Panspermia: |
Directed Panspermia
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Contents Introduction |
For maximising the probability of success, it is desirable to maximise the number of survivable units for a given total payload mass, and therefore to minimise the capsule size. From the drag considerations, the optimal size for penetrating the cloud is 1 mm. However, once in the target region, sufficient drag is in fact necessary for capture, and the capsule size can be reduced further. In fact, it is estimated that only dust particles in the range r = 0.6 - 60 m m can survive atmospheric entry and still remain cold enough to preserve organic matter [20]. A median size in this range, r = 30 m m and mass of 1.1E-10 kg is considered below. This requires that the millimeter size capsules will be designed to disintegrate into smaller capsules once within the target protostellar or accretion regions. For example, the 1 mm capsule may be made as a looser aggregate that will disintegrate by collisions with dust particles, or by evaporation of the binding matrix in the relatively warmer target zone, into of 30 m m capsules. This particle size is comparable to the <1E-10 kg particles that constitute about 10% of the zodiacal cloud. Significantly, this particle size will not be ejected from the solar system by radiation pressure [14]. |
