Breaking gravity, humans will conquer space walking, are you ready?

How long does it take to orbit the moon?

It may be faster than we think, but it is also a logistical hurdle.

(Photo source: supplier)

From our vantage point on Earth, the Moon looks small. But if you were to hop aboard a spacecraft, put on a spacesuit, and go on an epic lunar hike, how long would it take to orbit the Moon?

The answers cover everything from how fast you can walk, how much time you spend walking each day, to what detours you need to take to avoid dangerous terrain.

Such a trip around the moon could take more than a year, but in reality, there are many more challenges to overcome.

According to NASA, a total of 12 people have walked on the lunar surface, all as part of the Apollo program between 1969 and 1972. A video beamed back to Earth shows just how challenging (and apparently fun) it was to walk — or, more accurately, bounce — in the moon's low gravity (just one-sixth of Earth's).

However, NASA research suggests it is possible for humans to maneuver around the moon much faster than the Apollo astronauts did. In theory, it could be possible to walk around the moon faster than predicted.

Accelerate the pace

According to NASA, during the Apollo missions, astronauts hopped around the lunar surface at a speed of 1.4 mph (2.2 km/h). This slow pace was largely due to their bulky, pressurized space suits, which were not designed with flexibility in mind. If the "moonwalkers" had worn sleeker suits, they might have found it much easier to move around, and therefore picked up the pace.

In 2014, a NASA study published in the Journal of Experimental Biology tested how fast humans could walk and run in simulated lunar gravity. To do this, the team had eight participants (three of whom were astronauts) use treadmills in a DC-9 aircraft that flew along special parabolic trajectories around Earth to simulate lunar gravity for up to 20 seconds at a time.

The experiment showed that the participants were able to walk up to 3.1 mph (5 km/h) before starting to run. According to the researchers, this is not only more than twice the walking speed controlled by the Apollo astronauts, but also quite close to the average maximum walking speed of 4.5 mph (7.2 km/h) on Earth.

The participants were able to run so fast because they were able to swing their arms freely, much like how humans on Earth run. This pendulum motion created a downward force that partially compensated for the lack of gravity. One of the reasons the Apollo astronauts moved so slowly on the lunar surface was that their heavy space suits prevented them from reaching properly.

(Photo source: stock photo supplier)

At the new assumed maximum speed limit, a 6,786-mile (10,921-kilometer) orbit around the Moon would take about 91 days, and a nonstop (i.e., no sleep or meals) orbit around the Earth's 24,901-mile (40,075-kilometer) circumference would take about 334 days at that speed, although that would be impossible without crossing an ocean.

Obviously, it is impossible to walk non-stop for 91 days, and the actual journey around the moon would take much longer.

Plan your route

Walking on the moon also presents a host of unique challenges. "Logistically it can be done," Aidan Cowley, the space agency's science adviser, told Science Online. "It would be supported by a very strange mission."

One of the biggest challenges is delivering supplies, such as water, food and oxygen.

“I wouldn’t recommend putting them in a backpack,” Cowley said. “Because even at one-sixth gravity, that’s too big.”

You need a support vehicle, Cawley said. This vehicle can also serve as a shelter.

“A lot of agencies are working on the concept of a pressurized rover that could actually support astronauts as they go on exploration missions, kind of like a portable mini-base,” Cawley said. “You could use it at night, go in for supplies, then come out during the day and move around some more.”

Lunar explorers will also need a spacesuit designed to allow for optimal movement. Current spacesuits don't account for excessive movement, but some agencies are developing form-fitting suits that allow for the arm swings needed to properly walk on the moon, Cowley said.

The moon's harsh terrain makes it difficult to find a suitable route around it, especially with craters several miles deep. "You really want to go around (the craters)," Cowley said. "It's too dangerous."

Light and temperature must also be taken into account when planning routes. "At the moon's equator and during the day, the temperature is around 100 degrees Celsius (212 degrees Fahrenheit)," Cowley said. "At night, it drops to minus 145 degrees Celsius (minus 292 degrees Fahrenheit)."

The moon's cycle also means some days have little or no sunlight, and at least half the journey will be spent in darkness. It's possible to protect against these extreme temperatures with specially designed spacesuits and rovers, but temperatures could also change the state of the regolith -- a fine, gray soil that covers the moon's solid bedrock -- and affect how fast you can go, Cowley said.

This 1972 photo shows Apollo 17 lunar module pilot, scientist and astronaut Harrison H. Schmitt exploring with the aid of his adjustable sampling scoop. (Image credit: NASA/NASA Johnson Space Center)

However, radiation could pose a greater danger. Unlike Earth, the Moon has no magnetic field to help deflect radiation that would reach its surface.

“If there’s no major solar activity in a period, then it might not be that bad,” Cowley said. “But if there’s a solar flare or a coronal mass ejection and you’re exposed to high levels of radiation, that could make you very, very sick.” (Solar flares and coronal mass ejections both release large amounts of energy and magnetized particles, but they differ in the types of particles they release, the duration of the event and how the radiation they produce travels through space, according to NASA.)

This type of mission also requires a lot of endurance training, because low gravity exercises your muscles and cardiovascular system. "You'd have to send an ultramarathoner to do that," Cowley said.

"Under today's conditions, full-force walking would only sustain three to four hours a day," Cowley said. So if a person walked for four hours a day at 3.1 mph (5 km/h), it would take an estimated 547 days, or nearly 1.5 years, to walk around the moon, assuming your route is less affected by craters and you can account for temperature changes and radiation issues.

However, Cowley said humans won't have the technology or equipment to accomplish this feat until at least the late 2030s or early 2040s.

“You’d never find an institution to support something like this,” Cawley said. “But some crazy billionaire wants to give it a try, and maybe they can pull it off.”

BY: Harry Baker

FY:jane

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