Lysian sentry pods

Roondar · Post by **Roondar** » Tue Nov 20, 2007 7:15 pm

I recently watched Conundrum again, which, apart from being an entertaining episode in it's own right, also shows the use of the Enterprise's phasers versus several outclassed foes.

Now, the first of these is not quantifiable (Enterprise vs Lysian Destroyer) - yes, the Enterprise blows up the destroyer in no time flat using only it's phasers, but we do not know the size of the ship in question so we cannot determine any yields. It is, however, interesting to see a warship (which a destroyer is) be blown up in just one blast of the ships weapons.

--

However, more interestingly (in my view) is the rapid destruction of a number (five to ten) Lysian Sentry pods. These are described as unmanned, metal objects 29 meters long.

Since I readily admit that calculating weapon yields is not my strongest suit, the question becomes what a rough ballpark figure is for the destruction of the pods. The visuals show them more or less vaporized by the weapons. Since there are no secondary explosions involved, I'm confident that the effects where created by the ships phasers itself and not through reactor breaches or overloads.

I'll try to find some screenshots later, but a first question is if someone would be willing to assist me in determining a realistic effective yield. See, any fool can decide to make the ships a solid block of metal and quote the vaporising energy required. I'm more interested in seeing a more neutral approach though.

My goal here is partly to see a low end* of phaser capabilities vs metal object and secondly I wish to create a thread later that addresses the 'phasers are ineffective versus any metal' claim. This is a starting point of sorts.

I don't particularly care if the yield found is high or low, as long as it can be seen as realistic.

*) The Enterprise is clearly not using full power to achieve these effects per phaser burst because the main array fires multiple shots at different targets at the same time to achieve the effect.

Ted C · Post by **Ted C** » Wed Nov 21, 2007 9:46 pm

It should be possible to melt through the hulls of these rather small pods with gigawatt-range firepower or even less. If their engines, weapons, or power sources are as volatile as those typically seen in sci-fi warships, any hull breach could easily result in an explosion.

Since the Galaxy-class's phasers were at least capable of terawatt-range output, destroying these vessels would be a piece of cake.

These pods really aren't a very good measure of phaser firepower.

Post by **Mike DiCenso** » Wed Nov 21, 2007 10:36 pm

Using the multi-kilometers tall Lysian Central Command space station as a measure of firepower might be somewhat better since only one photon torpedo was all that was needed to destroy it and end the Satarran's war with them.
-Mike

Post by **Mike DiCenso** » Wed Nov 21, 2007 10:43 pm

Ted C wrote:It should be possible to melt through the hulls of these rather small pods with gigawatt-range firepower or even less. If their engines, weapons, or power sources are as volatile as those typically seen in sci-fi warships, any hull breach could easily result in an explosion.

Since the Galaxy-class's phasers were at least capable of terawatt-range output, destroying these vessels would be a piece of cake.

These pods really aren't a very good measure of phaser firepower.

Ted, you may have found a way to calculate minimum Galaxy class starship firepower here. Take the surface area of the phaser beam as it strikes each sentry pod, scaling the beam to the known dimensions of the 29 meter craft, then you can work out the area of the hull being melted or vaporized by the beam, and then derive a lower-limits firepower udner the assumption that the Lysian sentry pods are made of conventional modern day alloys.
-Mike

Roondar · Post by **Roondar** » Thu Nov 22, 2007 9:14 am

Ted C wrote:It should be possible to melt through the hulls of these rather small pods with gigawatt-range firepower or even less. If their engines, weapons, or power sources are as volatile as those typically seen in sci-fi warships, any hull breach could easily result in an explosion.

Since the Galaxy-class's phasers were at least capable of terawatt-range output, destroying these vessels would be a piece of cake.

These pods really aren't a very good measure of phaser firepower.

Of course they aren't a good measure for maximum phaser firepower. They are however, a starting point for the minimum phaser firepower versus metal objects.

Note that the pods in question where designed to be defensive vessels. I find it rather unlikely that their hull would be completely paper thin. Sure, it won't be 29 meters thick either, but it is a military design, not a civilian ship ;)

Roondar · Post by **Roondar** » Thu Nov 22, 2007 9:19 am

Mike DiCenso wrote:
Ted C wrote:It should be possible to melt through the hulls of these rather small pods with gigawatt-range firepower or even less. If their engines, weapons, or power sources are as volatile as those typically seen in sci-fi warships, any hull breach could easily result in an explosion.

Since the Galaxy-class's phasers were at least capable of terawatt-range output, destroying these vessels would be a piece of cake.

These pods really aren't a very good measure of phaser firepower.
Ted, you may have found a way to calculate minimum Galaxy class starship firepower here. Take the surface area of the phaser beam as it strikes each sentry pod, scaling the beam to the known dimensions of the 29 meter craft, then you can work out the area of the hull being melted or vaporized by the beam, and then derive a lower-limits firepower udner the assumption that the Lysian sentry pods are made of conventional modern day alloys.
-Mike

I think that would be difficult. The way it seemed to me was that the whole pod pretty much vanished the second the phasers hit it. I'd have to make screenshots to be sure tho. I will try to get some later today.

Roondar · Post by **Roondar** » Thu Nov 22, 2007 10:56 pm

Roondar · Post by **Roondar** » Fri Nov 23, 2007 2:27 pm

Well, I've attempted to do the scaling myself. I'm using the picture below as source:

Here are my conclusions:

Base assumption here is that the cutouts shown on the picture represent the craft as hit from it's length, i.e. in a horizontal posture. Since the craft is actually rotated to a degree this is not entirely accurate. However, since the pods (as seen on screen) are wider than they are long this assumption should not lead to higher numbers.

Note: calculation differences in the multiplications are due to me using the actual results instead of the rounded figures I give here. I've attempted to keep rounding to a minimum.

Note 2: the many assumptions about steel are because it is an alloy and hence has a range of possible values. I've attempted to use sane values here.

Pod size:
45x30 pixels
45 px = 29 meters
1 px = 0,6444 meters

4:3 aspect ratio, meaning 1 horizontal pixel equals 0.75 vertical ones.
1x1 px = 0,6444 x 0,8596 meters
45x30 = 29 x 25,778 meters

Phaser hitzone:
27x16 px equals 17,4 x 13,75 meters

Next up is calculating the energy and power in the blasts.
I'll assume that each phaser blast represents the same amount of energy. I do this to be able to better see how long each blast takes to correctly convert the energy level into a power one.

The second assumption is on hull thickness and material. For this calculation I'm going to go with plain old steel and a thickness of 10 centimeters (100mm). I'm assuming this is a good lower limit for the armor of a military vessel of any sort in this future scenario. If this is unreasonable (or any other part of this post for that matter!), by all means correct me :)

Note that my gut feeling says 100 mm steel is extraordinarily thin for a craft of this kind but I can't verify the exact thickness, hence the low claim.

I'm assuming that the Phaser merely melted the area affected, not vaporised. The affected area comes out to 17,4 x 13,75 x 0,10 = 23,931 m3. The starting temperature is assumed to be 20c (293.15K). The melting temperature of steel is assumed to be 1400c (1673.15k). The specific heat capacity of steel is assumed to be 420 (in J per KG per degree). Steel is assumed to weigh 7480 KG per m3

23,931 m3 of steel weighs 179003,88 KG (or about 179 metric tons). The steel needs to be raised 1380 degrees. Doing so takes 103 750 648 848 J, or 103,751 GJ.

Since the phaser blast took far less than one second to be formed the power requirements are, however, higher than 103 GW. As can be seen by watching frames 16-23 of the scene a phaser takes 6 frames to do it's job.

6 Frames is equal to 6/25th of a second, or 0,24 seconds (remember, I'm using a PAL source). However, since my videocapture software seems to occasionally take two frames in one instead of just one, I'll assume the scene took 12 frames (or 0,48 seconds) instead.

Result:

Each blast takes 103 GJ and requires a minimum of 216,15 GW of power capacity. Six pods where destroyed in total, taking ~618GJ and ~1,288 TW of power capacity.

These figures are naturally very much lower limits, but show that effective phaser yield versus metal objects is at least in the TW range. If this would be the limit of a phaser versus metal it would be able to melt about 1074 metric tons of steel per second, or about 144 m3*.

A three second phaser shot (which is not unreasonable) can therefore be expected to melt at least 3222 metric tons worth of steel or about 432 m3**.

For comparison with water:
Heating up 1KG of ice by 370 degrees (space-zero to steam at 4187 J per KG per degree) would take 1549190 J or 1,54919 MJ. Water weighs 1000KG per m3, so 1m3 would take 1,54919 GJ.

A three second phaser shot can be expected to vaporize at least 2494,2 m3*** (and likewise 2494,2 metric tons) of extremely low temperature ice, assuming equal effeciency.

*) A cube measuring 5,24 meters on all sides or a cube measuring 17,47 feet on all sides
**) A cube measuring 7,56 meters on all sides or a cube measuring 25,20 feet on all sides
***) A cube measuring 13,56 meters on all sides or a cube measuring 45,21 feet on all sides

--

Apologies for the length. Let me know what you think and if I made any glaring errors (quite possible, especially on the scaling itself).

Ted C · Post by **Ted C** » Mon Nov 26, 2007 8:53 pm

Mike DiCenso wrote:Ted, you may have found a way to calculate minimum Galaxy class starship firepower here. Take the surface area of the phaser beam as it strikes each sentry pod, scaling the beam to the known dimensions of the 29 meter craft, then you can work out the area of the hull being melted or vaporized by the beam, and then derive a lower-limits firepower udner the assumption that the Lysian sentry pods are made of conventional modern day alloys.
-Mike

Not so much. We have no idea how thick the hulls of those pods might be, nor do we know how much of a breach would be necessary to blow the pods.

You may, however, be able to estimate the diameter of a phaser beam from those shots. Knowing the length of the pods, you could presumably scale the width of the beam where it strikes them.

Post by **Mike DiCenso** » Mon Nov 26, 2007 10:26 pm

We may not know the thickness of the pods' hull plating, but we can start with basic assumptions, however, and work upward from there. That can gives us at least a rough ball-park figure.
-Mike

Ted C · Post by **Ted C** » Tue Nov 27, 2007 7:43 pm

Mike DiCenso wrote:We may not know the thickness of the pods' hull plating, but we can start with basic assumptions, however, and work upward from there. That can gives us at least a rough ball-park figure.

You might start from the hull thickness of Federation shuttlecraft. The Lysians would have little reason to put thicker hulls on their defense pods. We know they have shield technology, feeble thought it was by Federation standards, so they probably wouldn't rely on heavy armor to protect the pod (if shields didn't give better protection for the space/mass they need, they wouldn't be used). Since it shouldn't even need to be pressurized, a thicker hull is just adding mass, which will reduce the pod's acceleration.

So, the hull on a Federation shuttlecraft looks to be... what... a few centimeters thick?

Roondar · Post by **Roondar** » Tue Nov 27, 2007 8:31 pm

Ted C wrote:
Mike DiCenso wrote:We may not know the thickness of the pods' hull plating, but we can start with basic assumptions, however, and work upward from there. That can gives us at least a rough ball-park figure.
You might start from the hull thickness of Federation shuttlecraft. The Lysians would have little reason to put thicker hulls on their defense pods. We know they have shield technology, feeble thought it was by Federation standards, so they probably wouldn't rely on heavy armor to protect the pod (if shields didn't give better protection for the space/mass they need, they wouldn't be used). Since it shouldn't even need to be pressurized, a thicker hull is just adding mass, which will reduce the pod's acceleration.

So, the hull on a Federation shuttlecraft looks to be... what... a few centimeters thick?

It won't do us much good tho, ST shuttlecraft have pretty tough hulls by modern standards. Much better than what we've come up with at any rate.

On the other hand, heavier ST starships do sport heavy hull plating (certainly more than a few cm), suggesting that while shields are preferred they are not counted on to be the only defense. I don't think it's unlikely a nation which has shields that can't stop attacks very efficiently to still attempt to compensate with thicker hulls. Shields may be more efficient, but a lack of capability in projecting the shield at the strength wished for could call for a thicker hull.

... Then again, if the pods are in fact shielded then we can't calculate anything anyway since the interaction with a shield, however weak, would lower any figures we find. Which means we would not find a lower limit for phasers vs metal objects regardless.

Post by **Mike DiCenso** » Thu Nov 29, 2007 9:59 pm

All you need really do is to subtract the shield's rating from the total overall number. For instance, in the case of the Lysian Central Command, it was only rated at a few kilojoules. If that's the very best that the Lysians can do to protect such a vital asset, then their pods won't even be worth mentioning in any calculation.
-Mike