Fearless Son

Forgive me, but I thought only Thermal Control Systems (the radiators that deploy by unfolding) cool any part of the ship? I thought that fixed radiators only cool the part their directly attached to. Or has that changed in the last couple years?

It's a visual oddity of the game, but if you really need to land in a place and there's a reasonable chance it'll be dark where you touchdown, put landing lights on your lander. At least two lights in parallel around the bottom of your lander. I find they're also helpful for seeing how close you are to the ground, since due to the square-cube nature of their projection the breadth of illumination will narrow.

"I have people coming in here every other week to propose using giant rockets to put tiny probes into orbit, and here you are telling me you plan to put an entire goddamn spaceship up there?" "We're using nuclear bombs, sir. We can put something roughly the mass of downtown Chicago into orbit." - Apocryphal conversation attributed to engineers of Project Orion in a meeting with a United States Air Force admiral.

Oh Kod, I can hear this image...

I actually love those kinds of missions. I'll sometimes wait until I have a bunch of contracts that I can do in a single mission, then run through them all at once. Doing any one of the contracts is a simple enough engineering challenge, but trying to do all of them and figuring out how to do so cost-effectively is a lot of fun.

I'm betting Kerbal's would need a "Laythe-lung" rebreather to comfortably move around there without a helmet.

Here's an example of a small spaceplane as a proof-of-concept piece I called the "Flechette": Two Whiplash engines give this thing a great acceleration force as it rises up through the atmosphere. The aerospike engine is activated before the Whiplashes flame out, and the additional thrust from it forces more of the increasingly thin air into the Whiplashes, allowing them to continue to contribute thrust longer than they would alone. The LF/O engine continues to burn throughout the parabola of the launch, and cuts out at about the time it reaches the apoapsis or shortly thereafter. It doesn't even need a separate circularization burn, the initial one is enough. It does get a little nail-bitey though since it's not clear if you have enough delta-v to make orbit right up until the point you actually make orbit. If I had a gripe with the R.A.P.I.E.R., that would probably be it. It occurs a bit too late in the tech tree for my taste. It's advanced, sure, but not available at a time you would find it a practical upgrade compared to everything you had been doing prior to that point. If it were up to me, I would move the R.A.P.I.E.R. one node earlier and in it's place at the far end of the aerospace chain I would put a larger scale version of the same hybrid air-breathing/rocket engine. Same relative balancing of mass and performance, just everything bigger. It feels a little odd to see all these heavy spaceplaces with nearly a dozen R.A.P.I.E.R.s each to get to orbit, when a few larger versions of the same thing would probably be better suited to their mission profiles.

Maybe. I haven't tested it. But I do know that the Whiplash has a better TWR at high speed than the Panther does. I tend to use Panthers more in situations where I need a plane with a high gimble range on the engines or the ability to rapidly raise their thrust at a moment's notice. For something where you just push the throttle to max and go in a straight line at high altitude and high speed, my instincts tend toward the Whiplash.

Admittedly, I don't use R.A.P.I.E.R.s much for many of the reasons you just described. I find most spaceplanes I build tend to be built with high-thrust Whiplashes and a low-thrust, high ISP vacuum engine. Instead of the long, slow speed build up of the R.A.P.I.E.R., I go for an aggressive ascent at a forty-five degree (give or take) angle where the Whiplashes can build a bunch of speed and send the plane into a suborbital trajectory on air-breathing thrust alone, then uses a long, slow burn from it's vacuum engines to circularize. Such a design is not, strictly, as efficient as more "elegant" spaceplane designs, but it gets the job done in a shorter amount of time and doesn't require quite a fine-tuned an ascent pattern. It deals with more drag, but it also gets out of the draggy part of the atmosphere quicker and before spending too much fuel fighting it. It would burn up if it had to fly like that most of the time, but since it gets out of the atmosphere quickly, that's less of an issue for it. A small radiator can help bleed the heat off one it escapes the air.

It's a balance of utility. The R.A.P.I.E.R. isn't a very good (lower) atmosphere air breathing engine, nor is it a very good vacuum LFO engine. However, it does both of those things for a very modest amount of mass compared to mounting multiple engines that do only one of those things. And nothing else quite compares to it for building surface-tangential speed during higher atmospheric flight. I do admit sometimes being a bit frustrated at it's lack of thrust in the lower atmosphere, which often requires either lots more R.A.P.I.E.R.s than strictly necessary for most of it's flight or additional Whiplashes to help push it into it's ideal envelope, both of which involve a big tradeoff in mass, or giving it a RATO system. But hey! If it didn't have some disadvantages, we wouldn't need to find interesting ways to engineer around it.

Nebles Kerman was flown out to the southern Kerbin ice shelf to set up some additional solar panels and collect some barometric data to fulfill a contract. Unlike the last disastrous attempt, I had since upgrade my spaceplane hanger so it could have more than thirty parts on a plane. I set the plane up with a duel-wheel gear setup to better absorb the weight of the plane when it touches down (assuming all four tires impact the landing surface at the same time.) But I wasn't sure that would work, so I added about four parachutes on the wings and engine nacelles to allow it a vertical soft landing. And just to be safe (since the landing gear on the last one got too warm after extended flight) I added some radiators to the top of the engine nacelles (you can see them still glowing hot even after landing in the screenshot above.) So they got to you too. Open you mind, keeple!

Small jet engines in wheel hubs? Where have I seen that idea before...

Looking at your Minmus lander, I see it has some tail fins on it. That's great if you're going for aesthetics, but it does make the mission a little more difficult. They only add a little mass, comparatively speaking, but they do add a lot of drag relative to the mass of the lander, and further that drag will tend to pull the lander into a prograde facing when in atmosphere. That's fine if it was going up, but is going to work hard against you if you are trying to burn retrograde during aerobreaking. I suspect this is why your lander came apart when you were returning, the drag wanted it to go in nose-first, which since that was a lower-drag profile and generates a less powerful detached shockwave than if you had been able to keep the "blunter" end of the craft in the prograde direction. That detached shockwave can protect the more delicate parts from the worst effects of atmospheric compression (this is why so many return capsules and heat-shields have these broad bowl shapes on the side that goes in first.) So unless your really attached to the look, lose the fins on the lander. Now, the ascent is another matter. You want all the drag at the back of the craft and little drag at the front. You had the entire lander exposed on the way up, and all those little different pieces which aren't necessarily flush with one another is going to add a lot of drag on the nose. That can make it harder to control. You can overcome that with even more fins at the bottom, but that's kind of inelegant. Instead, I recommend you use an appropriately sized fairing to cover the lander. If you haven't played since fairings were introduced, they're a vertex-generated part where the user can define their exact shape by building them in sections, they can cover up more draggy elements, and they're staged so the fairing panels can be burst apart when you're out of the draggiest parts of the atmosphere and the upper-stage stuff can be deployed. Because the user can define the fairing's exact shape, it's possible to make the drag even worse if you make it too blunt, but so long as the fairing is tapered gently it should help cancel any drag caused by the shape of the lander itself, concentrating more drag at the bottom of the launch vehicle and making the ascent easier to control. Also a few nose-cones on the solid fuel boosters wouldn't hurt.

Nice mission you ran! I love those high-science single returns. Mind if I offer a little design advice to help you get up into space and back to Kerbin with less trouble?

Realized I recovered my landed plane before getting my final reading, so I have to fly back to the south pole. Also I might not have brought enough power for the monitoring station, so it was an excuse to drop off more solar panels. Unlocked the next node in the aircraft line of the tree, so I could use a design with Whesleys instead of Junos, which resulted in cutting the cruising time in half. ... unfortunately, there were some unforeseen complications on arrival. The fixed landing gear was heating up by the end of the trip, the atmospheric friction building heat just slightly faster than it could radiate it away. That, in itself, wasn't a danger since the heat built slowly enough I could be a quarter of the way around the planet before they got dangerous, but landing proved a disaster. I had to reload to quicksave over and over again, because every landing would be a crash. The plane handled fine, glided at low speed (under 50 m/s,) was easy to keep the nose pitched slightly up and roll level so the rear tires hit the very level ice shelf first... and every single time the landing gear would explode, followed by most of the rest of the plane. The earlier Juno-driven version didn't have this problem. I finally had to accept a wash when the "best" version of the landing I could get was one in which both cockpits survived (even if nothing else did) so we could recover the crew safely. Going to have to revisit this once unlocking some better landing systems. Or after I can afford to upgrade my SPH and runway over the first level version.