We’ve been to the moon and will do so again, most likely in 2024. Then it is on to Mars. But why Mars in particular and when?
That very question was put to Australian Space Agency head Dr Megan Clark by 13-year-old Ewan on the Australian Academy of Technology and Engineering Ask an Expert on its website.
So for anyone pondering the how, why and when of going to Mars, Dr Clark provides a thorough and lucid explanation.
First of all, why Mars?
Dr Clark said of all the planets other than Earth, Mars is the only realistic option for human habitation in the decades to come. It’s relatively close, with missions of six to nine months each way.
We also know about Mars’ surface conditions from successful orbiter, lander and rover missions. It’s a cold and extreme environment with summer days near the equator reaching a high of 20 degrees and winter days near the poles down to -125 degrees.
Mars may once have had conditions for life and finding evidence of life there would be a civilisation-level discovery.
To get to Mars, we’ll need to be able fund and sustain missions far longer than reaching the moon, use the resources at the destinations and overcome radiation, isolation, low gravity and extreme environments like never before.
Dr Clark said crews will be exposed to harsh radiation levels in deep space during their mission, but also on Mars, and that’s a significant challenge.
Radiation levels on Mars are much higher than Earth, with regular exposure to cosmic rays and solar wind and occasional blasts from solar flares.
“Mars also has dust storms and particles that can be toxic because of dangerous chlorine compounds,” she said.
“However, Mars does have useful resources like water and carbon dioxide. We could use these to make methane and oxygen for fuel, life support systems and food production. It also has soils and rock we could use for construction.”
NASA has pointed to a Mars mission some time after 2033.
Getting to Mars starts with the launching larger heavier payloads from Earth.
For that NASA is working with Boeing to develop the Space Launch System (SLS). Its first crewed launch is planned for 2022.
NASA is planning an outpost orbiting the moon called Gateway from which missions to the m oon and later Mars can be launched.
“After the rocket, next we need a capsule that can sustain humans through launch and deep space then return safely back to Earth,” Dr Clark said.
“Here, the plans are less clear. NASA is building Orion, its next-generation human space capsule, for return to the moon. But NASA has said we may need something more like the International Space Station for crews going to Mars.”
Dr Clark said it was important to think about people will cope with being away from Earth for what could be years at a time.
Work on the International Space Station 400 kilometres above the Earth has provided a much better understanding of the effects of space on humans and the best ways to protect astronauts.
The main concern here is particle radiation with energetic particles passing through the skin, damaging DNA or causing radiation sickness during the mission.
“Hydrogen is good at blocking these particles, so NASA and others are exploring the use of water and plastics (which are both partly made of hydrogen) to protect people from radiation,” Dr Clark said.
“Water shields around the sleeping pods is one idea that’s being explored.
“Low gravity also causes some real problems for astronauts’ eyes in missions greater than six months. Pressure can build up behind the eye and damage vision. This serious challenge will need to be solved for crewed trips to Mars.”
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