
On Saturday, May 16th, 2021, China became only the second nation in the world to successfully land a rover on the surface of Mars.
The 240-kg Zhurong rover touched down on the dunes of southern Utopia Planitia a few minutes after midnight, UTC (19:00 US Eastern on Friday, May 15th), some nine minutes after the lander and rover combination entered the Martian atmosphere.
The two form a part of the Tianwen-1 (Heavenly Questions) mission, operating alongside the mission’s titular orbiter, which arrived in Mars orbit in February this year. For the three months since that event, the orbiter has, as part of its overall mission, been surveying Utopia Planitia – a location first visited in the 1970s by NASA’s Viking 2 mission – in order for mission managers to confirm the best touch-down point for the lander / rover combination.
Following their separation from the Tianwen-1 orbiter, the lander and rover entered the Martian atmosphere protected by a heat shield and aeroshell, to commence an Entry Descent and Landing (EDL) very similar in nature to US Mars surface missions.

While China has successfully landed missions on the Moon – Chang’e 5 with its surface rover is still operating – a landing on Mars is far more complex in nature, simply because of the presence of an atmosphere that, while tenuous, nevertheless interacts with a vehicle to increase the potential for things going wrong.
However, Zhurong (named for a god of fire and of the south), completed the first part of its descent successfully, using the frictional heat generated be entry into the atmosphere to slow itself to a point where a supersonic parachute could be deployed by the aerodynamic backshell, which in turn triggered the jettisoning of the heat shield, exposing the lander / rover.
Approaching the ground, Zhurong deployed its landing legs whilst still attached to the aeroshell, prior dropping clear. once free, the lander’s rocket motor fired moving it clear of both the aeroshell and the parachute. As well as continuing to slow the craft in its descent, the rocket motor and the lander’s reaction control system worked with a downward-looking radar scan for potentially harmful surface obstacles, the motors then steering the craft away from them. The main motor then continued firing as the vehicle descended over its landing site, cutting out a couple of metres above the ground to let the lander make a soft, unpowered touchdown.
Carried out entirely autonomously, the landing appears to have been a complete success, although China has yet to confirm the precise time of touch-down or the overall status of the lander and rover. Following landing, the rover deployed its solar panels in order to commence charging its systems, while the mission control team work to carry out initial checks of the rover and prep its camera systems to take a complete a panoramic image of the landing area – although at the time of writing, images from the lander / rover had yet to be confirmed as being received.
Zhurong is roughly the size of NASA’s Spirit and Opportunity rovers and like them, is solar-powered, although it is around 55 kg heaver. It carries a payload of six science instruments, including a laser-induced breakdown spectroscopy instrument for analysing surface elements and minerals, panoramic and multispectral imagers, a climate station, magnetometer and a ground-penetrating radar.
With an initial primary mission period of 90 sols (around 93 terrestrial days), the mission aims to return data on potential water-ice deposits, weather, topography and geology, complementing science carried out by missions from other space agencies. Given the nature of Mars missions and China’s record on the Moon with Chang’e 5, should the rover survive the initial primary mission period, its work on Mars will likely be extended.
James Webb Tests Mirror a Final Time, but Launch likely to be Delayed
The James Web Space Telescope (JWST) unfolded its massive mirror for the final time whilst on Earth in a last test before it undergoes preparations for launch.
The 6.5 metre diameter mirror is a complex mechanism made up of 18 hexagonal sections, 12 of which form the main part of the mirror and the remaining six form two fold-out elements on either side. For launch, the mirror is folded down against the main sun shield that will protect it from the heat and light of the Sun once it is in space., and the two flanking sections folded back against it.

The May 11th test saw the entire telescope supported by a special crane to simulate zero gravity, allowing engineers to run the software that will control the mirror’s unfurling using 132 individual actuators. These actuators raise the mirror, then unfold the side panels before gently bending or flexing the 18 individual mirror segments to align and focus them on the telescope’s secondary mirror that directs the light caught by the primary into the instrument aperture at the centre of the primary.
Following the deployment test, the mirror was returned to its folded and stowed position. Later this year, the 6.5 tonne 20 x 14 metre telescope will be stowed in a climate controlled shipping container for a 2-week trip to the European rocket facility at Kourou in French Guiana. Once there, it will be integrated into the payload fairings of a European Ariane 5 rocket ready for a launch currently planned for the end of October.
That is, if the Ariane 5 cleared for launch.
Normally one of the most reliable launch vehicles on the market, the rocket has been grounded after the two last launches suffered issues with the payload fairing separation process – although the payloads from both flights were successfully place in orbit. Investigations into the issues are still in progress, but Arianespace has two launch commitments ahead of JWST, and so it is likely at the telescope’s launch will be delayed – the last in a long series of delays for JWST, all of which will hopefully mean that once it has been launched, the telescope will go on to be highly successful, operating in a halo orbit around the Lagrange L2 position on the opposite side of Earth compared to the Sun, and some 1.5 million kilometres from Earth.
Continue reading “Space Sunday: China on Mars, JWST and a space tourist”






















