China’s ambitious space program is continuing at a rapid pace — within days, its space station, Tianhe, will be manned with three crew members, who will enter the core module and work inside it for three months.
According to the China Manned Space Agency, the mission — Shenzhou XII — is slated to set off from Jiuquan Satellite Launch Center in northwestern China’s Gobi Desert on June 17 (tentative date).
A Long March 2F carrier rocket with the Shenzhou XII spacecraft on top of it was moved to its launch pad at the space complex on Wednesday evening, the People’s Daily online reported.
The agency said in a brief statement the rocket and the spaceship will receive prelaunch examinations and tests, adding the launch center is ready for the coming mission.
Tianhe, or “Harmony of Heaven,” was lifted by a Long March 5B heavy-lift rocket at the Wenchang Space Launch Center in Hainan province on April 29.
The largest and heaviest spacecraft China has ever built, the module is the first part of the Chinese space station, named Tiangong, or “Heavenly Palace.”
On May 29, the first visiting spacecraft to Tianhe, the Tianzhou 2 robotic cargo ship, was launched at the Wenchang center and soon docked with the module.
The combination is now traveling in a low-Earth orbit several hundred kilometers above the Earth.
China plans at least 10 more launches of other major modules, as well as crewed and cargo missions, to complete the station’s assembly by the end of 2022, Scientific American reported.
At that time Tianhe, also called the CSS (Chinese Space Station), will join the International Space Station (ISS) as the only fully operational space stations in orbit.
The T-shape, 100-metric-ton CSS will comprise three major modules: the 18-meter-long core module, called Tianhe, and two 14.4-meter-long experiment modules, called Wentian (“Quest for the Heavens”) and Mengtian (“Dreaming of the Heavens”), which will be permanently attached to either side of the core.
As the station’s management and control center, Tianhe can accommodate three astronauts for stays of up to six months.
Visiting crew and cargo spaceships will hook up to the core module from opposite ends.
Both it and Wentian are equipped with robotic arms on the outside, and Mengtian has an airlock for the maintenance and repair of experiments mounted on the exterior of the station.
Tianhe has a total of five docking ports, which means an extra module can be added for future expansion. The station is designed to operate for more than 10 years.
The CSS has less than one fourth the mass of the ISS — the largest and most expensive human-made structure in space, which was cooperatively built by 15 nations.
“We did not intend to compete with the ISS in terms of scale,” says Gu Yidong, chief scientist of the China Manned Space program.
Instead the three-module configuration is “based on China’s needs for scientific experiments” and “what we consider a reasonable size for the sake of cost-effectiveness.”
The CSS will house 14 refrigerator-size scientific experiment racks and a few general purpose racks that provide power, data, cooling and other services to various research projects.
The science inside and out will include space physiology, life science, fluid physics, materials science, astronomy and Earth observation.
So far, about 100 experiments have been selected from more than 800 domestic proposals, Gu says.
The station will also use the world’s most precise clocks and coldest atoms to support fundamental research in general relativity and quantum physics.
The clocks on the CSS are designed to reach incredibly low levels of instability, with only one second of error every three billion years. The ultracold-atoms experiment rack can cool atoms to 10–10 kelvin, the lowest temperature achievable with current technologies.
China also plans to launch a Hubble-size telescope that will operate in the same orbit a few hundred kilometers away.
As a part of the CSS, the China Sky Survey Telescope (also called Xuntian) will have 300 times Hubble’s field of view and will address a wide range of science in the near-ultraviolet and optical wave bands.
Yang Liwei, the first Chinese in space and now deputy chief planner of the country’s manned space program, told China Central Television, that during their three-month journey with Tianhe, two of the three-member crew, whose names have yet to be disclosed, will exit from the core module on spacewalks to examine, maintain or repair equipment.
Crew members of the Shenzhou XII and the next three manned spaceflights – Shenzhou XIII, XIV and XV — were selected from those in the first and second groups of astronauts, Yang said.
He added that the Shenzhou XII crew is all male, but there will be a woman in each of the next three missions.
Sources: People’s Daily, Scientific American, NASA, China News Service