Lunar round trip: How long would it take to walk around the Moon?

12th Jul 2022
Lunar round trip: How long would it take to walk around the Moon?

Earth is the fifth-largest planet in the solar system, with a great circle circumference of 40,000 km. At the beginning of the 16th century, it took Ferdinand Magellan three years to overcome this distance by sea. The first trip around the world was full of dangers and claimed the lives of many crew members, including Magellan himself. In 1889, journalist Nellie Bly, inspired by Jules Verne’s novel Around the World in 80 Days, set a world record by circumnavigating the Earth in 72 days and 6 hours. And 14 years later, the Wright brothers came up with an airplane, and it became possible to fly around the Earth in less than a month. Compared to the first flights into space, round-the-world travel finally ceased to be something extraordinary, and humanity rushed to conquer new horizons — the Moon.

From 1969 to 1972, 12 NASA astronauts walked on the Moon, but then the lunar program was closed due to high costs and low scientific value. Sixty years later, NASA announced its intention to return to the Moon to build a permanent base there and use this base as a waypoint for flights to Mars. And this means that soon, walks on the Moon may become as common as they are on Earth. We decided to find out how long it would take to walk around the Moon and what challenges one would have to overcome on this journey.

How long did Neil Armstrong walk on the Moon?

The first person to walk on the Moon, Apollo 11 astronaut Neil Armstrong, spent a total of 21 hours and 36 minutes on its surface. Most of the time, he was in the lunar module, and the total time of his walk on the Moon was 2 hours 31 minutes. With each subsequent mission, the Apollo astronauts’ walks became longer and longer, and the last one lasted a record 22 hours. During this time, Apollo 17 astronaut Eugene Cernan went to the surface of the Moon three times, but like all his other colleagues, he did not go far from the lunar module to avoid dangerous situations.

Today, when we know much more about the Moon than Apollo astronauts did, so we can calculate how long would it take to walk around the Moon. Let’s go!

Can we walk on the Moon as easily as on Earth?

In 1997, our British countryman Robert Garside went on a round-the-world trip on foot, having spent almost six years on it. How long would it take him to walk around the Moon? The circumference of the Moon at the equator is 10,921 km (6,786 miles), which is almost four times less than the circumference of the Earth. But do not rush to divide six years by 4 to calculate the time of the round-the-Moon trip. The calculation is more complicated since the conditions on the Moon are significantly different from those on Earth.

On Earth, the force of gravity affects us, so we cannot fly on our own and even jump high. There is gravity on the Moon, too, but it is only 17% of what we experience on Earth. That is, on the Moon, your weight will be almost six times less than on Earth!!! But there’s no atmosphere, so you’ll need a spacesuit that provides oxygen and protects you from the extremes of space.

A modern NASA spacesuit weighs 130 kg by earthly standards and 22 kg by lunar standards. It consists of 14 layers, each of which performs its own function, protects against cold, and micrometeorites, restrains air pressure around the body, etc. Add more gloves, boots, helmet, display and control module here, and imagine what a complex design you will have to wear.

space suit layers
source
TMG – Thermal Micrometoroid Garment
LCVG – Liquid Cooling and Ventilation Garment

How to walk around the Moon in the easiest way: expectations and reality

So, we found out that the low gravity of the Moon requires less energy from the astronaut to move, but the space suit severely limits his mobility. Under such conditions, jumping becomes optimal. Watch how Eugene Cernan walks on Moon.

Apollo astronauts bounced across the surface at an average speed of 1.4 miles per hour (2.2 km/h), according to NASA. If their suits were more flexible, they could have moved much faster. This was proven by a NASA study conducted in 2014. Eight participants used the treadmill aboard a DC-9 aircraft that flew on special parabolic trajectories on Earth to simulate lunar gravity. As a result of the experiment, they were able to reach a speed of 5 km/h. This was possible because they could swing their arms, as people on Earth do when they run. The pendulum-like movement created a downward force, partially compensating for the lack of gravity. The Apollo astronauts’ bulky suits did not allow such movements, which is why they moved so slowly.

What else affects, how long would it take to run around the whole Moon?

Given the new hypothetical top speed, it would take about 91 days to travel 6,786 miles (10,921 km) around the Moon, the time for respites excluded. However, it will take much more time and here’s why.

Landscape

The Moon’s rugged topography will make travel difficult, especially due to meteorite impact craters that can be several miles deep. The same goes for the lunar seas. There is no water in them, so you won’t be able to swim across them like on Earth, and the descent and ascent will slow you down.

Light and temperature

The temperature at the equator of the Moon during the day reaches 100 degrees Celsius and drops to minus 180 at night. Such fluctuations can affect the state of the regolith — the thin grey soil that covers the solid lunar rock and, as a result, affects your speed. In addition, the lunar cycle includes days when there is little or no sunlight, so you will have to walk at least half of the way in the dark.

Radiation

Unlike the Earth, the Moon does not have a magnetic field that helps reflect radiation from its surface. A solar flare or CME can expose you to high levels of radiation and make you very very sick.

Supply

Long walks on the Moon require a large supply of oxygen, water and food, which you will have to carry with you. Even with reduced gravity, this luggage will be quite bulky and will delay you.

So how long would it take to walk around the moon?

All things considered, the question of how long would it take to walk around the Moon is not that simple. Obviously, you won’t be able to walk without stopping, and you will need a lunar rover, at least as a shelter and transportation of supplies. But if you have a lunar rover, why not go around the Moon on it?

According to the scientific consultant of the European Space Agency Aidan Cowley, walking on the Moon objectively cannot exceed 4 hours a day. Thus, at a speed of 5 km/h, it would take 547 days, or almost 1.5 years, to go around the circumference of the Moon. However, humanity today does not have the technology to accomplish such a feat.

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