Whether we as a human race need to travel to Mars is two-fold: personal and scientific. Yet whether either of them will really bring much benefit to the human race is, I think, debatable.
In 1989, NASA estimated it would cost $400 billion to send someone to Mars. By 2004, this had escalated to at least $600 billion. With the level of international debt in the world, the poverty and suffering, this money could be put to better use by providing clean and safe water, basic education (literacy and numeracy) and reducing the impact of debt.
And how is this money to be raised? Possibly by increasing taxes or reducing expenditure on things like healthcare or education. Any trips to Mars are surely a waste of money when we have so many problems here on Earth.
2. THE STATE OF THE PLANET
As a race, humans are destroying this planet in a number of ways: pollution, deforestation, overuse to name just a few. The impact of climate change and the state of the environment are being affected adversely by human impact which is often caused by unnecessary greed and selfishness by an expanding and overcrowding population.
This means that we need another planet to live on, a fresh start, where we can expand to and get away from the Earth which we have ruined. Travelling and exploring Mars could give us this opportunity, or provide further information about how to adapt our lifestyles for our existing planet or reach somewhere else completely. The question then is whether we will also go on to ruin Mars.
3. SCIENTIFIC BENEFITS
Getting in a spacecraft and zooming through space to Mars could lead to a wealth of scientific breakthroughs and advances. We might find out more about the origin of the universe and whether the Big Bang theory really is true; we could discover more about other planets and the stars, comets and black holes; or we might see if there really are other lifeforms in space or further out in the galaxies. All of these would give us more information about the world we live in and could help us understand it.
If we reach Mars successfully, we might be able to exploit any natural resources on the planet, either for our use on Earth or there if we decide to stay. By understanding the geology and structure of Mars, we might be able to understand how we could maximise our use of the Earth.
But much of this could be done by analysing the rock structures we have to hand on Earth and using the information of Mars we already know. Some people argue that physically being on Mars will actually provide very little added benefit.
4. SENSE OF ACHIEVEMENT
Travelling to Mars would give us a sense of achievement in our self-obsessed world in the same way that space travel and the moon landing did in the post-war decades. Finding out about the history of the universe and travelling through space must be a wonderful experience and would certainly produce more than the average car journey across our busy cities on Earth and give a real sense of accomplishment.
To explore and discover is part of what makes us human; and continuing this outside our planet is the ultimate achievement. We know so much about Earth already but relatively little about other planets. Exploring Mars could change all this.
The standards of science and expertise would need to increase dramatically for a manned space journey to Mars. And by doing so this would symbolise a huge advance of our scientific knowledge and skills and a massive increase in our scientific expertise. If we could then harness this for general human advancement, we could use it to help the general world population and our fight against problems here on Earth.
However, it's a very long and dangerous journey and some people argue whether it would be possible to find and develop the expertise in our lifetimes. Maybe it would be better to wait either until it becomes realistically possible in a number of decades or generations' time, or instead concentrate our efforts here on Earth.