Failure is very much an option when you're involved in space exploration. Just ask Dr Ng Tze-chuen.
Ten years ago he was anticipating planetary sampling tools he had designed for the Beagle 2 would begin digging into the surface of Mars, but contact with the British-designed rover was lost after it landed on the red planet. Two years ago a Russian probe carrying tools Ng designed to Phobos, one of the planet's moons, veered disastrously off course.
Now, at the age of 60, the Hong Kong dentist is hoping it will be third time lucky for his Mars-bound tools.
New tools he has designed have been accepted and more are being considered for the ExoMars rover mission scheduled for 2018, a joint project of the European Space Agency and Russia's federal space agency Roscosmos.
"They'll be doing subsoil drilling several feet underground, and they'll need to retrieve the work sample and grind it to a fine powder … to a smoothness of a woman's compact [face powder]," says Ng, a Hong Kong dentist, who has designed a tool that pats down the powder samples that will be analysed for signs of life on Mars.
"It sounds very simple, but if you don't have the right shape for the blade, the surface will stay rough because the soil on Mars is cohesive. It sticks and adheres to the surface," says Lutz Richter, 45, the planetary sampling expert for German space technology company Kayser-Threde.
The company, which executes Ng's ideas, is under contract with the ESA to design and test planetary sampling tools to be used on the red planet.
The blade, Richter says, has two parts - one that initially clears the debris and a second that smooths out the powder.
Ng - who sticks out among the engineers and scientists that the firm usually receives ideas from - comes up with imaginative solutions to some engineering problems, then Kayser-Threde in the following months does the engineering and testing to make the designs work.
"We tend to design something that is reliable and we're not always good with clever concepts, so we're happy to work with people like [Ng]," said Richter.
It also helps that the dentist does not ask for payment for his designs and funds his own research.
Planetary sampling is a small part in the already small field of space exploration. Only around 100 or so people in the world design and create tools that can withstand the pressures of space - tools that are able to help scientists assess if Mars could in the future be a base for further space exploration.
"It's very earth-like. If you look at a panorama it looks like a desert on earth. To me it looks very inviting," says Richter. "There was liquid water, there were oceans, there were rivers and there's still a lot of ice. It explains why so many people are interested in going there."
Designs for the ExoMars mission are in the final stages of testing. The rover will take a nine-month journey to Mars, where it will trundle across the planet's surface looking for amino acids, sugars and water - some of the building blocks of life.
But missions to Mars take time and are no easy feat; a small miscalculation or change of circumstance could jeopardise the entire project. The last European effort led by British scientists, in 2003, ended when the Beagle 2 rover crashed into Mars' surface. Scientists speculated the air in the atmosphere may have been thinner than they anticipated.
The tools designed by Ng for that mission never had the chance to be used.So in his dentist's office in Causeway Bay, surrounded by posters of the 2003 Mars Express mission on the walls, along with gadgets, gizmos and copies of the ESA's bulletins and magazines, Ng waits for the day his tools can go to work.
"Maybe I'll be third time lucky," he says.
Meanwhile, with a boyish passion, he has started other, more earthly projects, such as exploring Mexican pyramids and attempting to get a line of clothing to a show in Paris. "I have 100 projects I want to do. I need to do as many as I can before I die."