Non-Nuclear Interplanetary

[whiterafter]

For quite a long time, I always used nuclear rockets to go interplanetary, it was just the way I did it, no matter whether it was one way or round trip.

Recently due to science affordability concerns I decided to use three light LVT-45s for my one-way transfer to Duna. It went fantastically and now I am wondering why I ever spent 30 minutes on nuclear rockets..

Does anyone have a similar experience?

[bigyihsuan]

I don't really use Nukes, but I only use it for the deltaV.

Otherwise, I just use regular chemical ones for the TWR.

[TokiTech]

After a comparison on the paper, 3 nuclear is not even close to a single LV-T45 on output and efficiency but more of a burden, over 7t vs single LV-T45 1.5t.

[LethalDose]

For quite a long time, I always used nuclear rockets to go interplanetary, it was just the way I did it, no matter whether it was one way or round trip.

I think a lot of players are like this. They just nukes because they always used nukes. It's good to look around and ask "why" sometimes though, because that's when you can learn something.

I agree with the others said: For most transfer stages, efficient chemical rockets are all you need. Nukes are nice for reusable tugs, but for lots of other IP transfers, you really don't need them. I especially like LV909s, Poodles, and that KR-2L.

[Rolanvorxariat]

KR-L2 and LV-45 for interplanetary transfers, NERVA's or KWR Vesta VR-1's if it is going to return (Sample Return probes, Kermanned missions)

[RobertR]

I use lv909 and poodle engines for most things that return to kerbin. I'll use nukes for tugs that remain in space like another poster mentioned. I just don't like the length and weight of them. Also the painfully long transfer burns.

[KevinW42]

For most purposes, the 48-7S is actually the most efficient chemical engine. The Vacuum Isp isn't exactly stellar, but their low weight and high TWR more than makes up for it. Of course, the LV-909 should also suffice if you want to avoid absurd parts counts.

[panzer1b]

Im a die-hard nuke user, since well it is the ONLY engine thats viable on a long range SSTO.

But for most rockets, unless you need over 10000 dV, nukes are more of a bother, and are actually very bad on small craft where the nuke can take up say 1/3 of the total mass. For rockets, the most common engines i use are the KR-2Ls (yeah we all know they are overpowered, great TWR and above average ISP). Also, outside of using part clipping (say moving engine body internally), nukes are in my opinion rather terrible looking. They are also unwieldy, and you will oftebn have trouble landing a nuke craft (either due to low TWR, or due to the long engine, provided you do not clip it internally).

Nukes are the best interplanetary engine for most craft (until larger more powerful ions come out), but they are far from the best if you are looking for a specific relatively short range vehicle

[Captain Sierra]

There is both a minimum dV and payload mass requirement for nukes to be practical. Its not huge, but anything to Duna (and arguably Eve) and probes to anywhere don't meet this and thus nukes are mathematically inferior in such a role. There's also plenty of middle ground where nukes are mathematically superior in terms of dV provided, but other variables play in to make the choice less clear cut. Small to mid sized payloads (<40t) to Jool are a good example. Economically, the extra fuel cost of using a chemical engine is equal to or lesser than the extra cost of using a nuclear engine. On larger vehicles, such as a tug hauling an entire station out to Jool, nukes become progressively better options as the payload mass goes up. That said, at such massive scales, the cost increases by using nukes are going to be rather small considering the massive budget you have to be sitting on to make such a thing happen to begin with.

[Hodo]

If you build correctly you can use Aerospikes or other high ISP non-nuke engines to do the job. I rather like using the Aerospikes.

[magnemoe]

For most purposes, the 48-7S is actually the most efficient chemical engine. The Vacuum Isp isn't exactly stellar, but their low weight and high TWR more than makes up for it. Of course, the LV-909 should also suffice if you want to avoid absurd parts counts.

For probes its only the 48-7S, if you only need 500 dV or something the ant can work not else.

48-7S is best up to stuff like an one man landing can on minus. If you want to haul 2 ton or one ton to Mun the 909 is better.

Nukes win if you use larger ships, say an hitchhiker module, Duna and Ike landers with goo and lab.

[NecroBones]

Yeah, I used to use nukes for everything. And they're still great for long-duration, multiple-destination trips. But I finally reached a point a while back where I wanted to use KR-2Ls instead. Short burns, FTW!

[Ravenchant]

I only use them for heavy cargo and crew transfers (let's say, >50 tons) to planets beyond Eve or Duna. LV-T30s or 45s work well enough for those two

[cantab]

I've tended to go with the nuclear engines to good effect. But chemical engines can be competitive. The KR-2L is a great pick for the really huge stuff.

[khyron42]

I tend to use nukes only on ships where the payload mass or dV is huge. Sending a space station (cupola + hitchhiker can + science lab + 3m docking hub) interplanetary to anywhere? nukes, to limit the amount of fuel I have to attach to that beast. Sending a probe down into a 100 km circular orbit around the sun? Nuke followed by ion engines. Generally speaking, mostly large manned missions. Small manned interplanetary missions or probes can use anything - I'll sometimes use nukes on probes just for the fun factor of flinging a nuclear reactor into interplanetary space, but not because it's more efficient.

[Francois424]

I use nukes ALL THE TIME. I mean, best space ISP with a reasonable burn time, so really no reason to use anything else, except on Tylo, Eve and Laythe. I try to keep the part count below 400 as much as I can nowadays, since I hate lag and my system handles well until 400. Well, having to lug around 30 tanks of fuel for a Mainsail or whatnot is not really interesting. Now if there was a 600 thrust / 600 isp engine, now I might use that instead of nukes for most missions.

( I also use a lot of Ions, but not thinking of Ions for a Jool-5 mothership of 300 tons, because of tiny fuel tanks and tiny thrust. I seriously wish for stock 1.25m Ion engines and big tanks to accompany that. That 4200 isp is awesome right now for small satellites and fly-by probes )

Until something better from stocks comes along, nukes all the way (in space)

[merendel]

Personaly I rarely use nukes on one off craft. If its just going to a target and back and going to be disposed of after it will often be a normal chemical rocket apropreate for the mission. However I do make heavy use of nukes for my space tugs that handle heavy transfers. Need to drag a couple orange tanks out to jool? I send them up into LKO and dock it with one of my tugs and it drags it out there and returns. I usualy have a couple variants with more or less engiens depending on the mass its expected to handle. The ones with more engiens tend to have a larger fuel tank to make up for engien mass on the return leg and those are only used for the really heavy loads when I want to keep the TWR and burn times reasonable. If the tug cant handle at least 1m/s^2 of acceleration with whatever its towing I'll send something bigger to do the job, I'd use ions if I wanted the leave the game on overnight doing a burn.

[Janos1986]

Poodles or LV909s and you're golden.

[Alewx]

I made a ship with 73 Ion Engines from Stock Expansion, but it had only 0.3 TWR, but the deltaV was awesome.

If just the performance with 1000+ parts would not be so bad

[SofusRud]

Back in .24 I had a career game going, and I decided to go interplanetary. To do this I had a mothership/tug craft that pulled a lander(s) and science station to each destination. This was pretty early in the tech tree, so it was powered by a pair of LV-909s. It was pretty successful, managed a Duna-Ike mission and a trip to Gilly with ease, as well as a Dres mission that ended up as only a flyby.

[KingPhantom]

i use often a combination. the big burns with KR-2L and some small corrections with 4 to 8 radial nukes... depends on the ship

[Frank327]

LV909 and Poodle are just so versatile. Unlocking the lv909 means I build my first orbital rocket and I won't stop using them until I need to go beyond Eve/Duna. I only use nukes if it's really necessary because of the long burn times and the difficulty with landing (if used on a lander).

This was my Duna + Ike mission.

[Kowgan]

-snip-

But for most rockets, unless you need over 10000 dV, nukes are more of a bother,(...)

That's true. The problem for me is that, for some reason, it's stuck in my head that any interplanetary mission will require far more than 10,000 dV, and I need to re-check those calculations every time in a dV Map. That probably happened because I first adventured myself on an IP mission before knowing about transfer windows.

[Frozen_Heart]

I use the Skipper for most of my interplanetary trips. Then again this isn't Manned so the payload is small.

[fairytalefox]

Nukelars are good when you want to bring 30+ tonnes of payload to Jool. You have to deal with putting, like, the whole big SLS rocket to LKO, most probably with refueling, multiple dockings/undockings etc, or you can just use one carrot tank, one LV-N, MechJeb and 45 minutes long burn (2x physical warp and alt-tabbing out of KSP recommended). Boring but relatively easy.

Smaller payloads and/or easier destinations work well with conventional engines for me.