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Raumfahrt - Startvorbereitung für China Tianwen-1 Mars mission launch

26.05.2020

Rocket arrives as China targets July for Tianwen-1 Mars mission launch

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HELSINKI — China is gearing up to launch its Tianwen-1 Mars mission following the delivery of a Long March 5 launch vehicle to Wenchang launch center.

The rocket components arrived at Wenchang May 24 following delivery to Hainan island via Yuanwang 21 and 22 cargo ships. The spacecraft arrived at the launch center April 10, after air delivery to Haikou airport. 

Space officials at China’s ongoing annual political sessions in Beijing confirmed launch of the combined orbiter and rover mission for July. The specific launch date was not announced.

Previous Long March 5 launch campaigns have taken two months, meaning launch can be expected late July. The launch window is likely similar to the July 17 – Aug. 5 window for NASA’s Perseverance rover. 

A successful landing would make China only the second country to land and operate a spacecraft on Mars after the United States.

The biggest challenge is the ‘seven minutes of terror’, said Bao Weimin, chief of China Aerospace Science and Technology Corporation (CASC) science and technology commission, at the political sessions. The phrase is borrowed from NASA Jet Propulsion Laboratory engineers to describe the entry, descent and landing (EDL) process.

During this time the landing segment for the rover is required to reduce speed from 20,000 kilometers per hour (12,427 mph) to zero, according to Bao. The Tianwen-1 rover is expected to attempt EDL from orbit, whereas Perseverance will land on arrival at Mars. 

The landing segment will utilize heat shielding and parachute technology derived from the Shenzhou spacecraft.  Propulsion will draw from the Chang’e lunar landers.

Deep space network upgrades

Upgrades and updates to China’s deep space network facilities are underway to support the mission. 

A 70-meter-diameter antenna was hoisted in Tianjin April 25 to support mission communications. Antennas in Miyun District, Beijing and Kunming, southwest China, will also receive data from Mars, which can be as far as 400 million kilometers distant.

The Yutu-2 Chang’e-4 rover is expected to remain stationary for the ongoing 18th lunar day on the lunar far side mission due to the upgrades.

Yuanwang 6, a space tracking ship, left port Wednesday to test new equipment and antennas for tracking and supporting the Tianwen-1 mission. 

The mission will fly on the fourth Long March 5, a heavy-lift rocket which had a successful return-to-flight in December. The second launch failed in 2017, grounding the rocket for more than 900 days.

China’s Tianwen-1 Mars rover undergoing thermal vacuum testing.
China’s Tianwen-1 Mars rover undergoing thermal vacuum testing. Credit: CCTV/frame grab

Tianwen-1 landing site

The Tianwen-1 spacecraft will arrive at Mars in February 2021 and enter orbit. The EDL attempt may not take place until weeks or months afterwards

Two landing areas have been outlined, with a candidate landing site in Utopia Planitia. The landing ellipse is understood to be around 100 x 40 kilometers.

The Tianwen-1 orbiter will be equipped with a high-resolution camera comparable to HiRise on board NASA’s Mars Reconnaissance Orbiter. It also carries a medium-resolution camera, subsurface radar, mineralogy spectrometer, neutral and energetic particle analyzers and a magnetometer. The orbiter will also play a relay role for the mission rover.

The roughly 240-kilogram solar-powered rover is nearly twice the mass of China’s lunar rovers. It will carry a ground-penetrating radar, multispectral camera and a Laser Induced Breakdown Spectroscopy instrument. Other payloads will analyze the climate and magnetic environment. 

China’s Mars exploration program suffered a loss May 21 with the death of its chief scientist following illness. Wan Weixing, 61, was a researcher at the Chinese Academy of Sciences.

Tianwen-1 will be followed by a Mars sample return mission around 2030. Single and two-launch mission profiles have been proposed, using either a Long March 9, or Long March 5 and Long March 3B launches.

The July mission will be China’s first independent interplanetary mission. The country’s Yinghuo-1 orbiter piggybacked on the Russian Phobos-Grunt mission in 2011, but the spacecraft failed to leave Earth orbit.

Quelle: SN

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Update: 27.06.2020

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Mars mission would put China among space leaders

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NASA’s Perseverance rover may have company on the Red Planet. China aims to leap to the front ranks in planetary exploration with an ambitious Mars mission, its first independent bid to reach the planet. Tianwen-1—“quest for heavenly truth”—consists of not only an orbiter, but also a lander and a rover, a trifecta no other nation has accomplished on its first Mars bid. “A successful landing would put China among elite company,” says Mason Peck, an aerospace engineer at Cornell University.

Due to launch in July, the mission, if successful, would mark dramatic progress for China’s space program. In recent years it has fielded several lunar landers but made only one attempt on Mars, an orbiter that piggybacked on a failed 2011 Russian mission to the martian moon Phobos.

A Mars landing is among the most challenging feats in spaceflight. Unlike the Moon, Mars has an atmosphere, which means landers need protection from the heat generated during descent. But its air is too thin for a parachute alone to slow a lander; retrorockets are needed as well. And the entire sequence must be executed autonomously. Of 18 lander or rover missions to Mars, only 10 have been successful. Nine of those 10 were NASA missions. A Russian probe landed successfully, but almost immediately lost communications.

Scientists involved in Tianwen-1 said they did not have permission from the China National Space Administration (CNSA) to speak to the press, and the agency did not respond to questions. Although state media have run stories about the mission, there is nothing like the fanfare that accompanies a NASA Mars landing. Several sources within China’s space community believe the agency is muting publicity to temper expectations for a risky mission.

China has not yet announced which of two candidate landing sites it prefers. Both are flat, smooth plains not far from where NASA’s Viking 1 and Viking 2 landers touched down in 1976. The low-lying sites give the lander’s parachute more time to work. Although scientists might have preferred a more rugged site at higher elevations with more interesting geology, “I speculate [CNSA engineers] are looking to particularly demonstrate a safe landing,” says Jim Bell, a planetary scientist at Arizona State University, Tempe, and veteran of several Mars rover missions.

Landing is not the only objective, however. “Our goal is to explore and gather as much scientific data as possible,” CNSA chief mission architect Zhang Rongqiao said during a July 2019 lecture on the mission. The orbiter aims to study the martian magnetic field and atmosphere. With a high-resolution camera, it will map the surface and characterize its geology.

The as-yet-unnamed, 240-kilogram rover, the size of a small golf cart and one-quarter the weight of Perseverance, carries six scientific instruments. Among them is a ground-penetrating radar (GPR) that, along with one on Perseverance, will be the first such devices on Mars, able to map subsurface features that orbiting radars see only dimly. “You can really investigate layering, structures, and the presence of permafrost or ice,” says Elena Pettinelli, a geophysicist at Roma Tre University, who has helped analyze GPR data from China’s Chang’e 3 and 4 missions to the Moon.

Tianwen-1 will take 7 months to reach Mars, and it will be several more months before the orbiter releases the lander, according to a 2017 paper outlining the mission in Science China Technological Sciences. After trundling off a ramp on the lander, the solar-powered rover is expected to operate for at least 90 martian days, using the orbiter as a communications relay. The orbiter will keep going for about one martian year, or roughly 23 months.

Dean Cheng, a China policy expert at the Heritage Foundation, a conservative U.S. think tank, says beyond demonstrating technological prowess, China wants to contribute “to the global pool of knowledge.” It believes “great powers are also scientific powers,” he says.

Tianwen-1 is not the only upcoming demonstration of those ambitions. Later this year, China plans to launch its Chang’e 5 mission, which would return the first Moon rocks since the last Soviet Union Luna mission in 1976; it will likely attempt a far-side sample return mission after that.

CNSA officials have suggested that if Tianwen-1 and Chang’e 5 go well, China could attempt to return samples from Mars beginning around 2030. That timeline puts it on the heels of the NASA–European Space Agency sample return mission—but not by much.

Quelle: AAAS

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Update: 3.07.2020

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China eyes July 20-25 launch for Mars rover

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A Long March rocket lifts off from the Xichang Satellite Launch Center in Xichang in China's southwestern Sichuan province in June 2020 AFP/STR

BEIJING: China's first Mars rover should launch later this month, authorities said Wednesday (Jul 1), as the country races to catch up with the US dominance of space.

The Tianwen-1 Mars rover is scheduled to blast off from Hainan island, off China's south coast, between Jul 20 - 25, according to the Xichang Satellite Launch Centre.

 

It will be China's first interplanetary mission, and takes place shortly before the next US Mars rover - timed to launch no earlier than Jul 30.

Named after an ancient Chinese poem, the Tianwen-1 consists of an orbiter, rover and lander, and is expected to collect samples from the planet's surface, the launch centre said.

The system will be carried into space on a Long March 5 rocket and is expected to reach Mars sometime in February 2021.

The dates have been chosen because the Earth and Mars are only aligned at an optimal position for spaceflight for a short period once every 26 months.

The US delayed the launch window of its own Peseverance probe - its fifth Mars rover mission - three times over the past month due to technical issues.

NASA initially said the launch must take place no later than Aug 15, but more recently suggested the window may be extended.

China has hugely expanded its space programme in recent years to compete with the US and Russia, and has ambitions to put a man on the Moon.

In 2019, it sent the Yutu-2 rover to the far side of the lunar surface in a world first, and has also touted its cooperation with the European Space Agency.

A Chang'e 5 lunar probe is set to launch later this year, and a new space station is due for completion in 2022.

The US banned Chinese astronauts from using the International Space Station because of national security concerns.

Last week, China also launched the final satellite in its homegrown Beidou navigational system, which competes with the GPS system pioneered by the United States.

Quelle: CNA

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