Keeping Our Sense of Direction: Dealing With a Dead Sensor
As the season has turned to winter in Jezero Crater, conditions have become increasingly challenging for Ingenuity, which was designed for a short flight-test campaign during the much warmer Martian spring. [...] In its new winter operations paradigm, Ingenuity is effectively shutting down during the night, letting its internal temperature drop to about minus 112 degrees Fahrenheit (minus 80 degrees Celsius) and letting the onboard electronics reset. This new way of operating carries with it risks to Ingenuity's electronic components, many of which are not designed to survive the temperatures they are being exposed to at night. Moreover, extreme temperature cycles between daytime and nighttime tend to cause stresses that can result in component failure.
Over the past several sols on Mars, the Ingenuity team has been busy recommissioning the helicopter for flight, going through a series of activities that include preflight checkout of sensors and actuators and a high-speed spin of the rotor. These activities have revealed that one of the helicopter's navigation sensors, called the inclinometer, has stopped functioning. A nonworking navigation sensor sounds like a big deal – and it is – but it's not necessarily an end to our flying at Mars.
[...] The inclinometer consists of two accelerometers, whose sole purpose is to measure gravity prior to spin-up and takeoff; the direction of the sensed gravity is used to determine how Ingenuity is oriented relative to the downward direction. The inclinometer is not used during the flight itself, but without it we are forced to find a new way to initialize the navigation algorithms prior to takeoff.
[...] However, we believe an IMU-based initial attitude estimate will allow us to take off safely and thus provides an acceptable fallback that will allow Ingenuity to resume flying.
Taking advantage of this redundancy requires a patch to Ingenuity's flight software. The patch inserts a small code snippet into the software running on Ingenuity's flight computer, intercepting incoming garbage packets from the inclinometer and injecting replacement packets constructed from IMU data. To the navigation algorithms, everything will look as before [...]
A helicopter on Mars must necessarily experience harsher conditions than would a helicopter on the moon.
(Score: 4, Funny) by sjames on Wednesday June 08 2022, @03:54PM (1 child)
But imagine the existential angst of not only being useless but of having no hope of ever being useful. That's pretty harsh.
(Score: 0) by Anonymous Coward on Wednesday June 08 2022, @04:38PM
Would depend on the species. Specimen of helicopteri burocratii would be fine, but h. engineerii would be, figuratively, panting for air.
(Score: 4, Touché) by srobert on Wednesday June 08 2022, @03:57PM (2 children)
"A helicopter on Mars must necessarily experience harsher conditions than would a helicopter on the moon."
The helicopter on the moon is in pristine condition but useless. Sort of like my friend's dad's 1967 Mustang that we were forbidden to take from the garage in the 1980's. It was a work of art, but not much use as a car.
(Score: 0) by Anonymous Coward on Wednesday June 08 2022, @05:25PM (1 child)
Your name isn't Ferris, by any chance, is it? Didn't you eventually take that car out one day with your friend Cameron?
(Score: 2) by srobert on Thursday June 09 2022, @04:59PM
We actually did take that car out joyriding. We didn't go far and we put it back exactly where it was. Actually put duct tape on the floor to mark the location of the wheels. We didn't try to run it backwards to reset the odometer like Ferris Bueller. Thankfully Tom's dad never noticed. When I saw that movie several years later, I thought, "I can totally relate to that!". Sadly my friend Tom died from cancer in 1995 at only 32 years old. But we never regretted taking that Mustang out.
(Score: -1, Spam) by Anonymous Coward on Wednesday June 08 2022, @04:34PM
i enjoy laying back in my huge bath tub, holding aloft a wine glass in my left hand.
i relax and let my penis furiously spin around and around by itself, catching some of the precious liquid into my wine glass.
sometimes the pee hits my mouth, which is a penalty and summons mr. tugboat.
mr. tugboat appears and launches a glob of feces into the water which must be dealt with or my skin will rot.
toot toot!
(Score: 2) by Mojibake Tengu on Wednesday June 08 2022, @04:39PM (1 child)
GLWT.
The edge of 太玄 cannot be defined, for it is beyond every aspect of design
(Score: 1) by liar on Wednesday June 08 2022, @05:27PM
they do say that The Moon Is a Harsh Mistress...
Noli nothis permittere te terere.
(Score: 0) by Anonymous Coward on Wednesday June 08 2022, @04:44PM (2 children)
The temperature difference between night and day is a lot greater on the moon, as is the difference between sunlight and shadow. There is also no protection from the sun's radiation or from micrometeorites. About the only good thing is that the moon doesn't have dust storms.
(Score: 2) by Freeman on Wednesday June 08 2022, @05:35PM
The Moon is also, much, much closer.
Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
(Score: 0) by Anonymous Coward on Wednesday June 08 2022, @05:43PM
As others have pointed out, the moon also has no atmosphere, so a helicopter there would be useless. It would just sit there doing nothing until it fell apart or was smashed by a meteor.
(Score: 3, Interesting) by dalek on Wednesday June 08 2022, @04:56PM (5 children)
I'm not sure I understand the intent of this comment. The atmospheric pressure on Mars is around 6-7 hPa. While the moon technically has an atmosphere, the pressure is around 0.3 nPa, so about 12 orders of magnitude less than the very thin Martian atmosphere. For comparison, standard sea level pressure on Earth is 1013.25 hPa.
Anyway, it sounds like the problem is that the solar panels don't produce enough power to warm the helicopter during the winter. Dust accumulating on solar panels has also been a problem for other Mars missions. It sounds like the lack of power has forced NASA to fully shut down the helicopter at night because of the lack of power, and the extremely low temperatures damaged these sensors. They had a backup plan in place, and are sending a software update to use other sensors that will be less accurate.
It seems like the better solution in the future is to use nuclear power. Lack of access to plutonium was a problem for NASA, but production of plutonium-238 has started again in the US for the purpose of supplying it to NASA. A couple of the recent rovers have used plutonium, and it seems like a better power source for many Mars missions. The problem is that the plutonium battery used for the Mars rovers is much too heavy for the helicopter, which has a total weight of around 4 points. My question is whether a smaller nuclear battery could be produced that would be capable of powering a helicopter. Weight is definitely a big problem, but a nuclear battery shouldn't have issues with the extreme conditions of the Martian winter.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest just whinge about SN.
(Score: 2) by DannyB on Wednesday June 08 2022, @05:21PM
A throwaway line for a laugh. Nothing more. Just like the 'dept' line above the article.
If you're unhappy with the effectiveness of helicopters on the moon, then lunar aerial cameras could be carried aloft on lightweight gas filled balloons.
How often should I have my memory checked? I used to know but...
(Score: 3, Interesting) by sjames on Wednesday June 08 2022, @05:51PM (2 children)
A hybrid approach might work. Solar panels for main power, and small nuclear heaters to keep the electronics from freezing. They could be a lot smaller and lighter since they wouldn't have to provide anything but heat.
(Score: 0) by Anonymous Coward on Thursday June 09 2022, @05:27AM (1 child)
Nuclear heaters would have killed the mission at the planning stages. Those are only allowed for flagship missions due to (lack of) fuel availability. The cold is a problem because Ingenuity wasn't expected to last through the summer let alone through the depths of a Martian winter, so it wasn't designed for it. Frankly it's amazing that it works at all in those conditions.
(Score: 2) by sjames on Thursday June 09 2022, @06:36AM
Then, yes. But for future missions now that the helicopter concept is proven and more fuel is being produced specifically for NASA missions, it might be a good approach.
(Score: 1, Interesting) by Anonymous Coward on Wednesday June 08 2022, @08:09PM
I doubt it. If they did make a new copter, they would want to use payload capacity for science sensors. I could see making the rover a base station for the chopper though where chopper docks to recharge and get heated through the night.
(Score: 2) by DannyB on Wednesday June 08 2022, @05:23PM
The real thing of interest here is the hack to get around the dead sensor. Without ever having any hope of hands on with the actual hardware.
How often should I have my memory checked? I used to know but...
(Score: 0) by Anonymous Coward on Wednesday June 08 2022, @05:58PM (5 children)
"Over the past several sols on Mars..."
Jeez, you could have written it in plain English for a wider audience this way:
"Over the past several Martian days..."
(Score: 2) by MrGuy on Wednesday June 08 2022, @06:58PM (1 child)
“Sols” is a pretty standard term when referring to “Martian days”. It avoids any need to ask “wait - mars days or earth days?” when talking about time periods.
(Score: 0) by Anonymous Coward on Wednesday June 08 2022, @08:04PM
Thus, "Martian days."
This is a PR piece aimed at the general public, not a scientific journal article.
(Score: 2) by janrinok on Wednesday June 08 2022, @07:10PM (2 children)
The word 'sols' appears in quoted text - if it is quoted we try not to change it. As someone as already said in a comment, the term is in quite common usage nowadays when discussing Mars.
If you are complaining that it was a word that you didn't recognise, then put that down to a little bit of knowledge that you have gained today
We expect a certain degree of intelligence in our community - and often they surprise us by far exceeding what we expect. We have a variety of subject experts among us who make this site so interesting for me. A day rarely goes by without somebody making me think about an issue I hadn't thought much about before.
We therefore have to pitch our stories to cover a broad spectrum - some might be too simplistic for you, others might make you have to think a little harder than you prefer to do.
(Score: 0) by Anonymous Coward on Wednesday June 08 2022, @08:01PM (1 child)
I am aware that this was straight from the article. As a matter of fact, I stated that in the title of my post!
I also already knew what a "sol" is. (Note that I gave a definition of it!) You will note in my post that I said some simple English instead would make it clearer for a wider variety of readers. Obscurantism (look at my fancy word, look it up, ignoramuses!) has no place in articles aimed at a general readership like this NASA PR story. Hey, the author even posted temps in Celsius AND Fahrenheit. He should have at least defined a "sol."
(Score: 0) by Anonymous Coward on Wednesday June 08 2022, @11:01PM
Eschew obfuscation.
(Score: 4, Insightful) by janrinok on Wednesday June 08 2022, @06:59PM
I find it interesting that we can discuss the successes and failures of a helicopter whose sole purpose was to see if it was even possible to fly on Mars!
That it has flown so well, far further than was ever expected of it, and has kept recharging itself reliably until now is one heck of an achievement. Yes we can pick holes in some of the design but it has done far more than the designers, engineers and scientists ever dared dream possible when it first left earth.
(Score: 2) by Snotnose on Wednesday June 08 2022, @07:44PM (2 children)
Boeing killed what, 350 folks on 2 airplanes due to a faulty sensor within the first year of MCAS going live, faulty software, and management that said "fuck you, you want 2 sensors that's gonna cost you orders of magnitude more than the cost of the hardware + installation".
I still don't get why 1) Boeing didn't get such a huge fine that the Cxx suite was threatened with their jobs; and 2) why nobody in the Cxx suite went to jail.
Anyone that ever worked for McDonnell Douglass, if they were above the "team lead of people fueling the plane" needs to be fired ASAP and put Boeing people back in their place. Except the Boeing folks are retired and upvoting this comment as we speak.
I just passed a drug test. My dealer has some explaining to do.
(Score: 0) by Anonymous Coward on Wednesday June 08 2022, @11:54PM
Wait, you didn't get any upvotes?! What happened to all the fired Boeing people?
(Score: 0) by Anonymous Coward on Thursday June 09 2022, @05:05AM
Boeing is "too big to punish". They have too many pets in Congress for them to ever be held to account. Airbus has the same status in France, which is why they get away with so much.
(Score: 0) by Anonymous Coward on Wednesday June 08 2022, @08:12PM
You just need to pulse the motor and/or make input to the controls, and with a little luck it'll vibrate enough to waddle over to an uneven surface where it'll lose balance. Then it could have one helluva flight as the rotor disintegrates.