We reproduce the opinion piece article written by Tecnun professor, Aitziber López, and published in Expansión on July 20, on the occasion of the 50th anniversary of man's landing on the moon.

In the early morning of July 21, 1969 (it was still the previous day in the United States) Neil Armstrong and Edwin Aldrin fulfilled their dream of walking on the lunar surface, while Mike Collins, the third member of the Apollo 11 crew, awaited their return at module . The technology of the time, which some have described as precarious, made it possible not only to successfully complete this feat, but also to broadcast it live on television. For many, this great milestone of which we commemorate the 50th anniversary is the first memory they have of a major event seen on the small screen. That first ride lasted a little more than two hours. In that time the astronauts collected about 20 kilos of moon rocks and soil samples, with the advantage that any object on the Moon weighs six times less than on Earth. 

In addition to taking these irrefutable proofs of their space visit , they also left behind several objects. On the one hand, the controversial flag and some other details of sentimental value. On the other hand, they installed scientific devices such as a seismograph and a laser reflector that, since then, allows to know the exact distance between the Earth and its satellite. As a curiosity, in several later missions the astronauts used all-terrain vehicles, or rovers, to get around. When it was time to return home, it did not seem logical to carry the rover again, so they stayed there, parked without risk of being fined, despite the fact that the last visit man to the Moon was in 1972.

Why were the lunar missions discontinued? It is a question of budget. The Cold War led the United States and the Soviet Union to invest exorbitantly in their space programs. But today, with advances in telecommunications and robotics, the most sensible thing to do is to send robots to the Moon that are controlled from Earth and with which communication is only a few seconds delayed. And not only to the Moon, several robots have successfully reached Mars. Currently, Curiosity has been operating since 2012 on the Red Planet, sending information back to Earth. To assess the additional difficulty of taking men to Mars, it is enough to look at the great distance that separates us. The distance from the Earth to the Moon is about 30 times the diameter of the Earth. On the other hand, the shortest distance between our planet and Mars is more than 4000 times the Earth's diameter. Compared to the 8 days in which Apollo 11 completed its mission statement round trip to the Moon, the trip to Mars could take between 50 and 300 days, depending on the relative positions of the two planets in their orbits around the Sun.

Man reached the Moon with a very basic technology, but one that had been proven in previous unmanned trips. The first challenge was to get enough propulsion to escape Earth's gravity. The United States designed the Saturn V, a rocket consisting of 3 liquid-fueled stages, with a total height equivalent to a 35-story building. After launch, the combustion stages were successively consumed and detached by small explosive detonators. Finally, only the command module and the lunar lander module remained, which is what would carry its two passengers to the lunar soil.

Another challenge was to simplify the operations for calculating trajectories and limit the use of report in order to manage with an onboard computer whose capacity was far below that of any mobile of ten years ago. The reduced computational capability became apparent at the time of the moon landing. The computer was directing them to an area not suitable for contact and Armstrong opted to switch to a control guide for fill in the descent. When they finally landed on the Moon there was barely enough fuel left for another 15 seconds. It was a very critical moment for mission statement when Armstrong, a former fighter pilot, had to make a quick decision that turned out to be the right one.

In any case, despite the fact that the budget to return to the Moon is estimated to exceed one hundred billion dollars, President Trump has urged NASA to carry out new manned missions. The Artemis program aims to establish a permanent colony there with the goal to study in a more realistic scenario the challenges of a Mars expedition. If everything goes according to plan, we will only have to wait three years to see a manned flight that will approach our satellite without actually landing on the moon. According to the schedule, it would be in 2024 when two astronauts would realize the dream that so far only a dozen U.S. astronauts have been able to see fulfilled.