Space exploration goals for the 21st century

This paper addresses, with examples, the essential need to devise important scientific research questions in order to set the objectives of space missions. However, the crucial objective of the human race is to survive the numerous hazards, both natural and anthropogenic, which may be expected to occur on Earth during the 21st century. With some experts believing that human civilisation may not survive to the end of the century, the main goals for space exploration should first be the preservation of planet Earth as a human habitat and, second, for human beings to settle in another haven, e.g. to colonise Mars. Treating this as an insurance policy, the annual premium for which could be around $16 billion, a globally cooperative plan should now be prepared and agreed. The fundamental message of this article echoes Zubrin's belief that, in order to survive, humanity must become a spacefaring species.