alokmohan:<br />We are not much sure that we know our own solar system well...<br /><br />Me:<br />Thats certainly true. We don't know all there is to know about Earth, much less our own solar system. Only real reason there is any hesitation about landing on the moon a second time, is cost. And again, your right, we are not 100% certain we can live on Mars. But before we undertake the lunar mars missions...we should know enough to judge whether we can take them or not.<br /><br />Prior to Apollo, some in the scientific community believed the moon to be covered in deep fine dust that they though a lunar lander would sink in. The answer to that question was obtained before sending humans. The unmanned Surveyor probes safely landed on the moon proving the surface was dusty, but only as a thin layer on a harder, landable surface.<br /><br />alokmohan:<br />With so much to know about our own solar system,how dare we take up journey to proximo!!<br /><br />Me:<br />We will not likely know every detail of our Earth or solar system. And by the time we are ready to undertake an interstellar journey, we will know quite a bit more but not know everything. Where cataloguing planets are concerned. Much of that work would be accomplished by astronomers by the time we go to another star system.<br /><br />We won't be able to know everything about a potential earthlike world before we go there. But we need only know the basics...can it support human life? How dare we...well, daring is a part of exploration. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>