(Article by Richard Heidmann, English translation by Pierre Brisson)

In the second half of 2014, we ventured into the perilous exercise of a “Mars Colonization Transport” (MCT) study, on the basis of the few hints that SpaceX released about its intent (study published (French) on planete-mars.com, the APM website). The major point among the few available data, was a definition of the launcher then apparently considered, a three core Falcon Super Heavy, reusable, with cores of 10 m in diameter each, equipped with 9 Raptor engines of 450 tons unit thrust and capable (we checked) of putting 300 tons into low earth orbit (LEO). This performance level allows sending about 100 tons towards Mars and, ultimately, if we assume that the ship is a fully reusable shuttle, to land on the surface of Mars a payload of a little less than 20 tons.

These results led to a conclusion of inconsistency with the very objective assigned by Elon Musk, of landing a payload of 100 tons. But the announced launcher looked already such a daring size that one could wonder whether the scope of the project should not, by necessity, be scaled down.

The statements of Elon Musk at the beginning of this year – 2015 – show that this is not the case, at least for the time being:

the specification of a100 tons payload on Mars is confirmed;

at the same time, the launcher design is completely rethought:

the thrust of the Raptor is lowered to about 250-270 tons, a level considered optimum in terms of mass over thrust ratio, an essential criterion for recovering the burnt stages;

a single core launcher formula (stages in line) is finally preferred to the three core Falcon Heavy style, being acknowledged that this leads to an even larger first stage size, with an impressive number of engines.

While remaining aware of the limits of the exercise, we wondered about the consequences of these new guidelines, trying to figure out the concept to which they could lead. The result we get leads to very odd proportions, up to the point that we may wonder whether other innovations should not be introduced for the sake of making the project more realistic.

Table of Contents

1. Single core MCT launcher Concept

1.1. The shuttle

1.2. Single core launcher

2. Multi core MCT launcher Concept

2.1. The shuttle

2.1.1. Classic return option

2.1.2. “Immediate” return option

2.2. Multi core launcher

Conclusion

