A bigger NERVA

[Kuu Lightwing]

Current NERVA is fine, but it's a bit too small. For any interplanetary craft of decent size I need to add quite a number of them. For example my Endurance interplanetary ships used six:

While this is something I took advantage from (there's a docking port at the back which I used for lander attachment), I feel like NERVA is something that you shouldn't need more than one or two. In fact most of the real life NERVA concepts used one engine per stage. And with 60 kN of thrust like it's in the game, we basically have to spam NERVAs all over the ship to go places, unless it's a small ship like this:

So, I suggest to either make the current NERVA heavier and more powerful, or add one more NTR which is bigger. Or maybe even other kind of NTR - liquid core or gas core engine, but that realistically should have more ISP and I'm not sure the game needs something like that.

[Grumman]

Making the current nuclear rocket heavier would obviously be bad, since it would break people's existing designs. Adding a bigger nuclear rocket is a good idea, though.

[Kuu Lightwing]

Ugh, 1.0 broke a lot of designs, and I would happily rebuild my rockets if atomic rocket changes.

[yorshee]

The Atomic Age pack contains a 2.5m NERVA engine, but I agree that a larger NERVA should be made stock.

[CaptainTurbomuffin]

I see your point, bigger nukes are necessary. But wouldn't they be overpowered? At least, they should be have performance than 1m nukes. Using the large one is comfortable, using many small ones is more efficient. Just like with other rockets. In career mode, I never use 2 or 3 m propulsion. Using lots of 1 m parts is a lot more efficient.

[r4pt0r]

What about a 2.5m nuke with the thrust of 3 nervas, but the weight of 3.25 of them? Never been a fan of bigger versions just being upscaled stats wise, I like them to be a bit different.

[Frozen_Heart]

I've seen a few mods that have 2.5m nervas. Really want to see it in the stock game though.

What about a 2.5m nuke with the thrust of 3 nervas, but the weight of 3.25 of them? Never been a fan of bigger versions just being upscaled stats wise, I like them to be a bit different.

If that was the case it would be better to use 3 normal LV-Ns.

[r4pt0r]

I've seen a few mods that have 2.5m nervas. Really want to see it in the stock game though.

If that was the case it would be better to use 3 normal LV-Ns.

not if the ISP was also different

Whatever, I just like more creativity in the parts, not just the same thing but bigger as I said.

Perhaps the bigger one might heat up slower, so really weight could be saved in the form of less radiators, if you designed it like so and cared about that efficiency stuff??

Edited July 27, 2015 by r4pt0r

[Jouni]

Since 1.0, large engines have been simply better than similar small engines. A 2.5 m nuclear engine could have the thrust of four 1.25 m engines for the mass of three, as well as slightly higher Isp.

[Kuu Lightwing]

The Atomic Age pack contains a 2.5m NERVA engine, but I agree that a larger NERVA should be made stock.

Atomic age is a mod by PorkJet, right? I read the description, but it doesn't say about a bigger NERVA, just nuclear lightbulb, which is an NTR, but a gas-core one. And it has pretty darn good ISP. Still, the mod looks pretty hot, but it's a mod after all.

What about a 2.5m nuke with the thrust of 3 nervas, but the weight of 3.25 of them? Never been a fan of bigger versions just being upscaled stats wise, I like them to be a bit different.

Well, I didn't mean flatly upscaling the current one, I just want an engine that I can use instead of spamming lots of current ones. 3x thurst is still a bit too low I think. Real life NERVA concept had 333kN of thrust, and the thing is, we don't KSP version to be much weaker, because long burns are quite tedious.

[yorshee]

Atomic age is a mod by PorkJet, right? I read the description, but it doesn't say about a bigger NERVA, just nuclear lightbulb, which is an NTR, but a gas-core one. And it has pretty darn good ISP. Still, the mod looks pretty hot, but it's a mod after all.

Ah, I don't know too much about the actual inner workings of that 2.5m engine, all I know is it's a nuclear engine that's pretty big.

[TheSaint]

There are a bunch of mods that add larger nuclear engines. KSPX has a 2.5m one that is stockalike. So does Modular Rocket Systems. Taurus HCV has a 3.75m version. Atomic Age has already been mentioned. I know there are others, these are just the ones that come to mind. But, yeah, we do need one in stock.

[CaptainTurbomuffin]

But increasing the thrust of1m nukes could also be a solution. Once their TWR was lowered by increasing their mass and lowering their thrust. The 'worst' was that they started to consume only LF, making NERVA-powered rockets carry more than half-empty fuel tanks (but also making them realistic). Instead of lowering their thrust, I think something should be done like removing gimbal, power generation, and limiting its usage. For example, you can run them for <balanced value here> minutes only, before their reactor core is depleted. After that, you have to recover them. 2m version: less effective than 1m versions, just like with any other engines, but having extras like gimbal and power gen, and longer life?

Having a right-click option for each fuel tank, to carry either LFO, LF, or nothing(structural) would also be nice.

[Windspren]

What about a 2.5m nuke with the thrust of 3 nervas, but the weight of 3.25 of them? Never been a fan of bigger versions just being upscaled stats wise, I like them to be a bit different.

That is also unrealistic. The large weight of the LV-N comes from the reactor, and it's insulation. It would actually have to weigh less, because you would only need one reactor instead of 3. You wouldn't need 3 seperate reactors or 3 sets of radiation insulating material.

[CaptainTurbomuffin]

That is also unrealistic. The large weight of the LV-N comes from the reactor, and it's insulation. It would actually have to weigh less, because you would only need one reactor instead of 3. You wouldn't need 3 seperate reactors or 3 sets of radiation insulating material.

Being realistic is not a point in KSP. We need a balanced one.

[Red Iron Crown]

A larger nuclear engine should be slightly better than a straight multiple of the LV-N, seeing as the larger chemical engines are for the most part strictly better than smaller ones. Have it appear later in the tech tree and be a bit more costly per unit of thrust for balancing.

[clivman]

That is also unrealistic. The large weight of the LV-N comes from the reactor, and it's insulation. It would actually have to weigh less, because you would only need one reactor instead of 3. You wouldn't need 3 seperate reactors or 3 sets of radiation insulating material.

Thrust scales linearly. So it would have less TWR. What we need is a stock nuke cluster for 2.5m

[Kuu Lightwing]

Being realistic is not a point in KSP. We need a balanced one.

Making a bigger engine worse than several small ones doesn't make it balanced. In fact it defeats the whole purpose of adding it in the first place. While it would serve a purpose of reducing the part count and maybe would have better aesthetics, the game would encourage you using a bunch of smaller engines which is not counter-intuitive.