Thursday, 9 August 2012

Science: It Works on Mars and on Earth

On Sunday the NASA Mars Science Laboratory rover, nicknamed Curiosity, landed on the Red Planet and began beaming pictures home.  This isn't a space exploration blog, but I'll explain the relevance in a moment.

As you might imagine, landing a 900-kilogram, six-wheeled, plutonium powered robot car on another planet is not easy. In fact, this was the most difficult and complex Mars landing attempt to date. Let's run through the main challenges:

1. Build a plutonium-powered robot vehicle than can operate semi-autonomously for an entire year, tolerate sub-freezing temperatures, radiation, dust storms and the vacuum of space.

2. Fit that vehicle into the nose cone of a 58-meter rocket, fill that rocket with an explosive mix of kerosene and liquid oxygen, aim it at the point in space where you expect Mars to be in eight months' time and fire it off.

3. Eight months later, drop the space capsule into the Martian atmosphere at 20,000 kilometers per hour.  If it enters at too steep an angle it will burn up; too shallow and it will skip away and be lost in space.  It's now 154 million miles away - too far for mission controllers to steer it in real time, so you will have to have made the capsule smart enough to make its own high-speed course adjustments.

4. Once the capsule has slowed from to only a thousand miles and hour, jettison the heat shield and pop open a parachute. This will slow it even more.  Again, the capsule is too far away for humans to control directly, so this has to happen automatically.

5. Once the capsule is 1.1 miles off the ground, fire the eight retro-rockets on the descent vehicle. These will steer the lander and bring the whole SUV-sized assembly to a hover over the surface of Mars. Yes, this has to happen autonomously, too.

6. Once the assembly is hovering on its retro-rockets, lower the robot car gently to the surface on a 7.5 meter nylon cable.  When the car has touched down, cut the cord and fly the rocket assembly off to crash a safe distance away.

7. If the vehicle is okay, it will begin sending photographs to Earth.  The signals will go from the rover to a space observatory that has been orbiting Mars for the past six years.  That orbiter will then bounce the signal off another orbiter that has been circling Mars for ten years in order to reach Earth! The mission controllers on Earth will find out fourteen minutes later whether it all worked.

And amazingly, it all worked!  The Curiosity rover is sitting safely on the surface of Mars and Scientists and engineers are celebrating a trove of exciting photos and video footage.

The successful Curiosity landing was a triumph of science and engineering.  We can use these tools to make accurate predictions about a long chain of complex events. And we can use our knowledge and ability to achieve complex and ambitious goals.

Here on Earth, few goals are as complex and ambitious as tackling climate change.  But the science is unambiguous.  We know what is causing climate change and we know that greenhouse gas emissions need to drop.  We even know what emission sources to address and already have the tools to do it.  Reducing greenhouse gas emissions to safe levels doesn't require any new technological advances or scientific inventions.  Existing clean energy, energy efficiency, resource efficiency and forest management systems can do it.  Renewable energy use is soaring across the world, major carmakers are bringing high-efficiency hybrid cars to market, and ever-larger forest protection projects are being launched in Asia, Africa and Latin America.  We know what to do and how to do it, but we're not yet doing it fast enough.

It is clear that governments can't get us there on their own. Politicians' incentive structures make it difficult to make major changes to the built environment and to our energy, transportation and agricultural systems. Governments have an important role to play in promoting transparency, overcoming market distortions, and ensuring a level playing field, but when government is slow to act individuals, communities, civil society and businesses should not hesitate to get involved.

Around the world, companies are switching to renewable energy and improving efficiency, restructuring supply chains to reduce their carbon footprint and save money, and investing in innovative emission reduction projects that help people in the developing world make the transition to a low-carbon future.

Compared to landing a one-tonne rover on Mars, the scientific challenges preventing us from tackling climate change look almost easy.  And the Curiosity rover is there, showing us what we can accomplish when we have the determination.