This little book is very informative on the history and present status of space exploration. Cockell says that two of the most important problems of our time are space exploration and environmentalism. He tries a bit too hard to relate the two. The title 'Space on Earth should be 'Earth in Space', which fits the author's thesis better. Care of earth and settlement of space are certainly important but finding a new habitat is a bit premature as space travel is in a very beginning stage although some rich individuals are ready to pay millions for the first ticket. Environmentalism has become highly politicized. I hope Cockell's attempt to associate the two disciplines doesn't lead to the same for space science.
I'm not one who thinks that space exploration is a waste of time, talent and money, but I don't subscribe to settlement of space as the primary motivation.
There are many other objectives, some of which relate to life on earth. Space exploration has much intrinsic worth apart from lebensraum. The book examines many aspects of space exploration. These include exploration for its own sake,
new technology has proven useful on earth, survival in the event of cosmic catastrophe such as a rogue asteroid trajectory, garnering of valuable material resources, answering questions posed by evolution, promoting international cooperation, and investigation of potential ET life. As Cockell points out, ultimate survival could depend on things learned in space. For example, we might need to deflect a dangerous asteroid trajectory. Searching for an alternate habitat is the least important goal.
There's a discussion of environmental ethics and space ethics. Animals and microbes have a right to existence independent of anthropomorphic utility. Space ethics involves value of space and contents independent of value to us earth residents. We need a new definition of intelligence to cover intrinsic value of life on earth as well as space. It's a very interesting contemplation, but legal rights for germs and microbes is getting a little carried away. The best of the book is a review and status report on programs such as IKONOS, LANDSAT, TOMS ozone monitoring, Galileo and MELISSA, to name a few. The Apollo programs and Biosphere 2 provide psychological insights applicable to earth and space. The Chinese Academy of Science leads the world in the development of support systems. That's one more example of fading US leadership.
It's fairly obvious that space exploration can affect life on earth. Cockell cites the environmental value of GPS in tracking wildlife and tectonic changes. Satellites inform and predict weather, crop conditions and oil exploration. Another example was discovery of the Van Allen radiation belts in 1958. Economic benefit can be derived from space such as materials from the asteroid belt or helium from the moon. Cockell thinks that influx of extensive space resources can be detrimental to our economy, sort of like the influx of gold from the new world ruined the Spanish economy in the 16th century. In reality, we would be be very fortune to merely recover the cost of space exploration.
Agree or disagree with the purpose, we can't ignore, as Cockell does, the realism of military reasons for development of space science. He overlooks military objectives and although he points out communication problems involving a 40 second lag between earth and Mars he ignores relativistic effects of space travel. Relativity will play a prominent and interesting role as speeds and distances increase. He points out that celestial and solar changes will eventually make the earth uninhabitable. It's good to plan ahead, but a billion years is ridiculous. Luckily there is value in the here and now for both space and earth science.