The AppleTV+ show For All Mankind envisions an alternative history where, instead of America landing on the Moon in 1969, the Russians got there first. This, the show posits, would have led to a fierce acceleration of the Apollo space programme, with a humiliated America becoming desperate to catch up to and exceed their Cold War rivals.


In the first two series, such acceleration leads to a fully operational base on the Moon, greater opportunities for female astronauts and an incident in which the Earth is pushed to the brink of nuclear armageddon. In series three, premiering on 10 June, the show goes even further: speculating that, by the early 1990s, humankind would have moved beyond the Moon, and set its sights on Mars.

But of course, embarking on a manned mission to Mars is a challenge enough for modern NASA, never mind a souped-up fictional 1990s version. “One of the big issues is distance,” explains astronomer Colin Stuart, author of books such as Mars: The Traveller’s Guide.

“It's a three-day trip to the Moon. And the thing is, it’s always three days because the Moon's distance from the Earth is always about the same. Whereas Mars’s distance from the Earth is changing all the time, because we're both going around the Sun at different speeds. Sometimes we're on the same side of the Sun as each other, sometimes we're on opposite sides. Even at its closest, it's a seven-month journey to get there, and the window of opportunity to do it in that time only comes around every 26 months.”

Mars landscape with mountains
The Mars environment, as photographed here by a NASA rover, is a hostile place for humans © Getty Images

This length of time, combined with such a short launch window, presents enormous challenges for any astronaut hoping to make the seven-month journey to Mars. Around halfway to Mars, communication between the ship and Earth would be delayed by 10 minutes each way.

“In a very fast emergency situation, 20 minutes can be the difference between life and death,” says Stuart. And even then, the astronauts are completely on their own.

“The International Space Station is only 400 kilometres up,” Stuart adds. “And they have an empty ship there at all times so that if anything goes wrong they can escape and be back on Earth in half a day. Halfway to Mars, you haven’t got that.”

There’s also the engineering issue of how to protect astronauts from radiation. “The Solar System is flooded with loads of high-energy particles,” says Stuart. “Down here on the ground we are protected from those things by the Earth’s atmosphere and the Earth's magnetic field.

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"Once you’re in space, beyond that field, you don't have that protection; your body is exposed to these high levels of radiation. Going to the Moon and back is a week, so it's not too bad. If you're going to be in space for 500 days, you don't have the option of outrunning this radiation. Just a single trip to Mars would expose an astronaut to their entire career's allowance of radiation.”

Possible solutions include lining the skin of the rocket with water (or frozen faeces!) as a shield; or adapting astronaut suits to give special protection to their vital organs.

Even if these travel issues are overcome, there is still the challenge of landing on the Red Planet. “Around a third of everything that has ever tried to land on Mars has failed,” says Stuart.

“When things come down to the Earth, if you get the angle right, you can use the Earth's atmosphere as a brake to slow you down. The issue with Mars is that the atmosphere is so thin that you don't have that at all. So you have to slow down, otherwise you're going to crash. And that's hard enough for a rover, which is the size of a car. But you’re talking about a starship which is as big as the biggest aeroplane in the world and is fully loaded with all the things a team of human astronauts need to survive. Slowing that down so that you land softly on Mars – that’s the real challenge.”

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The landing is so perilous that it’s often referred to as the seven minutes of terror, a reference to how long it typically takes to land a rover on Mars. And the aforementioned delay in communication only adds to the fear.

“Once you're at Mars, the delays are more like 20 minutes each way,” says Stuart. “When mission control on Earth get the signal that you hit the top of the Martian atmosphere, that's it. When communication is re-established you’re either alive on the ground or dead on the ground.”

If the astronauts of For All Mankind hope to establish a base on Mars, as they did on the Moon, then that also presents a whole new range of problems.

“The first thing you've got to deal with is you must respect your outside,” says Stuart. “You must wear a spacesuit at all times. The air on Mars is so thin that the boiling point of water is about 35°C. Your body temperature is 37°C. In other words, your blood will start to boil in your veins.”

For short-term visits, astronauts could only stay for around 30 days (because of the short window of time Mars is nearest to the Earth); longer term, astronauts would need to establish shelter from radiation (Stuart suggests that the lava tube network of regions such as Noctis Labyrinthus could provide protection).

Travelling to Mars requires long periods of time on a spaceship, with help from Earth a long way off © AppleTV+

Food and supplies, meanwhile, would require future planning. “Initially, you would need to send your food and rocket fuel for your return journey in advance. Long-term, you could talk about growing things on Mars,” says Stuart. “Oxygen-wise, the good news is there’s plenty of water on Mars. Although it’s not liquid, it’s frozen as ice.”

The bad news, however, is that converting this water into oxygen could be complicated due to Mars’s ferocious dust storms. “If you've got solar panels on the surface of Mars and these solar panels are completely coated in dust, and there's so much dust in the sky that it’s blocking out the Sun, then you’re in serious trouble if you're running your oxygen supply by using the electricity from solar panels to extract oxygen from water. These dust storms can last for months at a time. It can get dark and dingy on Mars.”

Yet even if the astronauts survive the journey, the landing and overcome all of Mars’s attempts to kill them, they must also contend with intense psychological difficulties. “No human in history will ever have been as isolated as those travellers,” says Stuart. “Even on the Moon, you can still see the Earth. It’s reassuringly there. Halfway to Mars, it is just a speck in the distance.”

Between 2007 and 2017, an experiment called MARS-500 sought to simulate the psychological conditions of travelling to Mars by locking up crews of astronauts together for 520 days. The crews weathered it relatively well, although some did suffer from sleep and psychological issues on their return journey.


Plus, as Stuart points out, such an experiment is no match for the reality. “You must have known you're actually in Moscow,” he says. “If you had a heart attack, someone’s going to come in and save you.” Whereas on Mars, there would be nothing but loneliness and dust.

About our expert, Colin Stuart

Colin is an award-winning astronomy writer and speaker. 

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Stephen Kelly is a freelance culture and science journalist. He oversees BBC Science Focus's Popcorn Science feature, where every month we get an expert to weigh in on the plausibility of a newly released TV show or film. Beyond BBC Science Focus, he has written for such publications as The Guardian, The Telegraph, The I, BBC Culture, Wired, Total Film, Radio Times and Entertainment Weekly. He is a big fan of Studio Ghibli movies, the apparent football team Tottenham Hotspur and writing short biographies in the third person.