If everything goes well, Marslander InSight’s journey will experience a grand finale today. If the probe is able to make at least a smooth landing on the surface of the red planet. NASA’s more than a billion-dollar Marsverkenner has been on the road for almost seven months. The last hours are unnerving.
Only when the InSight is on the red ground with three legs, the first part of the mission has succeeded. Everyone who is involved in the international project keeps a breath. The descent of InSight, a complete laboratory that will provide insight into the deepest mysteries of Mars over the next two years, is not exactly simple.
The precious device enters the thin atmosphere of Mars at a speed of nearly 20,000 kilometres per hour. In less than seven minutes, the spacecraft has to slow down from that dizzying speed to almost zero. The flight control on earth can only watch, intervention is impossible.
The capsule in which InSight makes its hellish descent towards the surface is similar to that with which the moon missions returned in the sixties and seventies: a conical shape, with a smooth flat bottom beneath. The bottom of the lander is of crucial importance to protect InSight from the enormous heat that is created when the Martian atmosphere penetrates. Apart from the heat shield, the angle at which the landing capsule touches the atmosphere of Mars is also extremely important. That angle must be exactly 12 degrees. If the angle is too small, InSight will bounce off and dive into the depths of the universe. If the angle is too large, the probe will go down like a raging fireball as a result of the friction with the air. And the mission literally in smoke.
Approximately three and a half minutes after the capsule hits the Mars atmosphere, a parachute opens which further slows the spacecraft. Fifteen seconds later, explosives blow away the heat shield and InSight prepares for the actual landing. After ten seconds, the probe extends three legs and dangles for another minute or two under the parachute. 45 seconds before landing, InSight leaves the capsule and takes its landing missiles to the last brake. The boosters also stop every horizontal movement of InSight, causing the thing to come down perpendicularly. With 15 seconds left, the speed is only 2.5 meters per second and the Marslab will hopefully smoothly hit the ground.
If InSight enters the surface after entering and descending at a speed higher than 8 kilometres per hour, it is still the end of the exercise. The probe crashes and the mission has failed before it can really begin. Eight minutes after the hopefully successful landing, the liberating life sign of InSight arrives on Earth. The place where the InSight will land after a journey of about 485 million km, Elysium Planitia, is a bare plain just above the equator of Mars. The flight control hopes that there are few rocks or stones that can thwart a soft landing. That the less interesting landscape has been chosen, has another reason: it is inSight not to do to the surface, like its predecessors, but to the inside of Mars.
Drill meter depth
InSight will drill meters deep into the soil of Mars so that scientists can learn what is under the surface and gain insight into the history of the red planet. That drilling is easier on a surface that is level. Because there are no shadows, the solar panels of the lander can also generate more energy.
A second task of InSight is to register quakes on Mars. The suspicion is that these quakes are there, only different than on Earth. Mars does not have tectonic plates like our planet, but researchers still expect to be able to observe dozens or hundreds of quakes in the coming years. These vibrations can also tell something about the interior of Mars. The detection of these ‘Marbvings’ will be done with the seismometer SEIS of the French space agency CNES.
With a view to future manned Mars missions it is also important to learn what the temperature is at a certain depth. If the temperature below the surface is warm enough, water could be present in liquid form. Until now it was always assumed that water only occurs as ice. Liquid water would make a stay on Mars considerably easier.
The KSB will also analyse the data from the American radio instrument RISE (Rotation and Interior Structure Experiment) to form an image of the internal structure of the planet. Professor Dehant is responsible at the Observatory for processing RISE data.
NASA will take the first steps next year to start a moon colony. A new space station, The Gateway, should serve as a base for the first residents who will set foot on the moon around 2030. The moon colony can be the advance to a colony on Mars, as tech billionaire Elon Musk would like. A large part depends on what InSights will bring to light. Provided he lands safely, of course.
NASA, which already visited the planet in the sixties with the Mariner missions, has a lot of experience when it comes to Mars. Yet it is already six years ago that the space agency put the mobile explorer Curiosity Rover on Marsian soil. The success rate of probes to land safely is 40 percent.
Mars is above all a true graveyard of failed missions. Various space agencies, including American and Russian, European, Indian and Japanese agencies, have sent 44 probes to Mars in recent decades. Of these, 18 were successful, with seven successful landings. 23 missions failed and three did hit the planet itself but failed on landing.