Feb 23 2024

Odysseus Lands on the Moon

December 11, 1972, Apollo 17 soft landed on the lunar surface, carrying astronauts Gene Cernan and Harrison Schmitt. This was the last time anything American soft landed on the moon, over 50 years ago. It seems amazing that it’s been that long. On February 22, 2024, the Odysseus soft landed on the Moon near the south pole. This was the first time a private company has achieved this goal, and the first time an American craft has landed on the Moon since Apollo 17.

Only five countries have ever achieved a soft landing on the moon, America, China, Russia, Japan, and India. Only America did so with a crewed mission, the rest were robotic. Even though this feat was first accomplished in 1966 by the Soviet Union, it is still an extremely difficult thing to pull off. Getting to the Moon requires powerful rocket. Inserting into lunar orbit requires a great deal of control, on a craft that is too far away for real time remote control. This means you either need pilots on the craft, or the craft is able to carry out a pre-programmed sequence to accomplish this goal. Then landing on the lunar surface is tricky. There is no atmosphere to slow the craft down, but also no atmosphere to get in the way. As the ship descends it burns fuel, which constantly changes the weight of the vehicle. It has to remain upright with respect to the lunar surface and reduce its speed by just the right amount to touch down softly – either with a human pilot or all by itself.

The Odysseus mission is funded by NASA as part of their program to develop private industry to send instruments and supplies to the Moon. It is the goal of their Artemis mission to establish a permanent base on the moon, which will need to be supported by regular supply runs. In January another company with a NASA grant under the same program, Astrobotic Technology, sent their own craft to the Moon, the Peregrine. However, a fuel leak prevented the craft from orienting its solar panels toward the sun, and the mission had to be abandoned. This left the door open for the Odysseus mission to grab the achievement of being the first private company to do so.

One of the primary missions of Odysseus is to investigate is the effect of the rocket’s exhaust on the landing site. When the Apollo missions landed the lander’s exhaust blasted regolith from the lunar surface at up to 3-4 km/second, faster than a bullet. With no atmosphere to slow down these particles, they blasted everything in the area and went a long distance. When Apollo 12 landed somewhat near the Surveyor 3 robotic lander the astronauts then walked to the Surveyor to bring back pieces for study. They found that the Surveyor had been “sandblasted” by the lander’s exhaust.

This is a much more serious problem for Artemis than Apollo. Sandblasting on landing is not really a problem if there is nothing else of value nearby. But with a permanent base on the Moon, and even possibly equipment from other nation’s lunar programs, this sandblasting can be dangerous and harm sensitive equipment. We need to know, therefore, how much damage it does, and how close landers can land to existing infrastructure.

There are potential ways to deal with the issue, including landing at a safe distance, but also erecting walls or curtains to block the blasted regolith from reaching infrastructure. A landing pad that is hardened and free of loose regolith is another option. These options, in turn, require a high degree of precision in terms of the landing location. For the Apollo missions, the designated landing areas were huge, with the landers often being kilometers away from their target. If the plan for Artemis is to land on a precise location, eventually onto a landing pad, then we need to not only pull off soft landings, but we need to hit a bullseye.

Fortunately, our technology is no longer in the Apollo era. SpaceX, for example, now routinely pulls off similar feats, with their reusable rockets that descend back down to Earth after launching their payload, and make a soft landing on a small target such as a floating platform.

The Odysseus craft will also carry out other experiments and missions to prepare the way for Artemis. This is also the first soft landing for the US near the south pole. All the Apollo missions landed near the equator. The craft will also be placing a laser retroreflector on the lunar surface. This is a reflector that can return a laser pointed at it directly back at the source. Such reflectors have been left on the Moon before and are used to do things like measure the precise distance between the Earth and Moon. NASA plans to place many retroreflectors on the Moon to use as a positioning system for spacecraft and satellites in lunar orbit.

This is all part of building an infrastructure for a permanent presence on the Moon. This, I think, is the right approach. NASA knows they need to go beyond the “flags and footprints” style one-off missions. Such missions are still useful for doing research and developing technology, but they are not sustainable. We should be focusing now on partnering with private industry, developing a commercial space industry, advancing international cooperation, developing long term infrastructure and reusable technology. While I’m happy to see the Artemis program get underway, I also hope this is the last time NASA develops these expensive one-time use rocket systems. Reusable systems are the way to go.


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