Friday , November 27 2020

Travel to the heart of the red planet to listen to your vital signs



"It is good to renew our ability to wonder," said the philosopher, "the interplanetary journey brings us back to childhood."

The phrase that precedes the classic edition of classic Ray Bradbury
chronic mArchangel (Minotauro, 1976, preceded by Borges), it is very appropriate to wait for the ineffective encounter that will happen today in the vastness of space. At 17, local time, after traveling for more than six months, NASA's Insight probe will land on Mars to begin a two-year mission on Earth that will allow us to understand the processes that formed the rocky planets on Earth. The solar system (itself Mars, Venus, Mercury and the same land), 4500 million years ago.

"This is a static ship, not a rover, like a viking," explains Argentine engineer Miguel San Martin, who, after conducting four successful descents in our space neighbor, is part of the group of advisers who are in charge of designing and testing this mission – So far most of the probes and satellites focused on the study of the surface and the discovery of whether or not there was Martian life has nothing to do with it, but the study of the interior: the Red Planet does not have a powerful magnetic field like the Earth, meaningful to protect the atmosphere of the solar wind. "

"Why did you lose it?" On the other hand, Earth is such an active planet that evidence of its formation is already infected, and where things are not as dynamic, we can better analyze them. It's like studying the past of the Earth on Mars and understanding why they are different, "he adds.

The planets of the Solar System were formed by a disk of rocks, ice and debris that circled around our home star. Mars is the most learned after the Earth, but astronomers know nothing about his interior. So far, the many missions that followed each other, as in 1971 NASA sent its first orbiting, Mariner 9 (which returned 7300 images to the surface and its two companions, Phobos and Deimos), analyzed the atmosphere, their dust storms and the wanted ones success) signs of life.

With the initial planning for 2016, which had to be postponed due to vacuum leakage in landing gear equipment, Insight (corresponding to an "internal survey using seismic survey, geodesy and heat transfer") has three main tools.

The seismograph will hear small vibrations on the ground, fractions of one nanometer (one billion feet), due to seismic waves that travel through the planet and will allow to create a 3D image of its interior.

The borehole will drill about five feet from the Martian bark to analyze the heat coming from the depths, and this gives an idea of ​​its activity. Another experiment will attempt to determine exactly how much the "Martian North Pole" that is traveling around the Sun is "displaced." These observations will provide detailed information on the size of the iron-rich core of Mars and will help to determine whether it is a liquid and what others contain elements.

"The most interesting thing about these missions is that they allow us to understand our world more," said Diego Bagu, an astronomer at La Plata National University and director of the planetarium in this city. "This is the first time we can train the Martian ground and find out if there are seismic movements and what is the heat flow, although there is no fractured crust like that which the Earth represents and consequently no movement of tectonic plates can have geological activity because of the influence of the meteorites, for example, exploring how seismic waves spread, will allow us to understand what the interior of the planet is. "

Seven minutes horror

Once it arrives in the destination, Insight will take one of the most important stages of the entire mission: to deploy its solar panels. Thus, by about one meter height and weighing 360 kilograms, it will reach six meters in length (equivalent to half to two thirds of the collective length). With these "wings" you can capture the sun's rays (which at this distance shine 50% less than on Earth) to give energy to the instruments.

Unlike other probes, you will need to use an articulated robotic hand for slow placement of tools on the surface, a process that will take about three months.

But to do this, you first have to overcome the "entry, descent and landing" (EDL) sequence, an operation that makes adrenaline move in the control center, because even though this is done repeatedly, this is absolute guaranteed.

"Although Insight is an almost identical copy of Phoenix since 2007, and we know that design is stable, there may always be a labor error," said San Martin, a veteran of these laws. but sometimes something happens to us. The atmosphere of Mars varies depending on the seasons, as is the case here. Pressure may increase or decrease. When it is less dense, the landing becomes more complicated. And there may also be dust storms. For this reason, a NASA JPL team was following the approach, trying to predict the crucial moment, as in theory the scales of the descent system could be changed to make them more stable. from Opportunity, for example, we had a disturbed atmosphere and made minor adjustments to increase our chances of success, "he adds.

Indeed, at the last moment of yesterday, the Insight team decided to make the last correction of the trajectory to move the landing site to about 16 kilometers.

There are other obstacles. In order for the ship to descend properly, it must enter the correct angle: if it is too steep, it may be burned; if, on the contrary, it is too open, it will shake off the atmosphere and remain floating in space.

"In about six and a half minutes, the module will move from a speed of nearly 20,000 km / h to eight," says Bagu, "and he must enter a" window "of about 10 km to 20 on each side, a smaller area of ​​town. "

Although the atmosphere of Mars is 100 times thinner than Earth, the input module must be shielded by a thermal shield fused to more than 1300 ° C. Then it will deploy its parachute and approximately 40 seconds before it reaches to contact with the earth, it will separate itself from both, extend its feet and light 12 pushers to reduce descent speed and perch in an area known as Elysium Planitia, chosen because it is dusty and flat and relatively free from rocks.

Marco Polo on Mars

Another innovation in this mission is that the probe travels accompanied by two ministers (or
CubeSat) from the approximate size of the Marco-A and MarCO-B shoe box (which missionaries call Marco / Polo) to be responsible for the provision of ground-based communication services as the module continues to perform a stage after landing and they are proof of the concept to be used in exploring the interplanetary space.

"In 1999, the ship told us" a show we're seeing on the surface, "and we've never heard of it again," says San Martin, "so NASA has ruled that each descent should have telemetry, so if This does not happen well and is fine in later trips We usually have spacecraft that are in orbit and they do us
relay, Insight brings these two
CubeSat which are released after the launch and run in parallel but in the back. As they land, these small satellites will receive the signal and pass it on to Earth. And the best thing is that if this happens, we will not worry that Mars has always a satellite "alive" in the right geometry of landing.

Contrary to what can be said, international success in decks is not high, about 40%. "Sometimes it seems that these things are already routine," Bagu concludes, "but in reality they are an extraordinary challenge."


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