DiscourseMay 5, 2021 09:19:44 IST
Recently, NASA landed the largest rover ever on Mars and its partner, ingenious helicopter, both of which have set new milestones since then.
The next visitor on the planet is a lander from Operation Tianwen-1, who is trying to reach the surface of Mars in mid-May. To get to the Martian atmosphere, it uses a slightly different technique than previous missions.
Landing on Mars is known to be dangerous – more tasks have failed than succeeded. A successful landing on Mars requires access to the atmosphere at very high speeds and then deceleration of the spacecraft in the right way as it approaches its landing site.
This phase of the operation, known as the start count, is the most critical. In previous missions, several different ways have been used for the atmosphere of Mars.
Improving access to the Martian atmosphere has been aided by the experience of returning spacecraft to Earth. The Earth may have a significantly different atmosphere than Mars, but the principles remain the same.
The spacecraft orbiting the planet moves very fast to keep itself tied to that orbit. But if the spacecraft arrived in the atmosphere at such a high speed, even as thin as Mars, it would return. Everything that enters the atmosphere must be significantly slowed down and the heat generated during this short journey must be rid of. There are several ways to go about it.
The spacecraft are protected from the heat generated during entry into the atmosphere by thermal protection. Previous assignments have used techniques such as heat absorption, insulating coating, reflecting heat back into the atmosphere, or burning ablation protection material.
On the duties of Apollo in the 1960s the newer SpaceX dragon, these techniques have been used successfully and they work really well on earth. But when it comes to Mars, engineers need to take some extra steps.
Landing on Mars
Orbits are designed to follow the planet’s surface from orbit and act as a relay station for communication. As you approach the planet, the spacecraft is usually guided sequentially along smaller elliptical orbits that slow down each time until it reaches its target orbit. This technique can also be used to calculate the orbit of a spacecraft before it enters the landing atmosphere.
The whole start-up takes a few months and requires no additional equipment – an effective way to save fuel. Because it uses the Earth’s upper atmosphere to apply the brakes, it is called aerobraking. Aerobraking has been used for a variety of Mars missions, including ExoMars Trace Gas Orbiter and Mars Reconnaissance Orbiter.
Aerobraking can significantly slow down a spacecraft, but with landing drivers it becomes more difficult. On Mars, the density of the atmosphere is only one percent of the earth, and the spacecraft cannot be safely splashed in the oceans. The dull shape of a spacecraft alone is not enough to reduce speed.
Additional measures have been used in previously successful assignments. The Mars Pathfinder used parachutes to slow down while relying on a unique airbag system that ignited during the last seconds dampen the descent blow. Spirit and Opportunity riders successfully landed on Mars with the same technology.
A few years later, Curiosity used a new invoicing system. In the last few seconds, rockets were fired that allowed the spacecraft to hover, while a belt – a sky crane – landed on Rover’s dusty surface of Mars. This new system showed a Bheavy payload for Mars and paved the way for larger tasks.
The Perseverance driver, who recently landed in early 2021, also used a reliable articulated crane two more advanced technologies. These new features which used live images taken from its cameras, allowed for a more accurate, reliable, and safer landing.
Zhurong: ‘fire god’
The Chinese Tianwen-1 landing is the next mission of Mars. The ambitious mission has rotating, descending and moving components – the first mission that includes all three in its first attempt. It has already been orbiting the red planet since it arrived on the Martian orbit on February 24 and is trying to land its rover Zhurong – which means fires – in mid-May.
Completely, Zhurong falls between the Spirit and perseverance and carries it six scientific devices. After landing, Zhurong explores the environment to study the soil, geomorphology, and atmosphere of Mars, as well as looking for signs of groundwater ice.
Traditionally, the Chinese authorities did not disclose much information before the incident. However, based early an overview of the task Some Chinese scientists know the landing sequence that the spacecraft is trying to follow.
On May 17, Zhurong – protected by an aeroshell (a protective shell surrounding the spacecraft that includes a thermal shield) – enters the atmosphere at a speed of four km / s. When it slows down enough, parachutes are deployed. In the last stage of the cycle, rockets with variable thrust motors are used for deceleration.
Unlike its American counterpart, the Tianwen-1 uses two reliable techniques – a laser rangefinder to determine the terrain of Mars and to determine the speed of the microwave sensor more accurately. These are used for navigation correction during parachute landing. At the end of the force descent phase, the optical and Lidar imaging helps identify hazards.
Just before touching, the automatic obstacle avoidance period begins for a soft landing. If the operation succeeds, China will be the first country to land a rover on Mars with its first attempt. A few days after that, Zhurong is ready to explore the surface.
Deep Bandivadekar, Doctoral Student, University of Strathclyde