Cargo spacecraft Tianzhou 1 docks with lab as 5 months of tests begin
China’s first cargo spacecraft, the Tianzhou 1, has docked with the country’s Tiangong II space laboratory and will stay in space about five months to conduct tests and experiments.
The docking took place on Saturday afternoon about 380 kilometers above the Earth, according to the China Manned Space Agency.
Tianzhou 1, the country’s largest and heaviest spacecraft, was lifted atop a Long March 7 rocket on Thursday night at the Wenchang Space Launch Center in Hainan province. The Tiangong II has been in space since mid-September and carried two Chinese astronauts from mid-October to mid-November. It is now unmanned.
The two spacecraft will stay in combined orbit for about two months, during which the Tianzhou 1 will resupply fuel to Tiangong II and conduct scientific experiments, the agency said.
After the two months, the cargo spacecraft will undo ck and re-dock with the space lab. It will then undock again and start a three-month independent flight before a third docking.
The cargo craft will inject fuel into T ian gong I I during the second and third doc kings. After the third docking, Tianzhou 1 will depart from Tiangong II and will be directed by ground control to fall back to Earth.
If the mission is successful, China will become the third nation to use its own technologyto conduct in-orbit refueling, joining Russia and the United States. It is part of China’s plan to have a manned space station in orbit by about 2022.
The reason for repeating the docking and undocking process is that scientists want to test the technology developed to enable a spacecraft to dock with a space station from different directions.
According to designers, after the first undocking from Tiangong II, the cargo vessel will fly to the opposite side of Tiangong II and dock with different section.
Xu Xiaoping, deputy chief designer of the Tianzhou 1 at the China Academy of Space Technology, said China’s space station will have multiple adapters to dock with spacecraft from various directions so Tianzhou 1’s dockings will help scientists collect experience and data.
Zhang Qiang, another deputy chief designer of the cargo ship, said Tianzhou 1 will make sophisticated, automated maneuvers circling T ian gong I I before the second docking. He said in the third docking, Tianzhou 1 will use fast-docking technology, which will take six hours for the entire process. By comparison, a typical docking will take two days.
In the future, the Tianzhou series will be tasked with bringing supplies of fuel and other necessities to China’s manned space station, for which constructionwill start around 2018.
The station will consist of three parts — a core module attached to two space labs, each weighing about 20 tons — and will operate for at least 10 years, according to the manned space agency.
Developed by the China Academy of Space Technology, Tianzhou 1 is 10.6 meters long and has a diameter of 3.35 meters. Its maximum takeoff weight is 13.5 metric tons, enabling it to carry up to 6.5 tons of supplies.
During the maiden voyage of Tianzhou 1, China’s first cargo spacecraft, scientists will test a medicine for treating bone loss that was developed for astronauts but which they hope will benefit ordinary people.
The main mission of Tianzhou 1, which was launched on Thursday, is to test propellant refueling technology, which is crucial for the construction and operation of China’s planned space station. However, each voyage presents a precious opportunity to conduct space experiments.
Chinese scientists will use the microgravity environment to test the role of an acid known as 3HB (for 3-hydroxybutyric acid) in preventing osteoporosis, according to research leader Chen Guoqiang, who is also director of Tsinghua University’s Center for Synthetic and Systems Biology.
Normally, the solid structure of bone tissue is stimulated and maintained by gravity and physical exercise. However, the microgravity environment of space eases the load, causing rapid bone loss and osteoporosis, Chen said.
“One day of bone loss in space is equivalent to a year on Earth,” he added.
Research shows astronauts suffer average monthly bone loss of 0.5 to 2 percent in space, especially in weightbearing bones such as the tibia, femur and vertebrae.
Back on Earth, they can take double or triple the time of their flight period to recover. Sometimes bone loss is permanent.
Microgravity mainly inhibits the differentiation of osteoblasts (bone-forming cells), which is accompanied by the mass growth of osteoclasts (bone-resorbing cells), causing bone structure to change, Chen said.
Standard drug treatments for osteoporosis have a range of side effects, including tumors or cardiovascular disease. The medicines are also relatively ineffective for treating osteoporosis caused by microgravity.
Chen said 3HB is one of the main components of ketone bodies — chemicals the body makes to compensate for a shortage of insulin in the blood for breaking down sugar. It occurs naturally in mammals and has been used to treat epilepsy for many years.
“We found that 3HB can promote bone formation,” he said, adding that in an experiment simulating a microgravity environment, the effect was obvious.
Unlike the chemical synthetic 3HB for treating epilepsy, Chen’s team uses microbial fermentation to produce 3HB, which has the same structure as the 3HB naturally existing in the human body. So it’s safer than chemical synthetic drugs, Chen said.
Experiments simulating a microgravity environment have been conducted on Earth. Scientists hung up mice by their hind legs, and found that those given 3HB had normal bones, while others suffered serious bone loss.
“We hope to test the effect of the medicine in a real microgravity environment in space,” Chen said.
As Tianzhou 1 cannot carry animals, scientists will compare the osteoblast cell samples that are treated to those not treated with 3HB. Microscope images of the samples will be transmitted to Earth.
Although China has conducted many experiments in the Shenzhou series of spacecraft, as well as in the Tiangong I and Tiangong II space labs, opportunities for space experiments remain rare.
“After more than a decade of research, we have one chance to conduct an experiment in space. We cherish the chance and hope Chinese scientists will have more opportunities to conduct experiments in China’s space station in the future,” Chen said.
Scientists believe the knowledge developed in space exploration can benefit ordinary people. For instance, modern baby diapers were originally developed for astronauts on extended spacewalks. The intensive care unit system in hospitals was first developed to monitor astronauts preparing to go to the moon in the 1970s.