Dreams of Mars

Sam Jenkins

In 2002, Elon Musk founded SpaceX, with the view of revolutionising space technology and the ultimate goal of making it possible for mankind to live on planets other than Earth. This came just a year after Musk detailed Mars Oasis, his plan designed to build public excitement at the idea of eventually walking on Mars, as he was disappointed with NASA’s lack of plans for sending any manned mission there. The idea was that a lander would be sent to the surface of the red planet, carrying a small greenhouse. On landing, seeds in dehydrated nutrient gels would be activated. The life and death of the plants they grew would give an insight into the challenges of sustaining life on Mars. However, Musk soon realised that the current level of technology was the main obstacle in seeing his dream succeed.

As you’d probably expect, getting to Mars is difficult. NASA has so far had six robotic landers successfully touch down on the surface, and although this is impressive, robotic missions are far easier than manned missions. This is because the manned missions not only have to carry the crew and supplies but also, crucially, fuel for the trip back home. For this reason, future manned missions will likely dock with a spacecraft in orbit around the planet, where fuel and supplies can be kept, rather than heading straight for the surface. While the journey to Mars would generally take about 300 days, much of the fuel on-board will get used at the very beginning and end of the trip. Firstly, the ship must be accelerated to roughly 25,000 miles per hour, to escape the gravitational pull of the Earth. Upon arrival at Mars, the ship must then decelerate, so it can be captured into circular orbit around the planet.

Traditionally firing booster rockets do this backwards, but to save on the amount of fuel required, scientists are employing new techniques. The first, known as aerobraking, has already been employed successfully in missions. This involves getting the ship into an orbit via reverse firing of rockets, and then using the drag caused by passing through the upper atmosphere of the planet to slow the ship, and achieve the desired circular orbit. The second, which has never been tried before, is known as aerocapture. Instead of using rockets to slow the ship down it goes straight into the atmosphere, at a slightly lower altitude than for aerobraking, and the drag from the atmosphere causes the ship to be captured straight into a circular orbit. This means a lot less fuel must be carried on the journey. Unfortunately, using this method of braking causes the kinetic energy of the rocket to be transformed into heat, requiring more thermal protection for the ship. Overall though, this weighs less than the fuel that would otherwise be needed, and any weight saving is an advantage when it comes to space travel. Sadly, funding cuts and tight budgets are causing NASAs plans to be slowed dramatically, and as such collaboration with other agencies such as SpaceX will be paramount to man’s ability to reach the red planet.

15 years since its founding, SpaceX has undoubtedly made large leaps in terms of their technology, frequently making headlines for vertical landings of rockets. For travel to Mars, SpaceX plans to employ their recently revised BFR rocket design, capable of carrying a payload along with an eight-story tall living space. Musk hopes that these will begin construction next year, with the potential for two carrying just cargo to launch in 2022. They would then aim to follow this two years later, with two carrying cargo and two carrying crew. Once there, the missions would aim to find water and establish a propellant plant, for running around trips between the Earth and Mars.

While some see these dates as ambitious, Musk describes them as “aspirational”. Regardless of whether these dates slip or not, manned missions to Mars are swiftly becoming a real possibility, and that is something we should all be very excited about.

#ElonMusk #SamJenkins

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