the old NASA space hotel picture of 1960s).
Then all floors will be placed at 1 g and fill almost whole circle.
Between the outer, living modules, you can place auxilliary stuff and dynamic counterweights.

And in case of the low-thrust ship (unlike that NASA hotel) the parallel cylinders should be attached, if simplify, from both ends with two trusses.
The rear end truss should have constant length but a hinge.
The front end truss should be telescopic.

Then the cylindric modules will tilt radial-out with their front ends, adjusting to the current ship acceleration.

As the small orbital stations should be probably the same as the low-g ship (just for unification), this adjustable two-end suspension is probably universal for both.

Edited November 22, 2019 by kerbiloid

[magnemoe]

5 hours ago, kerbiloid said:

The ring anyway should contain a lot of technical stuff, so be splitted into sectors.
As well, it should be splitted into sectors for the safety reasons: to hold the air if some place starts leaking, and to limit the permanent CoM displacement when people and goods are moving from sector to sector.

The radial scheme provides this by design, and also it's possible to place the radially moving counterweights between the modules to keep CoM stable.

Though, I can't fully agree with the depicted radial scheme (iirc, it's from the Nertea's station mod).
The radial habitat should not be radial, as the artificial gravity will vary from floor to floor, and very significantly (compare the rotation radii of the floors).
And as we can see, the 1 g floor area will be the least possible (compare the module width to the full circle length).

This scheme is appropriate in two cases:

1) A high-thrust (~1 g) space ship, when the modules get either radial (when drifting) or axial (when accelerating).
2) An on-ground habitat on a low-g celestial body. Then the modules hang down in the natural gravity, but spread out on rotation.

***

In case of an orbital station smaller than a kilometer in size, and as well in case of a low-thrust spaceship, the rotating habitat should be a bunch of parallel cylinders (like in the old NASA space hotel picture of 1960s).
Then all floors will be placed at 1 g and fill almost whole circle.
Between the outer, living modules, you can place auxilliary stuff and dynamic counterweights.

And in case of the low-thrust ship (unlike that NASA hotel) the parallel cylinders should be attached, if simplify, from both ends with two trusses.
The rear end truss should have constant length but a hinge.
The front end truss should be telescopic.

Then the cylindric modules will tilt radial-out with their front ends, adjusting to the current ship acceleration.

As the small orbital stations should be probably the same as the low-g ship (just for unification), this adjustable two-end suspension is probably universal for both.

If you made an large space station it would have an complete ring, obviously with bulkheads, it would be so heavy people moving would have negligible impact even if some event drew all to one location who we know will happen. 
You can use moving weights like batteries or other heavy stuff or ballast tanks if you want to compensate. 

An more realistic designs you use two or more arms with modules on the end. Pointed out that design in image has variable gravity on decks so you want something like two T joined at bottom. 
This works well for an below 0.1 g trust ship even if top of T is kind of banana shaped, yes an ball will roll to an corner at the outward cabins during trust. Not an huge deal people will not roll out of beds. 

On something like an touchsip liner capable of 1 g trust for an week then coasting this is more of an issue,  say an Earth Saturn run. And no you would not do an trust to turnover even with good fusion. 
For an small crew you use the T but for an passenger ship you might just as well have two sets of cabins and facilities I think. 

[HaplessBystander]

I'm aware of the concept of a gimbaled centrifuge habitat. What I'd like to know is, at what rate of acceleration does gimbaling become necessary? Is there a sweet spot where your ship's acceleration rate is low enough that your habitat section doesn't need gimbaling (and can thus be shaped as a simple ring) but high enough to support crewed expeditions to Mars or the outer solar system in a reasonable time frame?

[Guest]

So I know how to interpolate 2D (x, y(x)) points into a function. Recently, though, I've been wondering about interpolating a function from 3D points (x, y, z(x, y)) in space.

To my dismay, however, I can't seem to find out how to do it by hand - perhaps I'm looking up the wrong keywords? If someone could shine a light on this, please do. Thanks.

[magnemoe]

2 hours ago, HaplessBystander said:

I'm aware of the concept of a gimbaled centrifuge habitat. What I'd like to know is, at what rate of acceleration does gimbaling become necessary? Is there a sweet spot where your ship's acceleration rate is low enough that your habitat section doesn't need gimbaling (and can thus be shaped as a simple ring) but high enough to support crewed expeditions to Mars or the outer solar system in a reasonable time frame?

Well below 0.1 g its kind of pointless, 0.1 g I say its the sweet spot you can do without but its nice to have here so you rotate the first class cabins and perhaps the kitchen. 
If you get up to 0.25 g you need it seriously. 

However trust time also matter. say you have an orion pulse nuclear ship. its doing 2-4 g in an bumpy ride, for 9 hour with an break for toilet and food. now you coast for an month to mars there you are rotating the ship on the length axis. 
In short for realistic designs the trust is either to low to matter or the trust time is to low that you bother with this and you might want all in the storm cellar during burn. 

 

[Silavite]

How would the heliosphere and stellar bow shock affect our observations of objects outside the solar system, if at all?

[SuperFastJellyfish]

2 hours ago, Silavite said:

How would the heliosphere and stellar bow shock affect our observations of objects outside the solar system, if at all?

I'm no physicist, but I doubt either effect significantly affects our view.  The density of the heliosphere follows the inverse square law so it quickly loses its ability to obscure our view.   The bow shock arises from the velocity of our star through the galactic cloud.  This movement creates a low density interface between the heliosphere and the insterstellar medium.  The density is just too low to affect our view, AIUI.