1. Location                 

As its name suggests we chose to locate DL4 in an orbit about the Lagrangian libration point four.  This point is one of two stable libration points in the Earth-Moon system and is located 60° in front of the path of the Moon (see fig. 1a). The point represents the centre of a region which a large mass object would, if placed here, take approximately one month to orbit (ref. 37).

When the moon accelerates objects in the L4 region, their centrifugal force relative to Earth changes, causing them to climb away from or fall towards Earth, in which case their orbital speeds increase or decrease and they fall behind or pass L4 and the cycle repeats.

Previously suggested space settlements have traditionally been placed at L5.  This choice is based on somewhat arbitrary grounds, as the differences between L4 and L5 are only slight.  It is occasionally argued that the prejudice towards L5 exists as objects launched from the Moon require only slight deceleration to stop at L5.  However, it takes the same amount of energy to slow down at L5 as it does to speed up at L4 (ref. 42).  Therefore, we believe that L4 represents an excellent location for DaedalusaL4 and a great place from which to watch the L5 traffic jams of the future!

Since K. Kordylewski’s (ref. 27) observation of dust clouds at the L5 libration point, the issue of such Kordylewski clouds’ existence has been hotly debated.  However, recent studies (ref. 3, 11) suggest that while the particle flux rate increases by a factor of 10 near Earth there are no significant indications for dust clouds at either L4 or L5.  In any event, DL4’s Trans-Hab meteorite shielding (see 2.2 Torus – shielding) will be more than capable of coping with particles found in its path.