Juno during construction: NASA's Juno spacecraft was launched in August 2011 and will reach its destination, the gas giant Jupiter, in 2016, where it will spend one year mapping the behemoth planet's composition, atmosphere, gravity and magnetic field. (Credit: NASA/JPL-Caltech/LMSS)

Each year over US$100 billion is spent around the globe on space exploration by the space-faring nations of the world. But why....?

1. Technology - Space exploration commands the abilities of some of the finest scientists and engineers in the world. Their invaluable contributions frequently lead to new ideas and innovations that can be utilised by us mere mortals here on Earth. Revolutions in communications, materials, energy, meteorology and countless other disciplines take innovative ideas and concepts from the space arena on a frequent basis. Pushing ourselves beyond the limits of this world can make our lives easier, safer and more enjoyable here on earth.

2. Survival - there are serious risks to humanity both from space-borne dangers and earthly hazards, but greater investment in space exploration offers us the tantalizing prospect of salvation from either, or even both. Firstly, the greater our knowledge of our solar system and the dangers lurking within (or even without) it, the more prepared we can be to defend ourselves. Whether we are under threat from an errant asteroid or solar flare, greater understanding will enable us to combat these dangers in a more capable fashion. Secondly, should we lay waste to our planet by war, disease, famine or climate change, we might one day possess the means to move ourselves to a new home. Governments and private enterprises are already making the first steps toward making this distant fantasy a reality, and it is one day entirely possible that we will owe our very survival to the exploration and understanding of the cosmos around us.

3. Inspiration - Generations of scientists have been swept into their profession by wonder and awe inspired by the great innovators and explorers of their time. The Apollo programme has most likely been one of the most effective programmes that have encouraged young people to develop a keen interest in science, but the Hubble Space Telescope (HST), several generations of Mars rovers and the wonderful images sent back by the Cassini-Huygens mission continue to inspire delight and curiosity in adults and children alike. As was the case with Christopher Columbus, Charles Darwin, Roald Amundsen and countless others, without these great strides in exploration the world would be a very different and altogether less interesting place.

4. Global co-operation - Whilst it is true that the development of space flight was closely tied in with the development of nuclear weapons and other aggressive technologies, it has been, and indeed continues to be, a great drive toward further co-operation between space faring nations. "Despite the continued space competition between the United States and U.S.S.R., Khrushchev sent Kennedy a letter raising the possibility of space cooperation on a modest level [...in 1962]"(http://www.nasa.gov/50th/50th_magazine/coldWarCoOp.html) Then, in 1975 the US and USSR created the Apollo Soyuz Test Project - a primarily symbolic mission that has encouraged co-operation and mutually beneficial exploits in space ever since. Today, the ESA (European Space Agency) is a conglomeration of the efforts of unified countries in space. There have been major contributions to the International Space Station (ISS) by NASA, Roscosmos (Russia), the CSA (Canada), ESA and JAXA (Japan), as well as other contributions from several other nations. If these great success stories continue to grow and develop, it will encourage us to demonstrate better relations on the ground. Space exploration brings us closer to peace.

5. It is MAJORLY cool - on October 3rd 1957 there were no man-made objects in orbit around the earth. 54 years later, we have sent robotic explorers to seven planets , several non-planetary bodies and human beings have stood upon the Moon. We observe the sun with extremely high tech equipment 24 hours per day, 365 days per year, and we are discovering hundreds of planets around other stars. We can describe the inner dimensions of our great galaxy, and witness events in countless billions of others throughout the cosmos. We are finally en route to answering the question: Are we alone? We live in a truly amazing and awe inspiring time. Astronomy and space exploration promise to allow us to discover some of the most profound insights into our lives, and compels us to ask the most audacious of questions. Seriously, it's majorly cool.

The United States of America spends around a tenth of one percent of its annual budget on space exploration, much more than many of its fellows. If we can use this tiny amount to land on the moon, send probes to Mars, Jupiter and Saturn, and peer into the far reaches of the Universe, just think what we could achieve with a meagre on or two percent!

GS