NASA's InSight lander only has six and a half minutes to land in one piece on Mars

Early next week, NASA will attempt the feat of landing a spaceship on Mars, hoping to add to its growing collection of technologies on the surface of the red planet. This time, NASA hopes to place a robotic landing gear, called InSight, on a flat and boring part of the Martian terrain to study the inside of the planet. And to do this, the robot the size of a car must run a perfectly synchronized landing routine – an operation that will slow the vehicle from over 20,000 km / h to zero in just six and a half minutes .

Launched May 5 from California, InSight has been traveling in space for six months and is expected to enter the March atmosphere on Monday, November 26. During its descent to the surface, the undercarriage will be subjected to extremely high temperatures, speeds and forces. To survive, InSight will move autonomously through dozens of programmed steps, such as deploying a supersonic parachute and igniting embedded thrusters. Each step must take place at exactly the right time to help the landing gear to land safely. "[We have] to evacuate all our energy when we get to Mars so we can land smoothly when we get to the surface, "says Rob Grover, NASA's Jet Propulsion Laboratory's InSight Landing Systems Manager. The edge.

Such a complex procedure is necessary because landing on Mars is not a trivial task. The biggest hurdle that InSight engineers have had to face is the atmosphere of the planet. Even though the atmosphere of Mars is quite thin (less than one hundredth of its density), it is thick enough for arriving vehicles to warm up as they descend to the ground. This means that Martian spacecraft need appropriate armor if they hope to reach the surface without melting. But as the atmosphere is thinner than ours, it also means that parachutes on Mars are not as effective at slowing down spacecraft as they are on Earth. The engineers had to add thrusters to make sure the landing gear would land softly.

InSight is equipped for all this. But it is possible that the lander encounters a particularly unattractive environment upon arrival, as the vehicle will land in the middle of the dust storm season on Mars. So far, the weather seems calm, but it is possible that a storm is triggered before the landing of InSight. If this is the case, the mission team will have to rework the flight plan at the last minute – although it is convinced that InSight can handle it. "We designed the system to handle this range of environments," says Grover. "It seems we will not be dealing with a dust storm, but we still have [some time] go, and a dust storm can explode in a few days. "

For space enthusiasts, the landing of InSight could be reminiscent of NASA's latest Mars mission – when the space agency landed the Curiosity rover on the surface of the red planet. For this trip, the landing was nicknamed the "Seven Minutes of Terror". The label mentioned that Curiosity also had to perform a synchronized routine in a short time to fall into one piece. While using parachutes and thrusters, Curiosity had to be lowered with a specialized clip, called the Sky Crane, at the end of the fall, so that it could land safely.

At 789 pounds, InSight is not nearly as heavy as the Curiosity of nearly 2,000 pounds; his landing does not need to be so complicated (that is, he does not need a sky crane). However, he is similar in size and weight to another recent Martian Lander that has not weathered so well. In 2016, Roscosmos and the European Space Agency attempted to land on Mars with a satellite called Schiaparelli, in order to test the landing techniques of a future rover. But during his descent, the lander's computer received incorrect data from the spacecraft's instruments, causing the vehicle to release his parachute earlier than planned. As a result, Schiaparelli struck the Martian soil, creating a new crater on the surface.

Since 1999, when the agency lost Mars Lander, NASA has safely landed its vehicles on the red planet. Hope things are better for InSight. But the more recent Schiaparelli incident shows that every piece of the landing puzzle must be executed as intended – without any help from those on Earth. At the time of the InSight landing, a light signal from our planet will take about eight minutes to reach Mars. "By the time we understand what is happening with the landing, there is a significant enough delay that we can not control the vehicle from the Earth," says Grover. "Everything must be completely autonomous and automated."

As soon as InSight enters the atmosphere, this is the moment when the automated routine starts. At that time, InSight will move at approximately 12,300 miles per hour. The undercarriage goes down, equipped with a thermal shield pointing down. This is to protect the sensitive instruments of the spacecraft from temperatures reaching a maximum of 2700 degrees Fahrenheit. The atmosphere slows the undercarriage to less than 1,000 miles at the time.

When the vehicle reaches about seven miles above the surface, the lander deploys a supersonic parachute to slow down even more. The thermal shield eventually falls off and when the landing gear reaches a kilometer high, it moves away from the rear hull with the parachute and ignites its onboard thrusters. These engines move the LG into a safe place and gently lower the spacecraft to the ground.

During the past year, the mission team has organized several general rehearsals of the landing, which take place several days at a time. During these events, the InSight team imitated what it was going to do in the run-up to the landing using a test spacecraft located at Denver's headquarters at Lockheed Martin, the main subcontractor of InSight. Before the fatal fall, engineers will continuously assess the weather on Mars and the trajectory of the shuttle. They will then make changes to the planned landing sequence, based on the most up-to-date information available to them. For example, if a dust storm occurs before landing, they will change when the parachute will deploy to best fit the atmosphere.

They even did a dress rehearsal where everything was derailed. "We have a team of gremlins working behind the scenes who are asking us all kinds of problems so we can solve them during the rehearsal," says Grover. "This in particular is very fun and stressful for the team and prepares us for anything that could happen to us during the landing."

The team conducted its last dress rehearsal in October. The time has come to move on. InSight is scheduled to land on Mars around 15:00 ET on November 26. Once on the ground, the lander will send a beacon about 10 seconds after landing to alert engineers on Earth that the probe is alive and firmly in place. It is also possible to obtain an external perspective on the unfolding of the landing. Two experimental probes, known as MarCO satellites, go to the RedPlanet with the LG and will try to provide landing information from the space.

"As they are experimental, we are not quite sure they will work on the day of the landing," says Grover. "But if we have these data, we will have a lot of information on the LG and we will know with real clarity that we have managed to surface."

Image: NASA

If all goes well with the landing (which will result in a small celebration), the engineers will spend the next two or three months deploying the InSight instruments. The lander has two main tools to study the interior of the Martian territory: a seismometer to detect the earthquakes of Mars and a self-hammering nail that will plunge to a depth of 16 feet to take the temperature of the planet. InSight is equipped with a robotic arm that will gently move the two instruments away from the LG. And once deployed, the data collected from these instruments will help scientists better understand the types of rocks in the mantle and core of Mars.

However, these instruments are very sensitive and the seismometer must remain very still to obtain the best data. If the seismometer is deployed too close to InSight, even very small vibrations on the LG, possibly caused by the wind, may spoil the data. That's why scientists will spend a few weeks finding the best places to deploy these instruments using InSight cameras. "If you play these claw games at carnivals, you want to make sure that you are perfectly aligned with the price you want before you press the button to try to catch it," Elizabeth Barrett said. science systems engineer at NASA JPL, tells The edge.

NASA scientists have specifically chosen the flatter and more boring place on the planet Mars to help the instruments do their best work. However, Barrett says the instruments can still work if InSight lands on any slope. "We have a bit of inclination that we can always accept and achieve our mission goals," Barrett said. "We can work by placing instruments in locations that may not be perfect for them, but they can still get good science."

Scientists will know for sure what InSight's land looks like when it lands. But for now, the goal is to make sure the landing goes as planned. For many members of the team, landing on the surface of Mars will represent years of hard work and preparation culminating in one event. "We are delighted," says Grover, anticipating when he will be in the control room for the landing. "After spending so many years working on it, when the data arrives, it's a bit surreal."