It's a fair enough question OP. I think the simple answer is "No, it's not cheating". There are many games where use of mods is generally a little frowned upon or considered cheating, but a poke around the forums will likely convince you that this isn't one of them. Indeed, moreso than most other games, KSP is actually designed for modding. The developers have gone to quite a bit of effort to support mods. Also, as it's not finished at the moment and clearly a little simplified compared to what the final vision will be, and it's in a sandbox state with no particular goals built in, I think that the use of mods is particularly appropriate in this case. I always avoid mods initially, as I like to know what the vanilla game is like. But, mods can add an enourmous amount of flavour and depth to a game. They are also addictive (you'll start with one, and start to question yourself a bit after 20....), and will inevitably cause you some headaches, particularly when updates to the core game come out or when something unexpected happens. As other have mentioned though, mods can also ruin a game for you. My advice would be to have a good go at the vanilla game first. Then, once you're getting a little frustrated or bored, try installing a mod that will add some challenge or variety (like a parts pack, comms systems, oxygen requirements, or resource mining). Avoid the likes of MechJeb, that automate difficult tasks and make the game easier. Those mods have their place (e.g. to speed up testing of a difficult rocket design, or to give you an understanding of the general way to go about a launch procedure or landing), but if you use them too much early on you'll miss out on some of the sheer joy and sense of achievement that KSP has to offer, and that really is quite unique. The first time you achieve orbit, the first time you do a 3km flyby of the Mun, or land on another planet.... Those are moments when you sit back and feel proud of what you accomplished. A friend of mine came over for dinner and to have a look at KSP and get pointers from me for getting to the mun (my most recent achievement at the time). I had a ship fueled up and waiting in orbit, and we decided hey, Duna isn't THAT much further.... ended up staying up until 3am in the morning. We really felt like the two of us were tucked away in a dark tin can in the loneliness of deep space, making some educated guesses on burns, timing, direction etc, a million miles from home, all the while wondering if we'd just done something that would get us killed or leave us adrift in space for eternity. Eventually we made it after a very near miss with Duna's moon and barely a few drops of fuel left (Duna orbit that is, landing was a complete fiery failure), and what a sense of accomplishment in the face of adversity. You really feel like you could of been there with the astronauts on the way to the Moon. You won't get that if a mod flies you all the way there hands free.