My Challenge is eminently reasonable: Put kerbs on the moons of Jool and return them to Kerbin, but do so elegantly. Build one Interplanetary Space Transport (Space Bus) and several Landers. Put a kerbal on each of the moons of Jool. Perform SCIENCE!!! Upon completion of SCIENCE!!! return all landers to rendezvous with the space bus, either send them to the Space Bus' parking orbit or bring the space bus to them. Or get creative and build a Jool-system shuttle to do this taxi work for you. LEAVE NO KERBAL BEHIND. Once your explorers have gathered aboard the Space Bus, its time to go home. Get them back to KSC. I recommend a separate rendezvous in Low Kerbin Orbit with a specialized return vehicle. No non-stock engines. Crew Tanks will be needed for your Space Bus, Mechjeb will be helpful, but nothing that materially changes the performance of the stock engines and fuel. The point here is that every craft has a specific mission and can be tailored to it. No screaming towards the surface carrying all your return fuel and a bunch of nuclear engines. I imagine many of the landers could have RCS-only ascent stages. I am assembling my own flotilla in Kerbin Orbit now, awaiting my launch window. Good Luck. Order of Flights: 12 Crew in 9 ships to the CisJoolian region to land and perform SCIENCE!! Orbiters/Transporters: - 1. Space Bus 1: Out and Back Interplanetary Starship 3 crew 10 passenger capacity 2. Space Bus 2 Out and Back Interplanetary Starship - Backup 3 crew 10 passenger capacity 3. Jool Shuttle 1 Low Moons Mothership 1 Crew 5 Passengers 4. Jool Shuttle 2 High Moons Mothership - Backup 1 Crew 5 Passengers Landers: 5. Bop Lander RCS Descent/Ascent 1 Crew 6. Tylo Lander Powered Descent, RCS Ascent 1 Crew 7. Vall Lander Powered Descent, RCS Ascent 1 Crew 8. Laythe Lander Parachute/Powered Descent, Powered Ascent 1 Crew 9. Spare Lander Parachute/Powered Descent, Powered Ascent 1 Crew I have the four Transporters in LKO. I am going to test the no atmosphere lander designs on the Mun and Minimus. I think they are both fairly easy, lightweight designs. The Leythe Lander is giving me pause. Any ideas for that challenge are appreciated.