One Giant Leap: If History Had Gone Differently - Kerbal Space Program (RSS/RO)

In this alternate history President Nixon authorizes NASA to shoot for Mars, but only using Apollo hardware and other hardware available at the time. Using two launches, one a standard Saturn V with a modified Gemini spacecraft which would return to Earth - the Ares 5A - and a second upgraded Saturn V with 8 UA1205 boosters used on Titan III rockets that would launch the Mars Excursion Vehicle (MEM) to Mars. After cruising to Mars, the Ares 5A dives deep into the Martian atmosphere, using its density to