A momentous step

The other day, I was watching the Bruce Willis movie Armageddon on TV. The story is about how a group of intrepid astronauts ward off an asteroid on a collision course with the Earth. They actually land on the asteroid and of course, it is left for our hero Willis to blow up the asteroid with a nuclear bomb, so that it cannot fall on to the Earth in one piece. Nice story and not all that implausible either.

It will be decades before men actually land on an asteroid or comet, but much before that, our robots are doing the legwork for us. But even for a robot it is not an easy journey or an easy task.

How do you really catch a comet? After10 years and a journey of 6.4 billion Km, the European Space Agency’s (ESA) Rosetta spacecraft arrived at its destination on Wednesday for the first extended, close examination of a comet.

The name is rather appropriate, given that scientists will have to decipher the clues presented by the Comet, much like they did with the original Rosetta Stone from Egypt.

A six-minute thruster firing, the last in a series of 10 over the past few months, slowed Rosetta to the pace of a person walking, about two miles per hour relative to the speed of its target, Comet 67P/Churyumov-Gerasimenko.

Motorway

“It is like driving a car or a bus on a motorway for 10 years,” says Andrea Accomazzo, the flight director. “Now we have entered downtown. We are downtown and we have to start orienting ourselves. We don’t know the town yet, so we have to discover it first.” ESA's Director General, Jean-Jacques Dordain said: “Europe's Rosetta is now the first spacecraft in history to rendezvous with a comet, a major highlight in exploring our origins. Discoveries can start.”

Over the coming months, Rosetta and its comet, called C-G for short, will plunge together toward the Sun.

Launched in March 2004, Rosetta - a boxy structure roughly nine by seven feet, powered by two 47-foot-long solar panels - followed a circuitous route through the solar system, using flybys of the Earth and Mars to fling itself into the same orbital path as Comet C-G which is a mass of ice and dust just 4 Km wide. Churyumenko-Gerasimov's surface is strewn with boulders the size of houses and its icy cliffs rise as high as 150 meters.

In November, a small 100 Kg lander called Philae is to leave the spacecraft, set down on the comet and harpoon itself to the surface, the first time a spacecraft will gently land on a comet.

The ESA's science team will have to choose a suitable spot for Philae to drill into the surface, extract and analyse samples, and send pictures and data back to Earth.

At this point, the comet and its shadowing spacecraft are more than 530 million Km from the sun (more than three times as far out as Earth), travelling at 56,000 Km per hour. With the final firing of the thruster, Rosetta was a mere 100 Km from the comet’s surface.

“But this mission isn’t just about arriving at a comet,” he went on.

“It’s about studying the comet. It is about placing a lander on a comet, but again, the mission does not end there. The science continues. We’re trying to follow this comet all around its orbit.”

This is indeed a momentous occasion in the history of space exploration, because we had no close access to a comet before. We are fascinated by comets such as Halley’s, which is a regular visitor to the Solar System, but they remained shrouded in mystery.

This close call with Comet C-G will give scientists a better idea about how comets originate, their composition, their trajectory and even their lifespan. Comets can give us clues about the origin of the Solar System itself. What is even more exciting is that comets may contain the building blocks of life - there are many scientists who believe that life on Earth was ‘seeded’ from outer space, through comets, asteroids or meteorites.

Spectrometer

It will take years before the data is fully analysed and understood but it is a worthwhile exercise. During the coming months, it will employ its OSIRIS camera as well as a spectrometer called VIRTIS, a miniature radio telescope called MIRO and other scientific instruments.

This is certainly not the only space project that is hugging the limelight. Even as we write, USA’s NASA is funding next-generation space projects and propulsion technologies.

A submarine for diving through lakes of methane, a tiny satellite designed to snare an asteroid, and solar sail for deep-space probes are all among NASA's Innovative Advanced Concepts (NIAC) Program for 2014, as the space agency hunts for the next big thing in exploration and ultimately, deep space travel for humans.

NASA also has a plan to capture an asteroid in the near future (by 2020), but it will require more advanced technology than what is available now. This project, called the Asteroid Redirect Mission (ARM), aims to capture an asteroid, (there is one candidate already, a 20-metre long asteroid called 2011 MD), then send it to the moon orbit.

From there, NASA wants to put actual humans on the asteroid for study. If the agency cannot find a smaller asteroid to redirect, they are planning to snatch a portion of a larger asteroid for study.

As depicted in Armageddon, there are fears that an asteroid could strike Earth and space agencies worldwide are preparing for that eventuality too.

It costs billions of dollars to design and send a space probe to land on a celestial object (the Rosetta project cost nearly US$ 2 billion), but a manned mission will cost much, much more.

There are critics who question the usefulness of spending billions on projects like this while there are more pressing issues on Planet Earth itself.

However, by learning about the solar system and the universe, we learn more about how our solar system and by extension, life itself, originated. In the end, we are all made up of stardust.