A unified system of five space bases is proposed to achieve both the Planetary Defense of the Earth against dangerous asteroids and the RFI-free Radioastronomy from the farside of the Moon.We show that the layout of the Earth-Moon system with the five relevant Lagrangian points in space leads naturally to only one, unmistakable location of space bases within the sphere of influence of the Earth. This is:(1)The two Lagrangian Points L1 (in between the Earth and the Moon) and L3 (in the direction opposite to the Moon from the Earth) are to be utilized mainly for the Planetary Defense. This means placing at L1 and L3 bases of missiles capable of deflecting the trajectory of dangerous asteroids and comets by hitting them orthogonally to their impact trajectory toward the Earth, so as to maximize their deflection. In this paper we show that confocal conics are the best class of trajectories fulfilling this orthogonality requirement.(2)Out of all craters on the farside of the Moon, crater Daedalus (located just at the Earth's antipode at 180 o E) is to be reserved for RFI-free radioastronomy. By RFI-radioastronomy we mean radioastronomy kept free from the flood of man-made radio frequency interference (RFI) that is shielded by the body of the Moon. In particular, we also mean SETI, the search for extraterrestrial intelligence. The Saha crater usage for this task was suggested by the French Radioastronomer Jean Heidmann back in 1994, but he untimely passed away on 3 July 2000. Currently, the IAA Cosmic Study on ''Lunar SETI'', started by Heidmann, is being coordinated by the author of this paper under the more general name of ''Lunar Forscle Radio Lab''. Additionally, in this paper a new type of mission to the farside of the Moon is suggested for the first time: it is dubbed ''RadioMoon'' and intends to land a phased array for RFI-free radioastronomy and SETI inside crater Daedalus. The radio link and data downloading between the Earth and hidden crater Daedalus is envisaged to be done by a relay satellite orbiting the Moon in the equatorial plane.(3)The Lagrangian point L1 can be used for all purposes (in addition to the Planetary Defense listed at 1) in as much as the body of the Moon shields the whole of the farside from the RFI produced at L1.(4)The Lagrangian point L2 (beyond the Moon as seen from Earth) must be kept free from RFI-producing devices at all times in order not to damage the RFI-free environment on the farside of the Moon.(5)The Lagrangian point L4 (preceding the Moon at 60 o along its orbit around the Earth) can be used for all purposes, including all types of RFI-producing devices and possibly including a big space station of the Jerry O'Neill type (as shown in the ''2001: An Odyssey in Space'' movie). This is because the body of the Moon shields the farside from being reached by the RFI produced at L4. It could also be used for Planetary Defense.(6)The Lagrangian point L5 (following the Moon at 60 o along its orbit around the Earth) can be used for all purposes only in the plan of Moon farside activities put forward by the author in this paper (namely using crater Daedalus instead of Saha). However it could not be used in Jean Heidmann's plan because RFI-producing devices located at L5 would have polluted Saha directly. In this sense, the author's crater Daedalus proposal is an improvement over Heidmann's crater Saha proposal.
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