Mars attracts

PUBLISHED : Saturday, 21 April, 2007, 12:00am
UPDATED : Saturday, 21 April, 2007, 12:00am

To boldly go where no machine has gone before. That dream may soon become a reality for a team of Hong Kong university engineers who have been given the opportunity to design a piece of machinery vital to a mission to probe Phobos, the innermost moon to Mars.

For the team from Polytechnic University, it is a second chance to delve into the secrets of space after their last project, the Mars Rock Corer, disappeared on board the European Space Agency's ill-fated Beagle 2 Lander that reportedly crashed on Mars in 2003.

Their brief this time is to design a machine, weighing merely 230 grams and slightly larger than a pack of cigarettes, which will sift and grind material into a uniform size of slightly less than 1mm in diameter in preparation for analysis by the Phobos-Grunt Lander, scheduled for launch in 2009. The mission is a joint collaboration between Russia and China.

'The last project to Mars was to discover the origin of life. This project is to discover the origin of the solar system,' said Professor Yung Kai-leung, associate head of the Department of Industrial and Systems Engineering at PolyU, and head designer for the soil preparation system.

The origin of Mars' two satellites, Phobos - named after the Greek god of fear - and its smaller sister Deimos, is shrouded in mystery. Some of the darkest objects to have appeared through the lens of a telescope, they were discovered by American astronomer Asaph Hall in 1877. But the two moons of Mars were actually described 150 years earlier in Jonathan Swift's Gulliver's Travels, published in 1726, long before the age of powerful telescopes, and is regarded by scientists as an amazing coincidence.

Phobos orbits less than 6,000km above the surface of Mars, closer to a planet than any other moon in the solar system, and getting lower as it spirals faster and faster inward toward Mars. This phenomenon, known as secular acceleration, has inspired spectacular theories about the source and particular nature of the potato-shaped moon that are quite literally out of this world.

In the 1950s, noted Russian astronomer Iosif Shklovskii proposed the rapid rate of acceleration could only be explained if Phobos was light, even a hollow structure surrounded by thin sheet metal, leading to suggestions it was of artificial origin.

Siegfried Frederick Singer, scientific adviser to former US president Dwight D. Eisenhower, lent his support to this theory, going as far as to say that Phobos' 'purpose would probably be to sweep up radiation in Mars' atmosphere, so Martians could safely operate around their planet'. Even Nasa was rumoured to be considering the possibility that Phobos was a colossal space station.

More recently, that theory has been eclipsed by one that suggests Phobos and Deimos are from the asteroid belt and were captured by Mars' gravitational field, due to their similarity in appearance and density to asteroids.

Although the mechanism of the 'capture' is still unknown, testing the soil of Phobos could confirm or disprove this theory and shed much light on this piece of the jigsaw puzzle of how the solar system was formed.

If Phobos is a captured asteroid, its construction and composition could also yield many clues about the early evolution of the solar system.

Professor Yung rates the mission's chance of success at around 30 per cent, with good reason. Previous missions to Mars have been subject to the Mars Curse, which has claimed 19 of 37 attempts to explore Mars. Professor Yung explained that Mars, by dint of its relatively high gravity and thin atmosphere, lent itself to crash landings, a fate that is thought to have befallen the Beagle 2 Lander after it lost contact on Christmas Day 2003.

But he expects the trip to Phobos to be a smoother ride. 'Planets differ and Phobos is very different from Mars. It has far less gravity, about 2,000 times less gravity, so it will be much easier to avoid a crash. Rather it should float down like a leaf.'

Yet the lack of gravity presents the team with problems of its own. 'There is no gravity, so you cannot rely on it to bring the particles into the grinder. There has to be something to restrain particles and guide them into the machine,' he said.

Another challenge, according to German former aerospace engineer Peter Weiss, a member of the design team, was that they had so little information to work with.

'We don't really know what kind of material you find there. We have a good understanding but there are no certainties,' he said. 'It could be very fine powder, it could be very hard rock. Some scientists have even been talking about ice. So we need to make a machine that can deal with anything it will encounter.'

A fist-sized meteorite that fell on a Soviet military base in Yemen in 1980 may provide a few clues. Much of it consisted of a kind of carbon-rich material only found in asteroids, yet imbedded in it were bits of volcanic rock that only form in major planets with a core, mantle and crust.

Russian scientists finally decided it had probably come from Phobos, which orbits close enough to Mars to pick up fragments of Martian rock when other asteroids crashed into the planet.

That raised the intriguing prospect that a fragment from Phobos might possess highly coveted Martian material, which has spurred renewed interest in the moon, not only from Russia but also from the European Space Agency, which is considering its own mission in 2016.

Having just completed the initial design, Professor Yung's team will have to work quickly to finalise the device by the end of the year before it can be sent to Russia for testing.

The job of making sure it is ready on time falls to Chris Wong Ho-ching, director of PolyU's industrial centre, which will build the device.

'The hardest part is when we have made the model, only for them to change the specifications, to make it smaller, or lighter, or add or reduce a function. There is a lot of pressure to keep to the deadlines. And right until the moment of blast off I won't know if they will even use our parts,' Dr Wong said.

But Professor Yung said the real hurdle would be selling the idea back to the Russians. 'The Russians are nice people but very difficult to work with. They are a very intelligent bunch and they do not take other people's advice very kindly,' he said.

With such a low opinion of outside help, how did the PolyU team win the project? 'They came to us because we are good at making small things,' Professor Yung explained. 'It is always a myth that Hong Kong does not have technology ... it is just the government and public organisations fail to promote it. Take our previous designs of space tools, they require a wide range of technology.'

He said it was largely due to team leader and 'spark plug' Ng Tze-chuen, the pioneering dentist who took the concept of dental forceps beyond the final frontier and invented the Holinser Space Forceps. They were deployed on the Mir Space Station in the 1990s for cosmonauts to perform high-precision soldering.

Since he first heard the Russians were looking to collaborate with outsiders for the Phobos-Grunt mission in 1999, Dr Ng has spared no effort to claim the project for Hong Kong, making thousands of phone calls and knocking on hundreds of doors.

Thanks to Dr Ng, Hong Kong has become an unlikely hub for space engineering, attracting talent from around the world, including Mr Weiss, now studying for his PhD under Professor Yung.

Mr Weiss first met Dr Ng two years ago while working as a project manager for a French company specialising in sub-sea robotics, and his first impression was typical.

'Dr Ng came to us with a proposal for a sub-sea manipulator arm to excavate shipwrecks. My boss asked me to deal with it. I must say I didn't take it very seriously, it seemed so fantastic,' he said. 'But after I checked it out it did seem plausible. We spent the day together, I mentioned at the time I was thinking of doing a PhD and he said he would introduce me to Professor Yung.

'One of the main reasons I came to Hong Kong is they had a very good track record and a reputation for making things happen. At universities that is quite rare. And working on a project that has a chance to blast into space, it is more than an engineer can expect.'