Space Battleship Armor?

[Edont Knoff]

You do know "force/energy" fields are great for SiFi but not obtainable in reality?

Yes, with current technology we can't have the typical force field from the sci-fi series. But we still could use electric or magnetic fields to change the path of an ion or plasma beam. How useful that is for space ship defence stays open to debate.

But my question was about the ships armor, not so much the force fields.

 

[Edont Knoff]

Sure, my point is/was that armour is just one aspect in something that ideally needs to be considered holistically, i.e. shields, propulsion, armour etc should not be looked at in isolation.

[...]

If you prefer harder sci-fi then I would think shields would be less acceptable, and ships basically become submarines in space.
If you prefer the fantastical side like ST / SW then shields become more acceptable.

I have been researchin Star Wars recently and it makes the engineer in me cringe.

But back to the armor (or rather, holistic defense)

You are right there. All the measures must work together. Being agile to evade weapon effects can be a good option, if armor just means you get hit more often due to inertia, and the armor is not effective enough, armor is not the right decision.

For the shields I feel very uncertain. I like the concept. But I dislike that we don't have any sort of idea how to make such a force field, not even how it's supposed to interact with charged particles (ion, plasma beams), chargeles lasers beams, or impact based projectiles (which can be antimagnetic).

So for the moment I'm mostly considering electric and magnetic fields to guide ion or plasma beams to directiosn where they are less harmful, e.g. some particularly resistant parts of the hull, or, in the best case, away from the ship.

 

[Baldeee]

So for the moment I'm mostly considering electric and magnetic fields to guide ion or plasma beams to directiosn where they are less harmful, e.g. some particularly resistant parts of the hull, or, in the best case, away from the ship.

But what of kinetic weapons?

 

[DaveC426913]

But I see that the need to wear pressure suits reduces the effectivity of the crew.

Flood the compartments with oxygen-saturated fluid.
This allows them to undergo g forces vastly larger than they could in air.

 

[Edont Knoff]

Flood the compartments with oxygen-saturated fluid.
This allows them to undergo g forces vastly larger than they could in air.

That makes the effect of shock waves even worse though. Fludis transmit them even better than gases.
The idea to evacuate the ship was to eliminate shock and pressure waves runnign through the rooms and corridors.

 

[Edont Knoff]

But what of kinetic weapons?

Now you have me coinfused, but I guess I mis-grouped ion and plasma beams into "energy" weapons and not for their kinetic effect? Please elaborate what you want to tell.

 

[Gawdzilla Sama]

E.E. "Doc" Smith (1934) was a great "force field" fan, the energies he flung around his books were of such a scale as to make material objects irrelevant. The "wall shield" was the final point of resistance before the hull, and I don't recall internal force fields.

Niven and Pournelle (1974), during the epic MacArthur vs. the Brownies battle, had interior force fields. The brownies had developed a portable force field generator, implying that the ones the Empire of Man had were NOT portable. (In fact their shuttles used ablative heat shields rather than force fields to protect the hull.)

Between those two examples we had just about every variation. The reason I asked is the old rule for warships: Armor + Mobility + Offense = 1.

 

[Gawdzilla Sama]

That makes the effect of shock waves even worse though. Fludis transmit them even better than gases.
The idea to evacuate the ship was to eliminate shock and pressure waves runnign through the rooms and corridors.

Nongermane and deleted.

 

[Edont Knoff]

Between those two examples we had just about every variation. The reason I asked is the old rule for warships: Armor + Mobility + Offense = 1.

I see. I thought you were referring to the point of evacuating the ship to reduce pressure waves and fires. But now it seems to be about force field variants mostly.

 

[DaveC426913]

That makes the effect of shock waves even worse though. Fludis transmit them even better than gases.
The idea to evacuate the ship was to eliminate shock and pressure waves runnign through the rooms and corridors.

I should have clarified that the occupants breathe the oxygen-saturated fluid.

Damage from shock waves comes from differences in density between media, such as air-to-water.
If its all water, there's no damage.

Watch this video:

 

[Edont Knoff]

I should have clarified that the occupants breathe the oxygen-saturated fluid.

Damage from shock waves comes from differences in density between media, such as air-to-water.
If its all water, there's no damage.

I see. That won't work for humans though, we cannot breath water, we need fluids that contain more oxygen, and those presumably have a different density from the water in our bodies. You have a point there with the g-forces though, unless they happen in from of a shock.

But, even our bodies have parts of different density, so I still would prefer shock waves not to be transmitted to my body at all, thus, I'd prefer the airless ship and the pressure suit.

 

[DaveC426913]

I see. That won't work for humans though, we cannot breath water,

Watch The Abyss.

...presumably have a different density from the water in our bodies.

Shock forces are reduced inversely proportional to the difference between air and the fluid.

Air is 784 times less dense than water.
The ox-sat fluid will be within 10% or so of the density of water.

So it will reduce shock by something on the order of 1000 times.

 

[Edont Knoff]

So it will reduce shock by something on the order of 1000 times.

Point accepted. Vacuum still reduces it to zero at all, so I'll take that. It also reduces the mass of the ship drastically compared to a fluid, which might help evasive maneuvers.

 

[DaveC426913]

Vacuum still reduces it to zero at all, so I'll take that.

No it doesn't. Why do you think that?

The damage to occupants in a spaceship isn't due to their impact with the air, it's due to their impact with the spaceship.

Vacuum means there is nothing stopping the spaceship from busting their nose - like when it does a high-velocity maneuver.

 

[Gawdzilla Sama]

I see. I thought you were referring to the point of evacuating the ship to reduce pressure waves and fires. But now it seems to be about force field variants mostly.

Hmmm, never seen mention of a ship's atmosphere being retanked for that purpose. Probably why I went the way I did, going with what I had seen depicted. I got into SciFi in 1963. Bullard of the Space Patrol!

 

[Gawdzilla Sama]

No it doesn't. Why do you think that?

The damage to occupants in a spaceship isn't due to their impact with the air, it's due to their impact with the spaceship.

Vacuum means there is nothing stopping the spaceship from busting their nose - like when it does a high-velocity maneuver.

Atmosphere can transmit shock waves.

 

[DaveC426913]

Atmosphere can transmit shock waves.

Yes, but that is not the practical danger faced by the occupants.
If an explosion big enough to injure them with a shock wave went off, they'd be dead already.

The problem Edont is facing is that the occupants are limited to about 15Gs of acceleration because of fragile human bodies.

The fragility of human bodies is due to there heterogenous nature - their air-filled chambers which will collapse under high Gs.

 

[Baldeee]

Now you have me coinfused, but I guess I mis-grouped ion and plasma beams into "energy" weapons and not for their kinetic effect? Please elaborate what you want to tell.

I don't think plasma and ion weapons are used for their kinetic effect but because of the other energies that are contained in the stream (heat etc).
For example, a laser beam won't knock you off your feet but could kill you very quickly, whereas a watercannon might knock you backwards but would have a harder time killing you.

I always see shielding as being primarily against energy weapons - i.e. they disperse or deflect the energy being fired at the target.
If you're using magnetics or some other form of shielding to move the beam away then these might work because it would work on each of the individual photons or whatever is being fired.
But they might be useless against kinetic weapons where you fire a far larger lump of metal (or whatever) at the target.
The lump would be too large for such a shield to affect, and thus it would bypass the shields.

That's my thinking, anyway.

So if you want shielding for both (energy and kinetic) you would need to come up with a way for the shield to affect the mass of the kinetic weapon.

 

[Gawdzilla Sama]

Yes, but that is not the practical danger faced by the occupants.
If an explosion big enough to injure them with a shock wave went off, they'd be dead already.

The problem Edont is facing is that the occupants are limited to about 15Gs of acceleration because of fragile human bodies.

The fragility of human bodies is due to there heterogenous nature - their air-filled chambers which will collapse under high Gs.

Sorry, "air-fill chambers", being spaces inside the ship?

 

[DaveC426913]

Sorry, "air-fill chambers", being spaces inside the ship?

No. Being lungs and sinuses.

Check out the video in post 10, above.