Lunar Base for Mars Missions

Human missions to Mars are the challenge of the 21st century, and missions with ever-increasing complexity are planned to give more information about Mars and its environment.

In January 2004 two NASA rovers, Spirit and Opportunity, landed on Mars surface, and each rover carried sophisticated instruments. At the same time the ESA spacecraft, Mars Express, orbits around Mars and over several years will survey the entire planet in unprecedented detail, mapping the surface and analyzing the thin carbon-dioxide-rich atmosphere. For the next two-and-half decades, many NASA and ESA missions are scheduled with the goal of a human mission in 2030.

Typical spacecraft mass for a Mars mission is about 1000–2000 kg, whereas human missions, or a cargo mission, require a bigger total mass, and because of the large Earth gravitational constant the spacecraft is assembled in low Earth orbit rather than on the Earth surface. For 525,000 kg as initial mass in a circular parking orbit at 1200-km altitude the payload mass in a circular synchronous orbit around Mars (orbit of six Mars radii) is 40,000 kg for a 145-day transfer time and 70,000 kg for a 168-day transfer time. The result is caused principally by the fact that half of the initial mass is used to escape from the Earth gravity field. In nominal configuration performances of the European launcher Ariane 5 for final circular orbit at 1200-km altitude, the mass is approximately 18,000 kg, and for 525,000 kg of payload 30 missions are required.

For 2024 a human mission to the moon is scheduled to show the key life support and the habitation technologies, as well as the aspects of crew performance and adaptation and in situ resources utilization technologies. In fact, before the Mars adventure it is necessary to study permanent human mission on the moon, and innovative lunar base designs have been presented emphasizing the architecture to design novel base concepts. A lunar base for permanent human mission in space is demonstrated to be very useful also as initial base of launch for direct moon–Mars missions. Starting from the lunar surface, a total launch vehicle mass of 460,000 kg reaches a synchronous Mars orbit with a 64,000-kg payload. Using direct Earth–Mars transfer, half of the initial mass is needed to escape from the Earth gravity field, and 30 missions of the Ariane 5 launcher are required to obtained the same payload for synchronous Mars orbit.

Transfer to Mars via the moon is very advantageous with respect to classical direct Earth–Mars missions and gives a good opportunity for future Mars exploration.