China designs space helicopter for its Mars efforts

Chinese aerospace chiefs are considering deploying a helicopter in the country’s latest effort to retrieve samples from one of our closest planetary neighbours, Mars.

The Tianwen-3 Mars mission is expected to go ahead sometime near 2028. It promises to be the Chinese National Space Agency’s (CNSA) most complex endeavour to date, requiring the launch of two ultra-powerful Long March 5 rockets to deposit the vehicle stacks into space.

Details for China’s sample-return mission were shared via a slideshow on the popular Chinese social media platform, Weibo, in April.

Commentators and analysts alike were quick to notice the inclusion of what looks to be some assistance in the form of a small helicopter accompanied by a six-legged robotic device.

There are several benefits to operating a helicopter while exploring Mars. Flying vehicles can better survey large areas of terrain far more efficiently than land-bound rovers, and a helicopter’s ability to take off and land vertically means there are very few areas it can’t access.

However, the incredibly thin atmosphere on Mars means helicopters have to generate significantly more lift than what would be required on Earth.

The record for the highest altitude achieved by a helicopter was set by French test pilot, Jean Boulet, in the Aerospatiale SA315 ‘Lama’ in 1972.

A legendary figure in the industry, the Frenchman rose to a height of just over 12 400 metres above sea level before the Lama’s engines began to seize in the low-oxygen air when Boulet decided to cease climbing.

Chinese aerospace engineers will have to design a helicopter that needs to overcome an equivalent altitude starting at 30 000 metres above sea level – more than double the record set on Earth, if the craft is to become airborne.

The vehicles selected for the Tianwen-3 voyage include a lander for the mission’s arrival and a launcher for once the up to half-kilogram of sample materials have been collected in one stack.

The second Long March 5 rocket will launch the final stack, consisting of the mission orbiter and return craft into space, according to a presentation made at the International Conferences of Deep Space Sciences held in Hefei between the 23^rd and 27^th of April.

The samples could be retrieved from depths reaching 1.8 metres below the surface, thanks to a robotic arm and drill combination featured on one of the mission’s robotic assistants.

Chinese engineers are selecting a suitable landing site for Tianwen-3 and have prioritised locations with geological diversity and, most importantly, evidence of the presence of water, past or present, according to the astronomy website, Space News.

If CNSA’s planning process goes off without delay, analysts say Tianwen-3 could return its haul of precious red soil back to Earth as soon as 2031, a full three years after take-off.

https://interestingengineering.com/innovation/china-mars-sample-return-mission