“If we would have had the laser range-finders, we would have nailed the landing.”
Moon Tipper
Over the last two months, two separate Moon landers have successfully survived the harrowing journey down to the lunar surface – but neither stuck the landing, each embarrassingly falling over as a result.
Last month, NASA’s Odysseus lander, built and operated by Houston-based space company Intuitive Machines, kept moving sideways after making it down to the surface, scraping along the surface and eventually toppling over.
As reported, that may have something to do with its considerable height of 14 feet, including solar arrays; something so tall and top-heavy is bound to struggle to stay upright.
Unfortunately, the lander was also missing some crucial data. During its descent, its laser instruments meant for measuring altitude stopped working, leading to the lander’s continued sideways movement, which sealed its fate.
“If we would have had the laser range-finders, we would have nailed the landing,” Intuitive Machines CEO Steve Altemus told reporters last week.
Trip and Tumble
Former NASA engineer Philip Metzger tweeted his own explanation for why the “lunar environment makes everything tippier.”
“The side motion that can tip a lander of that size is only a few meters per second in lunar gravity,” he concluded.
As a result, Metzger argued that landing legs would have to be two and a half times as wide on the bottom on the Moon compared to the Earth.
“I’m sure the [NASA’s Commercial Lunar Payload Services] contractors know this and designed for it,” he argued. “My point is that the Moon does this to your hardware, so when things go wrong (as they do) then tipping happens more often than on Earth.”
Intuitive Machines was well aware of the considerable height of its lander, of course. Engineers had to take a whole host of factors into consideration when designing it, including the overall weight and surface area of insulation.
Altemus told the NYT last year that the height was largely due to the configuration of its liquid methane and oxygen propellant tanks, which were stacked on top of each other for balance.
Per the report, spreading out the load over a number of tanks likely would’ve added a considerable amount of complexity and potential points of failure.
However, Odysseus’ height also came with a potential advantage: if it were to have stayed upright, the solar arrays at the very top would’ve been able to stay out of the Moon’s long shadows longer when the Sun was setting.
But given its disastrous tumble, it never got the chance to stand tall and proud.
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Over the past two months,
two separate Moon landers faced a common misfortune – they failed to stick their landing on the lunar surface. The landers, each built and operated by different organizations, embarrassingly fell over after reaching their destination. One such example is NASA’s Odysseus lander, developed by Houston-based space company Intuitive Machines. Upon reaching the surface, it began moving sideways, ultimately toppling over altogether.
The primary reason behind these landing failures can be attributed to the significant height of the landers themselves. In the case of Odysseus, reported to be 14 feet tall, this considerable height caused instability during the landing process. The presence of solar arrays added to the top-heaviness, making it even more challenging for the lander to maintain its upright position.
Besides the height issue, inadequate data further contributed to the unsuccessful landings. During the descent, the laser instruments responsible for measuring altitude on Odysseus ceased functioning, resulting in the lander’s continued sideways motion. This lack of crucial data ultimately sealed its fate.
According to Intuitive Machines CEO Steve Altemus, if the laser range-finders had been operational, the landing could have been a success. The absence of this essential technology proved to be a significant setback for the mission.
Notably, former NASA engineer Philip Metzger took to Twitter to provide his insights into the peculiar challenges posed by the lunar environment. He explained that the relatively small side motion, only a few meters per second in lunar gravity, can easily tip a lander of that size. Metzger argued that to counter this effect, landing legs on the Moon should be two and a half times wider at the bottom compared to those used on Earth. He emphasized that landing failures occur more frequently on the Moon due to its unique gravitational conditions.
In the case of the Odysseus lander, its considerable height was a design consideration. The engineers at Intuitive Machines had to account for various factors, including weight distribution and insulation surface area. As mentioned in a previous New York Times report, the height of Odysseus primarily resulted from the configuration of its propellant tanks, which were stacked for balance. Although spreading the load across a greater number of tanks could have provided an alternative solution, it would have introduced complexity and potential points of failure.
Interestingly, if the lander had managed to stay upright, the solar arrays at the top would have remained in sunlight for an extended period even after sunset, thanks to the height advantage. Unfortunately, due to the unfortunate tumble, the lander could not capitalize on this potential benefit.
The recent Moon landing failures and the associated challenges shed light on the intricate complexities of lunar missions. Designing spacecraft for the Moon requires meticulous planning, accounting for the unique gravitational conditions and potential tipping hazards. As space exploration continues to advance, organizations like Intuitive Machines and NASA’s Commercial Lunar Payload Services will undoubtedly learn from these experiences and further enhance future lunar mission designs.
This relentless pursuit of exploration and innovation will pave the way for humanity to realize ambitious objectives, such as establishing a sustainable presence on the Moon and eventually venturing further into our solar system. With each mission, successful or otherwise, we gain valuable insights and lessons that propel us towards a future where space exploration is an integral part of our existence.
As we look ahead, it is essential to acknowledge the efforts of organizations like Intuitive Machines and the discoveries made by scientists and engineers in pushing the boundaries of human knowledge. By embracing the challenges posed by celestial bodies like the Moon, we unlock new possibilities, technologies, and scientific breakthroughs that will shape our collective future.
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