How to Land on Mars and Why is that Difficult?

The landing of the Mars rover Perseverance is nearing, and everyone who wants to explore space has thought about how to land on Mars. In this article, we’ll walk you through the procedure of a Mars landing and you’ll know just how arduous it is.

Years of Planning and Preparing

Firstly, the team has to plan the mission, probably taking years to complete. They have to observe the current mysteries and set scientific goals. Then, designing the spacecraft according to the goals is necessary to provide scientific value. You want a Mars mission to have some benefits for humans, right?

The mission team has to draw some drafts, select materials and parts earnestly, and rigorously test every component with the harshest conditions they will ever encounter.

All in all, these preparations and plannings take years to complete. To learn more about the procedures of creating a useful thing, please visit this page.

The Launch

To land on Mars, the spacecraft must arrive there beforehand. Therefore, launching the probe to space is essential, and the team has to choose the right rocket to achieve this. That’s because a spacecraft needs to reach Earth’s escape velocity to reach another planet.

Furthermore, the probe must align with Mars properly. There is a launch window every 26 months that makes it possible to take the most efficient and shortest path. Otherwise, the spacecraft could take years to intercept with Mars, and fuel would have run out.

En Route

After the launch, the spacecraft still has a long way to go. In fact, it took 8 months for Curiosity from launch to landing, and it takes a bit less than 7 months to do so on Perseverance.

Unfortunately, mistakes are always made, and sometimes they can spoil the entire mission. Therefore, the mission team will check the spacecraft’s equipment and health regularly and correct its path multiple times to ensure it lands at the right location.

The Entry, Descent, and Landing (EDL)

The entry, descent, and landing stage is ready when the solar panels eject from the spacecraft, known as the “Cruise Stage Separation”. After that, the EDL (Entry, Descent, and Landing) phase begins with the aeroshell (the spacecraft without the cruise stage) hitting the top of the atmosphere.

Afterward, the heat shield at the bottom of the aeroshell heats up to more than 1,000 Celsius due to the friction with the Martian atmosphere. Therefore, the shield should prevent the spacecraft from overheating during atmospheric entry.

But, slowing down from pure friction is not enough, and we have to increase it. That’s where a parachute comes into play. It brings the speed down significantly, but it’s still not enough to ensure a safe landing. Therefore, the only choice is to eject the heat shield, make the lander navigate, and release the descent stage at the right time.

When the lander is released from the backshell, it has to divert in time to prevent them from colliding with each other. It then uses rocket engines to slow it down and navigate it toward the ground.

The Final Approach

To land safely, we have to get the final approach to the surface right, or the spacecraft will crash. That depends on which type of lander you have.

If it’s a small rover or lander the airbags have to be inflated and use rocket engines on the backshell. Once it hits the surface, it bounces until it stops.

It’s easier to understand with a lander: Some rocket engines are installed on the lander to slow it down during landing, and it will touch down using its legs. A rover can be rolled out of the lander, too.

However, if it’s a larger one, the lander must use a more sophisticated maneuver: The sky crane maneuver. Firstly, the lander releases with its jetpack called the descent stage. Once it’s a few meters from the surface and has slowed down to a safe speed, the cables that connect the descent stage and the rover deploys, allowing its wheels to touch down without the air released by the rocket damaging its sensitive components.

But, the spacecraft faces a problem: If it only uses that method, the descent stage will fall on the rover when it stopped on touchdown! So, the cable needs to be cut off immediately on touchdown, and the descent stage will fly to a safe location, far from the rover.

Conclusion

So, here is the approximate procedure of a Mars landing. It seems complex, right? The stakes are high! Hundreds of things need to be lined up with perfection to achieve a successful and safe landing. If you’re interested, please check out the references below.

References and Credits

1. (2016, October 29). Student Video: Mars in a Minute: How Do You Get to Mars? | NASA/JPL Edu. Retrieved February 5, 2021, from https://www.jpl.nasa.gov/edu/learn/video/mars-in-a-minute-how-do-you-get-to-mars/
2. (2017, November 14). How Long Does It Take to Get to Mars? | Space. Retrieved February 5, 2021, from https://www.space.com/24701-how-long-does-it-take-to-get-to-mars.html
3. (n.d.). Cruise – NASA Mars – NASA’s Mars Exploration Program. Retrieved February 5, 2021, from https://mars.nasa.gov/mars2020/timeline/cruise/
4. NASA Jet Propulsion Laboratory. Mars in a Minute: How Do You Land on Mars? – YouTube. Retrieved February 5, 2021, from https://www.youtube.com/watch?v=8-X8acD_r38
5. (n.d.). Mars 2020 Entry Descent Landing. Retrieved February 28, 2021, from https://eyes.nasa.gov/apps/mars2020