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.
SpaceX Reveals Details of First Starship Orbital Flight
Papers filed with the Federal Aviation Authority (FAA) have revealed details of the first orbital flight SpaceX plans to attempt with its first starship / Super Heavy flight.
Due to comprise the first Super Heavy booster prototype to be fully constructed – number BN3 – and starship vehicle SN20, the flight will lift-off from the SpaceX facilities at Boca Chica, Texas. Two minutes and 49 seconds after launch, the booster will separate and commence a return to Earth, while SN20 continues up to orbit.
Following a “boost back” manoeuvre similar to those used with Falcon 9 first stages, the massive Super Heavy will descend to a point 32 km out to sea from the Texas coastline in the Gulf of Mexico. It’s not clear from the papers if this will be to land on a platform or simply splashdown in the sea – as happened with early Falcon 9 flights.
Meanwhile SN20 will continue around the Earth to perform a de-orbit burn as it starts its pass over the Pacific Ocean, and will splashdown in what SpaceX is calling “powered targeted landing” 100 km north-west of the Hawaiian island of Kauai approximately 90 minutes after lift-off.
Both of the water landings are intended to minimise the risk of either the booster or SN20 causing damage to life or property should anything go wrong – and given this will be the first flight of he Super Heavy, there is potentially a lot that could go wrong.
The plans have caused some speculation that SpaceX will suspend further starship flights in favour of focusing on this orbital attempt. However, the papers only request a 6-month Earth-pace communications window commencing on June 20th. As it is, any Super Heavy flight is contingent on the satisfactory completion of a FAA environmental assessment of the possible impact of Super Heavy launches from Boca Chica. Further, the BN3 prototype is still being fabricated / assembled, as are the launch facilities needed for Super Heavy / starship launches.
In the meantime, SN15 the first starship prototype to achieve a successful landing, has been moved from the landing pad following its flight and mounted on one of the two starship launch stands. It is anticipated that while there, the vehicle’s engine skirt will be more extensively examined for damage and six new landing legs will be fitted.
While SpaceX have not confirmed anything, it is also possible that one of the Raptor engines on the vehicle will be replaced. During the final phase of the vehicle’s flight, all three Raptors should have re-started ahead of the “flip-up” manoeuvre to raise the vehicle to a vertical orientation. However, only two of the motors actually re-started, indicating there may have been a issue with the third.
Whether or not SN15 will be turned around for a further flight is still unclear, but rather than moving SN16 to a launch stand as had been expected, that vehicle remains stowed in the assembly mid-bay assembly building.
Blue Origin to Fly Passengers in July
Blue Origin, the commercial space launch / space tourism company has announced it will undertake its first crewed launch of its sub-orbital New Shepard vehicle on July 20th, 2021. The flight will primarily comprise a trained flight crew – but one seat is being auctioned to the highest bidder, with all proceeds going to Blue Origin’s foundation, Club for the Future.
The auction was announced on the 60th anniversary of the first crewed flight to space by an American astronaut, Alan Shepard, for whom the vehicle is named, who completed his sub-orbital flight on on May 5th, 1961 aboard the Freedom 7 capsule.
Phase One of the auction began on May 5th with sealed on-line bidding (all bids are kept hidden on the auction website. Phase Two, comprising open bidding on-line will commence and run through until June 12th, when a live auction will be held on-line, after which the winning bid will be announced. The winner will join the crew on condition of them passing essential training and suitable fitness tests.
The flight will lift-off from the company’s launch facility near the town of Van Horn in West Texas. On reaching an altitude of 6.7 km, the crew capsule will separate from its launcher, which will continue on its own trajectory before it makes a return to the landing zone at the launch facilities.
The capsule will continue upwards on its own, reaching an apogee of around 100 km altitude, and those on board will experience around 3 minutes of weightlessness. The capsule will then descend back into the denser atmosphere, during which the crew will experience around 5.5 gee, then descend under parachute before using rocket motors to cushion touch-down on landing.
Blue Origin have not released how much tickets for future flights will be sold for, but Virgin Galactic are already selling tickets for their sub-orbital flights at US $250,000 apiece.