Chinese Space Station

Tiangong Space Station

Tiangong  is a permanently crewed space station constructed by China and operated by China Manned Space Agency (CMSA) in low Earth orbit between 340 and 450km above the Earth surface. It is China’s first long-term space station, it has a pressurised volume of 340 m³ and is one third the size of the International Space Station.

The first module, the Tianhe core module, was launched on 29 April 2021, followed by multiple crewed missions and two more laboratory cabin modules Wentian  launched on 24 July 2022 and Mengtian the final part launched on 31 October 2022.

Purpose and Mission

According to CMSA, the purpose and mission of Tiangong is to develop and gain experience in spacecraft rendezvous technology, permanent human operations in orbit, long-term autonomous spaceflight of the space station, regenerative life support technology and autonomous cargo and fuel supply technology.

CMSA also encourages commercial activities led by the private sector and hopes their involvement could bring cost-effective aerospace innovations. Space tourism at the space station is also considered.

Scientific Research

The space station will have 23 experimental racks in an enclosed, pressurised environment. There will also be platforms for exposed experiments

Agriculture in microgravity will be explored with cultivation of rice and Arabidopsis thaliana as sustainable food sources for long-term spaceflight.

Education and Cultural Outreach

The space station features space lectures and popular science experiments to educate, motivate and inspire the younger Chinese generation and world audience in science and technology.

The CSSARC is the Amateur Radio payload for the Chinese Space Station, proposed by the Chinese Radio Amateurs Club (CRAC), Aerospace System Engineering Research Institute of Shanghai (ASES) and Harbin Institute of Technology (HIT).

Structure

The space station is a third-generation modular space station. First-generation space stations, such as early Salyut, Almaz, and Skylab, were single-piece stations and not designed for resupply. Second generation Salyut 6 and 7, and Tiangong 1 and 2 stations, are designed for mid-mission resupply. Third-generation stations, such as Mir and the International Space Station, are modular space stations, assembled in orbit from pieces launched separately.

Modules

  • The Tianhe Core Cabin Module (CCM) provides life support, living quarters, guidance and navigation, for the station.  The living quarters will contain a kitchen and toilet, fire control equipment, atmospheric processing and control equipment, computers  and communications equipment.
  • Laboratory Cabin Modules (LCM), Wentian, provides additional avionics, propulsion and life support systems as backup functions for the CCM. This section contains an independent airlock cabin to serve as the main entry-exit point for extravehicular activities (EVA). This modules is equipped with multiple internal science racks and 22 payload adapters for various types of experiments.
  • The second LCM, Mengtian, this part is equipped with expanded in-orbit experiment capacity. The module is divided into multiple sections, including the pressurised crew working compartment, the unpressurised cargo section, the cargo airlock/on-orbit release mechanism, as well as the control module section featuring external experiment adapters, a communication antenna and two solar arrays.

Communication

  • The real-time communications, including live audio and video links, are provided by the Tianlian II series of data relay satellites.

Docking

Power Supply

  • Electrical power is provided by two steerable solar power arrays on each module. Energy is stored to power the station when it passes into the Earth’s shadow. The solar arrays are designed to last up to 15 years.

Propulsion

  • Tiangong space station is fitted with conventional chemical propulsion and ion thrusters to adjust and maintain the station’s orbit. Four Hall-effect thrusters are mounted on the hull of Tianhe core module.
  • A magnetic field and specially designed ceramic shield were created to prevent damaging particles and maintain the integrity of the thrusters. According to a report by the Chinese Academy of Sciences, the ion drive used on Tiangong ran continuously for 8,240 hours without a glitch during the testing phase.

Robotic Arms

  • The Tiangong station features five robotic arms. The longest one is the 10-meter-long, ISS Canadian-style SSRMS robotic arm, mounted on the Tianhe core module.
  • The Wentian module features a smaller, 5m long SSRMS robotic arm that is 5 times more accurate in positioning than the 10m one. The Wentian arm is primarily used to transfer extravehicular experiments and other hardware outside the station during astronaut EVAs.
  • The Mengtian module carries a payload release mechanism, installed to assist in cargo transfer. The robotic arm can retrieve experiments from the cargo airlock, then install them onto the external adapters.
  • Two Indexing robotic arms are fitted on top of docking ports for the two laboratory modules to help relocate them during construction.

Image: theconversation.com

Construction

Assembly

  • The construction of the Chinese Space Station officially began in April 2021. The planned 11 missions includes three module launches, four crewed missions, and four autonomous cargo flights.
  • On 29 April 2021, the first component of the station, Tianhe core module, was launched to the orbit aboard the Long March 5B rocket
  • On 29 May 2021, Tianzhou 2 autonomous cargo spacecraft was launched to the Tianhe core module .
  • On 17 June 2021, Shenzhou 12 team docked with the space station, marking them the first visitors to the Tiangong station. The first crew mission began the examination of the core module and verification of key technologies.
  • On 4 July 2021, Liu Boming and Tang Hongbo began their first spacewalk in an upgraded Chinese Feitian spacesuits, outfitting the space stations with extravehicular activity (EVA) equipment, such as foot restraints and the standing platform for Chinarm.
  • During a second space walk on 20 August 2021 a thermal control system and a panoramic camera were installed.
  • On 20 September 2021, Tianzhou 3 autonomous freighter was launched from the Wenchang Satellite Launch Center.
  • The Shenzhou 13 was the first six-month mission on the Tiangong station, docking with the space station on 15 October 2021. Missions for the Shenzhou 13 crew included orbit experiments, spacewalks and preparations for the station’s future expansion.
  • On 7 November 2021, Shenzhou 13 crew Zhai Zhigang and Wang Yaping conducted the first spacewalks to test the next-generation EVA suit and robotic Chinarm, making Wang Yaping China’s first female spacewalker. One of the missions in the 6.5-hour extravehicular activity was to install a dual-arm connector to the 10-meter-long robotic arm.
  • On 26 December 2021, Shenzhou 13 crew Zhai Zhigang and Ye Guangfu conducted the second spacewalk to install a panoramic camera, which will be used for space station monitoring and robotic arm observation.
  • On 5 January 2022, Shenzhou 13 team used the 10-meter long Chinarm to relocate the Tianzhou 2 supply ship by 20 degrees before returning it to the original location.
  • In March 2022, Shenzhou 13 crew began the preparation to undock from the space station. The crew landed in China on 16 April 2022, after staying 182 days in the low-Earth orbit.
  • Beginning with the Shenzhou 14, China officially started the final construction phase for the space station, with three astronauts tasked to oversee the arrival of two labotorary modules in 2022. On 5 June 2022, Shenzhou 14 and began the assembly of the Wentian and Mengtian
  • On 24 July 2022, the Wentian laboratory module was launched from the Wenchang space center and rendezvoused with the Tianhe core module on the same day.
  • On 2 September 2022, the crew member Chen Dong and Liu Yang performed their first spacewalk from the new Wentian airlock, installing and adjusting various external equipment as well as testing emergency return procedures.
  • In October 2022, CMSA prepared to launch the third and final module, Mengtian, to complete the construction for the Tiangong space station.

Expansion

  • According to CMSA, the Tiangong space station is expected to be expanded from three to six modules.
  • According to Wang Xiang, commander of the space station system at the China Academy of Space Technology (CAST), a next phase may be to add a new core module.
  • The Xuntian space telescope module is expected to launch in December 2023.

 

International Co-operation

  • Co-operation in the field of crewed space flight between the China Manned Space Agency (CMSA, formerly known as CMSEO) and the Italian Space Agency (ASI) was discussed in 2011, cooperation and visiting astronauts programs were also considered.
  • A co-operative agreement with China National Space Administration and the Italian Space Agency was signed in November 2011, Tiangong also involved cooperation from France, Sweden, and Russia.
  • On 22 February 2017, the CMSA and the Italian Space Agency (ASI) signed an agreement to cooperate on long-term human spaceflight activities. The European Space Agency (ESA) started human spaceflight training with CMSA in 2017, with the ultimate goal of sending ESA astronauts to Tiangong. However, in January 2023, ESA announced that the agency will not send its astronauts to China’s space station due to political and financial reasons.
  • International experiments were selected by the CMSA and the United Nations Office for Outer Space Affairs (UNOOSA) in a UN session in 2019. 42 applications were submitted, and nine experiments were accepted.

Food

  • Meals consisting of 120 different types of food, selected based on astronauts’ preferences, are stored aboard. Staples including shredded pork in garlic sauce, kung pao chicken, black pepper beef, yuxiang shredded pork, pickled cabbage, and beverages, including a variety of teas and juices.  Fresh fruits and vegetables are stored in coolers.
  • Condiments such as pork sauce and Sichuan pepper sauce are used to compensate for the changes in the sense of taste in microgravity.
  • The station has the first-ever microwave oven in spaceflight.

Operations

  • Tiangong is a permanently crewed station (from 5 June 2022), typically staffed with a crew of 3 people and can support up to 6 people. After the completion of the station in November 2022, it housed a crew of 6 people for the first time for 5 days during the crew rotation from in December 2022. To guarantee the safety of astronauts on board, a Long March 2F/G with a Shenzhou spacecraft will always be on standby for an emergency rescue mission.

Crewed mission

  • Missions starting with Shenzhou 13 are planned to last 180 days.
  • CMSA announced the testing of a next-generation crewed spacecraft to eventually replace Shenzhou. It is designed to carry astronauts to Tiangong and offer the capability for lunar exploration. China’s next-generation crew carrier is reusable with a detachable heat shield.

Cargo resupply

  • Tianzhou a modified derivative of the Tiangong-1 spacecraft, is used as robotic cargo spacecraft to resupply this station. The launch mass of Tianzhou is around 13,000kg with a payload of around 6,000kg. Launch, approach and docking is fully automated.

End of mission

  • Tiangong is designed to be used for 10 years. Crewed spacecraft use deorbital burns to slow their velocity, resulting in their re-entry to the Earth’s atmosphere. The station itself has no heat-shield, but small parts of space stations can reach the surface of the Earth, so uninhabited areas will be targeted for recovery.

Visibility

  • Similar to the ISS, the Tiangong space station can also be seen from earth with the naked eye. As it is smaller in size to the ISS, it will not be as bright. The Tiangong space station can reach a brightness of at least -2.2 mag.