[Spaceships] Missiles

[jacobmuller]

Missile stats for Spaceships?
I want to get a baseline to extrapolate from, eg if I want to use superscience reactionless drives instead of HEDM.
Are these design stats anywhere near correct?
Assuming* they're a control system plus warhead on top of engines and fuel (and would cost $# if SM4***; warhead excluded**):
TL7-8 2x 3G chemical rocket plus 16 fuel sections gives 4.8mps? ($155k)
TL9+ 5x 2G HEDM rocket plus 13 fuel sections for 10.4 mps? ($250k)

*Should a missile include a Tactical Sensor Array and/or ECM?
**How much does a warhead cost? $20K for 80cm?
***for targeting a 10 ton missile this is SM3, ditto for comparison to Consumables table but it has a 7.5ton and a 15ton.

[Ulzgoroth]

Missiles aren't designed using Spaceship parts. Which is a good thing, since most Spaceship parts cost less than a million dollars per ton!

Of course, that'll seem a bit threadbare if you can manage to design missiles that do use Spaceship parts, and work at least as well as official missiles, but cost much less.

[Wanderer]

If you want tactical (or enhanced) sensors wouldn't that be roughly the same as the 'Sensor Drones' of G:SS5? Missiles which apparently trade both the warhead armor piercing effect as well as proximity fuses for a sensor array.

[jacobmuller]

Originally Posted by Ulzgoroth

Missiles aren't designed using Spaceship parts. Which is a good thing, since most Spaceship parts cost less than a million dollars per ton!

Of course, that'll seem a bit threadbare if you can manage to design missiles that do use Spaceship parts, and work at least as well as official missiles, but cost much less.

Indeed. All of which makes me want to find stats that match the listed SS3 performance stats and have a guess at the resultant cost. Kinda ends up being "Dang, are warheads and missiles controls That expensive?"

[jacobmuller]

Originally Posted by Wanderer

If you want tactical (or enhanced) sensors wouldn't that be roughly the same as the 'Sensor Drones' of G:SS5? Missiles which apparently trade both the warhead armor piercing effect as well as proximity fuses for a sensor array.

Thanks - I'll take a look.

[cmdicely]

Originally Posted by jacobmuller

Missile stats for Spaceships?
I want to get a baseline to extrapolate from

A while back I wrote something up addressing this issue, which may be useful:

http://forums.sjgames.com/showthread.php?t=64962

[Wanderer]

Nice. Uses a bit different assumptions that what i did but it makes sense to use the bombs as 'warheads'. Didn't get the same costs though (edit. fuel tank is probably the reason)... Used SM+8 as the 'base hull' - ie. the hull and all the components are 1000 times larger than on 1 ton missile. As i made calc sheet in M$ all i need to do is to design the system as SM+8 and read the cost as k$ and i get the engine, fuel tank, and fuel costs for the 1 ton missile which in turn can be scaled for other sizes.

For low-end TL 7-8 Chemical i get '6 payload spaces' ie. room for the bomb then some options...

3.00G with 3.12 mps at non-payload cost of 6,42 k$ - low-performance 'torpedo'
6.00G with 2.52 mps at non-payload cost of 8,08 k$ - generic 'missile'
12.0G with 2.10 mps at non-payload cost of 11,4 k$ - anti-fighter/ordnance 'interceptor'

As for building those given how physics work we came up with rule - very much alike (essentially copied from :P) the missile auto-miss rule of GT:Starships - which stated that should missile G rating be equal or smaller than ship G rating then it will automatically miss a maneuvering ship. Issue is even more apparent if the missiles rely on full CG (command guidance) for the most of the travel and use terminal (ie. robot/ai) guidance only for the final intercept. Even the smallest 'c-lag' (assuming ranges can grow to level where that happens) would force the missiles require far higher G rating than what the target ship has - and again faster (higher mps) the missile intercepts its target the harder would it be to use CG to compensate - same as with the ballistic attacks.

Which should make especially the long range high mps missiles quite a bit easier to evade - at least for dedicated 'warships'. Say using a single Chemical or HEDM rocket (booster) to provide more 'evasion Gs' or something.

[jacobmuller]

Nice workups.
The payload space is the biggest puzzle for me.
With only 10% payload you can get TL7-8 5G, 5mps, TL9+ 10G 10mps*.
But SS3 has TL7-8 6G 6mps and TL9 5G 10mps. There's seems no way to get 6mps at TL7-8, unless I've got my numbers wrong (not a surprise) or the SS3 stats are wrong [errata?].

And then there's the probes - replace warhead with sensors, eg a 96cm drone has the same stats as an SM+5 vessel which puts the warhead weight at 5%...

*actually about 4.9 and 10.2 but they look nice GURPSed.

[Wanderer]

Well... There are always the solid rocket fuel boosters/rockers which were omitted from the drives from starships, however given that AFAIK once triggered they will burn until they run dry those wouldnt really be suitable for space missiles regardless.

Other, which on the other hand could wreak havoc with damages, could be the use of several stages.

Say 'upper stage' 6 spaces, Chemical rockets 2 spaces and 12 fuel bits would yield... 6 G and 2.52 mps, then second stage could have slightly smaller payload (say 4 spaces) leaving 2 for rockets and 14 for fuel and give another 3.36 mps (still at 6 G) with end result of 6Gs and 5.88 mps (~ 6 mps). Granted the payload is starting to get rather small by this time. With three stages you would get 6 mps and beyond but payload would again be drastically reduced.

Also given that 4 spaces at one SM lower translates into 1 & 1/3 space in missiles 'true size' makes it improvement over a single stage stick (1 & 1/3 payload, 2 engine, 16 & 2/3 fuel - > 6G & 5 mps) only at very meager margin.

Unless i got something wrong of course.

[Witchking]

Originally Posted by Wanderer

Well... There are always the solid rocket fuel boosters/rockers which were omitted from the drives from starships, however given that AFAIK once triggered they will burn until they run dry those wouldnt really be suitable for space missiles regardless.

Depending on the other techs available on a Spaceship you might not wish to use solid fuel rockets. The magazine for solid fuel rockets...if hit by battle damage...may cause your ship to resemble the Akagi and her sisters at Midway. A funeral pyre for her crew.

If it is the only choice, or if markedly superior, or if the other drive choices are dangerous in there own ways; then you might go for it. Otherwise a lot of naval designers might wish to avoid them...

IMHO and YMMV...