|Names||Huoxing-1 (火星-1) (2018–2020)|
|Mission type||Planetary science with an orbiter, lander and rover|
|Operator||China National Space Administration (CNSA)|
|Mission duration||291 days, 16 hours, 39 minutes (since launch)|
Orbiter: 2 Earth years (planned)
89 days, 9 hours, 28 minutes (since orbit insertion)
Rover: 90 sols (planned)
|Spacecraft type||Orbiter, lander, rover, TW-1 Deployable Camera (TDC)|
|Manufacturer||China National Space Administration|
|Launch mass||Total: 5,000 kg (11,000 lb)|
Orbiter: 3,175 kg (7,000 lb)
Rover：240 kg (530 lb)
|Dimensions||Rover: 2.6 × 3 × 1.85 metres|
|Start of mission|
|Launch date||23 July 2020, 04:41:15 UTC|
|Rocket||Long March 5|
|Launch site||Wenchang, LC-101|
|Contractor||China Aerospace Science and Technology Corporation (CASC)|
|Orbital insertion||10 February 2021|
|Landing date||17 May 2021 (planned)|
|Landing site||Utopia Planitia|
|Landing date||17 May 2021 (planned)|
|Landing site||Utopia Planitia|
China Mars Exploration mission logo
(Chinese: 中国行星探测) Mars logo
Tianwen-1 (TW-1; simplified Chinese: 天问; traditional Chinese: 天問; lit. 'heavenly questions') is an interplanetary mission by the China National Space Administration (CNSA) to send a robotic spacecraft to Mars, consisting of an orbiter, deployable camera, lander and the Zhurong rover. The spacecraft, with a total mass of nearly five tons, is one of the heaviest probes launched to Mars and carries 13 scientific instruments.
The mission was successfully launched from the Wenchang Spacecraft Launch Site on 23 July 2020 on a Long March 5 heavy-lift launch vehicle. After 7 months of transit, it entered orbit around Mars on 10 February 2021. For the next 3 months the space probe studied the target landing sites from a reconnaissance orbit; then in mid-May or June 2021 the planned landing phase should begin with the release of the capsule containing the lander/rover. The capsule is projected to make an atmospheric entry followed by a descent phase under parachute, after which the lander will use retro-propulsion to soft-land on Mars. If all goes according to plan, the lander will then deploy the rover, which is designed to explore the surface for 90 sols; the rover has a height of 1.85 meter and a mass of about 240 kg. On April 24, 2021, in anticipation of the upcoming landing attempt, CNSA announced the rover is to be named Zhurong (the name Zhurong references a mytho-historical figure in Chinese folklore usually associated with fire). After the planned rover deployment, the orbiter would serve as a telecommunications relay for the rover during its primary mission while continuing to conduct its own orbital observations of Mars.
If the rover landing and deployment are successful, China would become only the second country to accomplish this feat, after the United States. It would also become the third country to achieve a successful soft landing on Mars, after the Soviet Union and the United States.
The scientific objectives of the mission relate to the geology of Mars, the current and past presence of water, the internal structure of the planet, identification of minerals and rock types on the surface, as well as characterization of the space environment and atmosphere of Mars.
The Tianwen-1 mission was the second of three space missions sent toward Mars during the July 2020 Mars launch window, with missions also launched by the national space agencies of United Arab Emirates (Hope orbiter) and the United States (Mars 2020 with the Perseverance rover and Ingenuity helicopter drone).
On April 24, 2020, China's planetary exploration mission was officially named "Tianwen Series", the first Mars exploration mission was named "Tianwen-1", and subsequent planetary missions were numbered sequentially.
An online vote on public preferences for the rover's name was held between January 20, 2021 and February 28, 2021. The name Zhurong was ranked 1st with 504,466 votes. On April 24, 2021, CNSA formally announced that the rover is to be named Zhurong, which references a mytho-historical figure in Chinese folklore usually associated with fire and light. Some Chinese commentators suggest that the naming of the Tianwen-1 Mars rover for Zhurong is meant to ignite the fire of interstellar exploration in China and to symbolize the Chinese people's determination to explore the stars and to uncover unknowns in the universe.
China's Mars program started in partnership with Russia. In November 2011, the Russian spacecraft Fobos-Grunt, destined for Mars and Phobos, was launched from Baikonur Cosmodrome. The Russian spacecraft carried with it an attached secondary spacecraft, the Yinghuo-1, which was intended to become China's first Mars orbiter (Fobos-Grunt also carried experiments from The Planetary Society and Bulgaria). However, Fobos-Grunt's main propulsion unit failed to boost the Mars-bound stack from its initial Earth parking orbit and the combined multinational spacecraft and experiments eventually reentered in the atmosphere of Earth in January 2012. China subsequently began an independent Mars project, and the current mission which was formally approved by Chinese authorities in 2016, became a reality 5 years later.
The new Chinese Mars spacecraft, consisting of an orbiter and a lander with an attached rover, is developed by the China Aerospace Science and Technology Corporation (CASC) and managed by the National Space Science Centre (NSSC) in Beijing. If the landing is successful, the lander would then release a rover. This rover will be powered by solar panels and is expected to probe the Martian surface with radar and to perform chemical analyses on the soil; it would also look for biomolecules and biosignatures.
The TW-1 Deployable Camera (TDC) deployed from the orbiter in September 2020 while en route to Mars. Its mission was to photograph the Tianwen-1 orbiter and the lander's heat shield. Two wide-angle lenses on the deployable camera were programmed to one image a second. The images were transmitted back to Tianwen-1 via a wireless radio link, then downlinked back to teams in China.
This is China's first interplanetary mission, as well as its first independent probe to Mars. The goal is therefore first of all to validate the communication and control technologies in deep space, the placing in orbit around the planet and the landing on its surface. The orbiter must also make it possible to locate a site for a future return of Martian samples.
From a scientific point of view, the mission must meet 5 objectives:
The aims of the mission include searching for evidence of current and past life, producing surface maps, characterizing soil composition and water ice distribution, and examining the Martian atmosphere, and in particular its ionosphere.
The mission also serves as a technology demonstration that will be needed for an anticipated Chinese Mars sample-return mission proposed for the 2030s. Tianwen-1 will also cache rock and soil samples for retrieval by the later sample-return mission.
In late 2019, the Xi'an Aerospace Propulsion Institute, a subsidiary of China Aerospace Science and Technology Corporation (CASC), stated that the performance and control of the future spacecraft's propulsion system has been verified and had passed all requisite pre-flight tests, including tests for hovering, hazard avoidance, deceleration and landing. The main component of the lander's propulsion system consists of a single engine that provides 7,500 N (1,700 lbf) of thrust. The spacecraft's supersonic parachute system had also been successfully tested.
CNSA initially focused on the Chryse Planitia and Elysium Mons regions of Mars in its search for possible landing sites. However, in September 2019 during a joint meeting in Geneva, in Switzerland, of the European Planetary Science Congress-Division for Planetary Sciences, Chinese presenters announced that two preliminary sites in the Utopia Planitia region of Mars have instead been chosen for the anticipated landing attempt, with each site having a landing ellipse of approximately 100 by 40 kilometres.
In July 2020, CNSA provided landing coordinates of 110.318° east longitude and 24.748° north latitude, within the southern portion of Utopia Planitia, as the specific primary landing site. The area appears to provide a relatively safe place for a landing attempt but is also of great scientific interest, according to Alfred McEwen, director of the Planetary Image Research Laboratory at the University of Arizona. Simulated landings have been performed as part of mission preparations by the Beijing Institute of Space Mechanics and Electricity.
By 23 January 2020, the Long March 5 Y4 rocket's hydrogen-oxygen engine had completed a 100-seconds test, which was the last engine test prior to the final assembly of the launch vehicle. It successfully launched on 23 July 2020.
In September 2020 Tianwen-1 deployed the TW-1 Deployable Camera (TDC), a small satellite with two cameras that took photos of and tested a radio connection with Tianwen-1. Tianwen-1 also completed two mid-course orbital corrections and performed self diagnostics on multiple payloads. The spacecraft has begun to conduct scientific operations with the Mars Energetic Particle Analyzer, mounted on the orbiter, which has already transmitted data back to ground control.
Tianwen-1 spacecraft was launched by Long March 5 Heavy-lift launch vehicle on 23 July 2020. Having traveled for about seven months, it entered Mars orbit on 10 February 2021 by performing a burn of its engines to slow it down just enough to be captured by Mars' gravitational pull. The orbiter will spend the next few months scanning the surface to refine the target landing zone for the lander/rover, which is planned to occur in May or June 2021. It will approach at about 265 km (165 mi) to Mars' surface, allowing a high-resolution camera to return images to the Earth and to map the landing site in Utopia Planitia.
To achieve the scientific objectives of the mission, the Tianwen-1 orbiter and rover are equipped with 13 instruments:
Argentina's Comisión Nacional de Actividades Espaciales (CONAE) is collaborating on Tianwen-1 by way of a Chinese-run tracking station installed in Las Lajas, Neuquén. The facility played a previous role in China's landing of the Chang'e-4 spacecraft on the far side of the Moon in January 2019.
France's Institute for Research in Astrophysics and Planetology (IRAP) in Toulouse, in France, is collaborating on the Tianwen-1 rover. Sylvestre Maurice of IRAP said, "For their Laser Induced Breakdown Spectroscopy (LIBS) instrument, we have delivered a calibration target that is a French duplicate of a target which is on NASA's Curiosity Mars rover. The idea is to see how the two datasets compare".
Austria's Austrian Research Promotion Agency (FFG) aided in the development of a magnetometer installed on the Chinese Mars orbiter. The Space Research Institute of the Austrian Academy of Sciences in Graz has confirmed the group's contribution to the Tianwen-1 magnetometer and helped with the calibration of the flight instrument.
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