Steve Jackson Games Forums

Steve Jackson Games Forums (http://forums.sjgames.com/index.php)
-   GURPS (http://forums.sjgames.com/forumdisplay.php?f=13)
-   -   [Spaceships] TL10^ exploration frigate (http://forums.sjgames.com/showthread.php?t=40432)

Agemegos 05-25-2008 11:57 PM

[Spaceships] TL10^ exploration frigate
 
Necho-class exploration frigate (TL10^ superscience)

This is an interstellar naval vessel designed to carry a small multidisciplinary team of planetologists and social scientists on 'first contact' missions with non-starfaring cultures and exploring previously-unsurveyed habitable worlds. It is lightly armed and armoured, mostly for self-defence, but its tech edge might make it suitable for a little light gunboat diplomacy.

The Necho class frigate is built in a 3,000-ton unstreamlined hull 70 yards 'high' and 46 yards in diameter. Artifical gravity was not available to the designers, and the habitats were clustered in the core for safety, so that spin gravity was not practical. When not under acceleration, the ships are intended to be occupied in free fall. So that it remains habitable while under acceleration, this vessel is laid out as a 'tail-lander', with decks perpendicular to the acceleration axis and the drives in the 'basement', pointing down.

Necho-class frigates have a limited-superscience antimatter plasma torch drive giving 1 gee of acceleration, and allowing 3 gee of 'emergency thrust' when antimatter-boosted water from a special tank is used as propellant. They are capable of landing on and takeoff from any habitable planet under emergency thrust, but are not intended to do so because their drive exhaust would be immensely destructive. They therefore carry two ram-rocket-powered orbital shuttles for landing and recovering explorers with their gear. Interstellar performance is modest: Necho and her sister-ships were intended to proceed on their exploration circuits by a series of short hops from star to star.

Forward hull
[1] Hardened nanocomposite armour, $30M, —
[2] Hardened nanocomposite armour, $30M, —
[3] Cargo hold (150 tons), $ negligible, —
[4] Hangar bay (100 tons), $0.3M, —
[5] Open space (2 areas, garden), $0.2M, —
[6] Habitat (20 cabins specialised rooms), $3M, —
[core] Habitat (20 cabins accommodations), $3M, —
Midships hull
[1] Hardened nanocomposite armour, $30M, —
[2] Power plant, de-rated fusion (1 power, 400 years), $15M, —
[3!] Weapons, medium battery, $15M, —
  • turreted 300MJ UV laser
  • turreted 32cm missile launcher
  • turreted 3 MJ very-rapid-fire improved laser (RoF 200) [note 5]
[4] Tactical array, $30M, —
[5] Defensive ECM, $30M, —
[6] Engine room, $1M, 2
Aft hull
[core] Control room (Complexity 8, c/s 8, 6 control stations), $6M, —
[1] Hardened nanocomposite armour, $30M, —
[2!] Stardrive engine, $30M, —
[3] Fuel tank (150 tons antimatter-boosted hydrogen), $1M, —
[4] Fuel tank (150 tons antimatter-boosted hydrogen), $1M, —
[5] Fuel tank (150 tons antimatter-boosted water), $1M, — [note 1]
[6] Reaction engine, antimatter plasma torch (1 g), $30M, —
Basic Stat block
PILOTING/TL10 (HIGH-PERFORMANCE SPACECRAFT)
TL: 10^
Spacecraft: Necho-class exploration frigate
dST/HP: 100
Hnd/SR: -1 / 5
HT: 13 [note 2]
Move: 1 g. or 3 g. / 280 mi./sec. [note 1]
LWt.: 3 000 tons
Load: 170 tons
SM: +9
Occ.: 45 ASV
dDR: 60H / 30H / 30H
Range: 1x
Cost: $288.25M
Refuel: $54M [note 3]
Crew
  • Control room crew: 6
  • Engine room crew: 2
  • Turret gunners: 3
  • Damage control: 6

Fit-out
Cargo hold
  • 50 tons assorted spare parts for ship repairs [note 2]
  • 75 tons assorted camping, construction, survival, and security equipment
  • 15 tons assorted scientific instruments
  • 5 tons assorted medical supplies
  • 5 tons assorted trade goods
Hangar bay
  • Two SM+5 orbital shuttles
Forward habitat section
  • Establishment (wardroom), 2
  • Establishment (faculty centre), 2
  • Establishment (mess), 2
  • Establishment (gym), 2
  • Lab (Biology), 2, $1M
  • Office (captain's day cabin), 1
  • Briefing room (double size), 2
  • Minifac, 1, $0.5M [note 2]
  • Armory (10 tons steerage cargo), 2
  • Stowage (10 tons steerage cargo), 2
  • Cabins (visitors), 2
Core habitat section
  1. Single cabin (captain)
  2. Single cabin (ambassador)
  3. Single cabin (head of survey)
  4. Double cabin (1st Lieutenant & Chief Engineer)
  5. Double cabin (2 officers)
  6. Double cabin (2 officers)
  7. Double cabin (Ambassador's aide and advisor)
  8. Double cabin (2 Survey experts)
  9. Double cabin (2 Survey experts)
  10. Double cabin (2 Survey experts)
  11. Double cabin (2 Survey experts)
  12. Double cabin (2 Survey experts)
  13. Double cabin (2 Survey experts)
  14. Double cabin (Buffer and Helmsman)
  15. Bunkroom (4 ratings)
  16. Bunkroom (4 ratings)
  17. Double-sized bunkroom (8 marines)
  18. 2-bed Sickbay with auto-docs, $0.2M
Magazine
  • 5 of 32 cm missiles with 2.5 Mton antimatter warheads $10M
  • 15 of 32 cm missiles with conventional warheads $15M [note 4]
Notes
  1. I assume that a given antimatter plasma torch engine can run on either antimatter-boosted hydrogen or antimatter-boosted water without modification. If not, all tanks carry antimatter-boosted hydrogen, and Speed is 1 g. / 360 mi./sec..
  2. I assume that neither the spare parts in the cargo hold nor the minifac in the forward habitat section will give the bonus to HT that a factory would give.
  3. The Necho-class was designed for a setting in which limited superscience production of antimatter provides antimatter-boosted fuels for $120,000 per ton at TL10^. At book prices for antimatter a ship such as this is not economic, and the class should be re-designed with a fusion torch engine, which would raise the cost of the ship to $301.5M, and alter its Move to 0.5 g. / 45 mi./sec., or to 0.5 g or 1.5 g / 37.5 mi./sec.
  4. I reckon that the Weapons, medium battery table on p.27 lists missile shots per launcher. If not, the fit-out would be six or seven antimatter warheads and none conventional.
  5. The very-rapid-fire laser is meant for close defence against projectiles, and is designed on the assumption that any hit will kill a missile or shell. If you can be bothered to muck about with split systems, you might like to treat this turret as a SM+8 major battery, and replace it with an SM+8 tertiary battery of 30 turreted very-rapid-fire 100-kJ improved lasers, each with a RoF of 200.

Noven 05-26-2008 01:43 AM

Re: [Spaceships] TL10^ exploration frigate
 
I like it. From a quick first impression, it sounds like the Lewis & Clark from Event Horizon =)

Sanity 05-26-2008 02:33 AM

Re: [Spaceships] TL10^ exploration frigate
 
Hm.

* Lot of armor in front. Not needed, giving you one more module (going to one module there).

* 75 TONS of camping, construction, survival, and security equipment
equipment? Seriously? What are they carrying there? I count a total of 29 people on board in the cabins. That makes it 2586kg (!) of stuff per person, and this includes people never leaving the shop (captain etc.). Weapons I assume are not in there - that is a LOT. I would cut down on that, raising the trade goods to more, in the allocation. Or storing some fuel for the shuttles - yes, they are ram jet, but you may need to do some orbintal maneucering, and there it is always good to have SOME fuel with you.

* I would really get rid of the anti matter, if you can. Anti Matter is highly problematic. I can see it in use on military ships, but it is not something I would like to send to a first contact mission. Shooting starts, something hits the anti mater containment wrong, and next thing is you know you have a mortal enemy making a religion out of killing you because you killed half their planet, so to say. Without even wanting it. In addition, anti matter creation is problematic - unless they carry the equipment on board (which they do not). Getting some Hx (H2, H3) production going is a lot easier if you need more fuel than creating anti matter, and even if anti matter creation is simple (super-science) you may not want to tell the natives how that is done ;)

Peter Knutsen 05-26-2008 03:07 AM

Re: [Spaceships] TL10^ exploration frigate
 
Why only have 2 shuttles? IIRC SM+5 is 30 tonnes, so you'd be able to fit 3 such shuttles into a 100 ton hangar bay and still have 10 ton to spare.

Alternatively one SM+6 shuttle, since IIRC that equates to 100 tons.

Or a third option, split the hangar module so that only 2/3 of it is hangar bay, and the last 1/3 is either cargo storage, reaction mass or habitat (extra lab space or garden space).


Also, I agree with the armour. Why have double armour on front? Then again, the ship seems fairly upgunned, with one full mass module devoted to ECM.

Peter Knutsen 05-26-2008 03:15 AM

Re: [Spaceships] TL10^ exploration frigate
 
Quote:

Originally Posted by Sanity
* I would really get rid of the anti matter, if you can. Anti Matter is highly problematic. I can see it in use on military ships, but it is not something I would like to send to a first contact mission. Shooting starts, something hits the anti mater containment wrong, and next thing is you know you have a mortal enemy making a religion out of killing you because you killed half their planet, so to say. Without even wanting it. In addition, anti matter creation is problematic - unless they carry the equipment on board (which they do not). Getting some Hx (H2, H3) production going is a lot easier if you need more fuel than creating anti matter, and even if anti matter creation is simple (super-science) you may not want to tell the natives how that is done ;)

Switching to an easier-to-get fuel would be highly attractive, I think. Being able to refuel from gas giants, comets or planetary ocenas can be very useful.

However, I don't believe there are any great secrets to antimatter production. It just happens to require expensive equipment, lots of energy input (seeing as antimatter is actually about energy storage, never energy production or energy generation), and take lots of time.

I'm also unconvinced that even several tons of antimatter can cause significant damage to a planet. And are there several tons in this antimatter-boosted reaction mass? (I do have the PDF, but I'm too lazy to open it and check.)


Perhaps the ideal solution would be for the ship to devote an entire module to carrying nothing but pure antimatter, and then a second module that enables it to use this antimatter to create boosted reaction mass, e.g. from ocean water or gas giant atmosphere or comet materials?

Sanity 05-26-2008 01:49 PM

Re: [Spaceships] TL10^ exploration frigate
 
Quote:

I'm also unconvinced that even several tons of antimatter can cause significant damage to a planet.
You do not need to damage the planet in order to make the inhabitants enemies.

Even a kilo of antimatter exploding will look like a HUGH nuclear explosion. You do not want to dispute why you just did that to them ;) Remember that the biosphere, or the attitude of the peoples are more easily damaged than the planet.

Quote:

Perhaps the ideal solution would be for the ship to devote an entire module to carrying nothing but pure antimatter, and then a second module that enables it to use this antimatter to create boosted reaction mass, e.g. from ocean water or gas giant atmosphere or comet materials?
I would seriously like to stay away from antimatter if feasible. For a deep space mission the possible negative from any failure is just too hard - i mean, lets ignore the "ship blows up" thing. If for some reason you need more fuel, you just can not get it (maybe you needed to jettison it, whatever). This is ok fo ra military operation (which rarely is a single ship etc.), but not if you go on a deep space exploration mission. Smells like dying in another star systtem, unable to get fuel again.

Plus antimatter is tricky - if contianment fails you die. This can be a problem unless you get passive containment (i.e. a material that contains the antimatter without reaction, not something like a magnetic bottle that constantly needs energy).

Quote:

It just happens to require expensive equipment, lots of energy input (seeing as antimatter is actually about energy storage, never energy production or energy generation), and take lots of time.
First ppoint - antimatter may be bout energy creation. One of my older sf universes had cheap antimatter production though "misjumps". Certain musjumps let you get out of hyperspace as antimatter - normally resulted in immediate destruction, but you COULD force that in a lap as microjump (i.e. on space), so hugh facilities where build jumping tons of matter in kplace in a controlled misjump to create antimatter - you efficiently got energy out.

You need a similar mechanism, otherwise you will always have EXPENSIVE antimatter, as the energy needs to be generated in the first place ;) Which - is not nice.

Whateve, though, antimatter creation is tricky. You may not be able to get that in place if you need. Better just skim gas giants.

Peter Knutsen 05-26-2008 03:18 PM

Re: [Spaceships] TL10^ exploration frigate
 
Quote:

Originally Posted by Sanity
I would seriously like to stay away from antimatter if feasible. For a deep space mission the possible negative from any failure is just too hard - i mean, lets ignore the "ship blows up" thing. If for some reason you need more fuel, you just can not get it (maybe you needed to jettison it, whatever). This is ok fo ra military operation (which rarely is a single ship etc.), but not if you go on a deep space exploration mission. Smells like dying in another star systtem, unable to get fuel again.

You have misunderstood what I read. I did not write that the ship should devote one mass-module to antimatter storage and then use pure antimatter for propulsion.

Agemegos 05-26-2008 06:18 PM

Re: [Spaceships] TL10^ exploration frigate
 
Quote:

Originally Posted by Sanity
Lot of armor in front. Not needed, giving you one more module (going to one module there).

Point of disagreement between the Navy and the Colonial Office. The Navy thinks that this class is under-powered, under-gunned, and under-armoured to be going off into the Beyond all on its lonesome. Whereas the Colonial office think that it is cramped, wastefully armoured, and could do without the big laser, the missile launcher, the power generator, the ECM gear, and the array. You will note that the designers have filled the forward hull section with non-vital systems, so that the vessel can take a hit or two clean through its front armour and still be able to fight or run.

Quote:

75 TONS of camping, construction, survival, and security equipment
equipment? Seriously? What are they carrying there?
A couple of aircars. Two semi-rigid inflatable power-boats. A motorised pontoon. A minisub. Several prefab buildings. A bobcat tractor. Cement. Reinforcing mesh. Plumbing fittings, including pumps and water-purifiers. A couple of food synthesisers. Chainsaws. Fencing stakes. A posthole-auger. star-picket driver. A mattock. A shovel. Fencing wire. A generator. Floodlights. A miniframe computer. A communications base-station transceiver. Arctic kit. Tropical kit. Raincoats. Cots. Bedclothes. Chairs. Tables. It all adds up. Especially as some of the stuff is non-reusable and as they expect to explore several planets on each cruise.

Quote:

I count a total of 29 people on board in the cabins.
I make it 41, with four spare bunks.

Quote:

That makes it 2586kg (!) of stuff per person, and this includes people never leaving the shop (captain etc.).
There are 28 people with duties dirtside: 13 Survey folk, eight marines, three diplomats, and a pilot and flight engineer for each of two shuttles. But the captain is going to get morale problems if he tries any five-year-cruises with no surface leave.

Quote:

Weapons I assume are not in there
Correct. Smallarms are in the armoury (steerage cargo). Ten tons of them.

Quote:

I would cut down on that, raising the trade goods to more, in the allocation.
Maybe. Though you can bribe an awful lot of backwoods dictators with five tons of anti-aging drugs.

Quote:

Or storing some fuel for the shuttles - yes, they are ram jet, but you may need to do some orbintal maneucering, and there it is always good to have SOME fuel with you.
Store it in the shuttles' tanks. For that matter, I expect that the antimatter for the main drive is stored int eh engine, and that the main tanks are full of hydrogen and water that would do fine as shuttle propellant.

Quote:

I would really get rid of the anti matter, if you can.
See note 3. Without antimatter the ship's performance is compromised: halve acceleration and divide endurance by eight. Endurance would be so diminished that you would have to carry refinery gear for constant refuelling.

Quote:

Anti Matter is highly problematic. I can see it in use on military ships, but it is not something I would like to send to a first contact mission.
Like James Cook's HM Barque Endeavour, or Fitzroy's HMS Beagle, this is a naval ship.

The explorers of the Age of Sail never left home without a few tons of gunpowder.

Quote:

Shooting starts, something hits the anti mater containment wrong, and next thing is you know you have a mortal enemy making a religion out of killing you because you killed half their planet, so to say.
I estimate the exhaust power of this ship as 115 terawatts and its endurance as 45 kiloseconds. Multiplying out, I estimate that it puts 5.2 exajoules into its exhaust (ship energy is negligible in comparison, and waste heat had better be). 5.2 * 10^18 joules is 1.2 gigatons. The thermal radiation will produce three-degree burns at 213 km, and the fireball will be about 7.5 km across. But even ground burst that'll "only" kill everyone within 28 km and flatten buildings out to 75 km.

That's a big bang, no doubt. But to speak of killing half a planet is hyperbole. And considering that the ship is intended not to land—the worst that can happen is an explosion in low orbit, setting fires and inflicting flash burns in a area 400 km across.

Quote:

In addition, anti matter creation is problematic - unless they carry the equipment on board (which they do not). Getting some Hx (H2, H3) production going is a lot easier if you need more fuel than creating anti matter, and even if anti matter creation is simple (super-science) you may not want to tell the natives how that is done
True. But on the other hand I estimate that the Necho is carrying only about 30 kg of antimatter to power its drives. It wouldn't be prohibitive to carry extra antimatter fuel, and top up the propellant tanks with whatever is handy.

Agemegos 05-26-2008 06:39 PM

Re: [Spaceships] TL10^ exploration frigate
 
Quote:

Originally Posted by Peter Knutsen
Why only have 2 shuttles? IIRC SM+5 is 30 tonnes, so you'd be able to fit 3 such shuttles into a 100 ton hangar bay and still have 10 ton to spare.

Expense, mostly.

Necho was originally designed in a system without modules (edit: or rather, in which each module as ten tonnes mass and there was no limit on the number in a ship), and it had one thirty-ton shuttle in a bay and another in an external clamp. But you can't do that in Spaceships without splitting modules. I didn't want to split modules because I wanted to publish a RAW design.

I'll design the shuttles later, and see how much they end up costing. If they're cheap I'll consider adding a third. Or splitting the module and putting in a 30-ton shuttle fuel tank. Or indeed leaving bay space for visitor's craft. Not that I imagine any naval captains are going to give permission for foreigners to park a spacecraft inside their ships.

Quote:

Alternatively one SM+6 shuttle, since IIRC that equates to 100 tons.
Having only one shuttle is a bit chancy. If there is an accident to it you can end up with a crew etc. stuck on teh surface and no way to recover them.

Quote:

Or a third option, split the hangar module so that only 2/3 of it is hangar bay, and the last 1/3 is either cargo storage, reaction mass or habitat (extra lab space or garden space).
Yes, that is certainly a good idea for GMs who are happy with split modules.


Quote:

Also, I agree with the armour. Why have double armour on front? Then again, the ship seems fairly upgunned, with one full mass module devoted to ECM.
The Colonial office agree with you. They say that their field researchers need a single cabin each to himself or herself, or a shared cabin and an office, and preferrably both, and that the fourth armour module, the tactical array, and the ECM are superfluous. (Given splitt modules, they's also like to scrap the main gun and the missile launcher and squeeze a 1/3-sized power plant in with 2 1/3-sized tertiary batteries of v.r.f. improved lasers.

On the other hand, the Navy says that this ship is going off into the lonesome all by itself, that it will certainly be encountering spacefaring cultures and maybe pirates, alien empires, and God-knows-what. And if it can't fight, it ain't going.

The designer managed to not quite make either party pull the plug by stuffing the forward hull with non-vital systems that can sorta-kinda be considered ablative armour. Both sides are grumbling, but neither is quite cancelling the project.

Agemegos 05-26-2008 07:10 PM

Re: [Spaceships] TL10^ exploration frigate
 
Quote:

Originally Posted by Peter Knutsen
Switching to an easier-to-get fuel would be highly attractive, I think. Being able to refuel from gas giants, comets or planetary ocenas can be very useful.

True. But it would come at the price of having to. The version of Necho powered by fusion would have to refuel seven times to provide the delta-v available to the antimatter plasma torch version.

Quote:

However, I don't believe there are any great secrets to antimatter production. It just happens to require expensive equipment, lots of energy input (seeing as antimatter is actually about energy storage, never energy production or energy generation), and take lots of time.
CERN produces it (in truly tiny quantities) at TL8.

Quote:

I'm also unconvinced that even several tons of antimatter can cause significant damage to a planet. And are there several tons in this antimatter-boosted reaction mass? (I do have the PDF, but I'm too lazy to open it and check.)
150 tons of reaction mass gives 3,000 tonnes of ship a delta-v of 120 mi./sec., a.k.a. 192 km/s. That implies an effective exhaust speed of 3.84 Mm/s. The 3,000,000-kg ship has an acceleration of 10 m/s^2, implying thrust of 30 MN. Drive power is Fv = 30 MN * 3.84 Mm/s = 115.2 TW.

Each fuel tank gives 192 km/s at 10 m/s^2, implying endurance 19.2 ks. There are three tanks, giving a total burn time of 57.6 ks (sixteen hours). Total kinetic energy of the exhaust stream is 115.2 TW * 57.6 ks = 6.6 EJ. (Kinetic energy of the ship is negligible: about 3 PJ). Let's add 10% for waste heat. 7.26 * 10^18 J. Now a megaton is about 4.2 * 10^15 J, so we are talking about a 1.73 gigaton explosion.

Now, the antimatter annihilates an equal mass of matter, so we need the mass-equivalent of 3.63 EJ. c is about 3 * 10^8 m/s, so it's m = 3.63 * 10^18 / 9 * 10^16 = 40 kg.

Quote:

Perhaps the ideal solution would be for the ship to devote an entire module to carrying nothing but pure antimatter, and then a second module that enables it to use this antimatter to create boosted reaction mass, e.g. from ocean water or gas giant atmosphere or comet materials?
Yep. That would be great. Replace a fuel tank with a cargo compartment and call it antimatter storage. All we need is a canonical figure for how much antimatter you can store in a 150-ton container.


All times are GMT -6. The time now is 05:48 AM.

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2020, vBulletin Solutions, Inc.