Odysseus touchdown: Why it took 50 years for the US to return to the Moon

A United States company has gone to the Moon and with that has entered history books. Houston-based Intuitive Machines became the first commercial outfit to put a spacecraft on the lunar surface after its Odysseus robot landed near the lunar south pole.

“Houston, Odysseus has found its new home,” the company’s Chief Technology Officer Tim said as the robot touched down on the lunar surface after experiencing a few initial hiccups.

With this success, the US has returned to the lunar surface after an absence of over 50 years. The last time an American presence on the Moon was the Apollo mission in 1972. US space agency NASA’s administrator Bill Nelson congratulating Intuitive Machines said: “The US has returned to the Moon.”

But as America celebrates this landmark, why is it that even after 55 years since humans first landed on the Moon, is the task so difficult? What makes Moon landings so challenging and why have we not been able to perfect the science behind it?

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Where Odysseus succeeded, many failed

On Thursday, at 11.23 pm GMT (4.53 am IST), Intuitive Machines’ Odysseus lander touched down on the Moon’s surface, eliciting cries of celebration and cheer from its employees. However, it wasn’t all smooth sailing. The landing time was adjusted several times as Intuitive Machines adjusted the spacecraft’s orbit around the Moon.

And when it first touched down near a crater called Malapert A, close to the Moon’s south pole, there was no signal at all. However, after nail-biting minutes passed by a communications link was made and the company in a statement said: “Flight controllers have confirmed Odysseus is upright and starting to send data.”

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After troubleshooting communications, flight controllers have confirmed Odysseus is upright and starting to send data.
Right now, we are working to downlink the first images from the lunar surface.

— Intuitive Machines (@Int_Machines) February 23, 2024

After its successful landing, Intuitive Machines aims to operate Odysseus on the surface for up to seven days. As per a BBC report, one of the key investigations will be looking at the behaviour of lunar dust, which the Apollo astronauts found to be a serious nuisance, scratching and clogging their equipment. The agency’s scientists want to understand better how the dust is kicked up by landing craft to hang just above the surface before then settling back down.

However, it’s important to note here that not all lunar missions find success. Last month, Pittsburgh-based company Astrobotic attempted to send its Peregrine lander to the Moon, but the mission ended with the spacecraft burning up in Earth’s atmosphere.

Last August, Russia’s first lunar mission in over five decades, Luna-25, crashed into the Moon. Russia’s space agency had then said: “The apparatus moved into an unpredictable orbit and ceased to exist as a result of a collision with the surface of the Moon.”

Earlier in April 2023, the M1 spacecraft, built by Tokyo-based company ispace, also made an attempt to land on the Moon. However, it landed up becoming another name on the list of Moon missions that failed.

In July 2019, India’s Chandrayaan-2 also met with failure with then ISRO chief K Sivan revealing that a “small error” had led to the botched attempt. And in the same year, an attempt by the Israeli company SpaceIL ended in a crash-landing as well.

In fact, a CNN report states that overall, more than half of all lunar landing attempts have ended in failure.

The complications of a Moon mission

But why is it that we struggle with Moon landings even though Neil Armstrong and Buzz Aldrin touched down, and walked, on the Moon in the summer of 1969? Stephen Indyk, director of space systems at Honeybee Robotics in Greenbelt, Maryland told Nature.com, “What makes landing on the Moon so difficult is the number of variables to consider.”

To pull off a successful landing, engineers need to anticipate how a spacecraft will interact with this environment — and spend money testing how things might go wrong. “Tests, tests and more tests are needed to prove out the landing system in as many scenarios as possible,” Indyk was quoted as saying. “And even then, nothing is guaranteed.”

So, what are these many variables that Indyk made a mention of?

Reaching the moon: First, comes the journey to the Moon; it is arduous and a long, long way from Earth. The Moon is an estimated 3,84,400 kilometres away from us and depending on the path chosen, the distance can increase. A failure can occur anywhere on this extensive voyage.

There’s also the problem of the mode chosen to reach there. Each agency or company chooses a spacecraft of its choice and these aren’t mass produced. Also, once they are launched, they are on their own. As Jan Wörner, a former director general of the European Space Agency told The Guardian, “If you have trouble with your car, you can have it repaired, but in space there’s no opportunity. Space is a different dimension.”

Landing on the moon: And if a spacecraft survives the journey, the landing on the Moon is risky business. A spacecraft entering the lunar surface has to contend with the lack of atmosphere that can cause friction, reducing the speeds. The Moon’s atmosphere is extremely thin, which his means that slowing down is dependent on firing out bounties of propellant. Csaba Palotai, the program chair of space sciences in the Department of Aerospace, Physics and Space Sciences at the Florida Institute of Technology, explained in a Mashable report, “There’s no atmosphere, so we cannot float down. There’s nothing slowing you down except your engine.”

As the spacecraft depends on propellant to make a safe landing, space engineers have to then ensure that the module is carrying enough fuel to slow itself down. But carrying more fuel means the spacecraft is heavier.

Traversing the Moon: Unlike Earth where you have GPS to help you navigate your way, there’s no such system for the Moon. Computers have to make quick calculations and decisions to land itself and then move around on the Moon.

And this process is further complicated by the fact that the Moon has an uneven surface littered with craters and boulders and if one lands on those it could mean disaster.

Moreover, an increasing number of agencies are trying to land on the south pole of the Moon, where scientists believe ice and other valuable resources are found. However, the sun never passes overhead. It’s always near the horizon, and can cast long shadows over the ground. These shadows will warp the view of what’s below during a landing. Tom Percy, a lead Human Landing System engineer at NASA’s Marshall Space Flight Center, told Mashable: “The long shadows make it difficult to discern what the surface looks like. That’s especially challenging when you’re trying to land.”

Experts Speak

Many space scientists note that the Moon continues to be a learning for them. Malcolm Macdonald, a professor of spacecraft engineering at Strathclyde University, Scotland, was quoted telling The Hindu, “In the ’60s and ’70s, we simply didn’t understand the risks we were taking. Today, we have a better handle on those, but to overcome them, we add complexity to the solution. But complexity makes it easier to miss a mistake and for ‘anomalies’ to occur.”

They believe that even though companies may fail in Moon landings, each one of them provides insights and further learning. Scott Pace, director of George Washington University’s Space Policy Institute, speaking to CNN said it best: “Companies are failing, and some will go out of business. But if they learn from that failure and come back, now you’re going to have a strong team. This is really about educating a new generation.”

With inputs from agencies