Containing lubricants in low-pressured space environments has been a problem

Tag : lubricant
Among the 80 samples from four different kinds of lubricants theastronaut will retrieve will be molybdenum disulfide, the mostwidely used substance for space applications.

"In space projects, lubricants are very important, because allparts of the spacecraft rely on them to operate," ZhangShuguang, a professor with Beijing University of Aeronautics &Astronautics, said.

Even the air system in the extravehicular spacesuit needs a speciallubricant to make it work, she said.

But containing lubricants in low-pressured space environments hasbeen a problem, since conventional liquid lubricants are mostlyunstable and could cause contamination during their degradation,chief of Shenzhou VII's solid lubricant sub-system, Liu Weimin,said.

Unqualified or polluted lubricants could cause big problems inspace, Zhang Chunhui, director of the R&D department ofSinopec, said.

It was reported that polluted lubricants caused problems in thelaunch of an Ariane rocket in Europe in the 1990s, he said.

"It is because radiation in space can change the molecularstructure of a lubricant, making it dysfunctional, while thedramatic temperature changes in space can make some lubricantsfreeze or burn," Zhang Chunhui, said.

All this information is vital for space projects, he said.

"The lubricant used in the extravehicular spacesuit'sbreathing system must not pollute the air that the astronautbreathes," Zhang Chunhui said.

He said supported by more than 400 research staff at Sinopec's fourlabs, the company has improved its lubricants by making them"purer with lower volatility".

China is now one of the few countries that can develop andmanufacture space lubricants. Sinopec is the country's only spacelubricant supplier.

The environmental effects on solid lubricants in space are veryimportant to know, not the least, it will help develop newmaterials for space applications.

Shenzhou VII's solid lubricant experiment is similar to that of theUS space shuttle Atlantis in 1992, Gu Yidong, chief designer of theShenzhou VII project's space applications system, said.

Gu said results from the study could be beneficial to otherindustries.

"In the automotive industry, for example, high-performancelubricants could save about 2 percent of fuel, or 20 billion ($2.9billion) to 30 billion yuan each year," he said.

Source: China Daily