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a sensor has given up the ghost, the beginning of the end is looming on the horizon

The days of NASA’s formidable Martian helicopter are numbered… but its place in the history books is already locked no matter what.

Ingenuity will go down in history as one of the most spectacular craft ever produced by NASA. It was originally planned to remain a proof of concept that was simply to prove the viability of the concept in five consecutive Martian flights; he has since transformed into a luxury scout serving Perseverance with 28 flights to his credit.

It is largely thanks to this precious help that the illustrious rover was able to reach the delta of the crater of Jezero, which it is currently combing through in search of traces of past life. And the drone also led some solo expeditions. Last April, he notably offered himself a pilgrimage to the tunes of returning to his sources by returning to shoot the portrait at the capsule which deposited him on Mars.

You will have understood it: this little machine proved to be incredibly brave, well beyond all the expectations of the public and the agency. It would therefore be easy to forget that it will not be eternal; and recently, it was the failure of a very important sensor that brought engineers back to the harsh reality.

The tiltmeter breathed its last

Indeed, during the exhaustive control which follows each flight, the operators realized that the inclinometer was missing; the sensor has probably burned out, and the chances of it starting to respond again are unfortunately almost nil.

This is a problem, because this inclinometer is quite important for Ingenuity. It is an instrument composed of two accelerometers which makes it possible to measure the direction of gravity. It works much like an extremely accurate spirit level; it is thanks to him that the helicopter can know if it rests flat or if it is tilted.

Ingenuity has been a prime sidekick for Perseverance, here drilling the surface to collect a sample. © NASA/JPL-Caltech

Fortunately, this inclinometer is not used to manage trim – the angle at which the craft “climb” or “dives” during the flight. This is lucky, because on a single-rotor helicopter of this type, this would probably have signaled the end of the mission. But this malfunction will still put a spoke in the wheels – or rather, in the propellers – of the drone.

It is usually used on takeoff to ensure that Ingenuity can take off safely; by knowing its orientation with respect to the ground, it can avoid rushing towards a relief if it has to take off from a place which is not perfectly flat. And above all, this measurement gives the starting signal to the rest of the algorithms which make it possible to manage the theft.

A problematic, but not catastrophic malfunction

Without it, NASA had to find another system capable of providing this crucial information to the onboard computer. And fortunately, another instrument called “inertial measurement unit” can fulfill this role. The precision will be less good since this instrument was not designed specifically for this use. But at least it should allow Ingenuity to soar again.

For this, the agency will simply have to develop a firmware patch; it will replace the inclinometer with the IMU in the protocol that allows Ingenuity to take off. And the method is also very interesting, since they will not be able to directly modify the embedded program. Instead, they will have to intercept what would have corresponded to the data packets emitted by the inclinometer, then feed back the data collected by the IMU – all from Earth!

If all goes well, Ingenuity should therefore take off for its 29th flight in the relatively near future. But he will not be at the end of his troubles for all that, far from it; this failure will probably not be the last to accompany its inexorable decline. Its exceptional longevity is indeed beginning to turn into a real curse.

© NASA

Martian winter hell, synonymous with the beginning of the end?

He is currently evolving in an environment that is particularly inhospitable to him, to the point of considerably limiting his future prospects. Recall that it was only designed to fly five times; originally, engineers calibrated it specifically to fly in the Martian spring conditions that prevailed at the time of its arrival. But more than a year later, the situation has changed. The drone must now deal with the difficult conditions of the Martian winter.

It is a period during which the atmosphere of the Red Planet is particularly loaded with dust; conditions obviously far from ideal for an aircraft of this type. Moreover, during this season, it has the annoying habit of losing density.

However, the ability of such a machine to stay in the air depends directly on this variable. Very briefly, the higher it is, the easier it is for the machine to “lean “ on air. Conversely, if it is sparse as is the case at the moment, the lift drops. Ingenuity must therefore make extra efforts to fly.

It also means that there are fewer air molecules available to exchange heat with the robot. This therefore accumulates much more quickly when the engines are running at full speed; to avoid overheating, Ingenuity must therefore content itself with small leaps.

In addition, the average length of the day decreases. This has a considerable impact on the energy budget of the machine, which essentially runs on solar energy. This means he has a much harder time operating and protecting his instruments; the latter thus spend much more time exposed to the unforgiving cold of winter nights on Mars. It is probably for this reason that the famous inclinometer ended up giving up the ghost. And he is not excluded that other instruments suffer the same fate in the relatively near future.

An already historic device

We will therefore have to cross our fingers that this is an isolated case. It is also necessary to prepare psychologically for the death of this marvel of engineering which has amazed us regularly for months. But even if it never took off again, Ingenuity would have already far exceeded all of NASA’s and the public’s wildest expectations.

He has proven beyond a shadow of a doubt that flight to Mars is not only possible, but also and above all that it is a great technology platform that will definitely be reused in the future. Suffice to say that it will take advantage of the exploits of this precursor to the last drop before his inevitable death. Its days on Mars may be numbered, but its place in the history books and in the hearts of space lovers is already guaranteed forever.

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