Last week's launch of the Long March-5 carrier rocket was a milestone for China and also for the thousands of Chinese space workers who have spent years with the rocket. Over 90 percent of the rocket's technology is being used for the first time.

China's brand-new heavy-lift carrier rocket Long March-5 blasts off from Wenchang Space Launch center in south China's Hainan province, at 8:43 p.m. Beijing time, Nov. 3, 2016. (Xinhua/Li Gang)

It's the rocket known as the "Chubby Five". The Long March-5 has been 10 years in the design and development. Why Chubby?  For both its appearance, and how it's been fed to bursting by the sweat and dreams of Chinese space workers over 30 years.

Chubby is the most complex in the Long March family. The large thrust engine was one of the biggest challenges during its development.

"Many people say that, the large thrust engine's performance decides the destiny of the Long March-5's first launch," said Wang Weibin, Long March-5 Deputy Chief Designer.

The Long March-5 engine is powered by liquid oxygen and liquid hydrogen. The high-performance fuel is environmental friendly.  But it's also dangerous. The deputy chief designer remembers one test in 2012.

Wang said, "In an oxygen-rich environment, the metal becomes fuel. It took only a few seconds to melt the engine into a pile of scrap iron. The deadline was set for completing the engine and the rocket launch, and we were under a lot pressure."

The team had to go back to the drawing board 114 times before they succeeded. They managed to nearly double the reliability of the engine, making the launch possible. There are thousands of other members of the Long March-5 family like Wang Weibin. They consider the launch site as home.  A 30-hour work day is routine.

"The feeling is like parents sending their kids to take the college entrance exam, and they wait outside. At the moment before launch, you try to relax, but you can't," said Li Dong, Long March-5 chief designer.

The Long March-5's launch on Thursday also carried the space workers' hopes and dreams.  They may be able to relax for bit, but like proud parents, they'll miss their Chubby Five.