Updates Mars Science Laboratory (Curiosity)

[Ripley]

Isn't REMS Italian?? BBC says it's Spanish.


It's made by SITAEL

http://www.sitael.com/aerospace/references-and-customers/space-science
http://www.sitael.com/contacts

http://www.gravita-zero.org/2011/11/sitael-porta-litalia-bordo-del-rover.html


...not that, as an Italian, I'm proud that it's broken...

 

[Notebook]

Afraid I can't read the Italian page...however I see from the first link

MARS SCIENCE LABORATORY/CURIOSITY

Customers: NASA, EADS Astrium
Rover Environmental Monitoring System ASIC

Programme completed

I'm guessing ASIC is Application Specific Integrated Circuit.
Maybe the Prime Contractor is Spain, with that company supplying ICs?

Probably the BBC got it wrong, they are fairly rubbish on science these days.

EDIT: just noticed the article is by Jonathan Amos, he's usually quite good.

Looks like JA is correct:
http://www.nasa.gov/mission_pages/msl/multimedia/pia13646.html

N.

 

[Keatah]

The sensor was working during cruise. But they think a rock thrown up by the skycrane hit it.

From looking at pre-launch pics, the sensors weren't very well shielded against any form of debris. Also, there is a connector that seems to be out of place. Perhaps that was or was not noted. And maybe the final descent jarred it loose.

 

[N_Molson]

Problem is that for each gram of shielding you add on the rover, you need to add propellant on the rocket's upper stage, on the navigation thrusters, and on the skycrane...

 

[Keatah]

From a quick cursory look at the REMS instrument they left the kapton flex cable (with the sensor semiconductor substrate) pretty much fully exposed. Same thing with the ribbon cable connecting it to the main rover body.

This could have been put inside the mast for much of the distance (if they didn't want to mess with wires at the hinge). And they could have put the sensor's flex-cable-board inside the pitot-tube-like probes. In fact, doing it that way would have saved several grams - because you'd need to cut extra holes in the tube body to expose the silicon sensors. This is so easy to to do! And it demonstrates a lack of critical thinking.

Everyone knows pyro probes and thermocouple type wind sensors are shielded here on Earth against mis-handling, usually with a mesh screen or something. Bad design.. For chrissakes, they exposed the ASIC with it's multiple junction-per-die directly to the Martian environment, and to make it worse, with the mast stowed, one of these was sticking straight up and near the edge of the rover body. Think people think!
:facepalm:

They took the cheap way out and just pasted flex-circuit all over. They could have also toughened up the exposed ribbon with a strip or two of tape. This would have added fractions of a gram. And they could have drilled a few holes here and there elsewhere in a non-critical unrelated part of the rover body..and plugged them with silicon, thus offsetting any added weight. Surely a vehicle of this size has some extraneous material. And considering skycrane had 140kg of spare propellant... a tragedy fer'shure!
:facepalm:

Hopefully they'll image the non-functional wind sensor and its wiring with MAHLI and learn from this fiasco. Ugghhh!

http://msl-scicorner.jpl.nasa.gov/Instruments/REMS/
http://www.nasa.gov/images/content/678646main_pia13646_full.jpg
http://ashimaresearch.com/wp-content/uploads/papers/REMS_paper.pdf
http://www.bbc.co.uk/news/science-environment-19338870

 

[Screamer7]

It looks like my previous post about that dirt on Curiosity come true.
Post http://www.orbiter-forum.com/showthread.php?p=376613&postcount=682
Agggg.....:facepalm:

 

[Keatah]

This is not hindsight either. We had written in about this exact set of problems, but apparently got ignored. Ohh well, their loss, not mine. I could care less what direction the wind is blowing on Mars.

 

[Ripley]

Is NASA reading Orbiter Forum?
:lol:

 

[Urwumpe]

You don't even know what exactly is the problem, but yes, you have known it in advance, Nostradamus.

 

[N_Molson]

@Keatah : build a Mars lander/rover yourself if you think it's easy. Really, some comments are disheartening.

Be sure that if some parts were unprotected, there was a good reason, instead thinking you're all-knowing on that matter. How arrogant.

About the 140kg propellant : ever heard about safety margin ? What if there was a boulder right on the landing spot and an additionnal avoidement manoeuver was required ? Think people, think. :dry:

 

[Urwumpe]

About the 140kg propellant : ever heard about safety margin ? What if there was a boulder right on the landing spot and an additionnal avoidement manoeuver was required ? Think people, think. :dry:

Better: What if strong wind shear (even on Mars) meant the skycrane had to operate only 5 seconds longer?

 

[Screamer7]

IMHO that mishap is a small price to pay for the overall success Curiosity had so far.
But I can't decide if NASA and JPL where very very lucky, or that they are geniuses with that tricky landing of the Rover.:lol:

 

[T.Neo]

Problem is that for each gram of shielding you add on the rover, you need to add propellant on the rocket's upper stage, on the navigation thrusters, and on the skycrane...

But worth it, if it is required to prevent failures.

 

[orb]

Universe Today: Take a Look Through Curiosity’s ChemCam

This (adjusted) image was taken by ChemCam’s Remote Micro-Imager on Sol 15 (NASA/JPL-Caltech/LANL)

Images: NASA/JPL-Caltech/LANL. Edited by J. Major.​

 

[Artlav]

Take a Look Through Curiosity’s ChemCam

Would it be able to see fossilized bacteria on the rocks?

 

[orb]

Universe Today: Image: Curiosity’s First Wheel Tracks on Mars:

The rover (and her driving team) has done it! Curiosity has taken a little jaunt inside Gale Crater and here is an image of the wheel tracks to prove it! This image was taken by the right Navigation Camera on the rover Curiosity on Sol 16 (2012-08-22 15:00:53 UTC).

{...}

SPACE.com: Mars Rover Curiosity Takes 1st Martian Test Drive, Sees Tracks (Photos)

Discover Magazine - Bad Astronomy: Curiosity rolls!

RIA Novosti: NASA’s Curiosity Makes First Test Drive on Mars

 

[N_Molson]

A small wheel for the probe, a giant leap for Probekind !

 

[Keatah]

@Keatah : build a Mars lander/rover yourself if you think it's easy. Really, some comments are disheartening.

Be sure that if some parts were unprotected, there was a good reason, instead thinking you're all-knowing on that matter. How arrogant.

About the 140kg propellant : ever heard about safety margin ? What if there was a boulder right on the landing spot and an additionnal avoidement manoeuver was required ? Think people, think. :dry:

I'm almost certain I would not be able to build mars rover myself. Typically this is a team effort.

Sure, wind-speed sensors that rely on the wind to cool them down need to be exposed to the air. X amount of power is expended to keep a portion of the sensor chip at 100C. And as the speed of the wind varies, more or less current may be needed to keep it at 100C. And from there you compute the windspeed.

A bare ASIC exposed to the landing conditions at touchdown time is simply asking for trouble. The team took good measure to cover up the cameras with flip down protectors, or nestled the camera (mastcam) inside a protective cover/shield on the rover body. They were obviously aware of some debris. But, yet, they didn't shield the ASIC one iota.

This exposed ASIC is like lifting the heatspreader off your 70C CPU and exposing the die to ambient conditions. Now drop some pebbles on it and see if you don't crack it.

It would have been easy enough to put on a sliding shield or bolt a thin plate of metal to the rover body behind which the sensor could "hide" during descent ops.

Regarding the skycrane flight time. Sure, perhaps it might have needed extra gas to fight a crosswind, so I can see the point of the reserve there.

It should also be made known that the skycrane would not have "seen" a boulder and repositioned itself. The skycrane had no obstacle avoidance. It would have been entirely possible the rover could have tipped over on a 4 meter rock and the skycrane would be blissfully ignorant. The processing on MARDI imagery during the final phase was done to zero out lateral and vertical movement, not look for hazards.

 

[Gerdih]

As far as I know the wind sensor its made by Polytechnic University of Catalonia (My university) I hope the problem not to be a cause of negligence.

 

[Keatah]

I don't think the sensor and connective flex wiring is much at fault. It's perfectly acceptable to use a delicate low-thermal-inertia sensor in an environment where things aren't going to be touching it. It's not like there are space aliens to throw rocks around and damage it. Nor is it going to be handled and put away in a drawer after every use. It doesn't need to be armored. The problem was how it was integrated into the vehicle. So whoever designed the mounting and chose the position where it was mounted, that's where the blame goes.

This wind-sensor is basically the same material as the sensor inside your DSLR or the sensor in the mastcams. But the camera stuff is thoroughly shielded by necessity. You certainly don't want dust in the lens.

What happened here is the equivalent of you changing the lens on your DSLR while sitting next to a jackhammer at a construction site. Common sense dictates you'd turn your back to the flying debris. Or change it later when the sensor isn't exposed to flying debris.