Absolutely nothing special at all. I just felt like posting it because it's the first rocket I built to send to Jool. Or, more specifically, to Laythe; as evidenced by the parachute and lack of landing legs. So here it is, in case some crazy Kerbonaut out there wants to try their hand at it. Despite my best efforts the radial boosters have a tendency to cause it to roll, hence the winglets. It may be somewhat overkill for just sending one Kerbal with no equipment, but it was the first thing to come out of my design process and it worked, so I stuck with it. With the large fuel tank the upper stage should have plenty of delta-V to get you to Jool or pretty much anywhere else, but obviously it's not designed for powered landing. Not that this would stop Jeb from trying. Flight notes: The ASAS is more of a formality after I discovered it causes the vessel to wobble a bit too much to be...safe. As mentioned, you'll probably need to fight some roll but the radial boosters burn out pretty quickly so this shouldn't be too much of a problem. Flown well, the first stage core should be able to complete your LKO insertion and get you to about 2800m/s on the ejection to Jool. I haven't tried setting the upper stage down on any of Jool's other moons but I suspect it could be done if you're gentle and have burned through enough fuel.