In KSP, I ended my Orion missions with about 1800 Science, enough to buy three top-tier packages. I immediately bought a seismometer and it soon paid for itself with a few sub-orbital launches around Kerbin plus a Sunday drive on my one rover around the KSC. That gave me enough extra to buy the Mainsail motor, the "gravioli detector", and the last upgrade on rocket-building parts. I immediately settled down with the Mainsail and started working on a new heavy lifter.
I was really kind of treading water and I realized it. With Enterprise out of the picture for the Duna mission, I needed to think of another practical way to get out there. After the last Apollo missions, there was an "Apollo Applications Program" whose job it was to find interesting things for the remaining Apollo hardware to do. My own space station and Enterprise aside, this is sort of where I was. Go for Duna right away, or instead build some probes atop heavy lifters and shoot for some of the outer planets?
While I thought about it, I kept playing with Mainsail-based designs. Sure, I could go out on the net and see what other people have done with KSP's largest stock engine, but so far I've been resisting looking at other people's "fits" for lifters. I find the tinkering relaxing and besides, I was a model rocket builder back in the day and I understand a good bit of the physics. Still, the Mainsail was giving me fits. Confidently, I named the lifter the Ares series. But the damn thing is incredibly powerful; it kept either threatening to tear my designs apart or just flat out doing it. I decided to scale down my ambitions somewhat.
First thing, I wanted to get three or four of the five-man crew off Enterprise -- Jeb was up there and I wanted him back. ;-) So I kept it simple: one Mainsail, eight X200-16 series fuel tanks (which I added one or two at a time until I found the right balance), and six SRBs. The resulting lifter turned to have very few parts (once I replaced the eight X200-16s with two -64s), a nice clean design, and dead simple to fly:
Mainsail to 50% power or so until SRB separation, then 67% to a 10km gravity turn, then full power. A two tank third stage finished the job of putting a mid-size space taxi up to Enterprise's 500km parking orbit. I quickly decided it was also the right size and complexity to be my new Kerbin-orbit science rocket and it did this job admirably, placing gravioli detectors accurately wherever I liked on Kerbin. I even had no trouble hitting the Badlands with a probe, something I hadn't been able to do before.
The science I was getting out of the gravioli detector made me curious: how would it work on the Mun or on Minmus? I found that my Ares lifter and the associated booster (using my old stand-by Skipper engine) was the perfect size to put a medium weight science probe down in either place with remarkable precision.
When I sent the gravioli detector to Minmus, I started noticing odd things right away. I was getting different readings off it for "high above Minmus" and "close to Minmus" for virtually all of Minmus's many biomes. Each of these readings got transmitted back and at two readings per biome, this was adding up to about 34 Science per transmission... and it was a lot of transmissions! The booster was sufficient to put the lightweight probe close to a nice soft landing, with the help of four tiny engines and an insultingly small fuel tank. The first landing (near the pole) ended with the tank basically full, so I did a second landing (at the pole), then a third (south to the Great Flats), then a fourth (west to the Midlands). At each stop, gravioli detector and seismometer readings on the ground. Ground transmissions were worth 42 Science from the grav detector and another 27 from the seismometer.
I ended that single mission with about 1000 more Science! Score!
For the record, the gravioli detector is OP. At the very least it should lock after use the way the mystery goo container does. But I'm not complaining (too much). But in the meantime, it gave me the idea I need to get to Duna. Because of the way KSP is designed, a lander can can only carry one EVA report and one surface sample. I might need multiple landers for Jool but for Duna, if I give up on the idea of getting a surface sample and EVA report from Ike, I really only need... one.
And Enterprise can push one lander in front of it, no problem at all! I could go back to my previous Athena lander series for inspiration as well. For that one, I had put a docking port on either side of a Jr Science and strung all the science instruments to that. In those missions, the lander carried one of those down, I ran all the readings, brought it back up, then docked to the command module through the Jr Science's other docking collar, then cut the lander loose. I can do the same thing at Duna and Ike, just plugging the Jr Science into four of Enterprise's long axis docking points instead of full landers. The game should let me do that no problem, and it's something I can test easily in Kerbin orbit.
So the Ares series got one more mission... designing a heavy fueler to refuel Enterprise after her Mun mission. I ended up with a very simplistic unmanned design that does only one thing: delivers about 4000 fuel and oxidizer up to 500km. Two loads were sufficient to bring Enterprise up to 85% capacity, and the vehicle that carries the Jr. Science mods or the lander should be able to supply the rest. Jeb's already back aboard. ;-)
The top, fuel tank stage of the fueler doesn't even have a main engine! I use the last stage booster to get it up to 500km, run the rendezvous to 10km or so, then cut the booster loose and ran the docking strictly on RCS thrusters. Once empty, the fueler is so light that RCS thrusters alone are sufficient to bring it back down to a reentry so for grins I fitted it up with parachutes. ;-)
I'm finding as I gain more experience in KSP, my vehicles are actually getting simpler, with fewer parts and more streamlined designs. My Freedom space station actually looks slightly primitive to me now, with batteries and solar arrays and everything else strung all over it. I may or may not replace it with a simpler, cleaner design. In the meantime, next stop, Duna!