Hard sci-fi adventures?

[Shadowsoul]

Re: Hard sci-fi adventures?

 

There aren't that many places in a spaceship that you'd really want to have a shaped charge going off; even a small one.

[Nyrath]

Re: Hard sci-fi adventures?

 

If you are inside a spacecraft, shaped charges will damage the hearing of everybody without earplugs. They are hard on the ears in the best case, the interior of a metal spacecraft is going to be an echo chamber that will magnify the damage.

[tkdguy]

Re: Hard sci-fi adventures?

 

If you are inside a spacecraft' date=' shaped charges will damage the hearing of everybody without earplugs. They are hard on the ears in the best case, the interior of a metal spacecraft is going to be an echo chamber that will magnify the damage.[/quote']

That's important to remember. Would suppressors help?

[tkdguy]

Re: Hard sci-fi adventures?

 

I've also been thinking up an early military spacecraft design. How does this sound?

 

The spacecraft will be slightly larger than the space shuttle. It will have a maximum crew of ten. The crew will have to strap themselves in their seats while moving. The seats are always facing forward, so they'll feel the acceleration pressing against them.

 

The engine will be a fission-powered VASIMR drive. The main engine will be aft, but there will be smaller thrusters along the other sides of the ship, including "top" and "bottom" to aid in course correction.

 

The crew will be composed of a pilot/commander, co-pilot/XO, engineer, navigator, radioman/electronic warfare officer, and 2-3 gunners. A doctor may or may not be on board.

 

The spacecraft is armed with two missiles, a railgun, and four autocannons. The railgun is stationary and pointed forward, while the autocannons can swivel 180 degrees in the "up-down" and "sideways" axes. The missiles are also launched forward, but they can be guided by a gunner. The main engine is used to counter the change in momentum caused when the missiles and railgun are fired, while the thrusters are used to counter the change in momentum caused when the autocannons are fired. The railgun has a limited amount of ammunition and thus can only fire a few salvos.

 

The spacecraft has a range from Earth to Mars.

[ajackson]

Re: Hard sci-fi adventures?

 

That's important to remember. Would suppressors help?

Anything designed to deal with rapid pressure changes (such as, oh, vacc suits) would help.

[tkdguy]

Re: Hard sci-fi adventures?

 

Thanks, ajackson.

[Alibear]

Re: Hard sci-fi adventures?

 

Exactly. Except a bit more compact so one person can carry it.

 

One would think that whipping one out and waving it at your opponent would count as a presence attack.

 

Displaying a power - +1d6

[Nyrath]

Re: Hard sci-fi adventures?

 

That's important to remember. Would suppressors help?

Yes. This applies to firearms as well, the metal spaceship hull will add the echo chamber effect. Cut lose with a submachine gun, and your ears will be ringing for a long time.

 

This could count as "flash vs. hearing"

[Nyrath]

Re: Hard sci-fi adventures?

 

I've also been thinking up an early military spacecraft design. How does this sound?

 

The spacecraft will be slightly larger than the space shuttle. It will have a maximum crew of ten. The crew will have to strap themselves in their seats while moving. The seats are always facing forward, so they'll feel the acceleration pressing against them.

 

The engine will be a fission-powered VASIMR drive. The main engine will be aft, but there will be smaller thrusters along the other sides of the ship, including "top" and "bottom" to aid in course correction.

 

The crew will be composed of a pilot/commander, co-pilot/XO, engineer, navigator, radioman/electronic warfare officer, and 2-3 gunners. A doctor may or may not be on board.

 

The spacecraft is armed with two missiles, a railgun, and four autocannons. The railgun is stationary and pointed forward, while the autocannons can swivel 180 degrees in the "up-down" and "sideways" axes. The missiles are also launched forward, but they can be guided by a gunner. The main engine is used to counter the change in momentum caused when the missiles and railgun are fired, while the thrusters are used to counter the change in momentum caused when the autocannons are fired. The railgun has a limited amount of ammunition and thus can only fire a few salvos.

 

The spacecraft has a range from Earth to Mars.

Not bad. There should be an officer who also has to maintain the hydroponic farm in life support and/or the life support system.

 

Just be sure you have enough crew so the ship can be adequately manned while some of the crew is sleeping.

 

A real-world VASIMR could do Earth-Mars in about a month, but you can adjust that a bit up or down depending upon your campaign.

 

Keep in mind that while under thrust "forwards" will seem like "up", that is, the direction the exhaust is traveling is the direction of "down".

[Cancer]

Re: Hard sci-fi adventures?

 

I've also been thinking up an early military spacecraft design. How does this sound?

 

The spacecraft will be slightly larger than the space shuttle. It will have a maximum crew of ten. The crew will have to strap themselves in their seats while moving. The seats are always facing forward, so they'll feel the acceleration pressing against them.

 

The engine will be a fission-powered VASIMR drive. The main engine will be aft, but there will be smaller thrusters along the other sides of the ship, including "top" and "bottom" to aid in course correction.

 

The crew will be composed of a pilot/commander, co-pilot/XO, engineer, navigator, radioman/electronic warfare officer, and 2-3 gunners. A doctor may or may not be on board.

 

The spacecraft is armed with two missiles, a railgun, and four autocannons. The railgun is stationary and pointed forward, while the autocannons can swivel 180 degrees in the "up-down" and "sideways" axes. The missiles are also launched forward, but they can be guided by a gunner. The main engine is used to counter the change in momentum caused when the missiles and railgun are fired, while the thrusters are used to counter the change in momentum caused when the autocannons are fired. The railgun has a limited amount of ammunition and thus can only fire a few salvos.

 

The spacecraft has a range from Earth to Mars.

Here I expose (yet again) that I'm a "top-down" sort when it comes to game-world design.

 

What acceleration do you expect the engine to be able to develop? Alternately, what are the mass of the ship and the thrust of the engine? For reference, the Shuttle orbiter's maximum landing mass is 100 metric tons. I am having a hard time finding masses for lightweight reactors at the moment.

 

Do you expect the ship to be armored heavily enough to withstand autocannon fire?

 

What are the enemy, and how are they armed, armored, and powered?

 

What do you expect the endurance of the ship to be, and where does it get restocked?

 

Sorry, all those things shape your game-world, obviously, and others obviously go about their game-world creation very differently.

[IndianaJoe3]

Re: Hard sci-fi adventures?

 

I've also been thinking up an early military spacecraft design. How does this sound?

 

The spacecraft will be slightly larger than the space shuttle. It will have a maximum crew of ten. The crew will have to strap themselves in their seats while moving. The seats are always facing forward, so they'll feel the acceleration pressing against them.

 

Too small. The shuttle can carry 8, and it can only stay up for a couple of weeks. Something the size of Skylab seems better for the habitable section, with the engineering being separate.

 

The engine will be a fission-powered VASIMR drive. The main engine will be aft, but there will be smaller thrusters along the other sides of the ship, including "top" and "bottom" to aid in course correction.

 

The crew will be composed of a pilot/commander, co-pilot/XO, engineer, navigator, radioman/electronic warfare officer, and 2-3 gunners. A doctor may or may not be on board.

 

The spacecraft is armed with two missiles, a railgun, and four autocannons. The railgun is stationary and pointed forward, while the autocannons can swivel 180 degrees in the "up-down" and "sideways" axes. The missiles are also launched forward, but they can be guided by a gunner. The main engine is used to counter the change in momentum caused when the missiles and railgun are fired, while the thrusters are used to counter the change in momentum caused when the autocannons are fired. The railgun has a limited amount of ammunition and thus can only fire a few salvos.

 

The spacecraft has a range from Earth to Mars.

I'd ditch the railgun. It's only effective at extremely short ranges or against a non-maneuvering target. Missiles (nuclear warheads?) would be much more effective. The autocannons might be useful for point defense if they don't mass too much, but I'd rather take more missiles if I could.

 

I don't think that the weapons officers ("gunners") would be guiding the missiles, only picking their target and launching them. Also, you don't need to worry about the recoil from the missiles.

 

By the way, what sort of mission is this ship designed for?

[Nyrath]

Re: Hard sci-fi adventures?

 

Warning: Geek-talk starting...

 

What acceleration do you expect the engine to be able to develop? Alternately' date=' what are the mass of the ship and the thrust of the engine? For reference, the Shuttle orbiter's maximum landing mass is 100 metric tons. I am having a hard time finding masses for lightweight reactors at the moment.[/quote']

A VASIMR in "low gear" (i.e., increase the thrust at the expense of the specific impulse) will produce a (pretty wimpy) 400 Newtons of thrust per engine with a specific impulse of 2,300 seconds. In "high gear" (low thrust + high specific impulse) it produces a (even more wimpy) 40 Newtons per engine with a specific impulse of 30,000 seconds.

 

Low thrust is only a concern in two situations: take-off/landing and dodging during combat. Which means that the VASIMR is great for interplanetary exploration but lousy for combat. Perhaps some auxiliary chemical rockets can be added for combat (by comparison the Space Shuttle's chemical rocket main engine cluster produces a thrust of a whopping 7,000,000 Newtons with an abysmal specific impulse of 440 seconds).

 

For an advanced nuclear power plant, figure about 0.493 kilograms per kilowatt produced. One VASIMR engine requires about 10 megawatts which is 10,000 kilowatts. This would make the power plant about 5 metric tons.

 

What do you expect the endurance of the ship to be' date=' and where does it get restocked?[/quote']

If the ship has a closed ecological life support system, in theory the crew will have food and oxygen forever. In practice the system will probably not be 100% efficient, and the crew will revolt if fed a diet of green slime algae for months. In that case, figure on 2.3 kilogram of food per person per day (i.e., with 10 people, it will be 23 kilos per day).

 

If you want a spartan habitable area, figure on ten cubic meters per person. This is incredibly cramped. A more reasonable allowance is 17 to 20 cubic meters per person. So 10 people x 20 m^3 = 200 cubic meters. This could be a cylinder 7 meters long by 3 meters in radius.

 

However, having said all that, this is probably more geeky detail than your average Star Hero campaign needs.

[ajackson]

Re: Hard sci-fi adventures?

 

In that case' date=' figure on 2.3 kilogram of food per person per day[/quote']

Well, assuming nothing is produced on-board and you don't use much dehydrated food. Dry weight is around 400-500g/day, and you can save a considerable amount of wet weight by sending dry foods (including grains -- uncooked rice, for example), plus save both some wet and some dry by using hydroponics or aquaponics.

[tkdguy]

Re: Hard sci-fi adventures?

 

Not bad. There should be an officer who also has to maintain the hydroponic farm in life support and/or the life support system.

 

Just be sure you have enough crew so the ship can be adequately manned while some of the crew is sleeping.

 

A real-world VASIMR could do Earth-Mars in about a month, but you can adjust that a bit up or down depending upon your campaign.

 

Keep in mind that while under thrust "forwards" will seem like "up", that is, the direction the exhaust is traveling is the direction of "down".

 

I figure about a month of travel would be good for Earth to Mars travel for an early system. I like the hydroponic farm idea. I'll incorporate the idea. Thanks. I'll need a backup crew as well.

 

As for the forward direction being up when accelerating, that's why I made all the seats face forward. The seats would probably be more like sofas, so the crew can recline (one of the ideas I borrowed from your website. )

 

Here I expose (yet again) that I'm a "top-down" sort when it comes to game-world design.

 

What acceleration do you expect the engine to be able to develop? Alternately, what are the mass of the ship and the thrust of the engine? For reference, the Shuttle orbiter's maximum landing mass is 100 metric tons. I am having a hard time finding masses for lightweight reactors at the moment.

 

Do you expect the ship to be armored heavily enough to withstand autocannon fire?

 

What are the enemy, and how are they armed, armored, and powered?

 

What do you expect the endurance of the ship to be, and where does it get restocked?

 

Sorry, all those things shape your game-world, obviously, and others obviously go about their game-world creation very differently.

 

No need to apologize. I'm a top-down designer myself, so those questions are quite useful to me.

 

I'll have to put in a few details. This was sort of a "back-of-the-envelope calculation" type of design since I just brainstormed and added it lately. I loosely based it on the Flying Fortress, hence the ship's crew are similar to those of the B-17.

 

It will have some armor, but it will depend more on the point defenses.

 

There are habitats on the Moon, the Lagrange Points L4 and L5, and Mars where they can resupply. The Moon is international territory, but several countries have staked claims on various areas on Mars, L4 and L5. Since politics is similar to the cold war, there would be several power blocs that aren't on the best of terms.

 

Too small. The shuttle can carry 8, and it can only stay up for a couple of weeks. Something the size of Skylab seems better for the habitable section, with the engineering being separate.

 

I'd ditch the railgun. It's only effective at extremely short ranges or against a non-maneuvering target. Missiles (nuclear warheads?) would be much more effective. The autocannons might be useful for point defense if they don't mass too much, but I'd rather take more missiles if I could.

 

I don't think that the weapons officers ("gunners") would be guiding the missiles, only picking their target and launching them. Also, you don't need to worry about the recoil from the missiles.

 

By the way, what sort of mission is this ship designed for?

 

Okay, I'll make it bigger. The railgun is actually the "main gun" in the warships in my campaign. I started a thread about rail guns. The problems with the range were discussed there too. But I'm glad I don't need to worry about recoil from the missiles. The spacecraft would be used for patrol and escort and if necessary, combat.

 

Warning: Geek-talk starting...

 

 

A VASIMR in "low gear" (i.e., increase the thrust at the expense of the specific impulse) will produce a (pretty wimpy) 400 Newtons of thrust per engine with a specific impulse of 2,300 seconds. In "high gear" (low thrust + high specific impulse) it produces a (even more wimpy) 40 Newtons per engine with a specific impulse of 30,000 seconds.

 

Low thrust is only a concern in two situations: take-off/landing and dodging during combat. Which means that the VASIMR is great for interplanetary exploration but lousy for combat. Perhaps some auxiliary chemical rockets can be added for combat (by comparison the Space Shuttle's chemical rocket main engine cluster produces a thrust of a whopping 7,000,000 Newtons with an abysmal specific impulse of 440 seconds).

 

For an advanced nuclear power plant, figure about 0.493 kilograms per kilowatt produced. One VASIMR engine requires about 10 megawatts which is 10,000 kilowatts. This would make the power plant about 5 metric tons.

 

 

If the ship has a closed ecological life support system, in theory the crew will have food and oxygen forever. In practice the system will probably not be 100% efficient, and the crew will revolt if fed a diet of green slime algae for months. In that case, figure on 2.3 kilogram of food per person per day (i.e., with 10 people, it will be 23 kilos per day).

 

If you want a spartan habitable area, figure on ten cubic meters per person. This is incredibly cramped. A more reasonable allowance is 17 to 20 cubic meters per person. So 10 people x 20 m^3 = 200 cubic meters. This could be a cylinder 7 meters long by 3 meters in radius.

 

However, having said all that, this is probably more geeky detail than your average Star Hero campaign needs.

 

I can use all that, and probably will! Keep in mind this will be a prototype ship and will be considered antiquated in the campaign. The ships in the campaign will be fusion-powered, with a gas core reactor rocket engine. Still, perhaps nations that are not world powers may use this design.

 

Thanks for the input on the ship. Perhaps I should link my original thread to give you guys a better picture of the campaign.

 

Edit: Here it is. Please post your ideas on this thread, so we don't have to resort to thread necromancy.

[tkdguy]

Re: Hard sci-fi adventures?

 

If you are inside a spacecraft' date=' shaped charges will damage the hearing of everybody without earplugs. They are hard on the ears in the best case, the interior of a metal spacecraft is going to be an echo chamber that will magnify the damage.[/quote']

I was thinking of this comment today and had the wild thought about the heroes deafening the terrorists using just earplugs and a starter pistol.

[tkdguy]

Re: Hard sci-fi adventures?

 

Return to Hellas Planitia

 

Hellas Colony, located on Hellas Planitia, was humanity's first attempt at colonizing Mars. It ultimately failed, but it paved the way to Martian colonization. The colony lies abandoned, the first Martian ghost town.

 

Now that Mars has been successfully colonized, people are thinking of reestablishing Hellas Colony. But while founding the colony was originally an international effort, those seeking to rebuild Hellas wish to claim it for their own country. And with war on the horizon, controlling that area may prove to be a strategic advantage against a hostile nation.

[tkdguy]

Re: Hard sci-fi adventures?

 

In my campaign, some of the Martian and lunar colonies will have biodomes that have radiation shielding and allow for an earthlike atmosphere to exist inside. I'm making the assumption that these domes are built to withstand meteorites, so a bullet fired from a gun shouldn't even make a dent. A railgun salvo from a spacecraft would still damage it, however. Does that seem reasonable?

 

Note that firearms are not allowed in the Moon by international treaty, but no such agreement exists on Mars. In fact, several colonies have military contingents.

[ajackson]

Re: Hard sci-fi adventures?

 

In my campaign' date=' some of the Martian and lunar colonies will have biodomes that have radiation shielding and allow for an earthlike atmosphere to exist inside. I'm making the assumption that these domes are built to withstand meteorites, so a bullet fired from a gun shouldn't even make a dent. A railgun salvo from a spacecraft would still damage it, however. Does that seem reasonable?[/quote']

Well, effective cosmic ray shielding on the moon would be 2-3 meters of lunar soil (probably turned into a concrete-type material), so yeah, small arms won't do much of interest, but heavy weapons will.

[Nyrath]

Re: Hard sci-fi adventures?

 

In my campaign' date=' some of the Martian and lunar colonies will have biodomes that have radiation shielding and allow for an earthlike atmosphere to exist inside. I'm making the assumption that these domes are built to withstand meteorites, so a bullet fired from a gun shouldn't even make a dent. A railgun salvo from a spacecraft would still damage it, however. Does that seem reasonable?[/quote']

Even if your gun could puncture the dome, at the rate air would exit the hole, you'd have about a week's worth of time before the air pressure dropped to dangerous levels.

 

Naturally a railgun salvo is a bit different.

[ajackson]

Re: Hard sci-fi adventures?

 

Actually, a likely done thickness is one where the weight compensates for air pressure, which results in a mass density of up to about 28 tons/square meter on Mars and 60+ on the Moon.

[tkdguy]

Re: Hard sci-fi adventures?

 

I thought of a new one just this morning. It's a one-shot crossover with the horror genre.

 

Supply ships en route to a lunar or Martian colony were lost, and the colonists were in danger of starving. The PCs are part of the relief effort.

 

They find that some of the colonists have survived, although many perished. The colonists are acting as if they have something to hide. If the PCs investigate, they find out the survivors turned to cannibalism in order to survive. Some of them have grown to like the taste of human flesh, and all of them are determined to keep their secret.

 

The PCs had better watch their backs before they end up on the dinner table!

 

Variant: A couple of the supply ships actually did make it to the colony. The crews were killed and eaten, and the ships scrapped and recycled. The PCs may find some of the remains of the ship that survived. They may find a journal of a doomed crewman and discover the truth that way.

But if the PCs include a doctor or laboratory technician, perhaps the PCs will discover the truth when the doctor/lab tech finds traces of digested human flesh in the colonists' stool samples.

 

[Nyrath]

Re: Hard sci-fi adventures?

 

Variant: A couple of the supply ships actually did make it to the colony. The crews were killed and eaten' date=' and the ships scrapped and recycled. The PCs may find some of the remains of the ship that survived. They may find a journal of a doomed crewman and discover the truth that way.

But if the PCs include a doctor or laboratory technician, perhaps the PCs will discover the truth when the doctor/lab tech finds traces of digested human flesh in the colonists' stool samples.

[/quote']

A doctor can also suspect something if many of the survivors suffer from Creutzfeld Jacob disease or kuru. These generally can only be spread by cannibalism.

[tkdguy]

Re: Hard sci-fi adventures?

 

That's a good one! Thanks, Nyrath!

[DusterBoy]

Re: Hard sci-fi adventures?

 

Biotech can create horrors, too. . .

 

Transhuman Space: Orbital Decay:

Vandegrift Station, a top-secret orbital research lab, has suddenly stopped all transmissions. Why has the station gone silent? Where did all the researchers go?

 

What's that clawing at the airlock?

 

Clue: it's not Lassie.

[tkdguy]

Re: Hard sci-fi adventures?

 

Good idea, DusterBoy!

 

I got this idea from watching the "Space Wars" episode on The Universe tonight. It speculated a rogue lunar colony attacking nearby colonies.

 

In my campaign, all colonies on the Moon are international, with no one nation having sole control in any of them. That was agreed upon by the UN. That would make the Moon neutral territory once the war begins. That would bring about a couple of scenarios:

 

1. The war would bring in droves of refugees attempting to escape the destruction. How will the lunar colonies be able to cope? Will they have to turn away refugees?

 

2. What if some nation somehow gains military control of one of the colonies? Will the military imprison colonists who are citizens of a hostile power? And if the colony has a mass driver or spaceport, would the military use it to fire projectiles at a hostile power on Earth?