Chapter 1: The Complexity of Martian Landings

Landing on Mars is a task fraught with difficulties. Understanding the reasons behind these challenges provides insight into the complexity of space exploration.

The InSight lander marks the latest achievement in a long line of robotic missions to Mars, following the pioneering Viking landers of 1976. Despite advancements in technology, such as the reliability of drones and robotic flight, landing a probe on the Martian surface remains an intricate and hazardous endeavor. The history of Martian exploration is riddled with failures, with only a fraction of the total missions achieving their goals.

To date, there have been 45 missions directed at Mars, beginning with the Soviet Mars 1M in 1960 and culminating with NASA's InSight, which touched down in Elysium Planitia on November 26, 2018. Out of these missions, 19 have succeeded, while 23 have failed, and 3 have had mixed results, primarily due to issues with landers.

Why is landing on Mars such a formidable task? The journey itself poses significant challenges. During the most favorable windows, the distance from Earth to Mars can be reduced to approximately 55 million kilometers. However, the actual distance traveled can exceed 450 million kilometers due to the need for an elliptical trajectory, known as a Hohmann transfer orbit, which accommodates the orbital motions of both planets.

This journey resembles a strategic play in American football, where a quarterback throws the ball not to where a receiver currently is, but to where they will be. This complexity means that any mission must account for the varying positions of Earth and Mars during transit.

In 1962, the Soviet Mars 2MV-4 spacecraft was intended for a flyby of Mars but was lost in a launch failure, illustrating the precarious nature of space missions.

Once the spacecraft is successfully launched, the next challenge is coordinating its approach to Mars. Precise course corrections are essential, and any miscalculations can lead to disastrous outcomes, such as missing the planet or crashing into its surface.

One notable failure occurred in 1999 when NASA's Mars Climate Orbiter miscalculated its entry due to a software conversion error, resulting in its demise upon arrival. Similarly, the Japanese Nozomi probe failed to achieve orbit around Mars because of a fuel leak early in its journey.

If the launch and transit are successful, the final and most critical phase is the landing itself. Due to the significant delay in radio signal transmission—averaging 12.5 minutes—real-time control during descent is impossible. Thus, all landing procedures must be automated, leading to what is often referred to as the "six minutes of terror."

The entry into Mars' atmosphere requires precise angles to avoid catastrophic failure, and the heat shield plays a crucial role in protecting the spacecraft from intense frictional heating. For instance, during the descent of the Phoenix lander, images captured by the HiRise instrument showcased the intricate process of landing.

Around 9–10 kilometers above the Martian surface, parachutes deploy to slow descent, but due to Mars' thin atmosphere, additional braking systems, such as retro-rockets, are essential. The successful execution of numerous automated maneuvers is vital to ensure a safe landing.

NASA's Curiosity rover, which weighed approximately one ton, utilized a sky crane for its final descent, a method that allowed for a gentle touchdown.

The InSight mission employed retro-rockets integrated into its design for a smooth landing.

Artistic representation of InSight's descent onto Mars, showcasing its innovative landing technology.

Despite the daunting challenges, the technology to land on Mars has existed for over 40 years. The Viking landers of the 1970s utilized similar methods to those we see today, achieving remarkable scientific milestones.

Interestingly, the first successful soft landing on Mars was accomplished by the Soviet Mars 3 probe on December 2, 1971, five years before the Viking missions. However, it only transmitted data for 15 seconds post-landing, leaving many questions unanswered.

Chapter 2: The Journey Continues

This video, "Why It's HARD To Land on Mars," delves into the complexities and obstacles faced by missions aimed at Martian exploration.

In the video "Why It's So Hard to Land on Mars," experts explain the technical challenges that have historically hindered successful landings on the Red Planet.