The Chemical Rocket Third Imperium

[mike wightman]

They you'll get even closer to 2300 AD setting, where this is exactly what happens (most ships are powered by MHD plants there) .

The big ones all use fusion, as do the current military ships.

Remove the fusion plants from the Star Cruiser ship building tables and you can still build quite capable ships.

(There's an interview with Frank Chadwick where he states that GDW very nearly went with stutterwarp for the OTU when redesigning Traveller post MT/pre TNE).

 

[atpollard]

We can make and trap antimatter now.

In 2 TLs time a mature space industrial society could easily build the facilities for the mass production of antimatter.

Would it be for anything other than a warhead? How small could it become? Will I have AM batteries for my HandComp?

I guess my question is really what purpose does it serve, because as an Uber-Tech, it is every bit as pervasive as Gravity control was. It eliminates all fuel storage by converting EVERYTHING to an AM Battery powered device that may NEVER need charging in your lifetime. The ship is fueled up with AM when it is launched and is good to go for 40 years.

 

[mike wightman]

Let's run some numbers through a B.O.T.E. calculation and see what we get. Any idea on the mass and power output of a complete Fission Reactor?

I just look it all up at Atomic Rockets...

 

[McPerth]

One thing Thot gave a nod to was that Reaction Drive ships (absent some replacement handwave like HEPLAR as presented in TNE) will be FRAGILE craft, not the heavy armored gunships of the OTU. Mass REALLY is your enemy when 80-90% of a ship (by MASS) is going to be LH2 ... which is where the deep space, long endurance high ISP drives are going to lead you.

See that, by mass, fuel will be 8/9^ths liquid oxygen and 1/9^th liquid hydrogen (by volumen, oxygen wil lbe only 1/3^rd, though I guess this does not affect your main point here...

It just seems a radical departure from the Traveller TL timeline and a huge leap forward for a civilization that can't even control gravity. :rofl:

More than making Particle Acceleratior turrets TL8 in MgT1E, when they were TL14 in CT/MT?

The big ones all use fusion, as do the current military ships.

Remove the fusion plants from the Star Cruiser ship building tables and you can still build quite capable ships.

In 2300AD setting, most spaceships use MHD, some medium sized ones, fission, and really big ones fusin plants. That's why I thought your question about meking fusión plants too large to fit in anything but the largest ships will make it closer to 2300AD setting...

 

[mike wightman]

Would it be for anything other than a warhead? How small could it become? Will I have AM batteries for my HandComp?

I guess my question is really what purpose does it serve, because as an Uber-Tech, it is every bit as pervasive as Gravity control was. It eliminates all fuel storage by converting EVERYTHING to an AM Battery powered device that may NEVER need charging in your lifetime. The ship is fueled up with AM when it is launched and is good to go for 40 years.

Lol, I'm not talking CT antimatter batteries here - the real world numbers mean the containment and handling of antimatter make it useful for big ships only.

Antimatter is a way of storing energy, and can be used for really powerful ship engines.

 

[atpollard]

Just in case anyone was interested, here is some data on NTR vs LH2/LOX rocket performance from Selenian Boondocks

 

[Brandon C]

I think it could be argued that the reason antimatter plants don't appear at normal Traveller tech levels is because they are not financially competitive with cheap fusion plants. With such fusion plants not existing, I think it is reasonable to argue that expensive and bulky antimatter plants will appear earlier than listed on the Traveller tech tree.

 

[atpollard]

I think it could be argued that the reason antimatter plants don't appear at normal Traveller tech levels is because they are not financially competitive with cheap fusion plants. With such fusion plants not existing, I think it is reasonable to argue that expensive and bulky antimatter plants will appear earlier than listed on the Traveller tech tree.

The energy density of Anti-matter storage will effectively yield power supplies that never need refueling, will it not? One ton (metric or displacement) of antimatter is a whole lot of energy at total matter to energy conversion. That makes the size of the containment unit a fixed mass/volume with virtually infinite energy capacity.

My point is that eliminating the need for power plants to refuel will have a profound impact on a lot of things. For example, why not refuel with a small box of rocks and annihilate the matter with antimatter to expel a pure energy thrust at the speed of light? Or if you need more thrust and less velocity, just add more rocks and increase the ratio of plasma to photons (higher thrust, lower ISP). A scoop on the front might collect dust from space to supply the 'rocks' (Bussard Ramjet style).

 

[mike wightman]

Yup, a couple of Traveller's magitech assumptions are grav tech and fusion power plants that fit in a car.

The first hard sci-fi assumption was to get rid of grav tech, I am now suggesting fusion power, if it can ever be made to work, will require power stations the size of shopping malls.

Antimatter is something we can make, it is even used on a daily basis in medical applications. For my variant tech tree I am assuming in 2 TLs time we will be able to ramp up production using solar energy on stations that orbit the sun.

Antimatter/matter catalysed fusion then becomes a possibility, as do matter/antimatter engines/rockets.

By the way the amount of antimatter being produced by a factory is around about 0.001kg per day.

I've assumed for a while now that Traveller's standard TL16+ antimatter entry produces it by the ton by some clever manipulation of fundamental particle/field interactions (damper tech - strong force; meson tech - possible weak force; fundamental property manipulation)

 

[Xerxeskingofking]

one option not discussed yet as an alternative to pure Lhyd/LOX rockets is the nuclear thermal rocket design, which promises to offer about twice the speicifc impulse of Lhyd/LOX engines. in an earth to orbit context it works better as a upper stage of a staged launch system, but it might have room for application inside this no grav traveller.


another question that would need to be addressed is why would we move away form the existing staged launch system paradigm? theirs no point keeping the engines needed to move a thousand tons of mass if 900 tons of mass are used up by the time you get to orbit. you can ditch the now overlarge engines and empty fuel tanks and just have a smaller orbital engine to pootle around in orbit with.

 

[McPerth]

The energy density of Anti-matter storage will effectively yield power supplies that never need refueling, will it not? One ton (metric or displacement) of antimatter is a whole lot of energy at total matter to energy conversion. That makes the size of the containment unit a fixed mass/volume with virtually infinite energy capacity.

And what would be the effect of a hit in such a ton of fuel? I guess any charactr in the ship will begin CharGen again...

 

[atpollard]

And what would be the effect of a hit in such a ton of fuel? I guess any charactr in the ship will begin CharGen again...

What happens if you hit the LH2/LOX tanks in something like the Saturn V or the Shuttle External Tank ... While the explosion will be less impressive and there will be a debris cloud left to find, I think Chargen is still a foregone conclusion. Starship combat becomes a lot more like FGMP combat ... don't get hit. Which is how missile combat between Jet Fighters works today.

 

[Xerxeskingofking]

And what would be the effect of a hit in such a ton of fuel? I guess any charactr in the ship will begin CharGen again...

a (roughly) 40 kilotons of energy released per kilo of antimatter.......quite impressive, to say the least.


A lot of that 40 Kt would be "lost" into neutrinos and such, but still.....Big Bada Boom.

 

[McPerth]

What happens if you hit the LH2/LOX tanks in something like the Saturn V or the Shuttle External Tank ... While the explosion will be less impressive and there will be a debris cloud left to find, I think Chargen is still a foregone conclusion. Starship combat becomes a lot more like FGMP combat ... don't get hit. Which is how missile combat between Jet Fighters works today.

Agreed, and with the limited (either in Gs or in time) maneuverability the chemical rockets can give ot your ships, I guess avoiding being hit is not easy. So, combats wil lbe something to avoid, as they sure are quite deadly...

 

[aramis]

We can make and trap antimatter now.

In 2 TLs time a mature space industrial society could easily build the facilities for the mass production of antimatter.

Assumes several facts not in evidence -
1) the change from the current trap modality to a viable bottle modality for storage
2) adequate energy capture from M-AM annihilation (Which is exactly the same issue that makes fusion power not current TL8...)
3) Adequate transition from storage to use

#2 makes AM pretty much worthless... as fusion is currently at 99.5% recapture in labs (last I checked, a couple months back)... If you can capture more of the AM energy, you can capture more of the fusion, and suddenly fusion is practical.

#1 is a huge issue - current trap methods don't actually hold much, aren't viable for transfer, and so whether we're at TL-2 or TL-7 for practical AM handling is arguable.

#3 is tightly integrated with #1; if we can put them into the storage bottle, getting them back out is evolutionary, not revolutionary.

Fusion is FAR more likely than AM to be a viable power source for use.

 

[aramis]

a (roughly) 40 kilotons of energy released per kilo of antimatter.......quite impressive, to say the least.


A lot of that 40 Kt would be "lost" into neutrinos and such, but still.....Big Bada Boom.

Capture rates are (currently) unlikely to exceed 0.1%...

 

[atpollard]

If the goal is really a VERY hard science ATU, then all of the exotic technologies like Anti-matter and Fusion should be taken off the table. That seemed to be the original goal of what is the minimum 'handwavium' necessary (or can we build a TL 7-8 Imperium of some sort with only a FTL handwave?)

Real rocket scientists crunch the numbers and say that even NTR is within spitting distance of just being equal to Hydrolox, so you can use a Fission NTR if you want, but it isn't even needed.

Personally, transit times between planets measured in months sounds boring, but that is what Hard Science yields. So if that's what you want, then really embrace the existing and near future technology and run with it. Multi-stage rockets. Transfer orbits. Fuel depots. Solar Power Satellites. O'Niel Habitats. Cis-lunar tugs. Minimum DeltaV orbits for Cargo. Lunar Beanpole. Aerobraking. I mean, there is a lot of stuff to work with.

 

[mike wightman]

Personally, transit times between planets measured in months sounds boring, but that is what Hard Science yields. So if that's what you want, then really embrace the existing and near future technology and run with it. Multi-stage rockets. Transfer orbits. Fuel depots. Solar Power Satellites. O'Niel Habitats. Cis-lunar tugs. Minimum DeltaV orbits for Cargo. Lunar Beanpole. Aerobraking. I mean, there is a lot of stuff to work with.

Ok - so we limit ourselves to current TL7 (fusion, personal laser weapons and air/rafts are TL8).
Spaceplanes and reusable rockets to get to orbit.
LEO stations for transit/refuel to higher orbits.
GEO stations
Lagrange stations
O'Neil habitats
Moon base
Mars base
Solar powered ion drive spacecraft
Nuclear engines for military craft
Vehicle scale lasers, railguns, missiles, hypervelocity CPR

Jump drive reduces transit times around the solar system (this is what the Terrans did with it in the OTU initially).

Then we figure out how to make intersteller jumps...

 

[aramis]

Personally, transit times between planets measured in months sounds boring, but that is what Hard Science yields.

Except it's not truth.

We can, presently, build high delta-V orbit-to-orbit ships capable of Mars in a few (3-4) weeks with payloads in the 20 ton range, and venus in 2-3 weeks. O.01G, fission powered high-end ion thrusters.

Problems:
1 - they violate the Space Treaty. No Fission reactors allowed.
2 - they are orbit-to-orbit ONLY, as they're essentially sheets of ion thrusters with a crew/cargo capsue.
3 - It's still weeks (but at least it's not months)

Let's look at closest approach: 75.3e9 m 37.75e9 per half, and 1/100 G
D=0.5AT²
37.75e9=0.5•0.1T²
20*37.75e9=20*0.5*0.1t²
7.75e11=t²
880340=t
244.5 hours to midpoint
2.9 weeks orbit to orbit

NTRs are known tech, and quite workable, too - higher G, lower delta-V, but still well above H2/O2 rockets

 

[mike wightman]

You wouldn't need the nuclear plant for such a vessel, just a lot of solar panels. No treaty violation, but very expansive in terms of missions to get the panels into orbit and then the expense of assembly - astronaut time doesn't come cheap either.