The four challenges that stand between us and Mars

One of the proposed solutions involves using astronaut waste as a radiation shield.
Written by Janet Fang, Contributor

Last week, world’s first space tourist Dennis Tito and the Inspiration Mars Foundation announced their plans to set off on a journey to Mars on January 5, 2018.

The 501-day roundtrip fly-by will take the astronauts about a 100 miles above Mars, and then the Red Planet's gravity will slingshot the spacecraft back to Earth without burning any more fuel.

But first, here are the four challenges the Inspiration team must resolve. New Scientist reports.

1. Launch vehicle

The vehicle of choice is the Falcon Heavy rocket, which SpaceX has designed to carry about 30,000 pounds to the vicinity of Mars.

Falcon Heavy’s first demonstration flight is scheduled for later this year. The other option is NASA's Space Launch System, but its first flight isn't until 2017.

2. Crew life support system

Paragon Space Development Corporation is contracted to build a prototype this year. The system -- like the one on the International Space Station -- will convert exhaled carbon dioxide into oxygen, recycle water from urine and feces, filter the cabin air, and maintain its temperature and pressure.

But unlike the more automated ISS system, Inspiration's smaller life support will be run by the crew themselves – making it simpler, quicker and cheaper to build, and less likely to break.

3. Cosmic rays

A magnetosphere protects earthlings and even ISS astronauts, but there’s no natural radiation shield for the Mars voyage. So how do you protect the crew from charged particles that can damage DNA and heighten cancer risk?

One idea comes from NASA's Water Walls project. The nuclei in atoms block cosmic rays; and water molecules, made of three small atoms, contain more nuclei per volume than even metal. Water in polyethylene bags could create a 15-inch thick shield. But when NASA tested the system in 2011, they found it wasn't as efficient in orbit.

Another suggestion is to line the spacecraft’s walls with dehydrated feces, urine, and food. Like water, the hydrocarbons in excrement and food are rich in nuclei. After the feces is dehydrated by the cabin's water recycling system, it can be bagged up and fixed to the walls.

4. Velocity

As a result of its slingshot, the spacecraft will be traveling so fast it’ll need to spend 10 days in orbit just to lose speed. After that, it’ll still be traveling at a record 14 kilometers (about 8 miles) per second when it hits Earth's atmosphere – a higher velocity than anything manmade has ever had during re-entry.

NASA has agreed to help design the re-entry path and heat shields to protect Inspiration's astronauts.

So, if all four systems are in place by 2015, Inspiration just might make it.

[Via New Scientist]

Image: Mars atmosphere via Wikimedia

This post was originally published on Smartplanet.com

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