Tianhe core module

Tianhe

Rendering of the Tianhe core module
Module statistics
COSPAR ID	2021-035A
Part of	Tiangong space station
Launch date	29 April 2021, 03:23:15 UTC (11:23:15 CST)
Launch vehicle	Long March 5B (5B-Y2)
Mass	22,500 kg (49,600 lb)
Length	16.6 m (54 ft)
Width	4.2 m (14 ft)
Pressurised volume	113 m3 (4,000 cu ft) Habitable: 51 m3 (1,800 cu ft)
References: 1234567 Insignia
Configuration
Diagram of the Tianhe module

Tianhe (Chinese: 天和; pinyin: Tiānhé; lit. 'Harmony of the Heavens'),⁸⁹ officially the Tianhe core module (Chinese: 天和核心舱), is the first module to launch of the Tiangong space station. It was launched into orbit on 29 April 2021,⁷ as the first launch of the final phase of Tiangong program, part of the China Manned Space Program (Project 921).²⁴

Tianhe follows the earlier Tiangong-1 and Tiangong-2 space laboratories.¹⁰ It is the first module of a third-generation Chinese modular space station. Other examples of modular stations include the Soviet/Russian Mir and the International Space Station. Operations will be controlled from the Beijing Aerospace Flight Control Center.⁴

In 2018, a fullscale mockup of Tianhe was publicly presented at China International Aviation & Aerospace Exhibition in Zhuhai.¹¹¹² In October 2020, China selected 18 new astronauts ahead of the space station construction to participate in the country's space station project.¹³

The core module provides life support and living quarters for three crew members, and provides guidance, navigation, and orientation control for the station. The module also provides the station's power, propulsion, and life support systems. The module consists of three sections: habitable living quarters, a non-habitable service section, and a docking hub.⁴ The living quarters have a volume of 51 cubic metres (1,800 cu ft) of habitable space, compared to only 15 cubic metres (530 cu ft) for Tiangong-1.¹⁴

The living quarters include a kitchen, toilet, fire control equipment, air processing and control equipment, computers, scientific apparatus, and ground communications equipment.⁴ The station has a large robotic arm called the Core Module Manipulator (CMM).⁴¹⁵ The CMM has a wide range of mobility with seven axis of motion, the ability to be elongated, and crawl along the hull.¹⁶¹⁷ According to the latest reports, its ability is similar to Canadarm 2.¹⁸

Electrical power is provided by two steerable solar power arrays, which use photovoltaic cells to produce electricity. Energy is stored to power the station when it moves into the Earth's shadow. Tianzhou resupply ships replenish fuel for the module's propulsion engines for station-keeping to counter the effects of atmospheric drag.¹⁹ There are 4 ion engines for propulsion.²⁰

The forward docking hub has four ports: forward, port, starboard, and nadir (towards Earth). The Mengtian and Wentian modules are semi-permanently attached to the port and starboard ports, respectively. The forward and nadir ports are used by visiting crewed Shenzhou spacecraft, while the aft-facing port at the other end of the module is used by Tianzhou cargo spacecraft.¹⁵ The forward, nadir, and aft ports are equipped with equipment for automated rendezvous and docking.

Each experiment module was designed to carry a mechanical arm similar to the Russian Lyappa arm used on the Mir space station. New modules would initially dock at the forward port before being relocated to the port or starboard port by the arm.

During the early stages of station assembly, the zenith port served as the station's extravehicular activity (EVA) hatch, with the docking hub acting as an airlock.²¹ This role became unnecessary after the addition of the Wentian module, which includes a dedicated EVA airlock.

Earlier first-generation space stations, including the Soviet Salyut 1, NASA's Skylab, and Tiangong-1, were not designed for routine resupply missions. Later stations such as Salyut 6, Salyut 7, and Mir introduced multiple docking ports to support long-term crewed operations and resupply missions.²² The modular design of the Tiangong space station allows additional modules to be added or removed over time.²³ The station was designed for routine resupply and has a planned service life of at least 10 years.¹⁵²⁴

The module is 16.6 m (54 ft) long, with a maximum diameter of 4.2 m (14 ft) and an on-orbit mass of 22,500 kg (49,600 lb).⁶⁵

On 14 January 2021, CMSA announced the beginning of the construction phase for China's three-module space station. The core module, Tianhe, passed a flight acceptance review. This core module provides living space and life support for astronauts and houses the outpost's power and propulsion elements.²⁵²⁶

Tianhe launched on 29 April 2021, at 03:23:15 UTC atop a Long March 5B launch vehicle from the Wenchang Spacecraft Launch Site.⁶ After the core module was put into orbit, the empty first stage of its launch vehicle entered a temporary, uncontrolled failing orbit.²⁷ Some concerns were raised over possible damage from debris of the uncontrolled re-entry: observations showed the rocket was tumbling, which complicates predictions about an eventual landing area, although the most likely outcome was a maritime impact. Parallels were made with respect to a previous launch in May 2020²⁸ which reportedly caused some damage in the Côte d'Ivoire.²⁹ The rocket re-entered over the Arabian peninsula on 9 May at 02:24 UTC,³⁰ landing in the Indian Ocean west of the Maldives according to the CMSA, with much of it having reportedly burned up prior to impact.^{note 1} United States Space Command confirmed the re-entry location.^{31note 2}

The first spacecraft scheduled that visited the Tianhe core module was the Tianzhou 2 cargo resupply spacecraft on 29 May 2021, followed by Shenzhou 12, carrying a crew of three to the station on 17 June 2021.⁷ Tianzhou 3 and Shenzhou 13 were launched to the station on 20 September 2021 and 15 October 2021 respectively.³³³⁴

On 1 July 2021, the space station performed a maneuver in response to a possible close encounter with the Starlink-1095 communications satellite.⁷³ Another maneuver was carried out on 21 October of the same year in response to a possible collision with Starlink-2305.⁷³

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  Tianhe core module full-scale mockup
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  Folded solar panel on Tianhe core module full-scale mockup