Why can't humans fly to Mars yet?

Hello, humans have been able to fly into space, walk on the moon, which makes many people think: "setting foot on Mars is similar, it's just flying to Mars and landing only.", But the truth is that getting to Mars is a hundred times more difficult than going to the moon. Why is it so difficult to set foot on Mars?, let's find out in this video.

Up to now, the whole world has carried out 45 missions to launch spacecraft to Mars, mainly carrying research equipment on this planet, but not bringing humans. Even so, only 19 missions succeeded, the rest were mostly failures and each time like that hundreds of millions of dollars went up in smoke, a lower success rate than failure has shown us that flying to Mars is really difficult, but why is it difficult?

 

The first is the distance. It is much farther from Earth to Mars than from Earth to the Moon, because both Earth and Mars revolve around the same Sun, the position and distance between Earth and Mars is constantly changing. But even at the closest, they are still 55 million km apart and each time they are so close, they have to wait up to 2 years. However, 55 million km is not a problem, but in fact to fly from Earth to Mars, spacecraft must fly in an elliptical orbit known as the Hohmann transition orbit, you can see in the picture.

 

Why fly like that?, it is simply because both Earth and Mars revolve around the sun with their own orbits, so we cannot fly directly from earth to Mars. To fly to Mars, scientists must calculate the orbit to be the most economical but still have to ensure the technical factors to be able to land on this planet, so the most optimal orbital distance that NASA calculates is 480 million km and the spacecraft must travel in about 7 months. On this long orbit, errors can completely occur and ruin the entire mission.

 

For example, the Soviet Mars 2MV-4 and Mars 1971C spacecraft had technical problems and could not get to Mars, or NASA's climate probes or Japan's Nozomi spacecraft flew to Mars but due to a programming error that came too close or did not guarantee the required speed, resulting in a failed landing.

 

Maybe many of you will think that just flying to Mars and then landing we will control later but no, the process of flying to Mars and landing on it is completely automatic, must be programmed in advance, why?

 

The answer is still the distance, the time it takes for light and electronic signals to travel from Mars to the nearest Earth also takes 3 minutes and up to 22 minutes away. Therefore, a signal sent from the earth to the ship or vice versa from the ship to the earth will take many minutes to arrive.

 

Just imagine if texting your lover for 3 minutes without replying, she's already mad, let alone this is a ship moving at a speed of tens of thousands of kilometers per hour, but the command came after many minutes, the control was no longer effective, sometimes the ship has broken up and the signal has not arrived yet. So everything still has to be prepared in advance, the ship is forced to land on its own and succeed, with the shabby computers of the 1970's, programming the automatic ship like that was just unbelievable.

 

Then, if they have successfully flown 480 million km, the spacecraft will have to face a second challenge, which is the atmosphere of Mars. If the moon has almost no atmosphere, spacecraft can land vertically thanks to reverse boosters or the earth has a thick atmosphere that makes it possible for ships to glide and land lightly, Mars has a thin atmosphere, cannot glide like the earth nor land vertically. And to be able to land safely on the surface of Mars, scientists had to calculate that it had to land at exactly 12 degrees of inclination, otherwise it would burn up or turn into scrap because of the strong impact.

 

The process from reaching the Martian atmosphere to successful landing will take 7 minutes, people call it 7 minutes of horror. This is the decisive moment, if the failure of hundreds of millions of dollars and years of research, testing, design and launch, all will disappear.

 

First of all, to successfully land, the heat shield must work well, it must ensure to absorb most of the kinetic energy generated by the ship's friction with the atmosphere, slowing the ship from speeds above 20,000 km/h until it only 1,600 km/h, this process takes 2 minutes. In addition, it must protect the entire equipment in the ship from the heat generated by friction easily exceeding 1,000 degrees Celsius.

 

After passing the first 2 minutes, the ship will be about 10 km above the ground, at which point the landing will begin. Because the atmospheric pressure on Mars is only 1% of that on Earth, landing will be extremely difficult because the thinner the air, the harder it is to stop the spacecraft. To solve this problem, people have designed a parachute for the ship, usually consisting of a large parachute and possibly multiple parachutes, combined with it is a booster rocket to support the ship as it gradually touches the ground.

 

This is a process that requires extreme precision because the lowering process is completely automatic with no operator, so everything has to be perfect. First the altimeter must measure correctly, if it's wrong, then everything is wrong, the ship will rely on the altitude to automatically release the heat shield, if it's released early, the ship will burn, but if it's released late, the ship will be heavy, the parachute doesn't brake in time, the parachute also has to be on at the right time. Then the booster rocket must be activated correctly, soon it will run out of fuel or late it will not be able to stop the ship and many other factors, just one mistake and everything will fail.

 

So, you see that everything has to be perfect for the ship to land successfully, but this is just putting robots on Mars, and putting people on will have to face problems with weather, temperature, food, living space and the psychology of astronauts. So sending people to Mars is really a very difficult goal, thank you for watching the video, goodbye and see you again.