Nobody knows for sure. The two space agencies that want to take humans to the red planet – NASA, from the United States, and ESA, from 17 European countries – are still looking for answers to the problems of returning. One of the main ones is the enormous duration of the trip. “A manned mission to Mars should take about a thousand days: 350 on the way there, two weeks on the planet and the rest on the way back”, says Dutch engineer Dietrich Vennemann, from the ESA. What might happen to astronauts during that time is a mystery. To date, the record for staying in space is held by Russian cosmonaut Sergei Krikalev, who spent “only” 748 days in orbit. To reduce the roll, scientists project a speed of 43,200 km/h – 35 times the speed of sound and 120 times faster than a rifle bullet! This speed can cause the spacecraft to explode when friction with the Earth’s atmosphere. “It will be necessary to build a ship with materials that withstand overheating”, says American engineer Steve Wall, from NASA. The forecast is that the trip will consume 120 billion dollars, more than double the Apollo project, which took man to the moon. Is it worth it? Enthusiasts have no doubts. “Robots only repeat known experiences. The discoveries of science have always been made by humans”, says the Dutchman Dietrich, from the ESA.
slowly, slowly Returning to Earth would take about two years
1. To return to Earth, the first problem is to find fuel to return – for reasons of space and weight, it is not possible to attach a “supertank” to the ship. There are two solutions: send the fuel to Mars on an earlier trip, or produce fuel with resources from the red planet, using carbon dioxide from the atmosphere in a reaction with hydrogen taken from Earth to create oxygen and methanol.
2. With fuel, the space module that descended to the Martian soil will need to dock with a ship that will be orbiting Mars. The challenge here is to maneuver without causing damage to the ship. The remedy is simple: all it takes is for the module’s pilot to be skilled. This is considered the least of the problems. Docking is a standard procedure in space travel: it was used almost 40 years ago by the Apollo mission, which went to the Moon.
3. The third hurdle is for the ship to get enough momentum to turn around. Since most space travel is done in inertia (with the engines off), the spacecraft’s speed would come from Mars’ gravity – a turn in the planet’s orbit would accelerate the spacecraft. Therein lies the problem: as Mars only has 38% of Earth’s gravity, the speed provided would be much lower. Therefore, the return would take about twice as long as the outward journey.
4. The return of Mars would take about two years. This extended stint in space requires a lot of supplies, as well as high stress levels and unpredictable physical problems. A possible way out is to improve the psychological and physical preparation of the astronauts, in addition to reusing everything possible inside the spacecraft. Water, for example, can be recycled: at the limit, even pee can be purified and turned into drinking water
5. Upon arrival on Earth, a new challenge: re-entry. As the ship will be traveling at around 43,000 km/h, the possibility of it catching fire as a result of friction with the gases in the atmosphere is enormous. The solution is to create better metal alloys that can withstand higher temperatures. It is quite a challenge: with the materials available today, the European Agency (ESA) only guarantees safe re-entry at a maximum of 27,000 km/h
6. After re-entry, landing on Earth is still missing. The idea is for the module to detach itself from the spacecraft and fall somewhere in the ocean, as did the astronauts who went to the Moon. Nasa usually stipulates three to four different landing sites. The ship, after the module is detached, continues orbiting the Earth and becomes a kind of space junk
Read too:
– How can man get to Mars?
– How much poop is there on the moon?
– What would everyday life be like in a space colony on Mars?