21/04/2016 13:26 BST | Updated 21/04/2017 06:12 BST

Meeting Aliens: Why We Must Not Send Humans to Mars

Life may exist on Mars.

This is not crazy ranting from a tin foil hat redneck who has crop circle tattoos on their back, enjoys alcohol induced communions with a wounded mother Earth and is married to their sister called Kynleigh. I'm a planetary scientist specialising in Mars chemistry. Let me explain why sending human missions to Mars would be disastrous. It probably isn't why you think.


Image copyright courtesy of ESA/ATG medialab: EXOMARS 2016 approaching Mars.

Discovering alien life on another planet would change everything. Religion would need to revise their variegated vicious faeiry tales from the 6000-year-old, bearded, white, male sky God who created life on Sunday, October 23, 4004 B.C. (American education would never be the same again). Philosophy, science and politics would be required to radically adjust their foundation assumptions. We as humans, would need to fundamentally reconsider ourselves and our origins. Reassess life, and our species place and role in the universe. It would be the greatest shift since Copernicus realised the Earth wasn't the centre of the solar system.

This alien life is unlikely to be the Star Wars Cantina scene, unfortunately, but probably extremophile bacteria living in subsurface cracks filled with warm fluid, known as hydrothermal systems. These hydrothermal systems can form via meteorite impacts or internal volcanism. We have discovered life on Earth existing down to depths of greater than 1930m underground, utterly detached from sunlight and 'normal' life conditions. Life beneath the Martian surface is entirely plausible. So why shouldn't we send humans? Let's catch the usual suspects:

We are a virus, destroying all we contact and should keep our horribleness Earthbound.

You're a terminal misanthrope. Drain your cupboard of vodka then take a long swim in the sea. Or move to Glasgow.

Space exploration is needlessly endangering human life.

I guarantee any astronaut is fully aware and perfectly accepting of those risks. This argument surfaced a lot since the space shuttle Columbia explosion in 2003. Astronauts are intelligent, daring people: give them credit to make their own decisions.


Image copyright courtesy of ESA-Stephane Corvaja: EXOMARS 2016 lift off.

We should be curing cancer, not going to Mars.

Space and cancer research overlap more than you might think. Space is a dangerous place, full of high doses of radiation for astronauts, with up to 17800 millirem per mission (a CT scan is 700 millirem). There is a long history of cancer research in space, and the knowledge exchange benefits Earth bound cancer patients.

We have so many starving people on Earth, it's immoral to spend billions exploring space.

I have lived in illegal Delhi slums, surrounded by poverty and death. I now find myself working in space research. I've fought long battles and drank much alcohol over this question.

In developing nations such as India, the ability to launch other countries' satellites and rockets provide a huge source of revenue. The problem, of course, is that the idea of 'trickle down' wealth is a myth. But that is a systemic economic flaw rather than a space related one.

In developed nations investing in space provides a raft of technology useful on Earth. Satellites monitor our planet's surface, helping us to understand the complicated dynamics of climate change. These lessons can be used to mitigate food insecurity, flooding and droughts, which negatively impact poorer nations the most.

There are so many other space related benefits. Even exploration on other planets, such as Mars, can help us tackle climate change and carbon capture on Earth. In short, the argument that the money saved from not exploring space would help the starving on Earth is flawed and simplistic, not taking into account the climate lessons and tech spin off. If we want to help the poor we should drop fewer bombs, not cut space science budgets.


Image copyright courtesy of ESA/DLR/FU Berlin (G. Neukum): The flood after the impact in Hephaestus Fossae.

My reason for not sending humans to Mars is different.

We humans are big bags of bacteria. The average person has a 1.3:1 ratio of bacterial to human cells in their body. That is 39 trillion bacteria versus 30 trillion human cells for a 70 kilo human. Current Mars rovers and satellites are extensively plasma cleaned, radiation sterilised and dry heat treated before heading to the Red Planet, in accordance with stringent international guidelines from the committee on space research (COSPAR). Finding a bacterial removal mechanism for humans is both unlikely and unwise.

Space agencies are currently working on a plan to return physical drill samples from Mars to Earth using rovers. But even these missions, not involving humans directly landing on Mars, are fraught with biological contamination issues; both the problem of contaminating Mars with bacteria from Earth, but also bringing bacteria or viruses from Mars back to Earth: which could be deadly. Contamination risks associated with these robotic sample return missions are small, and the protection methods robust. Sending humans is another proposal entirely, and unjustifiable from a contamination angle.

Whichever country lands the first astronaut on Mars will receive a raft of prestige and honours. They will lead and sculpt the space race from that point forward. Egos would bloom. A generation would be inspired. Economic investment in everything space related would rocket. But in doing so we would lose the potential to answer that most valuable question 'is life unique to Earth?'. If we send humans, any microbes found on Mars would always have a question mark hanging over their origin. "Martian, or terrestrial contamination?" people would ask in endless and circular arguments.

Humans should resist landing on Mars until we have significantly advanced our robotic explorations of the planet, determining with greater clarity than at present whether Mars is a dead planet, or if life lurks under the surface.

Ego and pride damaging human potential to answer deep questions is not new. But I hope we can resist a while longer. Explore with robots a while more. The questions at stake are important and profound.


Image copyright courtesy of ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO: Arda Valles.