China embarks on first independent mission to Mars

CHINA (China Daily/ANN) -- China launched its first independent Mars mission on Thursday from the Wenchang Space Launch Center in Hainan province, marking the start of the nation’s planetary exploration programme.
As the launch sequence started at 12:41 pm, 10 engines at the bottom of the Long March 5 carrier rocket’s first core stage and four boosters roared to life, generating a combined thrust of more than 1,000 metric tonnes to lift the gigantic vehicle and its payload, the Tianwen 1 robotic

China’s unmanned Mars probe, Tianwen 1, blasts off on a Long March 5 rocket in Hainan.                     --Photo China Daily

probe, into a bright blue sky dotted with white clouds from the coastal launch complex in Wenchang.
The 57-metr rocket, the strongest and most technologically sophisticated in China’s launch vehicle family, flew for more than half an hour before placing the spacecraft on an Earth-Mars transfer trajectory. The flight set a speed record for the country’s rocket fleet as it surpassed the escape velocity of 11.2 kilometres per second required to get away from Earth’s gravitational pull.
If everything goes according to schedule, the 5-metric ton Tianwen 1, which consists of two major parts – an orbiter and a landing capsule – will travel more than 400 million kilometers in nearly seven months before getting captured by the Martian gravitational field, the China National Space Administration said.
Several mid-course and deep-space correction maneuvers will be made during the spaceflight to make sure the probe is precisely aimed at the red planet.
After the probe enters Mars orbit, it will revolve around the planet for two to three months to investigate the landing capsule’s preset landing site before descending to release the landing capsule, which will gradually drop through the Martian atmosphere.
During the entry, descent and landing process, the capsule will first use a heat shield to decelerate, which means the craft will rely on aerodynamic drag to slow itself down. It will then deploy a parachute to further reduce the speed and drop its heat shield and later its back shell. In the next step, the capsule will drop the parachute and ignite its retrorockets.
When the craft reaches about 100 meters above the surface, it will suspend the descent and spend some time observing and analyzing the selected landing point to check for obstacles like rocks. With a positive result, the lander will continue descending until the last moment, when the retrorockets will be shut down, allowing it to touch down steadily on Martian soil, according to the administration.
Experts have dubbed the entire landing operation, expected to take about seven minutes, “the riskiest moment” of the Mars mission.
The lander will later unlock the rover to allow it to move onto the Martian surface.
Weighing about 240 kilograms, the rover, which has yet to be named, has six wheels and four solar panels and will be able to move 200 meters per hour on Mars. It carries six scientific instruments, including a multispectral camera, ground-penetrating radar and a meteorological measuring device, and is expected to work on the planet for about three months. If the highly autonomous machine functions well, it will become the fifth rover deployed on Mars, following four from the United States.
Meanwhile, the orbiter will continue circling the red planet for mapping and measurement tasks with seven scientific apparatus, including a high-resolution imager and a magnetometer. It will also relay signals between ground control and the rover.
Liu Tongjie, deputy head of the space administration’s Lunar Exploration and Space Programmes Centre, said a Mars mission features plenty of uncertainties and risks. China became capable of planning and realising such a sophisticated mission because the country has gained a great deal of engineering capabilities and know-how through the successful implementation of the Chang’e lunar exploration program.
“We’ve made many tests and experiments to verify our plans and equipment. We have also prepared a vast ground-based network for deep-space tracking and remote control,” Liu said, adding that his engineers had produced a lot of emergency-response plans to handle unexpected scenarios.

(Latest Update July 24, 2020)