Searching for Extrasolar Life with Space Telescopes

It is noted that telescopes placed above the earth's atmosphere could obtain resolved images of planets around nearby stars. The minimum size telescope needed to resolve planets close enough to a number of good candidate stars is 1.5 m in diameter at optical wavelengths and 16-20 m in diameter at 10 microns. It is noted that the accuacy of the mirror surface required in the optical range far exceeds that of the Hubble space telescope. The problems of working in the IR range are the large size of the mirror and the need to operate it at a temperature of 80 K.