Explained: NASA’s rover Perseverance lands on Mars and makes it difficult to land on the Red Planet

On Thursday, NASA’s rover Perseverance is expected to land in the crater Lake on the Red Planet, after which it will continue to work on looking for signs of a past life.

The landing is the shortest, but one of the most important and at the same time the most difficult phases of the mission. NASA says that because it’s hard, only 40 percent of the missions space agencies around the world have ever sent to Mars are successful because “hundreds of things” have to go right to a nail-biting crash.

To give context to the difficulties of launching missions like this, there is the example of research mathematician Katherine Johnson. In the 2016 film Hidden figures, Taraji P. Henson played Johnson who worked on precise calculations that determined the trajectory of the capsule that would launch John Glenn into space in 1962.

Other missions to Mars

The second mission on Mars, Al Amal (hope) from the UAE – the first such mission in the Arab world –entered Mars orbit last week. However, this is an orbital mission and does not involve landing on the surface of the planet. In addition to the UAE, China launched the Mars mission during the July-August window.

In light of such ambitious space missions, some astrobiologists have expressed concern about possible ‘interplanetary contamination’. This means transporting microbes from the Earth to other celestial bodies and returning extraterrestrial microbes to Earth. The Space Research Committee (COSPAR) is establishing a ‘planetary protection policy’ that aims to limit the number of microbes sent to other planets, as well as to ensure that alien life does not wreak havoc on Earth.

How does a spacecraft get to Mars?

The usual journey to Mars, which is about 300 million miles away, takes about seven and eight months. Perseverance was launched on July 30, 2020, during a window when Mars and Earth were closest to each other. This window is important because the two planets orbit the Sun at different speeds and every two years the planets are in the position closest to each other. Space agencies want to launch spaceships during this window, because closer distance means less rocket fuel.

According to Purdue University analysis, the price of solid rocket fuel is estimated at $ 5 per kg. However, the car-sized Perseverance rover uses a nuclear-powered system. In almost 30 years, it will become the first rover to use domestic plutonium created by national laboratories in the United States. The rover will be powered by a generator that will convert the heat generated by the natural decay of plutonium-238 into electricity, which will maintain the operation of the rover and its tools as soon as it lands on Mars.

What is the cost of the Perseverance mission?

It is estimated that NASA will spend $ 2.7 billion on the mission, which includes the development of spacecraft, launch and maintenance costs of operations after it lands on Mars.

According to the Planetary Society, the use of plutonium-238 as a fuel has increased mission costs because nuclear material is associated with increased environmental and safety regulations. The total cost of the mission is equal to the amount of money Google earns in six days or the money Americans spend on their pets every 10 days, or the equivalent of 33 hours of running the U.S. Department of Defense, the company says.

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Why is landing on Mars difficult?

Entering, Landing, and Landing (EDL) is the name of the most intense phase of the Mars 2020 mission. For a Perseverance rover to successfully land on Mars, several things must go right. The EDL phase begins when the rover will reach the top of the Martian atmosphere traveling at a speed of 20,000 km per hour. The challenge for the rover is to reduce speed from approximately 20,000 km per hour to zero and at the same time land on a narrow surface on the crater.

The EDL phase, NASA says, will end in seven minutes when the rover will rest on the planet’s surface. After that, the brakes should be applied in a very “careful, creative and challenging way”.

Ten minutes before entering the atmosphere, the rover will launch its cruising stage, which consists of solar panels, radios and fuel tanks used during the flight. Only the protective air shell, which consists of a rover and a landing stage, will travel to the surface of the planet. As the spacecraft enters the surface of Mars, it will slow down by traction, which is when the friction of the planet’s atmosphere acts on the spacecraft’s surface, slowing it down and lowering its orbital height.

Although the resistance slows down the spacecraft, it also heats up and peak warming occurs about 80 seconds after the rover enters the atmosphere. But this does not affect the rover, which is housed in aero leather at room temperature.

As it descends through the atmosphere, the spacecraft will have to fire small thrusters to stay on the road, as it can be pushed out of the way due to small pockets of air of varying densities. After that, the heat shield will slow down the spacecraft to about 1,600 km per hour, at which point (about 240 seconds after entry) a supersonic parachute will be set up.

Twenty seconds after the parachute is set, the heat shield separates and the rover is exposed to the planet’s atmosphere for the first time. At this moment, the parachute is working on an additional deceleration of the vehicle. But since the atmosphere of Mars is thin, the vehicle still travels to the surface at a speed of 320 km per hour. Therefore, for a safe landing, the rover must leave the parachute and do the rest of the journey with rockets, part of the descent stage, whose engines will be started when the rover is about 2,100 meters above the surface.

The final speed of the rover’s descent is about 2.7 km per hour, which is slower than what the average person can cross on foot in an hour – about 5 km. At this stage, there are about 12 seconds left to touch the surface at about 66 feet above the surface, the rover descends to a set of cables. When the rover feels that its wheels have touched the ground, it cuts the cables, which then land on the surface independently and uncontrollably, somewhere away from the rover.

The United Atlas V launch vehicle carrying NASA’s Mars 2020 Perseverance Rover will take off from Cape Canaveral Air Force Base in Cape Canaveral, Florida, USA, on July 30, 2020 (NASA / Joel Kowsky / Handout via Reuters)

What will the rover Perseverance do on Mars?

Perseverance will spend one Martian year (two years on Earth) on the planet during which it will explore the region of the landing site. The crater Lake where it will land was once the site of an ancient river delta (scientists know this from evidence gathered during previous landed and orbital missions that point to wet conditions on the planet billions of years ago).

If Mars once had a warmer atmosphere that allowed water to flow in the distant past (3.5-3.8 billion years ago), and if microbial life existed on it, it is possible that it still exists in “special regions” today.

The Rover carries with it seven instruments that include an advanced camera system with zoom capability, a SuperCam, an instrument that will provide image and chemical composition analysis, and a spectrometer. However, one of the most interesting instruments on the rover is called MOXIE, which will produce oxygen from atmospheric carbon dioxide in the atmosphere of Mars. If this instrument is successful, then future astronauts (so far no man has set foot on Mars) can use it to burn rocket fuel to return to Earth.

The Rover will also carry the Ingenuity, the first helicopter to fly on Mars. This will help collect surface samples from places the rover cannot reach. All in all, the rover is designed to study the signs of ancient life, collect samples that could return to Earth during future missions, and test new technology that could benefit future robotic and human missions on the planet.