Putting Astronauts on Mars: Can Their Hearts Take It?

A team of space medicine experts from ANU have created a mathematical model which could be used to predict whether an astronaut can safely travel to Mars and fulfil their mission on the Red Planet.   

Travelling to Mars would take several months, and the human body, which is used to the gravity of Earth, would experience microgravity (close to zero gravity) for most of the journey. However, Mars does have gravity - about one-third that of Earth’s - and this might put a strain on astronauts’ hearts when they step off their spacecraft.

“We know it takes about six to seven months to travel to Mars and this could cause the structure of your blood vessels or the strength of your heart to change due to the weightlessness experienced as a result of zero gravity space travel,” said Dr Lex van Loon, a Research Fellow from the ANU Medical School and the lead author of the paper.

The team from ANU simulated what prolonged exposure to microgravity would do to the cardiovascular system and whether the human body could tolerate Mars’ gravity without fainting or experiencing a medical emergency when stepping off their spacecraft. The model could also be used to assess the impacts of short- and long-duration space flight on the body. 

So what happens to your body when travelling in space? Astrophysicist and emergency medicine registrar Dr Emma Tucker explained that spending long periods of time in zero gravity can make your heart lazy because it doesn't have to work as hard to overcome gravity in order to pump blood around the body.

“When you’re on Earth, gravity is pulling fluid to the bottom half of our body, which is why some people find their legs begin to swell up toward the end of the day. But when you go into space that gravitational pull disappears, which means the fluid shifts to the top half of your body and that triggers a response that fools the body into thinking there’s too much fluid,” said Dr Tucker. 

“As a result, you start going to the toilet a lot, you start getting rid of extra fluid, you don’t feel thirsty and you don’t drink as much, which means you become dehydrated in space.”

“This is why you might see astronauts on the news faint when they step foot on Earth again. This is quite a common occurrence as a result of space travel, and the longer you’re in space the more likely you are to collapse when you return to gravity.”

This new research from ANU is another piece of the puzzle when landing humans on Mars, and the team believe it should be possible for astronauts to safely arrive and work on Mars based on their model.

“The purpose of our model is to predict, with great accuracy, whether an astronaut can safely arrive on Mars without fainting. We believe it’s possible,” said Dr Tucker.

However, it’s not just professional astronauts aiming to set foot on Mars in the near future. 

“With the rise of commercial space flight agencies like Space X and Blue Origin, there’s more room for rich but not necessarily healthy people to go into space, so we want to use mathematical models to predict whether someone is fit to fly to Mars,” said Dr van Loon.

As non-professional astronauts may very well be able to travel to Mars sooner rather than later, the team hope to expand their model and simulate the impacts of space travel and landing on Mars on relatively unhealthy individuals or individuals with heart conditions.

Currently, the team’s model uses an algorithm based on astronaut data collected from past space expeditions, including the Apollo missions. But this data would be very different to that of an everyday person like you or me. Professional astronauts have a required level of physical fitness and are trained to respond appropriately to emergencies in the harsh environment of space.

When on Mars, there would be a communication delay that could last for approx. 20 minutes. For this reason, astronauts have to be well-prepared to deal with any immediate issues (such as medical emergencies) as well as continue with their duties without any assistance from support crews on Earth.

“If an astronaut faints when they first step out of the spacecraft or if there’s a medical emergency, they’ll be nobody on Mars to help them,” said Dr van Loon.

“This is why we must be absolutely certain the astronaut is fit to fly and can adapt to Mars’ gravitational field. They must be able to operate effectively and efficiently with minimal support during those crucial first few minutes.”

Hopefully, this new research helps astronauts from space agencies and commercial space enterprises alike prepare for Mars, the next frontier of space.