Both the CSS core module Tianhe and next-gen spacecraft had been shipped to Wenchang. The Tianhe core module will take part in a full dress launch rehersal, while the spacecraft will be launched on the CZ-5B.

Space Station

The CSS will be composed of three modules, the Tianhe, space lab 1, and space lab 2. The Tianhe is the core module, it has a length of 16.6 m, diameter 4.2 m, weighs about 22.5 tons. It will be the command, control and crew quarter, with certain capacity to perform lab experiments.

The Tianhe core module consist of a utlity node, a narrow section where a robotic arm is installed, a full width section, a resource comppartment and an aft channel that allows the cargo spacecraft to dock, and allow the crew to access the cargo spacecraft.

The fore utility node has four docks, the front and bottom are for spacecraft docking, the left and right are docks for the two space lab modules. The top is a hatch door for EVA.

Both the spacecraft and the cargo craft will be docked to the Tianhe core module in future.

The Tianhe core module provide around 50 cubic meter of presurrized space for the crew. With the addition of the two space labs, the presurrized space will reach up to 110 cubic meter. Each astronaut will be supplied with a pad computer to access and monitor devices onboard with wireless network.

The CSS is designed for a service life of 15 years, long term station for three person crew, with a rotational shift of six months. During the rotation shift, it can accomodate up to six person to stay for around 10 days, for transitional purpose.

In order to facilitate stable and long term stay, the CSS require new life support system not available in previous Tiangong space lab, including the recycle of oxygen and water. The recycling technologgy had been partially tested on Tiangong space lab.

To maintain the long service life, the space station need to have high maintainability. Beside increasing the lifespan of the onboard system, up to 60-70% of the onboard system could be maintained with repairs (perhaps with replacement also).

Space medicine, space biology, microgravity fluid study and a dozen of other experiments have been arranged to be conducted onboard. Exposed facility to conduct experiments outside is supported.

Next-Generation Spacecraft

The next-gen spacecraft is deisnged for near earth orbit and deep space flight. Deep space flight will result in greater re-entry velocity, raising the bar for the heat shield of the spacecraft. The heat shielding material and structure are completely new from Shenzhou, its heat shielding capability is 3-4 times that of Shenzhou. The spacecraft will have higher landing precision and lower G shock for the crew. Besides the parachute, the spacecraft will have air bags to cushion the landing impact.

After the launch and recovery of the test spacecraft, the development team will assess and analyse the test data. After verification of the performance, the spacecraft will enter the production state.

The next-gen spacecraft will carry up to six crew, up from three of the Shenzhou. When carrying only three crew, it will be able to ferry around 500 kg of cargo to the space station or back to Earth.

While the cargo spacecraft has a large capacity to carry supply to the space station, it lack the capability to ship items back to Earth.

The resulting sample of space biological experiment, or items manufactured in space will need to be shipped back to Earth for further study. The return of these items will be provided by the next-gen spacecraft. Both spacecraft will complement each other in ferry of cargo between the Earth and space station.

The next-gen spacecraft is designed for reuse. High value subsystem of the spacecraft are concentrated in the re-entry capsule in order to be reused.

The heat shield of the next-gen spacecraft are replaceable. The air cushion will protect the onboard system from damage on landing. With the heat shield replaced, the capsule will be ready for reuse for up to ten flights.

To simulate the space station launch mission, the rehersal will follow through the complete launch protocol, ending at just prior to pressing the launch button. The rehersal will take around three months and be used to discover any potential problem in the core module, the rocket, and the launch site.

The next-gen spacecraft has a length of 8.8 m and weighs 21.6 tons. For LEO flight, the spacecraft weighs around 14 tons and will be launched by CZ-7. So looks like this test flight will involve a deep space flight configuration of the spacecraft. Will it perform a lunar flight into the LTO?

The next-gen spacecraft will be prepared for its maiden flight along with the CZ-5B. As a test flight, it will be unmanned. This will also be the maiden flight of the CZ-5B configuration, which is used to launch payload up to 25 tons to LEO. In comparison the previous launch of CZ-5 Y3 mission in Dec 27, 2019, is of the type E configuration, it's the largest configuration of the CZ-5 family, capable of launching up to 14 tons into GTO.

BTW, after rehersal the Tianhe core module will be shipped back to the factory for further changes and optimization. Apparently its launch is still scheduled for next year. The good news is the launch of the next-gen spacecraft onboard CZ-5B will take place in the first half of 2020, which means it has moved forward to before the Mars mission. With three months of the space station rehersal, I guesstimate the launch date to be around May.