Why were fans disappointed with Battlestar Galactica's finally?

Derren

Hero
Barring a direct hit in which case nukes would be very effective, why would nukes be particularly more effective than conventional explosives? Presumably space faring ships would have to be extremely heavily radiation shielded and in a vacuum explosive force is largely irrelavent.

Doesn't really matter how big the bang is in a vacuum.

Dont forget the heat a exploding nuke radiates. A often overlooked aspect in SciFi is that heat management is quite a problem for spaceships as they have no way to remove excess heat besides slowly radiating it.
 

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Umbran

Mod Squad
Staff member
Supporter
Dont forget the heat a exploding nuke radiates.

Careful there. The nuke doesn't directly generate all that much heat. It generates lots of hard radiation, which gets absorbed by the atmosphere around it, which then heats up as a result. This is where a lot of the shockwave action of the bomb comes from as well.

If you set it off in a vacuum, the radiation will just streak away in all directions without being absorbed. If you set it off next to a space ship, the ship merely absorbs that portion of the radiation coming at it. You may instantly melt or vaporize material, but you aren't left with a long-term heat dissipation issue.

In general, explosives are a lot less impressive in a vacuum than they are in atmosphere.
 

Barring a direct hit in which case nukes would be very effective, why would nukes be particularly more effective than conventional explosives? Presumably space faring ships would have to be extremely heavily radiation shielded and in a vacuum explosive force is largely irrelavent.

Doesn't really matter how big the bang is in a vacuum.

That's one of the challenges in space combat; near misses are not nearly as effective as inside an atmosphere unless you're pushing a good sized cloud of shrapnel, because you don't get the benefits of the blast and heat effects. I supposed you could theorize some super-material that you could surround a nuke with that would become ultra-velocity shrapnel instead of being converted to molten material or plasma (it is sci-fi, after all), but you're better off going for the direct hit, especially against a (presumably armored) capital ship.

There's the benefit of EMP from the nuke explosion, but if the space fleet has nuclear ship-to-ship proximity weapons I'd assume they would harden against EMP. We do that for military electronics today in an environment (theoretically) much less likely to see a nuclear strike.

Ultimately the near miss value is for radiation, which appears to be quite dangerous close in if not shielded (see this NASA paper).
 

Umbran

Mod Squad
Staff member
Supporter
I supposed you could theorize some super-material that you could surround a nuke with that would become ultra-velocity shrapnel instead of being converted to molten material or plasma (it is sci-fi, after all)

Here's a simple solution - take an old, dead Battlestar. Set the nuke off *inside* it. The entire ship becomes shrapnel and debris...
 

Hussar

Legend
In other words, make REALLY big bombs. That would work.

One scene that always bugged me from BSG was when they showed a machine shop making cased rounds for Vipers. I know, it's SF and we're not supposed to get too wigged out by that sort of thing, but, jeez. There's no way you could accelerate a round fast enough to be effective in space based combat with a cased round. Anything powerful enough to make the round go fast enough would disintegrate the round itself. Anything slower would mean that the rounds would never be able to hit anything beyond a kilometre or so since you couldn't lead the target enough.

It always bugs me when SF shows, set in some future technology time, use technology that isn't even to todays standards, let alone centuries ahead of us. We already have electric guns and rail guns and x-ray lasers. Why on earth would I use dumb 25 mm rounds? (dumb as in no guidance system, not dumb as in stupid)

I mean, even today, in modern dogfights between aircraft, it's almost never going to come down to guns. It's going to be missile fire most of the time with guns primarily used against slow moving ground targets.
 

MarkB

Legend
In other words, make REALLY big bombs. That would work.

One scene that always bugged me from BSG was when they showed a machine shop making cased rounds for Vipers. I know, it's SF and we're not supposed to get too wigged out by that sort of thing, but, jeez. There's no way you could accelerate a round fast enough to be effective in space based combat with a cased round. Anything powerful enough to make the round go fast enough would disintegrate the round itself. Anything slower would mean that the rounds would never be able to hit anything beyond a kilometre or so since you couldn't lead the target enough.

Vipers don't seem to attack targets much further away than that in any case. Most combats we see take place at relatively close ranges.

It always bugs me when SF shows, set in some future technology time, use technology that isn't even to todays standards, let alone centuries ahead of us. We already have electric guns and rail guns and x-ray lasers. Why on earth would I use dumb 25 mm rounds? (dumb as in no guidance system, not dumb as in stupid)

I mean, even today, in modern dogfights between aircraft, it's almost never going to come down to guns. It's going to be missile fire most of the time with guns primarily used against slow moving ground targets.

BSG's technological schizophrenia was part of the show's quirky charm. It's an odd mix, as though they'd developed effective space flight and AI technologies while everything else was still at 1970s tech levels.
 

One scene that always bugged me from BSG was when they showed a machine shop making cased rounds for Vipers. I know, it's SF and we're not supposed to get too wigged out by that sort of thing, but, jeez. There's no way you could accelerate a round fast enough to be effective in space based combat with a cased round. Anything powerful enough to make the round go fast enough would disintegrate the round itself. Anything slower would mean that the rounds would never be able to hit anything beyond a kilometre or so since you couldn't lead the target enough.

It always bugs me when SF shows, set in some future technology time, use technology that isn't even to todays standards, let alone centuries ahead of us. We already have electric guns and rail guns and x-ray lasers. Why on earth would I use dumb 25 mm rounds? (dumb as in no guidance system, not dumb as in stupid)

Well, it does depend a bit on range. Modern 25mm cannon are effective beyond 3000 meters, and that range would be extended in space (no ballistic arc, no air resistance). So if the range is close enough and your target isn't exceptionally maneuverable, that +1000-1500 meters per second of velocity imparted by the gun is going to be sufficient to hit your target. The target's absolute speed is irrelevant; you just need enough delta-V to get to the target before it gets out of the way. The real challenge is predicting your target's flight path sufficiently.

That assumes some reason that you only have engagements at what is effectively knife-fighting range -- bad sensors, super-stealth, EMP fields that kill smart seekers on guided missiles, or something.

It's still silly, of course. Mostly fiction, less science.
 

I actually read something about the possible effects of nukes in space - and while things are different without the atmosphere, they are not ineffective at all and making a spacecraft tough enough to survive a near hit is non-trivial.

I suppose the thing to remember is - yes, the atmosphere absorbs radiation and heats up, generating a massive heat wave. But it doesn't mater whether we are in vacuum or in an atmosphere, the explosion spreads outwards evenly, so with our without atmosphere, the same amount of energy is hitting a target at distance. In one case, it might be superheated air, and in the other, it might be hard radiation, the energy hitting you is roughly the same, and if air can absorb hard radiation and heat up, what do you think other materials will do?
 

tomBitonti

Adventurer
Edit3: Links to the Cover Page and Table of Contents:

"86th Congress, 1st Session; House Document No. 86"

SPACE HANDBOOK: ASTRONAUTICS AND ITS APPLICATIONS
STAFF REPORT OF THE SELECT COMMITTEE ON ASTRONAUTICS AND SPACE EXPLORATION

http://history.nasa.gov/conghand/spcover.htm

http://history.nasa.gov/conghand/contents.htm

---

There is this:

http://history.nasa.gov/conghand/nuclear.htm#REF17-1

When a nuclear weapon is detonated close to the Earth's surface the density of the air is sufficient to attenuate nuclear radiation (neutrons and gamma rays) to such a degree that the effects of these radiations are generally less important than the effects of blast and thermal radiation. The relative magnitudes of blast, thermal and nuclear radiation effects are shown in figure 1 for a nominal fission weapon (20 kilotons) at sea level.1

And:

If a nuclear weapon is exploded in a vacuum-i. e., in space-the complexion of weapon effects changes drastically:

First, in the absence of an atmosphere, blast disappears completely.

Second, thermal radiation, as usually defined, also disappears. There is no longer any air for the blast wave to heat and much higher frequency radiation is emitted from the weapon itself.

Third, in the absence of the atmosphere, nuclear radiation will suffer no physical attenuation and the only degradation in intensity will arise from reduction with distance. As a result the range of significant dosages will be many times greater than is the case at sea level.

Figure 2 shows the dosage-distance relationship for a 20-kiloton explosion when the burst takes place at sea level and when the burst takes place in space. We see that in the range 500 to 5,000 roentgens the space radii are of the order of 8 to 17 times as large as the sea-level radii. At lower dosages the difference between the two cases becomes even larger.

A important consideration which is pointed out in some of the notes relating to nuclear weapons in space is a comment about the extra vulnerability to people: That is, because of radiation concerns, as pointed out above, in manned spacecraft, people can be a relatively vulnerable component.

Edit: To put some numbers on this, the charts show (approximately; the charts are hard to read in detail):

20KT Explosion

Air:
1000 RAD at about 0.7 miles
500 RAD at about 0.75 miles
100 RAD at about 0.8 miles

Vacuum:
1000 RAD at about 8.5 miles
500 RAD at about 13 miles
100 RAD at about 28 miles

The question then turns on the effectiveness of shielding, and on the relative vulnerability of electronics (I'm guessing the electronics of today are a lot more vulnerable than those of 1957, which is the date given for the referenced document.)

Edit2: Wow, some nice charts in that report, some very useful for game designers:

http://history.nasa.gov/conghand/mannedev.htm

Thx!

TomB
 
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